Adding upstream version 110.0.1.upstream/110.0.1upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

40 files changed, 5038 insertions, 0 deletions

diff --git a/third_party/python/ply/example/BASIC/README b/third_party/python/ply/example/BASIC/README
new file mode 100644
index 0000000000..be24a3005e
--- /dev/null
+++ b/third_party/python/ply/example/BASIC/README
@@ -0,0 +1,79 @@
+Inspired by a September 14, 2006 Salon article "Why Johnny Can't Code" by
+David Brin (http://www.salon.com/tech/feature/2006/09/14/basic/index.html),
+I thought that a fully working BASIC interpreter might be an interesting,
+if not questionable, PLY example.  Uh, okay, so maybe it's just a bad idea,
+but in any case, here it is.
+
+In this example, you'll find a rough implementation of 1964 Dartmouth BASIC
+as described in the manual at:
+
+   http://www.bitsavers.org/pdf/dartmouth/BASIC_Oct64.pdf
+
+See also:
+
+  http://en.wikipedia.org/wiki/Dartmouth_BASIC
+
+This dialect is downright primitive---there are no string variables
+and no facilities for interactive input. Moreover, subroutines and functions
+are brain-dead even more than they usually are for BASIC. Of course,
+the GOTO statement is provided.
+
+Nevertheless, there are a few interesting aspects of this example:
+
+  - It illustrates a fully working interpreter including lexing, parsing,
+    and interpretation of instructions.
+ 
+  - The parser shows how to catch and report various kinds of parsing
+    errors in a more graceful way.
+
+  - The example both parses files (supplied on command line) and
+    interactive input entered line by line.
+
+  - It shows how you might represent parsed information.  In this case,
+    each BASIC statement is encoded into a Python tuple containing the
+    statement type and parameters.  These tuples are then stored in
+    a dictionary indexed by program line numbers.
+
+  - Even though it's just BASIC, the parser contains more than 80
+    rules and 150 parsing states. Thus, it's a little more meaty than
+    the calculator example.
+
+To use the example, run it as follows:
+
+   % python basic.py hello.bas
+   HELLO WORLD
+   %
+
+or use it interactively:
+
+   % python basic.py
+   [BASIC] 10 PRINT "HELLO WORLD"
+   [BASIC] 20 END
+   [BASIC] RUN
+   HELLO WORLD
+   [BASIC]
+
+The following files are defined:
+
+   basic.py         - High level script that controls everything
+   basiclex.py      - BASIC tokenizer
+   basparse.py      - BASIC parser
+   basinterp.py     - BASIC interpreter that runs parsed programs.
+
+In addition, a number of sample BASIC programs (.bas suffix) are
+provided.  These were taken out of the Dartmouth manual.
+
+Disclaimer: I haven't spent a ton of time testing this and it's likely that
+I've skimped here and there on a few finer details (e.g., strictly enforcing
+variable naming rules).  However, the interpreter seems to be able to run
+the examples in the BASIC manual.
+
+Have fun!
+
+-Dave
+
+
+
+
+
+
diff --git a/third_party/python/ply/example/BASIC/basic.py b/third_party/python/ply/example/BASIC/basic.py
new file mode 100644
index 0000000000..70ac9e7c74
--- /dev/null
+++ b/third_party/python/ply/example/BASIC/basic.py
@@ -0,0 +1,65 @@
+# An implementation of Dartmouth BASIC (1964)
+#
+
+import sys
+sys.path.insert(0, "../..")
+
+if sys.version_info[0] >= 3:
+    raw_input = input
+
+import basiclex
+import basparse
+import basinterp
+
+# If a filename has been specified, we try to run it.
+# If a runtime error occurs, we bail out and enter
+# interactive mode below
+if len(sys.argv) == 2:
+    data = open(sys.argv[1]).read()
+    prog = basparse.parse(data)
+    if not prog:
+        raise SystemExit
+    b = basinterp.BasicInterpreter(prog)
+    try:
+        b.run()
+        raise SystemExit
+    except RuntimeError:
+        pass
+
+else:
+    b = basinterp.BasicInterpreter({})
+
+# Interactive mode.  This incrementally adds/deletes statements
+# from the program stored in the BasicInterpreter object.  In
+# addition, special commands 'NEW','LIST',and 'RUN' are added.
+# Specifying a line number with no code deletes that line from
+# the program.
+
+while 1:
+    try:
+        line = raw_input("[BASIC] ")
+    except EOFError:
+        raise SystemExit
+    if not line:
+        continue
+    line += "\n"
+    prog = basparse.parse(line)
+    if not prog:
+        continue
+
+    keys = list(prog)
+    if keys[0] > 0:
+        b.add_statements(prog)
+    else:
+        stat = prog[keys[0]]
+        if stat[0] == 'RUN':
+            try:
+                b.run()
+            except RuntimeError:
+                pass
+        elif stat[0] == 'LIST':
+            b.list()
+        elif stat[0] == 'BLANK':
+            b.del_line(stat[1])
+        elif stat[0] == 'NEW':
+            b.new()
diff --git a/third_party/python/ply/example/BASIC/basiclex.py b/third_party/python/ply/example/BASIC/basiclex.py
new file mode 100644
index 0000000000..4151f4c34f
--- /dev/null
+++ b/third_party/python/ply/example/BASIC/basiclex.py
@@ -0,0 +1,61 @@
+# An implementation of Dartmouth BASIC (1964)
+
+from ply import *
+
+keywords = (
+    'LET', 'READ', 'DATA', 'PRINT', 'GOTO', 'IF', 'THEN', 'FOR', 'NEXT', 'TO', 'STEP',
+    'END', 'STOP', 'DEF', 'GOSUB', 'DIM', 'REM', 'RETURN', 'RUN', 'LIST', 'NEW',
+)
+
+tokens = keywords + (
+    'EQUALS', 'PLUS', 'MINUS', 'TIMES', 'DIVIDE', 'POWER',
+    'LPAREN', 'RPAREN', 'LT', 'LE', 'GT', 'GE', 'NE',
+    'COMMA', 'SEMI', 'INTEGER', 'FLOAT', 'STRING',
+    'ID', 'NEWLINE'
+)
+
+t_ignore = ' \t'
+
+
+def t_REM(t):
+    r'REM .*'
+    return t
+
+
+def t_ID(t):
+    r'[A-Z][A-Z0-9]*'
+    if t.value in keywords:
+        t.type = t.value
+    return t
+
+t_EQUALS = r'='
+t_PLUS = r'\+'
+t_MINUS = r'-'
+t_TIMES = r'\*'
+t_POWER = r'\^'
+t_DIVIDE = r'/'
+t_LPAREN = r'\('
+t_RPAREN = r'\)'
+t_LT = r'<'
+t_LE = r'<='
+t_GT = r'>'
+t_GE = r'>='
+t_NE = r'<>'
+t_COMMA = r'\,'
+t_SEMI = r';'
+t_INTEGER = r'\d+'
+t_FLOAT = r'((\d*\.\d+)(E[\+-]?\d+)?|([1-9]\d*E[\+-]?\d+))'
+t_STRING = r'\".*?\"'
+
+
+def t_NEWLINE(t):
+    r'\n'
+    t.lexer.lineno += 1
+    return t
+
+
+def t_error(t):
+    print("Illegal character %s" % t.value[0])
+    t.lexer.skip(1)
+
+lex.lex(debug=0)
diff --git a/third_party/python/ply/example/BASIC/basiclog.py b/third_party/python/ply/example/BASIC/basiclog.py
new file mode 100644
index 0000000000..9dcc7feda6
--- /dev/null
+++ b/third_party/python/ply/example/BASIC/basiclog.py
@@ -0,0 +1,73 @@
+# An implementation of Dartmouth BASIC (1964)
+#
+
+import sys
+sys.path.insert(0, "../..")
+
+if sys.version_info[0] >= 3:
+    raw_input = input
+
+import logging
+logging.basicConfig(
+    level=logging.INFO,
+    filename="parselog.txt",
+    filemode="w"
+)
+log = logging.getLogger()
+
+import basiclex
+import basparse
+import basinterp
+
+# If a filename has been specified, we try to run it.
+# If a runtime error occurs, we bail out and enter
+# interactive mode below
+if len(sys.argv) == 2:
+    data = open(sys.argv[1]).read()
+    prog = basparse.parse(data, debug=log)
+    if not prog:
+        raise SystemExit
+    b = basinterp.BasicInterpreter(prog)
+    try:
+        b.run()
+        raise SystemExit
+    except RuntimeError:
+        pass
+
+else:
+    b = basinterp.BasicInterpreter({})
+
+# Interactive mode.  This incrementally adds/deletes statements
+# from the program stored in the BasicInterpreter object.  In
+# addition, special commands 'NEW','LIST',and 'RUN' are added.
+# Specifying a line number with no code deletes that line from
+# the program.
+
+while 1:
+    try:
+        line = raw_input("[BASIC] ")
+    except EOFError:
+        raise SystemExit
+    if not line:
+        continue
+    line += "\n"
+    prog = basparse.parse(line, debug=log)
+    if not prog:
+        continue
+
+    keys = list(prog)
+    if keys[0] > 0:
+        b.add_statements(prog)
+    else:
+        stat = prog[keys[0]]
+        if stat[0] == 'RUN':
+            try:
+                b.run()
+            except RuntimeError:
+                pass
+        elif stat[0] == 'LIST':
+            b.list()
+        elif stat[0] == 'BLANK':
+            b.del_line(stat[1])
+        elif stat[0] == 'NEW':
+            b.new()
diff --git a/third_party/python/ply/example/BASIC/basinterp.py b/third_party/python/ply/example/BASIC/basinterp.py
new file mode 100644
index 0000000000..67762c797b
--- /dev/null
+++ b/third_party/python/ply/example/BASIC/basinterp.py
@@ -0,0 +1,496 @@
+# This file provides the runtime support for running a basic program
+# Assumes the program has been parsed using basparse.py
+
+import sys
+import math
+import random
+
+
+class BasicInterpreter:
+
+    # Initialize the interpreter. prog is a dictionary
+    # containing (line,statement) mappings
+    def __init__(self, prog):
+        self.prog = prog
+
+        self.functions = {           # Built-in function table
+            'SIN': lambda z: math.sin(self.eval(z)),
+            'COS': lambda z: math.cos(self.eval(z)),
+            'TAN': lambda z: math.tan(self.eval(z)),
+            'ATN': lambda z: math.atan(self.eval(z)),
+            'EXP': lambda z: math.exp(self.eval(z)),
+            'ABS': lambda z: abs(self.eval(z)),
+            'LOG': lambda z: math.log(self.eval(z)),
+            'SQR': lambda z: math.sqrt(self.eval(z)),
+            'INT': lambda z: int(self.eval(z)),
+            'RND': lambda z: random.random()
+        }
+
+    # Collect all data statements
+    def collect_data(self):
+        self.data = []
+        for lineno in self.stat:
+            if self.prog[lineno][0] == 'DATA':
+                self.data = self.data + self.prog[lineno][1]
+        self.dc = 0                  # Initialize the data counter
+
+    # Check for end statements
+    def check_end(self):
+        has_end = 0
+        for lineno in self.stat:
+            if self.prog[lineno][0] == 'END' and not has_end:
+                has_end = lineno
+        if not has_end:
+            print("NO END INSTRUCTION")
+            self.error = 1
+            return
+        if has_end != lineno:
+            print("END IS NOT LAST")
+            self.error = 1
+
+    # Check loops
+    def check_loops(self):
+        for pc in range(len(self.stat)):
+            lineno = self.stat[pc]
+            if self.prog[lineno][0] == 'FOR':
+                forinst = self.prog[lineno]
+                loopvar = forinst[1]
+                for i in range(pc + 1, len(self.stat)):
+                    if self.prog[self.stat[i]][0] == 'NEXT':
+                        nextvar = self.prog[self.stat[i]][1]
+                        if nextvar != loopvar:
+                            continue
+                        self.loopend[pc] = i
+                        break
+                else:
+                    print("FOR WITHOUT NEXT AT LINE %s" % self.stat[pc])
+                    self.error = 1
+
+    # Evaluate an expression
+    def eval(self, expr):
+        etype = expr[0]
+        if etype == 'NUM':
+            return expr[1]
+        elif etype == 'GROUP':
+            return self.eval(expr[1])
+        elif etype == 'UNARY':
+            if expr[1] == '-':
+                return -self.eval(expr[2])
+        elif etype == 'BINOP':
+            if expr[1] == '+':
+                return self.eval(expr[2]) + self.eval(expr[3])
+            elif expr[1] == '-':
+                return self.eval(expr[2]) - self.eval(expr[3])
+            elif expr[1] == '*':
+                return self.eval(expr[2]) * self.eval(expr[3])
+            elif expr[1] == '/':
+                return float(self.eval(expr[2])) / self.eval(expr[3])
+            elif expr[1] == '^':
+                return abs(self.eval(expr[2]))**self.eval(expr[3])
+        elif etype == 'VAR':
+            var, dim1, dim2 = expr[1]
+            if not dim1 and not dim2:
+                if var in self.vars:
+                    return self.vars[var]
+                else:
+                    print("UNDEFINED VARIABLE %s AT LINE %s" %
+                          (var, self.stat[self.pc]))
+                    raise RuntimeError
+            # May be a list lookup or a function evaluation
+            if dim1 and not dim2:
+                if var in self.functions:
+                    # A function
+                    return self.functions[var](dim1)
+                else:
+                    # A list evaluation
+                    if var in self.lists:
+                        dim1val = self.eval(dim1)
+                        if dim1val < 1 or dim1val > len(self.lists[var]):
+                            print("LIST INDEX OUT OF BOUNDS AT LINE %s" %
+                                  self.stat[self.pc])
+                            raise RuntimeError
+                        return self.lists[var][dim1val - 1]
+            if dim1 and dim2:
+                if var in self.tables:
+                    dim1val = self.eval(dim1)
+                    dim2val = self.eval(dim2)
+                    if dim1val < 1 or dim1val > len(self.tables[var]) or dim2val < 1 or dim2val > len(self.tables[var][0]):
+                        print("TABLE INDEX OUT OUT BOUNDS AT LINE %s" %
+                              self.stat[self.pc])
+                        raise RuntimeError
+                    return self.tables[var][dim1val - 1][dim2val - 1]
+            print("UNDEFINED VARIABLE %s AT LINE %s" %
+                  (var, self.stat[self.pc]))
+            raise RuntimeError
+
+    # Evaluate a relational expression
+    def releval(self, expr):
+        etype = expr[1]
+        lhs = self.eval(expr[2])
+        rhs = self.eval(expr[3])
+        if etype == '<':
+            if lhs < rhs:
+                return 1
+            else:
+                return 0
+
+        elif etype == '<=':
+            if lhs <= rhs:
+                return 1
+            else:
+                return 0
+
+        elif etype == '>':
+            if lhs > rhs:
+                return 1
+            else:
+                return 0
+
+        elif etype == '>=':
+            if lhs >= rhs:
+                return 1
+            else:
+                return 0
+
+        elif etype == '=':
+            if lhs == rhs:
+                return 1
+            else:
+                return 0
+
+        elif etype == '<>':
+            if lhs != rhs:
+                return 1
+            else:
+                return 0
+
+    # Assignment
+    def assign(self, target, value):
+        var, dim1, dim2 = target
+        if not dim1 and not dim2:
+            self.vars[var] = self.eval(value)
+        elif dim1 and not dim2:
+            # List assignment
+            dim1val = self.eval(dim1)
+            if not var in self.lists:
+                self.lists[var] = [0] * 10
+
+            if dim1val > len(self.lists[var]):
+                print ("DIMENSION TOO LARGE AT LINE %s" % self.stat[self.pc])
+                raise RuntimeError
+            self.lists[var][dim1val - 1] = self.eval(value)
+        elif dim1 and dim2:
+            dim1val = self.eval(dim1)
+            dim2val = self.eval(dim2)
+            if not var in self.tables:
+                temp = [0] * 10
+                v = []
+                for i in range(10):
+                    v.append(temp[:])
+                self.tables[var] = v
+            # Variable already exists
+            if dim1val > len(self.tables[var]) or dim2val > len(self.tables[var][0]):
+                print("DIMENSION TOO LARGE AT LINE %s" % self.stat[self.pc])
+                raise RuntimeError
+            self.tables[var][dim1val - 1][dim2val - 1] = self.eval(value)
+
+    # Change the current line number
+    def goto(self, linenum):
+        if not linenum in self.prog:
+            print("UNDEFINED LINE NUMBER %d AT LINE %d" %
+                  (linenum, self.stat[self.pc]))
+            raise RuntimeError
+        self.pc = self.stat.index(linenum)
+
+    # Run it
+    def run(self):
+        self.vars = {}            # All variables
+        self.lists = {}            # List variables
+        self.tables = {}            # Tables
+        self.loops = []            # Currently active loops
+        self.loopend = {}            # Mapping saying where loops end
+        self.gosub = None           # Gosub return point (if any)
+        self.error = 0              # Indicates program error
+
+        self.stat = list(self.prog)  # Ordered list of all line numbers
+        self.stat.sort()
+        self.pc = 0                  # Current program counter
+
+        # Processing prior to running
+
+        self.collect_data()          # Collect all of the data statements
+        self.check_end()
+        self.check_loops()
+
+        if self.error:
+            raise RuntimeError
+
+        while 1:
+            line = self.stat[self.pc]
+            instr = self.prog[line]
+
+            op = instr[0]
+
+            # END and STOP statements
+            if op == 'END' or op == 'STOP':
+                break           # We're done
+
+            # GOTO statement
+            elif op == 'GOTO':
+                newline = instr[1]
+                self.goto(newline)
+                continue
+
+            # PRINT statement
+            elif op == 'PRINT':
+                plist = instr[1]
+                out = ""
+                for label, val in plist:
+                    if out:
+                        out += ' ' * (15 - (len(out) % 15))
+                    out += label
+                    if val:
+                        if label:
+                            out += " "
+                        eval = self.eval(val)
+                        out += str(eval)
