Adding upstream version 2:9.0.1378.upstream/2%9.0.1378upstream

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

1 files changed, 271 insertions, 0 deletions

diff --git a/runtime/macros/maze/maze_mac b/runtime/macros/maze/maze_mac
new file mode 100644
index 0000000..621aeec
--- /dev/null
+++ b/runtime/macros/maze/maze_mac
@@ -0,0 +1,271 @@
+" These macros 'solve' any maze produced by the a-maze-ing maze.c program.
+"
+" First, a bit of maze theory.
+" If you were put into a maze, a guaranteed method of finding your way
+" out of the maze is to put your left hand onto a wall and just keep walking,
+" never taking your hand off the wall. This technique is only guaranteed to
+" work if the maze does not have any 'islands', or if the 'exit' is on the
+" same island as your starting point. These conditions hold for the mazes
+" under consideration.
+"
+" Assuming that the maze is made up of horizontal and vertical walls spaced
+" one step apart and that you can move either north, south, east or west,
+" then you can automate this procedure by carrying out the following steps.
+"
+" 1. Put yourself somewhere in the maze near a wall.
+" 2. Check if you have a wall on your left. If so, go to step 4.
+" 3. There is no wall on your left, so turn on the spot to your left and step
+"    forward by one step and repeat step 2.
+" 4. Check what is directly in front of you. If it is a wall, turn on the
+"    spot to your right by 90 degrees and repeat step 4.
+" 5. There is no wall in front of you, so step forward one step and
+"    go to step 2.
+"
+" In this way you will cover all the corridors of the maze (until you get back
+" to where you started from, if you do not stop).
+"
+" By examining a maze produced by the maze.c program you will see that
+" each square of the maze is one character high and two characters wide.
+" To go north or south, you move by a one character step, but to move east or
+" west you move by a two character step. Also note that in any position
+" there are four places where walls could be put - to the north, to the south,
+" to the east and to the west.
+" A wall exists to the north of you if the character to the north of
+" you is a _ (otherwise it is a space).
+" A wall exists to the east of you if the character to the east of you
+" is a | (otherwise it is a .).
+" A wall exists to the west of you if the character to the west of you
+" is a | (otherwise it is a .).
+" A wall exists to the south of you if the character where you are
+" is a _ (otherwise it is a space).
+"
+" Note the difference for direction south, where we must examine the character
+" where the cursor is rather than an adjacent cell.
+"
+" If you were implementing the above procedure is a normal computer language
+" you could use a loop with if statements and continue statements,
+" However, these constructs are not available in vi macros so I have used
+" a state machine with 8 states. Each state signifies the direction you
+" are going in and whether or not you have checked if there is a wall on
+" your left.
+"
+" The transition from state to state and the actions taken on each transition
+" are given in the state table below.
+" The names of the states are N1, N2, S1, S2, E1, E2, W1, W2, where each letter
+" stands for a direction of the compass, the number 1 indicates that the we
+" have not yet checked to see if there is a wall on our left and the number 2
+" indicates that we have checked and there is a wall on our left.
+"
+" For each state we must consider the existence or not of a wall in a
+" particular direction. This direction is given in the following table.
+"
+" NextChar table:
+" state        direction       vi commands
+"  N1              W               hF
+"  N2              N               kF
+"  S1              E               lF
+"  S2              S               F
+"  E1              N               kF
+"  E2              E               lF
+"  W1              S               F
+"  W2              W               hF
+"
+" where F is a macro which yanks the character under the cursor into
+" the NextChar register (n).
+"
+" State table:
+" In the 'vi commands' column is given the actions to carry out when in
+" this state and the NextChar is as given. The commands k, j, ll, hh move
+" the current position north, south, east and west respectively. The
+" command mm is used as a no-op command.
+" In the 'next state' column is given the new state of the machine after
+" the action is carried out.
+"
+" current state        NextChar    vi commands  next state
+"      N1                 .            hh          W1
+"      N1                 |            mm          N2
