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-rw-r--r--third_party/python/ply/example/BASIC/basic.py65
1 files changed, 65 insertions, 0 deletions
diff --git a/third_party/python/ply/example/BASIC/basic.py b/third_party/python/ply/example/BASIC/basic.py
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+++ b/third_party/python/ply/example/BASIC/basic.py
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+# 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()