+                sys.stdout.write(out)
+                end = instr[2]
+                if not (end == ',' or end == ';'):
+                    sys.stdout.write("\n")
+                if end == ',':
+                    sys.stdout.write(" " * (15 - (len(out) % 15)))
+                if end == ';':
+                    sys.stdout.write(" " * (3 - (len(out) % 3)))
+
+            # LET statement
+            elif op == 'LET':
+                target = instr[1]
+                value = instr[2]
+                self.assign(target, value)
+
+            # READ statement
+            elif op == 'READ':
+                for target in instr[1]:
+                    if self.dc < len(self.data):
+                        value = ('NUM', self.data[self.dc])
+                        self.assign(target, value)
+                        self.dc += 1
+                    else:
+                        # No more data.  Program ends
+                        return
+            elif op == 'IF':
+                relop = instr[1]
+                newline = instr[2]
+                if (self.releval(relop)):
+                    self.goto(newline)
+                    continue
+
+            elif op == 'FOR':
+                loopvar = instr[1]
+                initval = instr[2]
+                finval = instr[3]
+                stepval = instr[4]
+
+                # Check to see if this is a new loop
+                if not self.loops or self.loops[-1][0] != self.pc:
+                    # Looks like a new loop. Make the initial assignment
+                    newvalue = initval
+                    self.assign((loopvar, None, None), initval)
+                    if not stepval:
+                        stepval = ('NUM', 1)
+                    stepval = self.eval(stepval)    # Evaluate step here
+                    self.loops.append((self.pc, stepval))
+                else:
+                    # It's a repeat of the previous loop
+                    # Update the value of the loop variable according to the
+                    # step
+                    stepval = ('NUM', self.loops[-1][1])
+                    newvalue = (
+                        'BINOP', '+', ('VAR', (loopvar, None, None)), stepval)
+
+                if self.loops[-1][1] < 0:
+                    relop = '>='
+                else:
+                    relop = '<='
+                if not self.releval(('RELOP', relop, newvalue, finval)):
+                    # Loop is done. Jump to the NEXT
+                    self.pc = self.loopend[self.pc]
+                    self.loops.pop()
+                else:
+                    self.assign((loopvar, None, None), newvalue)
+
+            elif op == 'NEXT':
+                if not self.loops:
+                    print("NEXT WITHOUT FOR AT LINE %s" % line)
+                    return
+
+                nextvar = instr[1]
+                self.pc = self.loops[-1][0]
+                loopinst = self.prog[self.stat[self.pc]]
+                forvar = loopinst[1]
+                if nextvar != forvar:
+                    print("NEXT DOESN'T MATCH FOR AT LINE %s" % line)
+                    return
+                continue
+            elif op == 'GOSUB':
+                newline = instr[1]
+                if self.gosub:
+                    print("ALREADY IN A SUBROUTINE AT LINE %s" % line)
+                    return
+                self.gosub = self.stat[self.pc]
+                self.goto(newline)
+                continue
+
+            elif op == 'RETURN':
+                if not self.gosub:
+                    print("RETURN WITHOUT A GOSUB AT LINE %s" % line)
+                    return
+                self.goto(self.gosub)
+                self.gosub = None
+
+            elif op == 'FUNC':
+                fname = instr[1]
+                pname = instr[2]
+                expr = instr[3]
+
+                def eval_func(pvalue, name=pname, self=self, expr=expr):
+                    self.assign((pname, None, None), pvalue)
+                    return self.eval(expr)
+                self.functions[fname] = eval_func
+
+            elif op == 'DIM':
+                for vname, x, y in instr[1]:
+                    if y == 0:
+                        # Single dimension variable
+                        self.lists[vname] = [0] * x
+                    else:
+                        # Double dimension variable
+                        temp = [0] * y
+                        v = []
+                        for i in range(x):
+                            v.append(temp[:])
+                        self.tables[vname] = v
+
+            self.pc += 1
+
+    # Utility functions for program listing
+    def expr_str(self, expr):
+        etype = expr[0]
+        if etype == 'NUM':
+            return str(expr[1])
+        elif etype == 'GROUP':
+            return "(%s)" % self.expr_str(expr[1])
+        elif etype == 'UNARY':
+            if expr[1] == '-':
+                return "-" + str(expr[2])
+        elif etype == 'BINOP':
+            return "%s %s %s" % (self.expr_str(expr[2]), expr[1], self.expr_str(expr[3]))
+        elif etype == 'VAR':
+            return self.var_str(expr[1])
+
+    def relexpr_str(self, expr):
+        return "%s %s %s" % (self.expr_str(expr[2]), expr[1], self.expr_str(expr[3]))
+
+    def var_str(self, var):
+        varname, dim1, dim2 = var
+        if not dim1 and not dim2:
+            return varname
+        if dim1 and not dim2:
+            return "%s(%s)" % (varname, self.expr_str(dim1))
+        return "%s(%s,%s)" % (varname, self.expr_str(dim1), self.expr_str(dim2))
+
+    # Create a program listing
+    def list(self):
+        stat = list(self.prog)      # Ordered list of all line numbers
+        stat.sort()
+        for line in stat:
+            instr = self.prog[line]
+            op = instr[0]
+            if op in ['END', 'STOP', 'RETURN']:
+                print("%s %s" % (line, op))
+                continue
+            elif op == 'REM':
+                print("%s %s" % (line, instr[1]))
+            elif op == 'PRINT':
+                _out = "%s %s " % (line, op)
+                first = 1
+                for p in instr[1]:
+                    if not first:
+                        _out += ", "
+                    if p[0] and p[1]:
+                        _out += '"%s"%s' % (p[0], self.expr_str(p[1]))
+                    elif p[1]:
+                        _out += self.expr_str(p[1])
+                    else:
+                        _out += '"%s"' % (p[0],)
+                    first = 0
+                if instr[2]:
+                    _out += instr[2]
+                print(_out)
+            elif op == 'LET':
+                print("%s LET %s = %s" %
+                      (line, self.var_str(instr[1]), self.expr_str(instr[2])))
+            elif op == 'READ':
+                _out = "%s READ " % line
+                first = 1
+                for r in instr[1]:
+                    if not first:
+                        _out += ","
+                    _out += self.var_str(r)
+                    first = 0
+                print(_out)
+            elif op == 'IF':
+                print("%s IF %s THEN %d" %
+                      (line, self.relexpr_str(instr[1]), instr[2]))
+            elif op == 'GOTO' or op == 'GOSUB':
+                print("%s %s %s" % (line, op, instr[1]))
+            elif op == 'FOR':
+                _out = "%s FOR %s = %s TO %s" % (
+                    line, instr[1], self.expr_str(instr[2]), self.expr_str(instr[3]))
+                if instr[4]:
+                    _out += " STEP %s" % (self.expr_str(instr[4]))
+                print(_out)
+            elif op == 'NEXT':
+                print("%s NEXT %s" % (line, instr[1]))
+            elif op == 'FUNC':
+                print("%s DEF %s(%s) = %s" %
+                      (line, instr[1], instr[2], self.expr_str(instr[3])))
+            elif op == 'DIM':
+                _out = "%s DIM " % line
+                first = 1
+                for vname, x, y in instr[1]:
+                    if not first:
+                        _out += ","
+                    first = 0
+                    if y == 0:
+                        _out += "%s(%d)" % (vname, x)
+                    else:
+                        _out += "%s(%d,%d)" % (vname, x, y)
+
+                print(_out)
+            elif op == 'DATA':
+                _out = "%s DATA " % line
+                first = 1
+                for v in instr[1]:
+                    if not first:
+                        _out += ","
+                    first = 0
+                    _out += v
+                print(_out)
+
+    # Erase the current program
+    def new(self):
+        self.prog = {}
+
+    # Insert statements
+    def add_statements(self, prog):
+        for line, stat in prog.items():
+            self.prog[line] = stat
+
+    # Delete a statement
+    def del_line(self, lineno):
+        try:
+            del self.prog[lineno]
+        except KeyError:
+            pass
diff --git a/third_party/python/ply/example/BASIC/basparse.py b/third_party/python/ply/example/BASIC/basparse.py
new file mode 100644
index 0000000000..d610c7d909
--- /dev/null
+++ b/third_party/python/ply/example/BASIC/basparse.py
@@ -0,0 +1,474 @@
+# An implementation of Dartmouth BASIC (1964)
+#
+
+from ply import *
+import basiclex
+
+tokens = basiclex.tokens
+
+precedence = (
+    ('left', 'PLUS', 'MINUS'),
+    ('left', 'TIMES', 'DIVIDE'),
+    ('left', 'POWER'),
+    ('right', 'UMINUS')
+)
+
+# A BASIC program is a series of statements.  We represent the program as a
+# dictionary of tuples indexed by line number.
+
+
+def p_program(p):
+    '''program : program statement
+               | statement'''
+
+    if len(p) == 2 and p[1]:
+        p[0] = {}
+        line, stat = p[1]
+        p[0][line] = stat
+    elif len(p) == 3:
+        p[0] = p[1]
+        if not p[0]:
+            p[0] = {}
+        if p[2]:
+            line, stat = p[2]
+            p[0][line] = stat
+
+# This catch-all rule is used for any catastrophic errors.  In this case,
+# we simply return nothing
+
+
+def p_program_error(p):
+    '''program : error'''
+    p[0] = None
+    p.parser.error = 1
+
+# Format of all BASIC statements.
+
+
+def p_statement(p):
+    '''statement : INTEGER command NEWLINE'''
+    if isinstance(p[2], str):
+        print("%s %s %s" % (p[2], "AT LINE", p[1]))
+        p[0] = None
+        p.parser.error = 1
+    else:
+        lineno = int(p[1])
+        p[0] = (lineno, p[2])
+
+# Interactive statements.
+
+
+def p_statement_interactive(p):
+    '''statement : RUN NEWLINE
+                 | LIST NEWLINE
+                 | NEW NEWLINE'''
+    p[0] = (0, (p[1], 0))
+
+# Blank line number
+
+
+def p_statement_blank(p):
+    '''statement : INTEGER NEWLINE'''
+    p[0] = (0, ('BLANK', int(p[1])))
+
+# Error handling for malformed statements
+
+
+def p_statement_bad(p):
+    '''statement : INTEGER error NEWLINE'''
+    print("MALFORMED STATEMENT AT LINE %s" % p[1])
+    p[0] = None
+    p.parser.error = 1
+
+# Blank line
+
+
+def p_statement_newline(p):
+    '''statement : NEWLINE'''
+    p[0] = None
+
+# LET statement
+
+
+def p_command_let(p):
+    '''command : LET variable EQUALS expr'''
+    p[0] = ('LET', p[2], p[4])
+
+
+def p_command_let_bad(p):
+    '''command : LET variable EQUALS error'''
+    p[0] = "BAD EXPRESSION IN LET"
+
+# READ statement
+
+
+def p_command_read(p):
+    '''command : READ varlist'''
+    p[0] = ('READ', p[2])
+
+
+def p_command_read_bad(p):
+    '''command : READ error'''
+    p[0] = "MALFORMED VARIABLE LIST IN READ"
+
+# DATA statement
+
+
+def p_command_data(p):
+    '''command : DATA numlist'''
+    p[0] = ('DATA', p[2])
+
+
+def p_command_data_bad(p):
+    '''command : DATA error'''
+    p[0] = "MALFORMED NUMBER LIST IN DATA"
+
+# PRINT statement
+
+
+def p_command_print(p):
+    '''command : PRINT plist optend'''
+    p[0] = ('PRINT', p[2], p[3])
+
+
+def p_command_print_bad(p):
+    '''command : PRINT error'''
+    p[0] = "MALFORMED PRINT STATEMENT"
+
+# Optional ending on PRINT. Either a comma (,) or semicolon (;)
+
+
+def p_optend(p):
+    '''optend : COMMA 
+              | SEMI
+              |'''
+    if len(p) == 2:
+        p[0] = p[1]
+    else:
+        p[0] = None
+
+# PRINT statement with no arguments
+
+
+def p_command_print_empty(p):
+    '''command : PRINT'''
+    p[0] = ('PRINT', [], None)
+
+# GOTO statement
+
+
+def p_command_goto(p):
+    '''command : GOTO INTEGER'''
+    p[0] = ('GOTO', int(p[2]))
+
+
+def p_command_goto_bad(p):
+    '''command : GOTO error'''
+    p[0] = "INVALID LINE NUMBER IN GOTO"
+
+# IF-THEN statement
+
+
+def p_command_if(p):
+    '''command : IF relexpr THEN INTEGER'''
+    p[0] = ('IF', p[2], int(p[4]))
+
+
+def p_command_if_bad(p):
+    '''command : IF error THEN INTEGER'''
+    p[0] = "BAD RELATIONAL EXPRESSION"
+
+
+def p_command_if_bad2(p):
+    '''command : IF relexpr THEN error'''
+    p[0] = "INVALID LINE NUMBER IN THEN"
+
+# FOR statement
+
+
+def p_command_for(p):
+    '''command : FOR ID EQUALS expr TO expr optstep'''
+    p[0] = ('FOR', p[2], p[4], p[6], p[7])
+
+
+def p_command_for_bad_initial(p):
+    '''command : FOR ID EQUALS error TO expr optstep'''
+    p[0] = "BAD INITIAL VALUE IN FOR STATEMENT"
+
+
+def p_command_for_bad_final(p):
+    '''command : FOR ID EQUALS expr TO error optstep'''
+    p[0] = "BAD FINAL VALUE IN FOR STATEMENT"
+
+
+def p_command_for_bad_step(p):
+    '''command : FOR ID EQUALS expr TO expr STEP error'''
+    p[0] = "MALFORMED STEP IN FOR STATEMENT"
+
+# Optional STEP qualifier on FOR statement
+
+
+def p_optstep(p):
+    '''optstep : STEP expr
+               | empty'''
+    if len(p) == 3:
+        p[0] = p[2]
+    else:
+        p[0] = None
+
+# NEXT statement
+
+
+def p_command_next(p):
+    '''command : NEXT ID'''
+
+    p[0] = ('NEXT', p[2])
+
+
+def p_command_next_bad(p):
+    '''command : NEXT error'''
+    p[0] = "MALFORMED NEXT"
+
+# END statement
+
+
+def p_command_end(p):
+    '''command : END'''
+    p[0] = ('END',)
+
+# REM statement
+
+
+def p_command_rem(p):
+    '''command : REM'''
+    p[0] = ('REM', p[1])
+
+# STOP statement
+
+
+def p_command_stop(p):
+    '''command : STOP'''
+    p[0] = ('STOP',)
+
+# DEF statement
+
+
+def p_command_def(p):
+    '''command : DEF ID LPAREN ID RPAREN EQUALS expr'''
+    p[0] = ('FUNC', p[2], p[4], p[7])
+
+
+def p_command_def_bad_rhs(p):
+    '''command : DEF ID LPAREN ID RPAREN EQUALS error'''
+    p[0] = "BAD EXPRESSION IN DEF STATEMENT"
+
+
+def p_command_def_bad_arg(p):
+    '''command : DEF ID LPAREN error RPAREN EQUALS expr'''
+    p[0] = "BAD ARGUMENT IN DEF STATEMENT"
+
+# GOSUB statement
+
+
+def p_command_gosub(p):
+    '''command : GOSUB INTEGER'''
+    p[0] = ('GOSUB', int(p[2]))
+
+
+def p_command_gosub_bad(p):
+    '''command : GOSUB error'''
+    p[0] = "INVALID LINE NUMBER IN GOSUB"
+
+# RETURN statement
+
+
+def p_command_return(p):
+    '''command : RETURN'''
+    p[0] = ('RETURN',)
+
+# DIM statement
+
+
+def p_command_dim(p):
+    '''command : DIM dimlist'''
+    p[0] = ('DIM', p[2])
+
+
+def p_command_dim_bad(p):
+    '''command : DIM error'''
+    p[0] = "MALFORMED VARIABLE LIST IN DIM"
+
+# List of variables supplied to DIM statement
+
+
+def p_dimlist(p):
+    '''dimlist : dimlist COMMA dimitem
+               | dimitem'''
+    if len(p) == 4:
+        p[0] = p[1]
+        p[0].append(p[3])
+    else:
+        p[0] = [p[1]]
+
+# DIM items
+
+
+def p_dimitem_single(p):
+    '''dimitem : ID LPAREN INTEGER RPAREN'''
+    p[0] = (p[1], eval(p[3]), 0)
+
+
+def p_dimitem_double(p):
+    '''dimitem : ID LPAREN INTEGER COMMA INTEGER RPAREN'''
+    p[0] = (p[1], eval(p[3]), eval(p[5]))
+
+# Arithmetic expressions
+
+
+def p_expr_binary(p):
+    '''expr : expr PLUS expr
+            | expr MINUS expr
+            | expr TIMES expr
+            | expr DIVIDE expr
+            | expr POWER expr'''
+
+    p[0] = ('BINOP', p[2], p[1], p[3])
+
+
+def p_expr_number(p):
+    '''expr : INTEGER
+            | FLOAT'''
+    p[0] = ('NUM', eval(p[1]))
+
+
+def p_expr_variable(p):
+    '''expr : variable'''
+    p[0] = ('VAR', p[1])
+
+
+def p_expr_group(p):
+    '''expr : LPAREN expr RPAREN'''
+    p[0] = ('GROUP', p[2])
+
+
+def p_expr_unary(p):
+    '''expr : MINUS expr %prec UMINUS'''
+    p[0] = ('UNARY', '-', p[2])
+
+# Relational expressions
+
+
+def p_relexpr(p):
+    '''relexpr : expr LT expr
+               | expr LE expr
+               | expr GT expr
+               | expr GE expr
+               | expr EQUALS expr
+               | expr NE expr'''
+    p[0] = ('RELOP', p[2], p[1], p[3])
+
+# Variables
+
+
+def p_variable(p):
+    '''variable : ID
+              | ID LPAREN expr RPAREN
+              | ID LPAREN expr COMMA expr RPAREN'''
+    if len(p) == 2:
+        p[0] = (p[1], None, None)
+    elif len(p) == 5:
+        p[0] = (p[1], p[3], None)
+    else:
+        p[0] = (p[1], p[3], p[5])
+
+# Builds a list of variable targets as a Python list
+
+
+def p_varlist(p):
+    '''varlist : varlist COMMA variable
+               | variable'''
+    if len(p) > 2:
+        p[0] = p[1]
+        p[0].append(p[3])
+    else:
+        p[0] = [p[1]]
+
+
+# Builds a list of numbers as a Python list
+
+def p_numlist(p):
+    '''numlist : numlist COMMA number
+               | number'''
+
+    if len(p) > 2:
+        p[0] = p[1]
+        p[0].append(p[3])
+    else:
+        p[0] = [p[1]]
+
+# A number. May be an integer or a float
+
+
+def p_number(p):
+    '''number  : INTEGER
+               | FLOAT'''
+    p[0] = eval(p[1])
+
+# A signed number.
+
+
+def p_number_signed(p):
+    '''number  : MINUS INTEGER
+               | MINUS FLOAT'''
+    p[0] = eval("-" + p[2])
+
+# List of targets for a print statement
+# Returns a list of tuples (label,expr)
+
+
+def p_plist(p):
+    '''plist   : plist COMMA pitem
+               | pitem'''
+    if len(p) > 3:
+        p[0] = p[1]
+        p[0].append(p[3])
+    else:
+        p[0] = [p[1]]
+
+
+def p_item_string(p):
+    '''pitem : STRING'''
+    p[0] = (p[1][1:-1], None)
+
+
+def p_item_string_expr(p):
+    '''pitem : STRING expr'''
+    p[0] = (p[1][1:-1], p[2])
+
+
+def p_item_expr(p):
+    '''pitem : expr'''
+    p[0] = ("", p[1])
+
+# Empty
+
+
+def p_empty(p):
+    '''empty : '''
+
+# Catastrophic error handler
+
+
+def p_error(p):
+    if not p:
+        print("SYNTAX ERROR AT EOF")
+
+bparser = yacc.yacc()
+
+
+def parse(data, debug=0):
+    bparser.error = 0
+    p = bparser.parse(data, debug=debug)
+    if bparser.error:
+        return None
+    return p
diff --git a/third_party/python/ply/example/BASIC/dim.bas b/third_party/python/ply/example/BASIC/dim.bas
new file mode 100644
index 0000000000..87bd95b32e
--- /dev/null
+++ b/third_party/python/ply/example/BASIC/dim.bas
@@ -0,0 +1,14 @@
+5 DIM A(50,15)
+10 FOR I = 1 TO 50
+20 FOR J = 1 TO 15
+30   LET A(I,J) = I + J
+35 REM  PRINT I,J, A(I,J)
+40 NEXT J
+50 NEXT I
+100 FOR I = 1 TO 50
+110 FOR J = 1 TO 15
+120   PRINT A(I,J),
+130 NEXT J
+140 PRINT 
+150 NEXT I
+999 END
diff --git a/third_party/python/ply/example/BASIC/func.bas b/third_party/python/ply/example/BASIC/func.bas
new file mode 100644
index 0000000000..447ee16a92
--- /dev/null
+++ b/third_party/python/ply/example/BASIC/func.bas
@@ -0,0 +1,5 @@
+10 DEF FDX(X) = 2*X
+20 FOR I = 0 TO 100
+30 PRINT FDX(I)
+40 NEXT I
+50 END
diff --git a/third_party/python/ply/example/BASIC/gcd.bas b/third_party/python/ply/example/BASIC/gcd.bas
new file mode 100644
index 0000000000..d0b7746089
--- /dev/null
+++ b/third_party/python/ply/example/BASIC/gcd.bas
@@ -0,0 +1,22 @@
+10 PRINT "A","B","C","GCD"
+20 READ A,B,C
+30 LET X = A
+40 LET Y = B
+50 GOSUB 200
+60 LET X = G
+70 LET Y = C
+80 GOSUB 200
+90 PRINT A, B, C, G
+100 GOTO 20
+110 DATA 60, 90, 120
+120 DATA 38456, 64872, 98765
+130 DATA 32, 384, 72
+200 LET Q = INT(X/Y)
+210 LET R = X - Q*Y
+220 IF R = 0 THEN 300
+230 LET X = Y
+240 LET Y = R
+250 GOTO 200
+300 LET G = Y
+310 RETURN
+999 END
diff --git a/third_party/python/ply/example/BASIC/gosub.bas b/third_party/python/ply/example/BASIC/gosub.bas
new file mode 100644
index 0000000000..99737b16f1
--- /dev/null
+++ b/third_party/python/ply/example/BASIC/gosub.bas
@@ -0,0 +1,13 @@
+100 LET X = 3
+110 GOSUB 400
+120 PRINT U, V, W
+200 LET X = 5
+210 GOSUB 400
+220 LET Z = U + 2*V + 3*W
+230 PRINT Z
+240 GOTO 999
+400 LET U = X*X
+410 LET V = X*X*X
+420 LET W = X*X*X*X + X*X*X + X*X + X
+430 RETURN
+999 END
diff --git a/third_party/python/ply/example/BASIC/hello.bas b/third_party/python/ply/example/BASIC/hello.bas
new file mode 100644
index 0000000000..cc6f0b0b51
--- /dev/null
+++ b/third_party/python/ply/example/BASIC/hello.bas
@@ -0,0 +1,4 @@
+5  REM HELLO WORLD PROGAM
+10 PRINT "HELLO WORLD"
+99 END
+
diff --git a/third_party/python/ply/example/BASIC/linear.bas b/third_party/python/ply/example/BASIC/linear.bas
new file mode 100644
index 0000000000..56c08220b3
--- /dev/null
+++ b/third_party/python/ply/example/BASIC/linear.bas
@@ -0,0 +1,17 @@
+1  REM ::: SOLVE A SYSTEM OF LINEAR EQUATIONS
+2  REM ::: A1*X1 + A2*X2 = B1
+3  REM ::: A3*X1 + A4*X2 = B2
+4  REM --------------------------------------
+10 READ A1, A2, A3, A4
+15 LET D = A1 * A4 - A3 * A2
+20 IF D = 0 THEN 65
+30 READ B1, B2
+37 LET X1 = (B1*A4 - B2*A2) / D
+42 LET X2 = (A1*B2 - A3*B1) / D
+55 PRINT X1, X2
+60 GOTO 30
+65 PRINT "NO UNIQUE SOLUTION"
+70 DATA 1, 2, 4
+80 DATA 2, -7, 5
+85 DATA 1, 3, 4, -7
+90 END
diff --git a/third_party/python/ply/example/BASIC/maxsin.bas b/third_party/python/ply/example/BASIC/maxsin.bas
new file mode 100644
index 0000000000..b96901530c
--- /dev/null
+++ b/third_party/python/ply/example/BASIC/maxsin.bas
@@ -0,0 +1,12 @@
+5 PRINT "X VALUE", "SINE", "RESOLUTION"
+10 READ D
+20 LET M = -1
+30 FOR X = 0 TO 3 STEP D
+40 IF SIN(X) <= M THEN 80
+50 LET X0 = X
+60 LET M = SIN(X)
+80 NEXT X
+85 PRINT X0, M, D
+90 GOTO 10
+100 DATA .1, .01, .001
+110 END
diff --git a/third_party/python/ply/example/BASIC/powers.bas b/third_party/python/ply/example/BASIC/powers.bas
new file mode 100644
index 0000000000..a454dc3e21
--- /dev/null
+++ b/third_party/python/ply/example/BASIC/powers.bas
@@ -0,0 +1,13 @@
+5 PRINT "THIS PROGRAM COMPUTES AND PRINTS THE NTH POWERS"
+6 PRINT "OF THE NUMBERS LESS THAN OR EQUAL TO N FOR VARIOUS"
+7 PRINT "N FROM 1 THROUGH 7"
+8 PRINT
+10 FOR N = 1 TO 7
+15 PRINT "N = "N
+20 FOR I = 1 TO N
+30 PRINT I^N,
+40 NEXT I
+50 PRINT
+60 PRINT
+70 NEXT N
+80 END
diff --git a/third_party/python/ply/example/BASIC/rand.bas b/third_party/python/ply/example/BASIC/rand.bas
new file mode 100644
index 0000000000..4ff7a14670
--- /dev/null
+++ b/third_party/python/ply/example/BASIC/rand.bas
@@ -0,0 +1,4 @@
+10 FOR I = 1 TO 20
+20 PRINT INT(10*RND(0))
+30 NEXT I
+40 END
diff --git a/third_party/python/ply/example/BASIC/sales.bas b/third_party/python/ply/example/BASIC/sales.bas
new file mode 100644
index 0000000000..a39aefb762
--- /dev/null
+++ b/third_party/python/ply/example/BASIC/sales.bas
@@ -0,0 +1,20 @@
+10 FOR I = 1 TO 3
+20 READ P(I)
+30 NEXT I
+40 FOR I = 1 TO 3
+50 FOR J = 1 TO 5
+60 READ S(I,J)
+70 NEXT J
+80 NEXT I
+90 FOR J = 1 TO 5
+100 LET S = 0
+110 FOR I = 1 TO 3
+120 LET S = S + P(I) * S(I,J)
+130 NEXT I
+140 PRINT "TOTAL SALES FOR SALESMAN"J, "$"S
+150 NEXT J
+200 DATA 1.25, 4.30, 2.50
+210 DATA 40, 20, 37, 29, 42
+220 DATA 10, 16, 3, 21, 8
+230 DATA 35, 47, 29, 16, 33
+300 END
diff --git a/third_party/python/ply/example/BASIC/sears.bas b/third_party/python/ply/example/BASIC/sears.bas
new file mode 100644
index 0000000000..5ced3974e2
--- /dev/null
+++ b/third_party/python/ply/example/BASIC/sears.bas
@@ -0,0 +1,18 @@
+1 REM :: THIS PROGRAM COMPUTES HOW MANY TIMES YOU HAVE TO FOLD
+2 REM :: A PIECE OF PAPER SO THAT IT IS TALLER THAN THE
+3 REM :: SEARS TOWER.
+4 REM ::       S = HEIGHT OF TOWER (METERS)
+5 REM ::       T = THICKNESS OF PAPER (MILLIMETERS)
+10 LET S = 442
+20 LET T = 0.1
+30 REM CONVERT T TO METERS
+40 LET T = T * .001
+50 LET F = 1
+60 LET H = T
+100 IF H > S THEN 200
+120 LET H = 2 * H
+125 LET F = F + 1
+130 GOTO 100
+200 PRINT "NUMBER OF FOLDS ="F
+220 PRINT "FINAL HEIGHT    ="H
+999 END
diff --git a/third_party/python/ply/example/BASIC/sqrt1.bas b/third_party/python/ply/example/BASIC/sqrt1.bas
new file mode 100644
index 0000000000..6673a91524
--- /dev/null
+++ b/third_party/python/ply/example/BASIC/sqrt1.bas
@@ -0,0 +1,5 @@
+10 LET X = 0
+20 LET X = X + 1
+30 PRINT X, SQR(X)
+40 IF X < 100 THEN 20
+50 END
diff --git a/third_party/python/ply/example/BASIC/sqrt2.bas b/third_party/python/ply/example/BASIC/sqrt2.bas
new file mode 100644
index 0000000000..862d85ef26
--- /dev/null
+++ b/third_party/python/ply/example/BASIC/sqrt2.bas
@@ -0,0 +1,4 @@
+10 FOR X = 1 TO 100
+20 PRINT X, SQR(X)
+30 NEXT X
+40 END
diff --git a/third_party/python/ply/example/GardenSnake/GardenSnake.py b/third_party/python/ply/example/GardenSnake/GardenSnake.py
new file mode 100644
index 0000000000..8b493b40dc
--- /dev/null
+++ b/third_party/python/ply/example/GardenSnake/GardenSnake.py
@@ -0,0 +1,777 @@
+# GardenSnake - a parser generator demonstration program
+#
+# This implements a modified version of a subset of Python:
+#  - only 'def', 'return' and 'if' statements
+#  - 'if' only has 'then' clause (no elif nor else)
+#  - single-quoted strings only, content in raw format
+#  - numbers are decimal.Decimal instances (not integers or floats)
+#  - no print statment; use the built-in 'print' function
+#  - only < > == + - / * implemented (and unary + -)
+#  - assignment and tuple assignment work
+#  - no generators of any sort
+#  - no ... well, no quite a lot
+
+# Why?  I'm thinking about a new indentation-based configuration
+# language for a project and wanted to figure out how to do it.  Once
+# I got that working I needed a way to test it out.  My original AST
+# was dumb so I decided to target Python's AST and compile it into
+# Python code.  Plus, it's pretty cool that it only took a day or so
+# from sitting down with Ply to having working code.
+
+# This uses David Beazley's Ply from http://www.dabeaz.com/ply/
+
+# This work is hereby released into the Public Domain. To view a copy of
+# the public domain dedication, visit
+# http://creativecommons.org/licenses/publicdomain/ or send a letter to
+# Creative Commons, 543 Howard Street, 5th Floor, San Francisco,
+# California, 94105, USA.
+#
+# Portions of this work are derived from Python's Grammar definition
+# and may be covered under the Python copyright and license
+#
+#          Andrew Dalke / Dalke Scientific Software, LLC
+#             30 August 2006 / Cape Town, South Africa
+
+# Changelog:
+#  30 August - added link to CC license; removed the "swapcase" encoding
+
+# Modifications for inclusion in PLY distribution
+import sys
+sys.path.insert(0, "../..")
+from ply import *
+
+##### Lexer ######
+#import lex
+import decimal
+
+tokens = (
+    'DEF',
+    'IF',
+    'NAME',
+    'NUMBER',  # Python decimals
+    'STRING',  # single quoted strings only; syntax of raw strings
+    'LPAR',
+    'RPAR',
+    'COLON',
+    'EQ',
+    'ASSIGN',
+    'LT',
+    'GT',
+    'PLUS',
+    'MINUS',
+    'MULT',
+    'DIV',
+    'RETURN',
+    'WS',
+    'NEWLINE',
+    'COMMA',
+    'SEMICOLON',
+    'INDENT',
+    'DEDENT',
+    'ENDMARKER',
+)
+
+#t_NUMBER = r'\d+'
+# taken from decmial.py but without the leading sign
+
+
+def t_NUMBER(t):
+    r"""(\d+(\.\d*)?|\.\d+)([eE][-+]? \d+)?"""
+    t.value = decimal.Decimal(t.value)
+    return t
+
+
+def t_STRING(t):
+    r"'([^\\']+|\\'|\\\\)*'"  # I think this is right ...
+    t.value = t.value[1:-1].decode("string-escape")  # .swapcase() # for fun
+    return t
+
+t_COLON = r':'
+t_EQ = r'=='
+t_ASSIGN = r'='
+t_LT = r'<'
+t_GT = r'>'
+t_PLUS = r'\+'
+t_MINUS = r'-'
+t_MULT = r'\*'
+t_DIV = r'/'
+t_COMMA = r','
+t_SEMICOLON = r';'
+
+# Ply nicely documented how to do this.
+
+RESERVED = {
+    "def": "DEF",
+    "if": "IF",
+    "return": "RETURN",
+}
+
+
+def t_NAME(t):
+    r'[a-zA-Z_][a-zA-Z0-9_]*'
+    t.type = RESERVED.get(t.value, "NAME")
+    return t
+
+# Putting this before t_WS let it consume lines with only comments in
+# them so the latter code never sees the WS part.  Not consuming the
+# newline.  Needed for "if 1: #comment"
+
+
+def t_comment(t):
+    r"[ ]*\043[^\n]*"  # \043 is '#'
+    pass
+
+
+# Whitespace
+def t_WS(t):
+    r' [ ]+ '
+    if t.lexer.at_line_start and t.lexer.paren_count == 0:
+        return t
+
+# Don't generate newline tokens when inside of parenthesis, eg
+#   a = (1,
+#        2, 3)
+
+
+def t_newline(t):
+    r'\n+'
+    t.lexer.lineno += len(t.value)
+    t.type = "NEWLINE"
+    if t.lexer.paren_count == 0:
+        return t
+
+
+def t_LPAR(t):
+    r'\('
+    t.lexer.paren_count += 1
+    return t
+
+
+def t_RPAR(t):
+    r'\)'
+    # check for underflow?  should be the job of the parser
+    t.lexer.paren_count -= 1
+    return t
+
+
+def t_error(t):
+    raise SyntaxError("Unknown symbol %r" % (t.value[0],))
+    print "Skipping", repr(t.value[0])
+    t.lexer.skip(1)
+
+# I implemented INDENT / DEDENT generation as a post-processing filter
+
+# The original lex token stream contains WS and NEWLINE characters.
+# WS will only occur before any other tokens on a line.
+
+# I have three filters.  One tags tokens by adding two attributes.
+# "must_indent" is True if the token must be indented from the
+# previous code.  The other is "at_line_start" which is True for WS
+# and the first non-WS/non-NEWLINE on a line.  It flags the check so
+# see if the new line has changed indication level.
+
+# Python's syntax has three INDENT states
+#  0) no colon hence no need to indent
+#  1) "if 1: go()" - simple statements have a COLON but no need for an indent
+#  2) "if 1:\n  go()" - complex statements have a COLON NEWLINE and must indent
+NO_INDENT = 0
+MAY_INDENT = 1
+MUST_INDENT = 2
+
+# only care about whitespace at the start of a line
+
+
+def track_tokens_filter(lexer, tokens):
+    lexer.at_line_start = at_line_start = True
+    indent = NO_INDENT
+    saw_colon = False
+    for token in tokens:
+        token.at_line_start = at_line_start
+
+        if token.type == "COLON":
+            at_line_start = False
+            indent = MAY_INDENT
+            token.must_indent = False
+
+        elif token.type == "NEWLINE":
+            at_line_start = True
+            if indent == MAY_INDENT:
+                indent = MUST_INDENT
+            token.must_indent = False
+
+        elif token.type == "WS":
+            assert token.at_line_start == True
+            at_line_start = True
+            token.must_indent = False
+
+        else:
+            # A real token; only indent after COLON NEWLINE
+            if indent == MUST_INDENT:
+                token.must_indent = True
+            else:
+                token.must_indent = False
+            at_line_start = False
+            indent = NO_INDENT
+
+        yield token
+        lexer.at_line_start = at_line_start
+
+
+def _new_token(type, lineno):
+    tok = lex.LexToken()
+    tok.type = type
+    tok.value = None
+    tok.lineno = lineno
+    return tok
+
+# Synthesize a DEDENT tag
+
+
+def DEDENT(lineno):
+    return _new_token("DEDENT", lineno)
+
+# Synthesize an INDENT tag
+
+
+def INDENT(lineno):
+    return _new_token("INDENT", lineno)
+
+
+# Track the indentation level and emit the right INDENT / DEDENT events.
+def indentation_filter(tokens):
+    # A stack of indentation levels; will never pop item 0
+    levels = [0]
+    token = None
+    depth = 0
+    prev_was_ws = False
+    for token in tokens:
+        # if 1:
+        # print "Process", token,
+        # if token.at_line_start:
+        # print "at_line_start",
+        # if token.must_indent:
+        # print "must_indent",
+        # print
+
+        # WS only occurs at the start of the line
+        # There may be WS followed by NEWLINE so
+        # only track the depth here.  Don't indent/dedent
+        # until there's something real.
+        if token.type == "WS":
+            assert depth == 0
+            depth = len(token.value)
+            prev_was_ws = True
+            # WS tokens are never passed to the parser
+            continue
+
+        if token.type == "NEWLINE":
+            depth = 0
+            if prev_was_ws or token.at_line_start:
+                # ignore blank lines
+                continue
+            # pass the other cases on through
+            yield token
+            continue
+
+        # then it must be a real token (not WS, not NEWLINE)
+        # which can affect the indentation level
+
+        prev_was_ws = False
+        if token.must_indent:
+            # The current depth must be larger than the previous level
+            if not (depth > levels[-1]):
+                raise IndentationError("expected an indented block")
+
+            levels.append(depth)
+            yield INDENT(token.lineno)
+
+        elif token.at_line_start:
+            # Must be on the same level or one of the previous levels
+            if depth == levels[-1]:
+                # At the same level
+                pass
+            elif depth > levels[-1]:
+                raise IndentationError(
+                    "indentation increase but not in new block")
+            else:
+                # Back up; but only if it matches a previous level
+                try:
+                    i = levels.index(depth)
+                except ValueError:
+                    raise IndentationError("inconsistent indentation")
+                for _ in range(i + 1, len(levels)):
+                    yield DEDENT(token.lineno)
+                    levels.pop()
+
+        yield token
+
+    ### Finished processing ###
+
+    # Must dedent any remaining levels
+    if len(levels) > 1:
+        assert token is not None
+        for _ in range(1, len(levels)):
+            yield DEDENT(token.lineno)
+
+
+# The top-level filter adds an ENDMARKER, if requested.
+# Python's grammar uses it.
+def filter(lexer, add_endmarker=True):
+    token = None
+    tokens = iter(lexer.token, None)
+    tokens = track_tokens_filter(lexer, tokens)
+    for token in indentation_filter(tokens):
+        yield token
+
+    if add_endmarker:
+        lineno = 1
+        if token is not None:
+            lineno = token.lineno
+        yield _new_token("ENDMARKER", lineno)
+
+# Combine Ply and my filters into a new lexer
+
+
+class IndentLexer(object):
+
+    def __init__(self, debug=0, optimize=0, lextab='lextab', reflags=0):
+        self.lexer = lex.lex(debug=debug, optimize=optimize,
+                             lextab=lextab, reflags=reflags)
+        self.token_stream = None
+
+    def input(self, s, add_endmarker=True):
+        self.lexer.paren_count = 0
+        self.lexer.input(s)
+        self.token_stream = filter(self.lexer, add_endmarker)
+
+    def token(self):
+        try:
+            return self.token_stream.next()
+        except StopIteration:
+            return None
+
+##########   Parser (tokens -> AST) ######
+
+# also part of Ply
+#import yacc
+
+# I use the Python AST
+from compiler import ast
+
+# Helper function
+
+
+def Assign(left, right):
+    names = []
+    if isinstance(left, ast.Name):
+        # Single assignment on left
+        return ast.Assign([ast.AssName(left.name, 'OP_ASSIGN')], right)
+    elif isinstance(left, ast.Tuple):
+        # List of things - make sure they are Name nodes
+        names = []
+        for child in left.getChildren():
+            if not isinstance(child, ast.Name):
+                raise SyntaxError("that assignment not supported")
+            names.append(child.name)
+        ass_list = [ast.AssName(name, 'OP_ASSIGN') for name in names]
+        return ast.Assign([ast.AssTuple(ass_list)], right)
+    else:
+        raise SyntaxError("Can't do that yet")
+
+
+# The grammar comments come from Python's Grammar/Grammar file
+
+# NB: compound_stmt in single_input is followed by extra NEWLINE!
+# file_input: (NEWLINE | stmt)* ENDMARKER
+def p_file_input_end(p):
+    """file_input_end : file_input ENDMARKER"""
+    p[0] = ast.Stmt(p[1])
+
+
+def p_file_input(p):
+    """file_input : file_input NEWLINE
+                  | file_input stmt
+                  | NEWLINE
+                  | stmt"""
+    if isinstance(p[len(p) - 1], basestring):
+        if len(p) == 3:
+            p[0] = p[1]
+        else:
+            p[0] = []  # p == 2 --> only a blank line
+    else:
+        if len(p) == 3:
+            p[0] = p[1] + p[2]
+        else:
+            p[0] = p[1]
+
+
+# funcdef: [decorators] 'def' NAME parameters ':' suite
+# ignoring decorators
+def p_funcdef(p):
+    "funcdef : DEF NAME parameters COLON suite"
+    p[0] = ast.Function(None, p[2], tuple(p[3]), (), 0, None, p[5])
+
+# parameters: '(' [varargslist] ')'
+
+
+def p_parameters(p):
+    """parameters : LPAR RPAR
+                  | LPAR varargslist RPAR"""
+    if len(p) == 3:
+        p[0] = []
+    else:
+        p[0] = p[2]
+
+
+# varargslist: (fpdef ['=' test] ',')* ('*' NAME [',' '**' NAME] | '**' NAME) |
+# highly simplified
+def p_varargslist(p):
+    """varargslist : varargslist COMMA NAME
+                   | NAME"""
+    if len(p) == 4:
+        p[0] = p[1] + p[3]
+    else:
+        p[0] = [p[1]]
+
+# stmt: simple_stmt | compound_stmt
+
+
+def p_stmt_simple(p):
+    """stmt : simple_stmt"""
+    # simple_stmt is a list
+    p[0] = p[1]
+
+
+def p_stmt_compound(p):
+    """stmt : compound_stmt"""
+    p[0] = [p[1]]
+
+# simple_stmt: small_stmt (';' small_stmt)* [';'] NEWLINE
+
+
+def p_simple_stmt(p):
+    """simple_stmt : small_stmts NEWLINE
+                   | small_stmts SEMICOLON NEWLINE"""
+    p[0] = p[1]
+
+
+def p_small_stmts(p):
+    """small_stmts : small_stmts SEMICOLON small_stmt
+                   | small_stmt"""
+    if len(p) == 4:
+        p[0] = p[1] + [p[3]]
+    else:
+        p[0] = [p[1]]
+
+# small_stmt: expr_stmt | print_stmt  | del_stmt | pass_stmt | flow_stmt |
+#    import_stmt | global_stmt | exec_stmt | assert_stmt
+
+
+def p_small_stmt(p):
+    """small_stmt : flow_stmt
+                  | expr_stmt"""
+    p[0] = p[1]
+
+# expr_stmt: testlist (augassign (yield_expr|testlist) |
+#                      ('=' (yield_expr|testlist))*)
+# augassign: ('+=' | '-=' | '*=' | '/=' | '%=' | '&=' | '|=' | '^=' |
+#             '<<=' | '>>=' | '**=' | '//=')
+
+
+def p_expr_stmt(p):
+    """expr_stmt : testlist ASSIGN testlist
+                 | testlist """
+    if len(p) == 2:
+        # a list of expressions
+        p[0] = ast.Discard(p[1])
+    else:
+        p[0] = Assign(p[1], p[3])
+
+
+def p_flow_stmt(p):
+    "flow_stmt : return_stmt"
+    p[0] = p[1]
+
+# return_stmt: 'return' [testlist]
+
+
+def p_return_stmt(p):
+    "return_stmt : RETURN testlist"
+    p[0] = ast.Return(p[2])
+
+
+def p_compound_stmt(p):
+    """compound_stmt : if_stmt
+                     | funcdef"""
+    p[0] = p[1]
+
+
+def p_if_stmt(p):
+    'if_stmt : IF test COLON suite'
+    p[0] = ast.If([(p[2], p[4])], None)
+
+
+def p_suite(p):
+    """suite : simple_stmt
+             | NEWLINE INDENT stmts DEDENT"""
+    if len(p) == 2:
+        p[0] = ast.Stmt(p[1])
+    else:
+        p[0] = ast.Stmt(p[3])
+
+
+def p_stmts(p):
+    """stmts : stmts stmt
+             | stmt"""
+    if len(p) == 3:
+        p[0] = p[1] + p[2]
+    else:
+        p[0] = p[1]
+
+# No using Python's approach because Ply supports precedence
+
+# comparison: expr (comp_op expr)*
+# arith_expr: term (('+'|'-') term)*
+# term: factor (('*'|'/'|'%'|'//') factor)*
+# factor: ('+'|'-'|'~') factor | power
+# comp_op: '<'|'>'|'=='|'>='|'<='|'<>'|'!='|'in'|'not' 'in'|'is'|'is' 'not'
+
+
+def make_lt_compare((left, right)):
+    return ast.Compare(left, [('<', right), ])
+
+
+def make_gt_compare((left, right)):
+    return ast.Compare(left, [('>', right), ])
+
+
+def make_eq_compare((left, right)):
+    return ast.Compare(left, [('==', right), ])
+
+
+binary_ops = {
+    "+": ast.Add,
+    "-": ast.Sub,
+    "*": ast.Mul,
+    "/": ast.Div,
+    "<": make_lt_compare,
+    ">": make_gt_compare,
+    "==": make_eq_compare,
+}
+unary_ops = {
+    "+": ast.UnaryAdd,
+    "-": ast.UnarySub,
+}
+precedence = (
+    ("left", "EQ", "GT", "LT"),
+    ("left", "PLUS", "MINUS"),
+    ("left", "MULT", "DIV"),
+)
+
+
+def p_comparison(p):
+    """comparison : comparison PLUS comparison
+                  | comparison MINUS comparison
+                  | comparison MULT comparison
+                  | comparison DIV comparison
+                  | comparison LT comparison
+                  | comparison EQ comparison
+                  | comparison GT comparison
+                  | PLUS comparison
+                  | MINUS comparison
+                  | power"""
+    if len(p) == 4:
+        p[0] = binary_ops[p[2]]((p[1], p[3]))
+    elif len(p) == 3:
+        p[0] = unary_ops[p[1]](p[2])
+    else:
+        p[0] = p[1]
+
+# power: atom trailer* ['**' factor]
+# trailers enables function calls.  I only allow one level of calls
+# so this is 'trailer'
+
+
+def p_power(p):
+    """power : atom
+             | atom trailer"""
+    if len(p) == 2:
+        p[0] = p[1]
+    else:
+        if p[2][0] == "CALL":
+            p[0] = ast.CallFunc(p[1], p[2][1], None, None)
+        else:
+            raise AssertionError("not implemented")
+
+
+def p_atom_name(p):
+    """atom : NAME"""
+    p[0] = ast.Name(p[1])
+
+
+def p_atom_number(p):
+    """atom : NUMBER
+            | STRING"""
+    p[0] = ast.Const(p[1])
+
+
+def p_atom_tuple(p):
+    """atom : LPAR testlist RPAR"""
+    p[0] = p[2]
+
+# trailer: '(' [arglist] ')' | '[' subscriptlist ']' | '.' NAME
+
+
+def p_trailer(p):
+    "trailer : LPAR arglist RPAR"
+    p[0] = ("CALL", p[2])
+
+# testlist: test (',' test)* [',']
+# Contains shift/reduce error
+
+
+def p_testlist(p):
+    """testlist : testlist_multi COMMA
+                | testlist_multi """
+    if len(p) == 2:
+        p[0] = p[1]
+    else:
+        # May need to promote singleton to tuple
+        if isinstance(p[1], list):
+            p[0] = p[1]
+        else:
+            p[0] = [p[1]]
+    # Convert into a tuple?
+    if isinstance(p[0], list):
+        p[0] = ast.Tuple(p[0])
+
+
+def p_testlist_multi(p):
+    """testlist_multi : testlist_multi COMMA test
+                      | test"""
+    if len(p) == 2:
+        # singleton
+        p[0] = p[1]
+    else:
+        if isinstance(p[1], list):
+            p[0] = p[1] + [p[3]]
+        else:
+            # singleton -> tuple
+            p[0] = [p[1], p[3]]
+
+
+# test: or_test ['if' or_test 'else' test] | lambdef
+#  as I don't support 'and', 'or', and 'not' this works down to 'comparison'
+def p_test(p):
+    "test : comparison"
+    p[0] = p[1]
+
+
+# arglist: (argument ',')* (argument [',']| '*' test [',' '**' test] | '**' test)
+# XXX INCOMPLETE: this doesn't allow the trailing comma
+def p_arglist(p):
+    """arglist : arglist COMMA argument
+               | argument"""
+    if len(p) == 4:
+        p[0] = p[1] + [p[3]]
+    else:
+        p[0] = [p[1]]
+
+# argument: test [gen_for] | test '=' test  # Really [keyword '='] test
+
+
+def p_argument(p):
+    "argument : test"
+    p[0] = p[1]
+
+
+def p_error(p):
+    # print "Error!", repr(p)
+    raise SyntaxError(p)
+
+
+class GardenSnakeParser(object):
+
+    def __init__(self, lexer=None):
+        if lexer is None:
+            lexer = IndentLexer()
+        self.lexer = lexer
+        self.parser = yacc.yacc(start="file_input_end")
+
+    def parse(self, code):
+        self.lexer.input(code)
+        result = self.parser.parse(lexer=self.lexer)
+        return ast.Module(None, result)
+
+
+###### Code generation ######
+
+from compiler import misc, syntax, pycodegen
+
+
+class GardenSnakeCompiler(object):
+
+    def __init__(self):
+        self.parser = GardenSnakeParser()
+
+    def compile(self, code, filename="<string>"):
+        tree = self.parser.parse(code)
+        # print  tree
+        misc.set_filename(filename, tree)
+        syntax.check(tree)
+        gen = pycodegen.ModuleCodeGenerator(tree)
+        code = gen.getCode()
+        return code
+
+####### Test code #######
+
+compile = GardenSnakeCompiler().compile
+
+code = r"""
+
+print('LET\'S TRY THIS \\OUT')
+  
+#Comment here
+def x(a):
+    print('called with',a)
+    if a == 1:
+        return 2
+    if a*2 > 10: return 999 / 4
+        # Another comment here
+
+    return a+2*3
+
+ints = (1, 2,
+   3, 4,
+5)
+print('mutiline-expression', ints)
+
+t = 4+1/3*2+6*(9-5+1)
+print('predence test; should be 34+2/3:', t, t==(34+2/3))
+
+print('numbers', 1,2,3,4,5)
+if 1:
+ 8
+ a=9
+ print(x(a))
+
+print(x(1))
+print(x(2))
+print(x(8),'3')
+print('this is decimal', 1/5)
+print('BIG DECIMAL', 1.234567891234567e12345)
+
+"""
+
+# Set up the GardenSnake run-time environment
+
+
+def print_(*args):
+    print "-->", " ".join(map(str, args))
+
+globals()["print"] = print_
+
+compiled_code = compile(code)
+
+exec compiled_code in globals()
+print "Done"
diff --git a/third_party/python/ply/example/GardenSnake/README b/third_party/python/ply/example/GardenSnake/README
new file mode 100644
index 0000000000..4d8be2db05
--- /dev/null
+++ b/third_party/python/ply/example/GardenSnake/README
@@ -0,0 +1,5 @@
+This example is Andrew Dalke's GardenSnake language. It shows how to process an
+indentation-like language like Python.   Further details can be found here:
+
+http://dalkescientific.com/writings/diary/archive/2006/08/30/gardensnake_language.html
+
diff --git a/third_party/python/ply/example/README b/third_party/python/ply/example/README
new file mode 100644
index 0000000000..63519b557f
--- /dev/null
+++ b/third_party/python/ply/example/README
@@ -0,0 +1,10 @@
+Simple examples:
+   calc       - Simple calculator
+   classcalc  - Simple calculate defined as a class
+   
+Complex examples
+   ansic       - ANSI C grammar from K&R
+   BASIC       - A small BASIC interpreter
+   GardenSnake - A simple python-like language
+   yply        - Converts Unix yacc files to PLY programs.
+
diff --git a/third_party/python/ply/example/ansic/README b/third_party/python/ply/example/ansic/README
new file mode 100644
index 0000000000..e049d3b4e4
--- /dev/null
+++ b/third_party/python/ply/example/ansic/README
@@ -0,0 +1,2 @@
+This example is incomplete.  Was going to specify an ANSI C parser.
+This is part of it.
diff --git a/third_party/python/ply/example/ansic/clex.py b/third_party/python/ply/example/ansic/clex.py
new file mode 100644
index 0000000000..4bde1d730b
--- /dev/null
+++ b/third_party/python/ply/example/ansic/clex.py
@@ -0,0 +1,168 @@
+# ----------------------------------------------------------------------
+# clex.py
+#
+# A lexer for ANSI C.
+# ----------------------------------------------------------------------
+
+import sys
+sys.path.insert(0, "../..")
+
+import ply.lex as lex
+
+# Reserved words
+reserved = (
+    'AUTO', 'BREAK', 'CASE', 'CHAR', 'CONST', 'CONTINUE', 'DEFAULT', 'DO', 'DOUBLE',
+    'ELSE', 'ENUM', 'EXTERN', 'FLOAT', 'FOR', 'GOTO', 'IF', 'INT', 'LONG', 'REGISTER',
+    'RETURN', 'SHORT', 'SIGNED', 'SIZEOF', 'STATIC', 'STRUCT', 'SWITCH', 'TYPEDEF',
+    'UNION', 'UNSIGNED', 'VOID', 'VOLATILE', 'WHILE',
+)
+
+tokens = reserved + (
+    # Literals (identifier, integer constant, float constant, string constant,
+    # char const)
+    'ID', 'TYPEID', 'ICONST', 'FCONST', 'SCONST', 'CCONST',
+
+    # Operators (+,-,*,/,%,|,&,~,^,<<,>>, ||, &&, !, <, <=, >, >=, ==, !=)
+    'PLUS', 'MINUS', 'TIMES', 'DIVIDE', 'MOD',
+    'OR', 'AND', 'NOT', 'XOR', 'LSHIFT', 'RSHIFT',
+    'LOR', 'LAND', 'LNOT',
+    'LT', 'LE', 'GT', 'GE', 'EQ', 'NE',
+
+    # Assignment (=, *=, /=, %=, +=, -=, <<=, >>=, &=, ^=, |=)
+    'EQUALS', 'TIMESEQUAL', 'DIVEQUAL', 'MODEQUAL', 'PLUSEQUAL', 'MINUSEQUAL',
+    'LSHIFTEQUAL', 'RSHIFTEQUAL', 'ANDEQUAL', 'XOREQUAL', 'OREQUAL',
+
+    # Increment/decrement (++,--)
+    'PLUSPLUS', 'MINUSMINUS',
+
+    # Structure dereference (->)
+    'ARROW',
+
+    # Conditional operator (?)
+    'CONDOP',
+
+    # Delimeters ( ) [ ] { } , . ; :
+    'LPAREN', 'RPAREN',
+    'LBRACKET', 'RBRACKET',
+    'LBRACE', 'RBRACE',
+    'COMMA', 'PERIOD', 'SEMI', 'COLON',
+
+    # Ellipsis (...)
+    'ELLIPSIS',
+)
+
+# Completely ignored characters
+t_ignore = ' \t\x0c'
+
+# Newlines
+
+
+def t_NEWLINE(t):
+    r'\n+'
+    t.lexer.lineno += t.value.count("\n")
+
+# Operators
+t_PLUS = r'\+'
+t_MINUS = r'-'
+t_TIMES = r'\*'
+t_DIVIDE = r'/'
+t_MOD = r'%'
+t_OR = r'\|'
+t_AND = r'&'
+t_NOT = r'~'
+t_XOR = r'\^'
+t_LSHIFT = r'<<'
+t_RSHIFT = r'>>'
+t_LOR = r'\|\|'
+t_LAND = r'&&'
+t_LNOT = r'!'
+t_LT = r'<'
+t_GT = r'>'
+t_LE = r'<='
+t_GE = r'>='
+t_EQ = r'=='
+t_NE = r'!='
+
+# Assignment operators
+
+t_EQUALS = r'='
+t_TIMESEQUAL = r'\*='
+t_DIVEQUAL = r'/='
+t_MODEQUAL = r'%='
+t_PLUSEQUAL = r'\+='
+t_MINUSEQUAL = r'-='
+t_LSHIFTEQUAL = r'<<='
+t_RSHIFTEQUAL = r'>>='
+t_ANDEQUAL = r'&='
+t_OREQUAL = r'\|='
+t_XOREQUAL = r'\^='
+
+# Increment/decrement
+t_PLUSPLUS = r'\+\+'
+t_MINUSMINUS = r'--'
+
+# ->
+t_ARROW = r'->'
+
+# ?
+t_CONDOP = r'\?'
+
+# Delimeters
+t_LPAREN = r'\('
+t_RPAREN = r'\)'
+t_LBRACKET = r'\['
+t_RBRACKET = r'\]'
+t_LBRACE = r'\{'
+t_RBRACE = r'\}'
+t_COMMA = r','
+t_PERIOD = r'\.'
+t_SEMI = r';'
+t_COLON = r':'
+t_ELLIPSIS = r'\.\.\.'
+
+# Identifiers and reserved words
+
+reserved_map = {}
+for r in reserved:
+    reserved_map[r.lower()] = r
+
+
+def t_ID(t):
+    r'[A-Za-z_][\w_]*'
+    t.type = reserved_map.get(t.value, "ID")
+    return t
+
+# Integer literal
+t_ICONST = r'\d+([uU]|[lL]|[uU][lL]|[lL][uU])?'
+
+# Floating literal
+t_FCONST = r'((\d+)(\.\d+)(e(\+|-)?(\d+))? | (\d+)e(\+|-)?(\d+))([lL]|[fF])?'
+
+# String literal
+t_SCONST = r'\"([^\\\n]|(\\.))*?\"'
+
+# Character constant 'c' or L'c'
+t_CCONST = r'(L)?\'([^\\\n]|(\\.))*?\''
+
+# Comments
+
+
+def t_comment(t):
+    r'/\*(.|\n)*?\*/'
+    t.lexer.lineno += t.value.count('\n')
+
+# Preprocessor directive (ignored)
+
+
+def t_preprocessor(t):
+    r'\#(.)*?\n'
+    t.lexer.lineno += 1
+
+
+def t_error(t):
+    print("Illegal character %s" % repr(t.value[0]))
+    t.lexer.skip(1)
+
+lexer = lex.lex()
+if __name__ == "__main__":
+    lex.runmain(lexer)
diff --git a/third_party/python/ply/example/ansic/cparse.py b/third_party/python/ply/example/ansic/cparse.py
new file mode 100644
index 0000000000..5fe9bce042
--- /dev/null
+++ b/third_party/python/ply/example/ansic/cparse.py
@@ -0,0 +1,1048 @@
+# -----------------------------------------------------------------------------
+# cparse.py
+#
+# Simple parser for ANSI C.  Based on the grammar in K&R, 2nd Ed.
+# -----------------------------------------------------------------------------
+
+import sys
+import clex
+import ply.yacc as yacc
+
+# Get the token map
+tokens = clex.tokens
+
+# translation-unit:
+
+
+def p_translation_unit_1(t):
+    'translation_unit : external_declaration'
+    pass
+
+
+def p_translation_unit_2(t):
+    'translation_unit : translation_unit external_declaration'
+    pass
+
+# external-declaration:
+
+
+def p_external_declaration_1(t):
+    'external_declaration : function_definition'
+    pass
+
+
+def p_external_declaration_2(t):
+    'external_declaration : declaration'
+    pass
+
+# function-definition:
+
+
+def p_function_definition_1(t):
+    'function_definition : declaration_specifiers declarator declaration_list compound_statement'
+    pass
+
+
+def p_function_definition_2(t):
+    'function_definition : declarator declaration_list compound_statement'
+    pass
+
+
+def p_function_definition_3(t):
+    'function_definition : declarator compound_statement'
+    pass
+
+
+def p_function_definition_4(t):
+    'function_definition : declaration_specifiers declarator compound_statement'
+    pass
+
+# declaration:
+
+
+def p_declaration_1(t):
+    'declaration : declaration_specifiers init_declarator_list SEMI'
+    pass
+
+
+def p_declaration_2(t):
+    'declaration : declaration_specifiers SEMI'
+    pass
+
+# declaration-list:
+
+
+def p_declaration_list_1(t):
+    'declaration_list : declaration'
+    pass
+
+
+def p_declaration_list_2(t):
+    'declaration_list : declaration_list declaration '
+    pass
+
+# declaration-specifiers
+
+
+def p_declaration_specifiers_1(t):
+    'declaration_specifiers : storage_class_specifier declaration_specifiers'
+    pass
+
+
+def p_declaration_specifiers_2(t):
+    'declaration_specifiers : type_specifier declaration_specifiers'
+    pass
+
+
+def p_declaration_specifiers_3(t):
+    'declaration_specifiers : type_qualifier declaration_specifiers'
+    pass
+
+
+def p_declaration_specifiers_4(t):
+    'declaration_specifiers : storage_class_specifier'
+    pass
+
+
+def p_declaration_specifiers_5(t):
+    'declaration_specifiers : type_specifier'
+    pass
+
+
+def p_declaration_specifiers_6(t):
+    'declaration_specifiers : type_qualifier'
+    pass
+
+# storage-class-specifier
+
+
+def p_storage_class_specifier(t):
+    '''storage_class_specifier : AUTO
+                               | REGISTER
+                               | STATIC
+                               | EXTERN
+                               | TYPEDEF
+                               '''
+    pass
+
+# type-specifier:
+
+
+def p_type_specifier(t):
+    '''type_specifier : VOID
+                      | CHAR
+                      | SHORT
+                      | INT
+                      | LONG
+                      | FLOAT
+                      | DOUBLE
+                      | SIGNED
+                      | UNSIGNED
+                      | struct_or_union_specifier
+                      | enum_specifier
+                      | TYPEID
+                      '''
+    pass
+
+# type-qualifier:
+
+
+def p_type_qualifier(t):
+    '''type_qualifier : CONST
+                      | VOLATILE'''
+    pass
+
+# struct-or-union-specifier
+
+
+def p_struct_or_union_specifier_1(t):
+    'struct_or_union_specifier : struct_or_union ID LBRACE struct_declaration_list RBRACE'
+    pass
+
+
+def p_struct_or_union_specifier_2(t):
+    'struct_or_union_specifier : struct_or_union LBRACE struct_declaration_list RBRACE'
+    pass
+
+
+def p_struct_or_union_specifier_3(t):
+    'struct_or_union_specifier : struct_or_union ID'
+    pass
+
+# struct-or-union:
+
+
+def p_struct_or_union(t):
+    '''struct_or_union : STRUCT
+                       | UNION
+                       '''
+    pass
+
+# struct-declaration-list:
+
+
+def p_struct_declaration_list_1(t):
+    'struct_declaration_list : struct_declaration'
+    pass
+
+
+def p_struct_declaration_list_2(t):
+    'struct_declaration_list : struct_declaration_list struct_declaration'
+    pass
+
+# init-declarator-list:
+
+
+def p_init_declarator_list_1(t):
+    'init_declarator_list : init_declarator'
+    pass
+
+
+def p_init_declarator_list_2(t):
+    'init_declarator_list : init_declarator_list COMMA init_declarator'
+    pass
+
+# init-declarator
+
+
+def p_init_declarator_1(t):
+    'init_declarator : declarator'
+    pass
+
+
+def p_init_declarator_2(t):
+    'init_declarator : declarator EQUALS initializer'
+    pass
+
+# struct-declaration:
+
+
+def p_struct_declaration(t):
+    'struct_declaration : specifier_qualifier_list struct_declarator_list SEMI'
+    pass
+
+# specifier-qualifier-list:
+
+
+def p_specifier_qualifier_list_1(t):
+    'specifier_qualifier_list : type_specifier specifier_qualifier_list'
+    pass
+
+
+def p_specifier_qualifier_list_2(t):
+    'specifier_qualifier_list : type_specifier'
+    pass
+
+
+def p_specifier_qualifier_list_3(t):
+    'specifier_qualifier_list : type_qualifier specifier_qualifier_list'
+    pass
+
+
+def p_specifier_qualifier_list_4(t):
+    'specifier_qualifier_list : type_qualifier'
+    pass
+
+# struct-declarator-list:
+
+
+def p_struct_declarator_list_1(t):
+    'struct_declarator_list : struct_declarator'
+    pass
+
+
+def p_struct_declarator_list_2(t):
+    'struct_declarator_list : struct_declarator_list COMMA struct_declarator'
+    pass
+
+# struct-declarator:
+
+
+def p_struct_declarator_1(t):
+    'struct_declarator : declarator'
+    pass
+
+
+def p_struct_declarator_2(t):
+    'struct_declarator : declarator COLON constant_expression'
+    pass
+
+
+def p_struct_declarator_3(t):
+    'struct_declarator : COLON constant_expression'
+    pass
+
+# enum-specifier:
+
+
+def p_enum_specifier_1(t):
+    'enum_specifier : ENUM ID LBRACE enumerator_list RBRACE'
+    pass
+
+
+def p_enum_specifier_2(t):
+    'enum_specifier : ENUM LBRACE enumerator_list RBRACE'
+    pass
+
+
+def p_enum_specifier_3(t):
+    'enum_specifier : ENUM ID'
+    pass
+
+# enumerator_list:
+
+
+def p_enumerator_list_1(t):
+    'enumerator_list : enumerator'
+    pass
+
+
+def p_enumerator_list_2(t):
+    'enumerator_list : enumerator_list COMMA enumerator'
+    pass
+
+# enumerator:
+
+
+def p_enumerator_1(t):
+    'enumerator : ID'
+    pass
+
+
+def p_enumerator_2(t):
+    'enumerator : ID EQUALS constant_expression'
+    pass
+
+# declarator:
+
+
+def p_declarator_1(t):
+    'declarator : pointer direct_declarator'
+    pass
+
+
+def p_declarator_2(t):
+    'declarator : direct_declarator'
+    pass
+
+# direct-declarator:
+
+
+def p_direct_declarator_1(t):
+    'direct_declarator : ID'
+    pass
+
+
+def p_direct_declarator_2(t):
+    'direct_declarator : LPAREN declarator RPAREN'
+    pass
+
+
+def p_direct_declarator_3(t):
+    'direct_declarator : direct_declarator LBRACKET constant_expression_opt RBRACKET'
+    pass
+
+
+def p_direct_declarator_4(t):
+    'direct_declarator : direct_declarator LPAREN parameter_type_list RPAREN '
+    pass
+
+
+def p_direct_declarator_5(t):
+    'direct_declarator : direct_declarator LPAREN identifier_list RPAREN '
+    pass
+
+
+def p_direct_declarator_6(t):
+    'direct_declarator : direct_declarator LPAREN RPAREN '
+    pass
+
+# pointer:
+
+
+def p_pointer_1(t):
+    'pointer : TIMES type_qualifier_list'
+    pass
+
+
+def p_pointer_2(t):
+    'pointer : TIMES'
+    pass
+
+
+def p_pointer_3(t):
+    'pointer : TIMES type_qualifier_list pointer'
+    pass
+
+
+def p_pointer_4(t):
+    'pointer : TIMES pointer'
+    pass
+
+# type-qualifier-list:
+
+
+def p_type_qualifier_list_1(t):
+    'type_qualifier_list : type_qualifier'
+    pass
+
+
+def p_type_qualifier_list_2(t):
+    'type_qualifier_list : type_qualifier_list type_qualifier'
+    pass
+
+# parameter-type-list:
+
+
+def p_parameter_type_list_1(t):
+    'parameter_type_list : parameter_list'
+    pass
+
+
+def p_parameter_type_list_2(t):
+    'parameter_type_list : parameter_list COMMA ELLIPSIS'
+    pass
+
+# parameter-list:
+
+
+def p_parameter_list_1(t):
+    'parameter_list : parameter_declaration'
+    pass
+
+
+def p_parameter_list_2(t):
+    'parameter_list : parameter_list COMMA parameter_declaration'
+    pass
+
+# parameter-declaration:
+
+
+def p_parameter_declaration_1(t):
+    'parameter_declaration : declaration_specifiers declarator'
+    pass
+
+
+def p_parameter_declaration_2(t):
+    'parameter_declaration : declaration_specifiers abstract_declarator_opt'
+    pass
+
+# identifier-list:
+
+
+def p_identifier_list_1(t):
+    'identifier_list : ID'
+    pass
+
+
+def p_identifier_list_2(t):
+    'identifier_list : identifier_list COMMA ID'
+    pass
+
+# initializer:
+
+
+def p_initializer_1(t):
+    'initializer : assignment_expression'
+    pass
+
+
+def p_initializer_2(t):
+    '''initializer : LBRACE initializer_list RBRACE
+                   | LBRACE initializer_list COMMA RBRACE'''
+    pass
+
+# initializer-list:
+
+
+def p_initializer_list_1(t):
+    'initializer_list : initializer'
+    pass
+
+
+def p_initializer_list_2(t):
+    'initializer_list : initializer_list COMMA initializer'
+    pass
+
+# type-name:
+
+
+def p_type_name(t):
+    'type_name : specifier_qualifier_list abstract_declarator_opt'
+    pass
+
+
+def p_abstract_declarator_opt_1(t):
+    'abstract_declarator_opt : empty'
+    pass
+
+
+def p_abstract_declarator_opt_2(t):
+    'abstract_declarator_opt : abstract_declarator'
+    pass
+
+# abstract-declarator:
+
+
+def p_abstract_declarator_1(t):
+    'abstract_declarator : pointer '
+    pass
+
+
+def p_abstract_declarator_2(t):
+    'abstract_declarator : pointer direct_abstract_declarator'
+    pass
+
+
+def p_abstract_declarator_3(t):
+    'abstract_declarator : direct_abstract_declarator'
+    pass
+
+# direct-abstract-declarator:
+
+
+def p_direct_abstract_declarator_1(t):
+    'direct_abstract_declarator : LPAREN abstract_declarator RPAREN'
+    pass
+
+
+def p_direct_abstract_declarator_2(t):
+    'direct_abstract_declarator : direct_abstract_declarator LBRACKET constant_expression_opt RBRACKET'
+    pass
+
+
+def p_direct_abstract_declarator_3(t):
+    'direct_abstract_declarator : LBRACKET constant_expression_opt RBRACKET'
+    pass
+
+
+def p_direct_abstract_declarator_4(t):
+    'direct_abstract_declarator : direct_abstract_declarator LPAREN parameter_type_list_opt RPAREN'
+    pass
+
+
+def p_direct_abstract_declarator_5(t):
+    'direct_abstract_declarator : LPAREN parameter_type_list_opt RPAREN'
+    pass
+
+# Optional fields in abstract declarators
+
+
+def p_constant_expression_opt_1(t):
+    'constant_expression_opt : empty'
+    pass
+
+
+def p_constant_expression_opt_2(t):
+    'constant_expression_opt : constant_expression'
+    pass
+
+
+def p_parameter_type_list_opt_1(t):
+    'parameter_type_list_opt : empty'
+    pass
+
+
+def p_parameter_type_list_opt_2(t):
+    'parameter_type_list_opt : parameter_type_list'
+    pass
+
+# statement:
+
+
+def p_statement(t):
+    '''
+    statement : labeled_statement
+              | expression_statement
+              | compound_statement
+              | selection_statement
+              | iteration_statement
+              | jump_statement
+              '''
+    pass
+
+# labeled-statement:
+
+
+def p_labeled_statement_1(t):
+    'labeled_statement : ID COLON statement'
+    pass
+
+
+def p_labeled_statement_2(t):
+    'labeled_statement : CASE constant_expression COLON statement'
+    pass
+
+
+def p_labeled_statement_3(t):
+    'labeled_statement : DEFAULT COLON statement'
+    pass
+
+# expression-statement:
+
+
+def p_expression_statement(t):
+    'expression_statement : expression_opt SEMI'
+    pass
+
+# compound-statement:
+
+
+def p_compound_statement_1(t):
+    'compound_statement : LBRACE declaration_list statement_list RBRACE'
+    pass
+
+
+def p_compound_statement_2(t):
+    'compound_statement : LBRACE statement_list RBRACE'
+    pass
+
+
+def p_compound_statement_3(t):
+    'compound_statement : LBRACE declaration_list RBRACE'
+    pass
+
+
+def p_compound_statement_4(t):
+    'compound_statement : LBRACE RBRACE'
+    pass
+
+# statement-list:
+
+
+def p_statement_list_1(t):
+    'statement_list : statement'
+    pass
+
+
+def p_statement_list_2(t):
+    'statement_list : statement_list statement'
+    pass
+
+# selection-statement
+
+
+def p_selection_statement_1(t):
+    'selection_statement : IF LPAREN expression RPAREN statement'
+    pass
+
+
+def p_selection_statement_2(t):
+    'selection_statement : IF LPAREN expression RPAREN statement ELSE statement '
+    pass
+
+
+def p_selection_statement_3(t):
+    'selection_statement : SWITCH LPAREN expression RPAREN statement '
+    pass
+
+# iteration_statement:
+
+
+def p_iteration_statement_1(t):
+    'iteration_statement : WHILE LPAREN expression RPAREN statement'
+    pass
+
+
+def p_iteration_statement_2(t):
+    'iteration_statement : FOR LPAREN expression_opt SEMI expression_opt SEMI expression_opt RPAREN statement '
+    pass
+
+
+def p_iteration_statement_3(t):
+    'iteration_statement : DO statement WHILE LPAREN expression RPAREN SEMI'
+    pass
+
+# jump_statement:
+
+
+def p_jump_statement_1(t):
+    'jump_statement : GOTO ID SEMI'
+    pass
+
+
+def p_jump_statement_2(t):
+    'jump_statement : CONTINUE SEMI'
+    pass
+
+
+def p_jump_statement_3(t):
+    'jump_statement : BREAK SEMI'
+    pass
+
+
+def p_jump_statement_4(t):
+    'jump_statement : RETURN expression_opt SEMI'
+    pass
+
+
+def p_expression_opt_1(t):
+    'expression_opt : empty'
+    pass
+
+
+def p_expression_opt_2(t):
+    'expression_opt : expression'
+    pass
+
+# expression:
+
+
+def p_expression_1(t):
+    'expression : assignment_expression'
+    pass
+
+
+def p_expression_2(t):
+    'expression : expression COMMA assignment_expression'
+    pass
+
+# assigment_expression:
+
+
+def p_assignment_expression_1(t):
+    'assignment_expression : conditional_expression'
+    pass
+
+
+def p_assignment_expression_2(t):
+    'assignment_expression : unary_expression assignment_operator assignment_expression'
+    pass
+
+# assignment_operator:
+
+
+def p_assignment_operator(t):
+    '''
+    assignment_operator : EQUALS
+                        | TIMESEQUAL
+                        | DIVEQUAL
+                        | MODEQUAL
+                        | PLUSEQUAL
+                        | MINUSEQUAL
+                        | LSHIFTEQUAL
+                        | RSHIFTEQUAL
+                        | ANDEQUAL
+                        | OREQUAL
+                        | XOREQUAL
+                        '''
+    pass
+
+# conditional-expression
+
+
+def p_conditional_expression_1(t):
+    'conditional_expression : logical_or_expression'
+    pass
+
+
+def p_conditional_expression_2(t):
+    'conditional_expression : logical_or_expression CONDOP expression COLON conditional_expression '
+    pass
+
+# constant-expression
+
+
+def p_constant_expression(t):
+    'constant_expression : conditional_expression'
+    pass
+
+# logical-or-expression
+
+
+def p_logical_or_expression_1(t):
+    'logical_or_expression : logical_and_expression'
+    pass
+
+
+def p_logical_or_expression_2(t):
+    'logical_or_expression : logical_or_expression LOR logical_and_expression'
+    pass
+
+# logical-and-expression
+
+
+def p_logical_and_expression_1(t):
+    'logical_and_expression : inclusive_or_expression'
+    pass
+
+
+def p_logical_and_expression_2(t):
+    'logical_and_expression : logical_and_expression LAND inclusive_or_expression'
+    pass
+
+# inclusive-or-expression:
+
+
+def p_inclusive_or_expression_1(t):
+    'inclusive_or_expression : exclusive_or_expression'
+    pass
+
+
+def p_inclusive_or_expression_2(t):
+    'inclusive_or_expression : inclusive_or_expression OR exclusive_or_expression'
+    pass
+
+# exclusive-or-expression:
+
+
+def p_exclusive_or_expression_1(t):
+    'exclusive_or_expression :  and_expression'
+    pass
+
+
+def p_exclusive_or_expression_2(t):
+    'exclusive_or_expression :  exclusive_or_expression XOR and_expression'
+    pass
+
+# AND-expression
+
+
+def p_and_expression_1(t):
+    'and_expression : equality_expression'
+    pass
+
+
+def p_and_expression_2(t):
+    'and_expression : and_expression AND equality_expression'
+    pass
+
+
+# equality-expression:
+def p_equality_expression_1(t):
+    'equality_expression : relational_expression'
+    pass
+
+
+def p_equality_expression_2(t):
+    'equality_expression : equality_expression EQ relational_expression'
+    pass
+
+
+def p_equality_expression_3(t):
+    'equality_expression : equality_expression NE relational_expression'
+    pass
+
+
+# relational-expression:
+def p_relational_expression_1(t):
+    'relational_expression : shift_expression'
+    pass
+
+
+def p_relational_expression_2(t):
+    'relational_expression : relational_expression LT shift_expression'
+    pass
+
+
+def p_relational_expression_3(t):
+    'relational_expression : relational_expression GT shift_expression'
+    pass
+
+
+def p_relational_expression_4(t):
+    'relational_expression : relational_expression LE shift_expression'
+    pass
+
+
+def p_relational_expression_5(t):
+    'relational_expression : relational_expression GE shift_expression'
+    pass
+
+# shift-expression
+
+
+def p_shift_expression_1(t):
+    'shift_expression : additive_expression'
+    pass
+
+
+def p_shift_expression_2(t):
+    'shift_expression : shift_expression LSHIFT additive_expression'
+    pass
+
+
+def p_shift_expression_3(t):
+    'shift_expression : shift_expression RSHIFT additive_expression'
+    pass
+
+# additive-expression
+
+
+def p_additive_expression_1(t):
+    'additive_expression : multiplicative_expression'
+    pass
+
+
+def p_additive_expression_2(t):
+    'additive_expression : additive_expression PLUS multiplicative_expression'
+    pass
+
+
+def p_additive_expression_3(t):
+    'additive_expression : additive_expression MINUS multiplicative_expression'
+    pass
+
+# multiplicative-expression
+
+
+def p_multiplicative_expression_1(t):
+    'multiplicative_expression : cast_expression'
+    pass
+
+
+def p_multiplicative_expression_2(t):
+    'multiplicative_expression : multiplicative_expression TIMES cast_expression'
+    pass
+
+
+def p_multiplicative_expression_3(t):
+    'multiplicative_expression : multiplicative_expression DIVIDE cast_expression'
+    pass
+
+
+def p_multiplicative_expression_4(t):
+    'multiplicative_expression : multiplicative_expression MOD cast_expression'
+    pass
+
+# cast-expression:
+
+
+def p_cast_expression_1(t):
+    'cast_expression : unary_expression'
+    pass
+
+
+def p_cast_expression_2(t):
+    'cast_expression : LPAREN type_name RPAREN cast_expression'
+    pass
+
+# unary-expression:
+
+
+def p_unary_expression_1(t):
+    'unary_expression : postfix_expression'
+    pass
+
+
+def p_unary_expression_2(t):
+    'unary_expression : PLUSPLUS unary_expression'
+    pass
+
+
+def p_unary_expression_3(t):
+    'unary_expression : MINUSMINUS unary_expression'
+    pass
+
+
+def p_unary_expression_4(t):
+    'unary_expression : unary_operator cast_expression'
+    pass
+
+
+def p_unary_expression_5(t):
+    'unary_expression : SIZEOF unary_expression'
+    pass
+
+
+def p_unary_expression_6(t):
+    'unary_expression : SIZEOF LPAREN type_name RPAREN'
+    pass
+
+# unary-operator
+
+
+def p_unary_operator(t):
+    '''unary_operator : AND
+                    | TIMES
+                    | PLUS 
+                    | MINUS
+                    | NOT
+                    | LNOT '''
+    pass
+
+# postfix-expression:
+
+
+def p_postfix_expression_1(t):
+    'postfix_expression : primary_expression'
+    pass
+
+
+def p_postfix_expression_2(t):
+    'postfix_expression : postfix_expression LBRACKET expression RBRACKET'
+    pass
+
+
+def p_postfix_expression_3(t):
+    'postfix_expression : postfix_expression LPAREN argument_expression_list RPAREN'
+    pass
+
+
+def p_postfix_expression_4(t):
+    'postfix_expression : postfix_expression LPAREN RPAREN'
+    pass
+
+
+def p_postfix_expression_5(t):
+    'postfix_expression : postfix_expression PERIOD ID'
+    pass
+
+
+def p_postfix_expression_6(t):
+    'postfix_expression : postfix_expression ARROW ID'
+    pass
+
+
+def p_postfix_expression_7(t):
+    'postfix_expression : postfix_expression PLUSPLUS'
+    pass
+
+
+def p_postfix_expression_8(t):
+    'postfix_expression : postfix_expression MINUSMINUS'
+    pass
+
+# primary-expression:
+
+
+def p_primary_expression(t):
+    '''primary_expression :  ID
+                        |  constant
+                        |  SCONST
+                        |  LPAREN expression RPAREN'''
+    pass
+
+# argument-expression-list:
+
+
+def p_argument_expression_list(t):
+    '''argument_expression_list :  assignment_expression
+                              |  argument_expression_list COMMA assignment_expression'''
+    pass
+
+# constant:
+
+
+def p_constant(t):
+    '''constant : ICONST
+               | FCONST
+               | CCONST'''
+    pass
+
+
+def p_empty(t):
+    'empty : '
+    pass
+
+
+def p_error(t):
+    print("Whoa. We're hosed")
+
+import profile
+# Build the grammar
+
+yacc.yacc()
+#yacc.yacc(method='LALR',write_tables=False,debug=False)
+
+#profile.run("yacc.yacc(method='LALR')")
diff --git a/third_party/python/ply/example/calc/calc.py b/third_party/python/ply/example/calc/calc.py
new file mode 100644
index 0000000000..824c3d7d0a
--- /dev/null
+++ b/third_party/python/ply/example/calc/calc.py
@@ -0,0 +1,123 @@
+# -----------------------------------------------------------------------------
+# calc.py
+#
+# A simple calculator with variables.   This is from O'Reilly's
+# "Lex and Yacc", p. 63.
+# -----------------------------------------------------------------------------
+
+import sys
+sys.path.insert(0, "../..")
+
+if sys.version_info[0] >= 3:
+    raw_input = input
+
+tokens = (
+    'NAME', 'NUMBER',
+)
+
+literals = ['=', '+', '-', '*', '/', '(', ')']
+
+# Tokens
+
+t_NAME = r'[a-zA-Z_][a-zA-Z0-9_]*'
+
+
+def t_NUMBER(t):
+    r'\d+'
+    t.value = int(t.value)
+    return t
+
+t_ignore = " \t"
+
+
+def t_newline(t):
+    r'\n+'
+    t.lexer.lineno += t.value.count("\n")
+
+
+def t_error(t):
+    print("Illegal character '%s'" % t.value[0])
+    t.lexer.skip(1)
+
+# Build the lexer
+import ply.lex as lex
+lex.lex()
+
+# Parsing rules
+
+precedence = (
+    ('left', '+', '-'),
+    ('left', '*', '/'),
+    ('right', 'UMINUS'),
+)
+
+# dictionary of names
+names = {}
+
+
+def p_statement_assign(p):
+    'statement : NAME "=" expression'
+    names[p[1]] = p[3]
+
+
+def p_statement_expr(p):
+    'statement : expression'
+    print(p[1])
+
+
+def p_expression_binop(p):
+    '''expression : expression '+' expression
+                  | expression '-' expression
+                  | expression '*' expression
+                  | expression '/' expression'''
+    if p[2] == '+':
+        p[0] = p[1] + p[3]
+    elif p[2] == '-':
+        p[0] = p[1] - p[3]
+    elif p[2] == '*':
+        p[0] = p[1] * p[3]
+    elif p[2] == '/':
+        p[0] = p[1] / p[3]
+
+
+def p_expression_uminus(p):
+    "expression : '-' expression %prec UMINUS"
+    p[0] = -p[2]
+
+
+def p_expression_group(p):
+    "expression : '(' expression ')'"
+    p[0] = p[2]
+
+
+def p_expression_number(p):
+    "expression : NUMBER"
+    p[0] = p[1]
+
+
+def p_expression_name(p):
+    "expression : NAME"
+    try:
+        p[0] = names[p[1]]
+    except LookupError:
+        print("Undefined name '%s'" % p[1])
+        p[0] = 0
+
+
+def p_error(p):
+    if p:
+        print("Syntax error at '%s'" % p.value)
+    else:
+        print("Syntax error at EOF")
+
+import ply.yacc as yacc
+yacc.yacc()
+
+while 1:
+    try:
+        s = raw_input('calc > ')
+    except EOFError:
+        break
+    if not s:
+        continue
+    yacc.parse(s)
diff --git a/third_party/python/ply/example/calcdebug/calc.py b/third_party/python/ply/example/calcdebug/calc.py
new file mode 100644
index 0000000000..06831e2ca5
--- /dev/null
+++ b/third_party/python/ply/example/calcdebug/calc.py
@@ -0,0 +1,129 @@
+# -----------------------------------------------------------------------------
+# calc.py
+#
+# This example shows how to run the parser in a debugging mode
+# with output routed to a logging object.
+# -----------------------------------------------------------------------------
+
+import sys
+sys.path.insert(0, "../..")
+
+if sys.version_info[0] >= 3:
+    raw_input = input
+
+tokens = (
+    'NAME', 'NUMBER',
+)
+
+literals = ['=', '+', '-', '*', '/', '(', ')']
+
+# Tokens
+
+t_NAME = r'[a-zA-Z_][a-zA-Z0-9_]*'
+
+
+def t_NUMBER(t):
+    r'\d+'
+    t.value = int(t.value)
+    return t
+
+t_ignore = " \t"
+
+
+def t_newline(t):
+    r'\n+'
+    t.lexer.lineno += t.value.count("\n")
+
+
+def t_error(t):
+    print("Illegal character '%s'" % t.value[0])
+    t.lexer.skip(1)
+
+# Build the lexer
+import ply.lex as lex
+lex.lex()
+
+# Parsing rules
+
+precedence = (
+    ('left', '+', '-'),
+    ('left', '*', '/'),
+    ('right', 'UMINUS'),
+)
+
+# dictionary of names
+names = {}
+
+
+def p_statement_assign(p):
+    'statement : NAME "=" expression'
+    names[p[1]] = p[3]
+
+
+def p_statement_expr(p):
+    'statement : expression'
+    print(p[1])
+
+
+def p_expression_binop(p):
+    '''expression : expression '+' expression
+                  | expression '-' expression
+                  | expression '*' expression
+                  | expression '/' expression'''
+    if p[2] == '+':
+        p[0] = p[1] + p[3]
+    elif p[2] == '-':
+        p[0] = p[1] - p[3]
+    elif p[2] == '*':
+        p[0] = p[1] * p[3]
+    elif p[2] == '/':
+        p[0] = p[1] / p[3]
+
+
+def p_expression_uminus(p):
+    "expression : '-' expression %prec UMINUS"
+    p[0] = -p[2]
+
+
+def p_expression_group(p):
+    "expression : '(' expression ')'"
+    p[0] = p[2]
+
+
+def p_expression_number(p):
+    "expression : NUMBER"
+    p[0] = p[1]
+
+
+def p_expression_name(p):
+    "expression : NAME"
+    try:
+        p[0] = names[p[1]]
+    except LookupError:
+        print("Undefined name '%s'" % p[1])
+        p[0] = 0
+
+
+def p_error(p):
+    if p:
+        print("Syntax error at '%s'" % p.value)
+    else:
+        print("Syntax error at EOF")
+
+import ply.yacc as yacc
+yacc.yacc()
+
+import logging
+logging.basicConfig(
+    level=logging.INFO,
+    filename="parselog.txt"
+)
+
+while 1:
+    try:
+        s = raw_input('calc > ')
+    except EOFError:
+        break
+    if not s:
+        continue
+    yacc.parse(s, debug=logging.getLogger())
diff --git a/third_party/python/ply/example/calceof/calc.py b/third_party/python/ply/example/calceof/calc.py
new file mode 100644
index 0000000000..22b39a41a8
--- /dev/null
+++ b/third_party/python/ply/example/calceof/calc.py
@@ -0,0 +1,132 @@
+# -----------------------------------------------------------------------------
+# calc.py
+#
+# A simple calculator with variables.  Asks the user for more input and
+# demonstrates the use of the t_eof() rule.
+# -----------------------------------------------------------------------------
+
+import sys
+sys.path.insert(0, "../..")
+
+if sys.version_info[0] >= 3:
+    raw_input = input
+
+tokens = (
+    'NAME', 'NUMBER',
+)
+
+literals = ['=', '+', '-', '*', '/', '(', ')']
+
+# Tokens
+
+t_NAME = r'[a-zA-Z_][a-zA-Z0-9_]*'
+
+
+def t_NUMBER(t):
+    r'\d+'
+    t.value = int(t.value)
+    return t
+
+t_ignore = " \t"
+
+
+def t_newline(t):
+    r'\n+'
+    t.lexer.lineno += t.value.count("\n")
+
+
+def t_eof(t):
+    more = raw_input('... ')
+    if more:
+        t.lexer.input(more + '\n')
+        return t.lexer.token()
+    else:
+        return None
+
+
+def t_error(t):
+    print("Illegal character '%s'" % t.value[0])
+    t.lexer.skip(1)
+
+# Build the lexer
+import ply.lex as lex
+lex.lex()
+
+# Parsing rules
+
+precedence = (
+    ('left', '+', '-'),
+    ('left', '*', '/'),
+    ('right', 'UMINUS'),
+)
+
+# dictionary of names
+names = {}
+
+
+def p_statement_assign(p):
+    'statement : NAME "=" expression'
+    names[p[1]] = p[3]
+
+
+def p_statement_expr(p):
+    'statement : expression'
+    print(p[1])
+
+
+def p_expression_binop(p):
+    '''expression : expression '+' expression
+                  | expression '-' expression
+                  | expression '*' expression
+                  | expression '/' expression'''
+    if p[2] == '+':
+        p[0] = p[1] + p[3]
+    elif p[2] == '-':
+        p[0] = p[1] - p[3]
+    elif p[2] == '*':
+        p[0] = p[1] * p[3]
+    elif p[2] == '/':
+        p[0] = p[1] / p[3]
+
+
+def p_expression_uminus(p):
+    "expression : '-' expression %prec UMINUS"
+    p[0] = -p[2]
+
+
+def p_expression_group(p):
+    "expression : '(' expression ')'"
+    p[0] = p[2]
+
+
+def p_expression_number(p):
+    "expression : NUMBER"
+    p[0] = p[1]
+
+
+def p_expression_name(p):
+    "expression : NAME"
+    try:
+        p[0] = names[p[1]]
+    except LookupError:
+        print("Undefined name '%s'" % p[1])
+        p[0] = 0
+
+
+def p_error(p):
+    if p:
+        print("Syntax error at '%s'" % p.value)
+    else:
+        print("Syntax error at EOF")
+
+import ply.yacc as yacc
+yacc.yacc()
+
+while 1:
+    try:
+        s = raw_input('calc > ')
+    except EOFError:
+        break
+    if not s:
+        continue
+    yacc.parse(s + '\n')
diff --git a/third_party/python/ply/example/classcalc/calc.py b/third_party/python/ply/example/classcalc/calc.py
new file mode 100755
index 0000000000..ada4afd426
--- /dev/null
+++ b/third_party/python/ply/example/classcalc/calc.py
@@ -0,0 +1,165 @@
+#!/usr/bin/env python
+
+# -----------------------------------------------------------------------------
+# calc.py
+#
+# A simple calculator with variables.   This is from O'Reilly's
+# "Lex and Yacc", p. 63.
+#
+# Class-based example contributed to PLY by David McNab
+# -----------------------------------------------------------------------------
+
+import sys
+sys.path.insert(0, "../..")
+
+if sys.version_info[0] >= 3:
+    raw_input = input
+
+import ply.lex as lex
+import ply.yacc as yacc
+import os
+
+
+class Parser:
+    """
+    Base class for a lexer/parser that has the rules defined as methods
+    """
+    tokens = ()
+    precedence = ()
+
+    def __init__(self, **kw):
+        self.debug = kw.get('debug', 0)
+        self.names = {}
+        try:
+            modname = os.path.split(os.path.splitext(__file__)[0])[
+                1] + "_" + self.__class__.__name__
+        except:
+            modname = "parser" + "_" + self.__class__.__name__
+        self.debugfile = modname + ".dbg"
+        self.tabmodule = modname + "_" + "parsetab"
+        # print self.debugfile, self.tabmodule
+
+        # Build the lexer and parser
+        lex.lex(module=self, debug=self.debug)
+        yacc.yacc(module=self,
+                  debug=self.debug,
+                  debugfile=self.debugfile,
+                  tabmodule=self.tabmodule)
+
+    def run(self):
+        while 1:
+            try:
+                s = raw_input('calc > ')
+            except EOFError:
+                break
+            if not s:
+                continue
+            yacc.parse(s)
+
+
+class Calc(Parser):
+
+    tokens = (
+        'NAME', 'NUMBER',
+        'PLUS', 'MINUS', 'EXP', 'TIMES', 'DIVIDE', 'EQUALS',
+        'LPAREN', 'RPAREN',
+    )
+
+    # Tokens
+
+    t_PLUS = r'\+'
+    t_MINUS = r'-'
+    t_EXP = r'\*\*'
+    t_TIMES = r'\*'
+    t_DIVIDE = r'/'
+    t_EQUALS = r'='
+    t_LPAREN = r'\('
+    t_RPAREN = r'\)'
+    t_NAME = r'[a-zA-Z_][a-zA-Z0-9_]*'
+
+    def t_NUMBER(self, t):
+        r'\d+'
+        try:
+            t.value = int(t.value)
+        except ValueError:
+            print("Integer value too large %s" % t.value)
+            t.value = 0
+        # print "parsed number %s" % repr(t.value)
+        return t
+
+    t_ignore = " \t"
+
+    def t_newline(self, t):
+        r'\n+'
+        t.lexer.lineno += t.value.count("\n")
+
+    def t_error(self, t):
+        print("Illegal character '%s'" % t.value[0])
+        t.lexer.skip(1)
+
+    # Parsing rules
+
+    precedence = (
+        ('left', 'PLUS', 'MINUS'),
+        ('left', 'TIMES', 'DIVIDE'),
+        ('left', 'EXP'),
+        ('right', 'UMINUS'),
+    )
+
+    def p_statement_assign(self, p):
+        'statement : NAME EQUALS expression'
+        self.names[p[1]] = p[3]
+
+    def p_statement_expr(self, p):
+        'statement : expression'
+        print(p[1])
+
+    def p_expression_binop(self, p):
+        """
+        expression : expression PLUS expression
+                  | expression MINUS expression
+                  | expression TIMES expression
+                  | expression DIVIDE expression
+                  | expression EXP expression
+        """
+        # print [repr(p[i]) for i in range(0,4)]
+        if p[2] == '+':
+            p[0] = p[1] + p[3]
+        elif p[2] == '-':
+            p[0] = p[1] - p[3]
+        elif p[2] == '*':
+            p[0] = p[1] * p[3]
+        elif p[2] == '/':
+            p[0] = p[1] / p[3]
+        elif p[2] == '**':
+            p[0] = p[1] ** p[3]
+
+    def p_expression_uminus(self, p):
+        'expression : MINUS expression %prec UMINUS'
+        p[0] = -p[2]
+
+    def p_expression_group(self, p):
+        'expression : LPAREN expression RPAREN'
+        p[0] = p[2]
+
+    def p_expression_number(self, p):
+        'expression : NUMBER'
+        p[0] = p[1]
+
+    def p_expression_name(self, p):
+        'expression : NAME'
+        try:
+            p[0] = self.names[p[1]]
+        except LookupError:
+            print("Undefined name '%s'" % p[1])
+            p[0] = 0
+
+    def p_error(self, p):
+        if p:
+            print("Syntax error at '%s'" % p.value)
+        else:
+            print("Syntax error at EOF")
+
+if __name__ == '__main__':
+    calc = Calc()
+    calc.run()
diff --git a/third_party/python/ply/example/cleanup.sh b/third_party/python/ply/example/cleanup.sh
new file mode 100755
index 0000000000..3e115f41c4
--- /dev/null
+++ b/third_party/python/ply/example/cleanup.sh
@@ -0,0 +1,2 @@
+#!/bin/sh
+rm -f */*.pyc */parsetab.py */parser.out */*~ */*.class
diff --git a/third_party/python/ply/example/closurecalc/calc.py b/third_party/python/ply/example/closurecalc/calc.py
new file mode 100644
index 0000000000..6031b05813
--- /dev/null
+++ b/third_party/python/ply/example/closurecalc/calc.py
@@ -0,0 +1,132 @@
+# -----------------------------------------------------------------------------
+# calc.py
+#
+# A calculator parser that makes use of closures. The function make_calculator()
+# returns a function that accepts an input string and returns a result.  All
+# lexing rules, parsing rules, and internal state are held inside the function.
+# -----------------------------------------------------------------------------
+
+import sys
+sys.path.insert(0, "../..")
+
+if sys.version_info[0] >= 3:
+    raw_input = input
+
+# Make a calculator function
+
+
+def make_calculator():
+    import ply.lex as lex
+    import ply.yacc as yacc
+
+    # ------- Internal calculator state
+
+    variables = {}       # Dictionary of stored variables
+
+    # ------- Calculator tokenizing rules
+
+    tokens = (
+        'NAME', 'NUMBER',
+    )
+
+    literals = ['=', '+', '-', '*', '/', '(', ')']
+
+    t_ignore = " \t"
+
+    t_NAME = r'[a-zA-Z_][a-zA-Z0-9_]*'
+
+    def t_NUMBER(t):
+        r'\d+'
+        t.value = int(t.value)
+        return t
+
+    def t_newline(t):
+        r'\n+'
+        t.lexer.lineno += t.value.count("\n")
+
+    def t_error(t):
+        print("Illegal character '%s'" % t.value[0])
+        t.lexer.skip(1)
+
+    # Build the lexer
+    lexer = lex.lex()
+
+    # ------- Calculator parsing rules
+
+    precedence = (
+        ('left', '+', '-'),
+        ('left', '*', '/'),
+        ('right', 'UMINUS'),
+    )
+
+    def p_statement_assign(p):
+        'statement : NAME "=" expression'
+        variables[p[1]] = p[3]
+        p[0] = None
+
+    def p_statement_expr(p):
+        'statement : expression'
+        p[0] = p[1]
+
+    def p_expression_binop(p):
+        '''expression : expression '+' expression
+                      | expression '-' expression
+                      | expression '*' expression
+                      | expression '/' expression'''
+        if p[2] == '+':
+            p[0] = p[1] + p[3]
+        elif p[2] == '-':
+            p[0] = p[1] - p[3]
+        elif p[2] == '*':
+            p[0] = p[1] * p[3]
+        elif p[2] == '/':
+            p[0] = p[1] / p[3]
+
+    def p_expression_uminus(p):
+        "expression : '-' expression %prec UMINUS"
+        p[0] = -p[2]
+
+    def p_expression_group(p):
+        "expression : '(' expression ')'"
+        p[0] = p[2]
+
+    def p_expression_number(p):
+        "expression : NUMBER"
+        p[0] = p[1]
+
+    def p_expression_name(p):
+        "expression : NAME"
+        try:
+            p[0] = variables[p[1]]
+        except LookupError:
+            print("Undefined name '%s'" % p[1])
+            p[0] = 0
+
+    def p_error(p):
+        if p:
+            print("Syntax error at '%s'" % p.value)
+        else:
+            print("Syntax error at EOF")
+
+    # Build the parser
+    parser = yacc.yacc()
+
+    # ------- Input function
+
+    def input(text):
+        result = parser.parse(text, lexer=lexer)
+        return result
+
+    return input
+
+# Make a calculator object and use it
+calc = make_calculator()
+
+while True:
+    try:
+        s = raw_input("calc > ")
+    except EOFError:
+        break
+    r = calc(s)
+    if r:
+        print(r)
diff --git a/third_party/python/ply/example/hedit/hedit.py b/third_party/python/ply/example/hedit/hedit.py
new file mode 100644
index 0000000000..32da745677
--- /dev/null
+++ b/third_party/python/ply/example/hedit/hedit.py
@@ -0,0 +1,48 @@
+# -----------------------------------------------------------------------------
+# hedit.py
+#
+# Paring of Fortran H Edit descriptions (Contributed by Pearu Peterson)
+#
+# These tokens can't be easily tokenized because they are of the following
+# form:
+#
+#   nHc1...cn
+#
+# where n is a positive integer and c1 ... cn are characters.
+#
+# This example shows how to modify the state of the lexer to parse
+# such tokens
+# -----------------------------------------------------------------------------
+
+import sys
+sys.path.insert(0, "../..")
+
+
+tokens = (
+    'H_EDIT_DESCRIPTOR',
+)
+
+# Tokens
+t_ignore = " \t\n"
+
+
+def t_H_EDIT_DESCRIPTOR(t):
+    r"\d+H.*"                     # This grabs all of the remaining text
+    i = t.value.index('H')
+    n = eval(t.value[:i])
+
+    # Adjust the tokenizing position
+    t.lexer.lexpos -= len(t.value) - (i + 1 + n)
+
+    t.value = t.value[i + 1:i + 1 + n]
+    return t
+
+
+def t_error(t):
+    print("Illegal character '%s'" % t.value[0])
+    t.lexer.skip(1)
+
+# Build the lexer
+import ply.lex as lex
+lex.lex()
+lex.runmain()
diff --git a/third_party/python/ply/example/newclasscalc/calc.py b/third_party/python/ply/example/newclasscalc/calc.py
new file mode 100755
index 0000000000..43c9506a8a
--- /dev/null
+++ b/third_party/python/ply/example/newclasscalc/calc.py
@@ -0,0 +1,167 @@
+#!/usr/bin/env python
+
+# -----------------------------------------------------------------------------
+# calc.py
+#
+# A simple calculator with variables.   This is from O'Reilly's
+# "Lex and Yacc", p. 63.
+#
+# Class-based example contributed to PLY by David McNab.
+#
+# Modified to use new-style classes.   Test case.
+# -----------------------------------------------------------------------------
+
+import sys
+sys.path.insert(0, "../..")
+
+if sys.version_info[0] >= 3:
+    raw_input = input
+
+import ply.lex as lex
+import ply.yacc as yacc
+import os
+
+
+class Parser(object):
+    """
+    Base class for a lexer/parser that has the rules defined as methods
+    """
+    tokens = ()
+    precedence = ()
+
+    def __init__(self, **kw):
+        self.debug = kw.get('debug', 0)
+        self.names = {}
+        try:
+            modname = os.path.split(os.path.splitext(__file__)[0])[
+                1] + "_" + self.__class__.__name__
+        except:
+            modname = "parser" + "_" + self.__class__.__name__
+        self.debugfile = modname + ".dbg"
+        self.tabmodule = modname + "_" + "parsetab"
+        # print self.debugfile, self.tabmodule
+
+        # Build the lexer and parser
+        lex.lex(module=self, debug=self.debug)
+        yacc.yacc(module=self,
+                  debug=self.debug,
+                  debugfile=self.debugfile,
+                  tabmodule=self.tabmodule)
+
+    def run(self):
+        while 1:
+            try:
+                s = raw_input('calc > ')
+            except EOFError:
+                break
+            if not s:
+                continue
+            yacc.parse(s)
+
+
+class Calc(Parser):
+
+    tokens = (
+        'NAME', 'NUMBER',
+        'PLUS', 'MINUS', 'EXP', 'TIMES', 'DIVIDE', 'EQUALS',
+        'LPAREN', 'RPAREN',
+    )
+
+    # Tokens
+
+    t_PLUS = r'\+'
+    t_MINUS = r'-'
+    t_EXP = r'\*\*'
+    t_TIMES = r'\*'
+    t_DIVIDE = r'/'
+    t_EQUALS = r'='
+    t_LPAREN = r'\('
+    t_RPAREN = r'\)'
+    t_NAME = r'[a-zA-Z_][a-zA-Z0-9_]*'
+
+    def t_NUMBER(self, t):
+        r'\d+'
+        try:
+            t.value = int(t.value)
+        except ValueError:
+            print("Integer value too large %s" % t.value)
+            t.value = 0
+        # print "parsed number %s" % repr(t.value)
+        return t
+
+    t_ignore = " \t"
+
+    def t_newline(self, t):
+        r'\n+'
+        t.lexer.lineno += t.value.count("\n")
+
+    def t_error(self, t):
+        print("Illegal character '%s'" % t.value[0])
+        t.lexer.skip(1)
+
+    # Parsing rules
+
+    precedence = (
+        ('left', 'PLUS', 'MINUS'),
+        ('left', 'TIMES', 'DIVIDE'),
+        ('left', 'EXP'),
+        ('right', 'UMINUS'),
+    )
+
+    def p_statement_assign(self, p):
+        'statement : NAME EQUALS expression'
+        self.names[p[1]] = p[3]
+
+    def p_statement_expr(self, p):
+        'statement : expression'
+        print(p[1])
+
+    def p_expression_binop(self, p):
+        """
+        expression : expression PLUS expression
+                  | expression MINUS expression
+                  | expression TIMES expression
+                  | expression DIVIDE expression
+                  | expression EXP expression
+        """
+        # print [repr(p[i]) for i in range(0,4)]
+        if p[2] == '+':
+            p[0] = p[1] + p[3]
+        elif p[2] == '-':
+            p[0] = p[1] - p[3]
+        elif p[2] == '*':
+            p[0] = p[1] * p[3]
+        elif p[2] == '/':
+            p[0] = p[1] / p[3]
+        elif p[2] == '**':
+            p[0] = p[1] ** p[3]
+
+    def p_expression_uminus(self, p):
+        'expression : MINUS expression %prec UMINUS'
+        p[0] = -p[2]
+
+    def p_expression_group(self, p):
+        'expression : LPAREN expression RPAREN'
+        p[0] = p[2]
+
+    def p_expression_number(self, p):
+        'expression : NUMBER'
+        p[0] = p[1]
+
+    def p_expression_name(self, p):
+        'expression : NAME'
+        try:
+            p[0] = self.names[p[1]]
+        except LookupError:
+            print("Undefined name '%s'" % p[1])
+            p[0] = 0
+
+    def p_error(self, p):
+        if p:
+            print("Syntax error at '%s'" % p.value)
+        else:
+            print("Syntax error at EOF")
+
+if __name__ == '__main__':
+    calc = Calc()
+    calc.run()
diff --git a/third_party/python/ply/example/optcalc/README b/third_party/python/ply/example/optcalc/README
new file mode 100644
index 0000000000..53dd5fcd55
--- /dev/null
+++ b/third_party/python/ply/example/optcalc/README
@@ -0,0 +1,9 @@
+An example showing how to use Python optimized mode.
+To run:
+
+  - First run 'python calc.py'
+
+  - Then run 'python -OO calc.py'
+
+If working correctly, the second version should run the
+same way.
diff --git a/third_party/python/ply/example/optcalc/calc.py b/third_party/python/ply/example/optcalc/calc.py
new file mode 100644
index 0000000000..0c223e5994
--- /dev/null
+++ b/third_party/python/ply/example/optcalc/calc.py
@@ -0,0 +1,134 @@
+# -----------------------------------------------------------------------------
+# calc.py
+#
+# A simple calculator with variables.   This is from O'Reilly's
+# "Lex and Yacc", p. 63.
+# -----------------------------------------------------------------------------
+
+import sys
+sys.path.insert(0, "../..")
+
+if sys.version_info[0] >= 3:
+    raw_input = input
+
+tokens = (
+    'NAME', 'NUMBER',
+    'PLUS', 'MINUS', 'TIMES', 'DIVIDE', 'EQUALS',
+    'LPAREN', 'RPAREN',
+)
+
+# Tokens
+
+t_PLUS = r'\+'
+t_MINUS = r'-'
+t_TIMES = r'\*'
+t_DIVIDE = r'/'
+t_EQUALS = r'='
+t_LPAREN = r'\('
+t_RPAREN = r'\)'
+t_NAME = r'[a-zA-Z_][a-zA-Z0-9_]*'
+
+
+def t_NUMBER(t):
+    r'\d+'
+    try:
+        t.value = int(t.value)
+    except ValueError:
+        print("Integer value too large %s" % t.value)
+        t.value = 0
+    return t
+
+t_ignore = " \t"
+
+
+def t_newline(t):
+    r'\n+'
+    t.lexer.lineno += t.value.count("\n")
+
+
+def t_error(t):
+    print("Illegal character '%s'" % t.value[0])
+    t.lexer.skip(1)
+
+# Build the lexer
+import ply.lex as lex
+lex.lex(optimize=1)
+
+# Parsing rules
+
+precedence = (
+    ('left', 'PLUS', 'MINUS'),
+    ('left', 'TIMES', 'DIVIDE'),
+    ('right', 'UMINUS'),
+)
+
+# dictionary of names
+names = {}
+
+
+def p_statement_assign(t):
+    'statement : NAME EQUALS expression'
+    names[t[1]] = t[3]
+
+
+def p_statement_expr(t):
+    'statement : expression'
+    print(t[1])
+
+
+def p_expression_binop(t):
+    '''expression : expression PLUS expression
+                  | expression MINUS expression
+                  | expression TIMES expression
+                  | expression DIVIDE expression'''
+    if t[2] == '+':
+        t[0] = t[1] + t[3]
+    elif t[2] == '-':
+        t[0] = t[1] - t[3]
+    elif t[2] == '*':
+        t[0] = t[1] * t[3]
+    elif t[2] == '/':
+        t[0] = t[1] / t[3]
+    elif t[2] == '<':
+        t[0] = t[1] < t[3]
+
+
+def p_expression_uminus(t):
+    'expression : MINUS expression %prec UMINUS'
+    t[0] = -t[2]
+
+
+def p_expression_group(t):
+    'expression : LPAREN expression RPAREN'
+    t[0] = t[2]
+
+
+def p_expression_number(t):
+    'expression : NUMBER'
+    t[0] = t[1]
+
+
+def p_expression_name(t):
+    'expression : NAME'
+    try:
+        t[0] = names[t[1]]
+    except LookupError:
+        print("Undefined name '%s'" % t[1])
+        t[0] = 0
+
+
+def p_error(t):
+    if t:
+        print("Syntax error at '%s'" % t.value)
+    else:
+        print("Syntax error at EOF")
+
+import ply.yacc as yacc
+yacc.yacc(optimize=1)
+
+while 1:
+    try:
+        s = raw_input('calc > ')
+    except EOFError:
+        break
+    yacc.parse(s)
diff --git a/third_party/python/ply/example/unicalc/calc.py b/third_party/python/ply/example/unicalc/calc.py
new file mode 100644
index 0000000000..901c4b9d76
--- /dev/null
+++ b/third_party/python/ply/example/unicalc/calc.py
@@ -0,0 +1,133 @@
+# -----------------------------------------------------------------------------
+# calc.py
+#
+# A simple calculator with variables.   This is from O'Reilly's
+# "Lex and Yacc", p. 63.
+#
+# This example uses unicode strings for tokens, docstrings, and input.
+# -----------------------------------------------------------------------------
+
+import sys
+sys.path.insert(0, "../..")
+
+tokens = (
+    'NAME', 'NUMBER',
+    'PLUS', 'MINUS', 'TIMES', 'DIVIDE', 'EQUALS',
+    'LPAREN', 'RPAREN',
+)
+
+# Tokens
+
+t_PLUS = ur'\+'
+t_MINUS = ur'-'
+t_TIMES = ur'\*'
+t_DIVIDE = ur'/'
+t_EQUALS = ur'='
+t_LPAREN = ur'\('
+t_RPAREN = ur'\)'
+t_NAME = ur'[a-zA-Z_][a-zA-Z0-9_]*'
+
+
+def t_NUMBER(t):
+    ur'\d+'
+    try:
+        t.value = int(t.value)
+    except ValueError:
+        print "Integer value too large", t.value
+        t.value = 0
+    return t
+
+t_ignore = u" \t"
+
+
+def t_newline(t):
+    ur'\n+'
+    t.lexer.lineno += t.value.count("\n")
+
+
+def t_error(t):
+    print "Illegal character '%s'" % t.value[0]
+    t.lexer.skip(1)
+
+# Build the lexer
+import ply.lex as lex
+lex.lex()
+
+# Parsing rules
+
+precedence = (
+    ('left', 'PLUS', 'MINUS'),
+    ('left', 'TIMES', 'DIVIDE'),
+    ('right', 'UMINUS'),
+)
+
+# dictionary of names
+names = {}
+
+
+def p_statement_assign(p):
+    'statement : NAME EQUALS expression'
+    names[p[1]] = p[3]
+
+
+def p_statement_expr(p):
+    'statement : expression'
+    print p[1]
+
+
+def p_expression_binop(p):
+    '''expression : expression PLUS expression
+                  | expression MINUS expression
+                  | expression TIMES expression
+                  | expression DIVIDE expression'''
+    if p[2] == u'+':
+        p[0] = p[1] + p[3]
+    elif p[2] == u'-':
+        p[0] = p[1] - p[3]
+    elif p[2] == u'*':
+        p[0] = p[1] * p[3]
+    elif p[2] == u'/':
+        p[0] = p[1] / p[3]
+
+
+def p_expression_uminus(p):
+    'expression : MINUS expression %prec UMINUS'
+    p[0] = -p[2]
+
+
+def p_expression_group(p):
+    'expression : LPAREN expression RPAREN'
+    p[0] = p[2]
+
+
+def p_expression_number(p):
+    'expression : NUMBER'
+    p[0] = p[1]
+
+
+def p_expression_name(p):
+    'expression : NAME'
+    try:
+        p[0] = names[p[1]]
+    except LookupError:
+        print "Undefined name '%s'" % p[1]
+        p[0] = 0
+
+
+def p_error(p):
+    if p:
+        print "Syntax error at '%s'" % p.value
+    else:
+        print "Syntax error at EOF"
+
+import ply.yacc as yacc
+yacc.yacc()
+
+while 1:
+    try:
+        s = raw_input('calc > ')
+    except EOFError:
+        break
+    if not s:
+        continue
+    yacc.parse(unicode(s))
diff --git a/third_party/python/ply/example/yply/README b/third_party/python/ply/example/yply/README
new file mode 100644
index 0000000000..bfadf36436
--- /dev/null
+++ b/third_party/python/ply/example/yply/README
@@ -0,0 +1,41 @@
+yply.py
+
+This example implements a program yply.py that converts a UNIX-yacc
+specification file into a PLY-compatible program.  To use, simply
+run it like this:
+
+   % python yply.py [-nocode] inputfile.y >myparser.py
+
+The output of this program is Python code. In the output,
+any C code in the original file is included, but is commented out.
+If you use the -nocode option, then all of the C code in the
+original file is just discarded.
+
+To use the resulting grammer with PLY, you'll need to edit the
+myparser.py file. Within this file, some stub code is included that
+can be used to test the construction of the parsing tables. However,
+you'll need to do more editing to make a workable parser.
+
+Disclaimer:  This just an example I threw together in an afternoon.
+It might have some bugs.  However, it worked when I tried it on
+a yacc-specified C++ parser containing 442 rules and 855 parsing
+states.
+
+Comments:
+
+1. This example does not parse specification files meant for lex/flex.
+   You'll need to specify the tokenizer on your own.
+
+2. This example shows a number of interesting PLY features including
+    
+     - Parsing of literal text delimited by nested parentheses
+     - Some interaction between the parser and the lexer.
+     - Use of literals in the grammar specification
+     - One pass compilation.  The program just emits the result,
+       there is no intermediate parse tree.
+
+3. This program could probably be cleaned up and enhanced a lot.
+   It would be great if someone wanted to work on this (hint).
+
+-Dave
+       
diff --git a/third_party/python/ply/example/yply/ylex.py b/third_party/python/ply/example/yply/ylex.py
new file mode 100644
index 0000000000..16410e250e
--- /dev/null
+++ b/third_party/python/ply/example/yply/ylex.py
@@ -0,0 +1,119 @@
+# lexer for yacc-grammars
+#
+# Author: David Beazley (dave@dabeaz.com)
+# Date  : October 2, 2006
+
+import sys
+sys.path.append("../..")
+
+from ply import *
+
+tokens = (
+    'LITERAL', 'SECTION', 'TOKEN', 'LEFT', 'RIGHT', 'PREC', 'START', 'TYPE', 'NONASSOC', 'UNION', 'CODE',
+    'ID', 'QLITERAL', 'NUMBER',
+)
+
+states = (('code', 'exclusive'),)
+
+literals = [';', ',', '<', '>', '|', ':']
+t_ignore = ' \t'
+
+t_TOKEN = r'%token'
+t_LEFT = r'%left'
+t_RIGHT = r'%right'
+t_NONASSOC = r'%nonassoc'
+t_PREC = r'%prec'
+t_START = r'%start'
+t_TYPE = r'%type'
+t_UNION = r'%union'
+t_ID = r'[a-zA-Z_][a-zA-Z_0-9]*'
+t_QLITERAL  = r'''(?P<quote>['"]).*?(?P=quote)'''
+t_NUMBER = r'\d+'
+
+
+def t_SECTION(t):
+    r'%%'
+    if getattr(t.lexer, "lastsection", 0):
+        t.value = t.lexer.lexdata[t.lexpos + 2:]
+        t.lexer.lexpos = len(t.lexer.lexdata)
+    else:
+        t.lexer.lastsection = 0
+    return t
+
+# Comments
+
+
+def t_ccomment(t):
+    r'/\*(.|\n)*?\*/'
+    t.lexer.lineno += t.value.count('\n')
+
+t_ignore_cppcomment = r'//.*'
+
+
+def t_LITERAL(t):
+    r'%\{(.|\n)*?%\}'
+    t.lexer.lineno += t.value.count("\n")
+    return t
+
+
+def t_NEWLINE(t):
+    r'\n'
+    t.lexer.lineno += 1
+
+
+def t_code(t):
+    r'\{'
+    t.lexer.codestart = t.lexpos
+    t.lexer.level = 1
+    t.lexer.begin('code')
+
+
+def t_code_ignore_string(t):
+    r'\"([^\\\n]|(\\.))*?\"'
+
+
+def t_code_ignore_char(t):
+    r'\'([^\\\n]|(\\.))*?\''
+
+
+def t_code_ignore_comment(t):
+    r'/\*(.|\n)*?\*/'
+
+
+def t_code_ignore_cppcom(t):
+    r'//.*'
+
+
+def t_code_lbrace(t):
+    r'\{'
+    t.lexer.level += 1
+
+
+def t_code_rbrace(t):
+    r'\}'
+    t.lexer.level -= 1
+    if t.lexer.level == 0:
+        t.type = 'CODE'
+        t.value = t.lexer.lexdata[t.lexer.codestart:t.lexpos + 1]
+        t.lexer.begin('INITIAL')
+        t.lexer.lineno += t.value.count('\n')
+        return t
+
+t_code_ignore_nonspace = r'[^\s\}\'\"\{]+'
+t_code_ignore_whitespace = r'\s+'
+t_code_ignore = ""
+
+
+def t_code_error(t):
+    raise RuntimeError
+
+
+def t_error(t):
+    print("%d: Illegal character '%s'" % (t.lexer.lineno, t.value[0]))
+    print(t.value)
+    t.lexer.skip(1)
+
+lex.lex()
+
+if __name__ == '__main__':
+    lex.runmain()
diff --git a/third_party/python/ply/example/yply/yparse.py b/third_party/python/ply/example/yply/yparse.py
new file mode 100644
index 0000000000..1f2e8d0922
--- /dev/null
+++ b/third_party/python/ply/example/yply/yparse.py
@@ -0,0 +1,244 @@
+# parser for Unix yacc-based grammars
+#
+# Author: David Beazley (dave@dabeaz.com)
+# Date  : October 2, 2006
+
+import ylex
+tokens = ylex.tokens
+
+from ply import *
+
+tokenlist = []
+preclist = []
+
+emit_code = 1
+
+
+def p_yacc(p):
+    '''yacc : defsection rulesection'''
+
+
+def p_defsection(p):
+    '''defsection : definitions SECTION
+                  | SECTION'''
+    p.lexer.lastsection = 1
+    print("tokens = ", repr(tokenlist))
+    print()
+    print("precedence = ", repr(preclist))
+    print()
+    print("# -------------- RULES ----------------")
+    print()
+
+
+def p_rulesection(p):
+    '''rulesection : rules SECTION'''
+
+    print("# -------------- RULES END ----------------")
+    print_code(p[2], 0)
+
+
+def p_definitions(p):
+    '''definitions : definitions definition
+                   | definition'''
+
+
+def p_definition_literal(p):
+    '''definition : LITERAL'''
+    print_code(p[1], 0)
+
+
+def p_definition_start(p):
+    '''definition : START ID'''
+    print("start = '%s'" % p[2])
+
+
+def p_definition_token(p):
+    '''definition : toktype opttype idlist optsemi '''
+    for i in p[3]:
+        if i[0] not in "'\"":
+            tokenlist.append(i)
+    if p[1] == '%left':
+        preclist.append(('left',) + tuple(p[3]))
+    elif p[1] == '%right':
+        preclist.append(('right',) + tuple(p[3]))
+    elif p[1] == '%nonassoc':
+        preclist.append(('nonassoc',) + tuple(p[3]))
+
+
+def p_toktype(p):
+    '''toktype : TOKEN
+               | LEFT
+               | RIGHT
+               | NONASSOC'''
+    p[0] = p[1]
+
+
+def p_opttype(p):
+    '''opttype : '<' ID '>'
+               | empty'''
+
+
+def p_idlist(p):
+    '''idlist  : idlist optcomma tokenid
+               | tokenid'''
+    if len(p) == 2:
+        p[0] = [p[1]]
+    else:
+        p[0] = p[1]
+        p[1].append(p[3])
+
+
+def p_tokenid(p):
+    '''tokenid : ID 
+               | ID NUMBER
+               | QLITERAL
+               | QLITERAL NUMBER'''
+    p[0] = p[1]
+
+
+def p_optsemi(p):
+    '''optsemi : ';'
+               | empty'''
+
+
+def p_optcomma(p):
+    '''optcomma : ','
+                | empty'''
+
+
+def p_definition_type(p):
+    '''definition : TYPE '<' ID '>' namelist optsemi'''
+    # type declarations are ignored
+
+
+def p_namelist(p):
+    '''namelist : namelist optcomma ID
+                | ID'''
+
+
+def p_definition_union(p):
+    '''definition : UNION CODE optsemi'''
+    # Union declarations are ignored
+
+
+def p_rules(p):
+    '''rules   : rules rule
+               | rule'''
+    if len(p) == 2:
+        rule = p[1]
+    else:
+        rule = p[2]
+
+    # Print out a Python equivalent of this rule
+
+    embedded = []      # Embedded actions (a mess)
+    embed_count = 0
+
+    rulename = rule[0]
+    rulecount = 1
+    for r in rule[1]:
+        # r contains one of the rule possibilities
+        print("def p_%s_%d(p):" % (rulename, rulecount))
+        prod = []
+        prodcode = ""
+        for i in range(len(r)):
+            item = r[i]
+            if item[0] == '{':    # A code block
+                if i == len(r) - 1:
+                    prodcode = item
+                    break
+                else:
+                    # an embedded action
+                    embed_name = "_embed%d_%s" % (embed_count, rulename)
+                    prod.append(embed_name)
+                    embedded.append((embed_name, item))
+                    embed_count += 1
+            else:
+                prod.append(item)
+        print("    '''%s : %s'''" % (rulename, " ".join(prod)))
+        # Emit code
+        print_code(prodcode, 4)
+        print()
+        rulecount += 1
+
+    for e, code in embedded:
+        print("def p_%s(p):" % e)
+        print("    '''%s : '''" % e)
+        print_code(code, 4)
+        print()
+
+
+def p_rule(p):
+    '''rule : ID ':' rulelist ';' '''
+    p[0] = (p[1], [p[3]])
+
+
+def p_rule2(p):
+    '''rule : ID ':' rulelist morerules ';' '''
+    p[4].insert(0, p[3])
+    p[0] = (p[1], p[4])
+
+
+def p_rule_empty(p):
+    '''rule : ID ':' ';' '''
+    p[0] = (p[1], [[]])
+
+
+def p_rule_empty2(p):
+    '''rule : ID ':' morerules ';' '''
+
+    p[3].insert(0, [])
+    p[0] = (p[1], p[3])
+
+
+def p_morerules(p):
+    '''morerules : morerules '|' rulelist
+                 | '|' rulelist
+                 | '|'  '''
+
+    if len(p) == 2:
+        p[0] = [[]]
+    elif len(p) == 3:
+        p[0] = [p[2]]
+    else:
+        p[0] = p[1]
+        p[0].append(p[3])
+
+#   print("morerules", len(p), p[0])
+
+
+def p_rulelist(p):
+    '''rulelist : rulelist ruleitem
+                | ruleitem'''
+
+    if len(p) == 2:
+        p[0] = [p[1]]
+    else:
+        p[0] = p[1]
+        p[1].append(p[2])
+
+
+def p_ruleitem(p):
+    '''ruleitem : ID
+                | QLITERAL
+                | CODE
+                | PREC'''
+    p[0] = p[1]
+
+
+def p_empty(p):
+    '''empty : '''
+
+
+def p_error(p):
+    pass
+
+yacc.yacc(debug=0)
+
+
+def print_code(code, indent):
+    if not emit_code:
+        return
+    codelines = code.splitlines()
+    for c in codelines:
+        print("%s# %s" % (" " * indent, c))
diff --git a/third_party/python/ply/example/yply/yply.py b/third_party/python/ply/example/yply/yply.py
new file mode 100755
index 0000000000..e24616c831
--- /dev/null
+++ b/third_party/python/ply/example/yply/yply.py
@@ -0,0 +1,51 @@
+#!/usr/local/bin/python
+# yply.py
+#
+# Author: David Beazley (dave@dabeaz.com)
+# Date  : October 2, 2006
+#
+# Converts a UNIX-yacc specification file into a PLY-compatible
+# specification.   To use, simply do this:
+#
+#   % python yply.py [-nocode] inputfile.y >myparser.py
+#
+# The output of this program is Python code. In the output,
+# any C code in the original file is included, but is commented.
+# If you use the -nocode option, then all of the C code in the
+# original file is discarded.
+#
+# Disclaimer:  This just an example I threw together in an afternoon.
+# It might have some bugs.  However, it worked when I tried it on
+# a yacc-specified C++ parser containing 442 rules and 855 parsing
+# states.
+#
+
+import sys
+sys.path.insert(0, "../..")
+
+import ylex
+import yparse
+
+from ply import *
+
+if len(sys.argv) == 1:
+    print("usage : yply.py [-nocode] inputfile")
+    raise SystemExit
+
+if len(sys.argv) == 3:
+    if sys.argv[1] == '-nocode':
+        yparse.emit_code = 0
+    else:
+        print("Unknown option '%s'" % sys.argv[1])
+        raise SystemExit
+    filename = sys.argv[2]
+else:
+    filename = sys.argv[1]
+
+yacc.parse(open(filename).read())
+
+print("""
+if __name__ == '__main__':
+    from ply import *
+    yacc.yacc()
+""")