+"      N2                 _            mm          E1
+"      N2               space          k           N1
+"      S1                 .            ll          E1
+"      S1                 |            mm          S2
+"      S2                 _            mm          W1
+"      S2               space          j           S1
+"      E1               space          k           N1
+"      E1                 _            mm          E2
+"      E2                 |            mm          S1
+"      E2                 .            ll          E1
+"      W1               space          j           S1
+"      W1                 _            mm          W2
+"      W2                 |            mm          N1
+"      W2                 .            hh          W1
+"
+"
+" Complaint about vi macros:
+" It seems that you cannot have more than one 'undo-able' vi command
+" in the one macro, so you have to make lots of little macros and
+" put them together.
+"
+" I'll explain what I mean by an example. Edit a file and
+" type ':map Q rXY'. This should map the Q key to 'replace the
+" character under the cursor with X and yank the line'.
+" But when I type Q, vi tells me 'Can't yank inside global/macro' and
+" goes into ex mode. However if I type ':map Q rXT' and ':map T Y',
+" everything is OK. I`m doing all this on a Sparcstation.
+" If anyone reading this has an answer to this problem, the author would
+" love to find out. Mail to gregm@otc.otca.oz.au.
+"
+" The macros:
+" The macro to run the maze solver is 'g'. This simply calls two other
+" macros: I, to initialise everything, and L, to loop forever running
+" through the state table.
+" Both of these macros are long sequences of calls to other macros. All
+" of these other macros are quite simple and so to understand how this
+" works, all you need to do is examine macros I and L and learn what they
+" do (a simple sequence of vi actions) and how L loops (by calling U, which
+" simply calls L again).
+"
+" Macro I sets up the state table and NextChar table at the end of the file.
+" Macro L then searches these tables to find out what actions to perform and
+" what state changes to make.
+"
+" The entries in the state table all begin with a key consisting of the
+" letter 's', the current state and the NextChar.  After this is the
+" action to take in this state and after this is the next state to change to.
+"
+" The entries in the NextChar table begin with a key consisting of the
+" letter 'n' and the current state. After this is the action to take to
+" obtain NextChar - the character that must be examined to change state.
+"
+" One way to see what each part of the macros is doing is to type in the
+" body of the macros I and L manually (instead of typing 'g') and see
+" what happens at each step.
+"
+" Good luck.
+"
+" Registers used by the macros:
+" s (State)        - holds the state the machine is in
+" c (Char)         - holds the character under the current position
+" m (Macro)        - holds a vi command string to be executed later
+" n (NextChar)     - holds the character we must examine to change state
+" r (Second Macro) - holds a second vi command string to be executed later
+"
+set remap
+set nomagic
+set noterse
+set wrapscan
+"
+"================================================================
+" g - go runs the whole show
+"        I - initialise
+"        L - then loop forever
+map g   IL
+"
+"================================================================
+" I - initialise everything before running the loop
+"   G$?.^M - find the last . in the maze
+"        ^ - replace it with an X (the goal)
+"   GYKeDP - print the state table and next char table at the end of the file
+"       0S - initialise the state of the machine to E1
+"      2Gl - move to the top left cell of the maze
+map I   G$?.
^GYKeDP0S2Gl
+"
+"================================================================
+" L - the loop which is executed forever
+"        Q - save the current character in the Char register
+"        A - replace the current character with an 'O'
+"       ma - mark the current position with mark 'a'
+"      GNB - on bottom line, create a command to search the NextChar table
+"            for the current state
+" 0M0E@m^M - yank the command into the Macro register and execute it
+"       wX - we have now found the entry in the table, now yank the
+"            following word into the Macro register
+"     `a@m - go back to the current position and execute the macro, this will
+"            yank the NextChar in register n
+"   GT$B$R - on bottom line, create a command to search the state table
+"            for the current state and NextChar
+" 0M0E@m^M - yank the command into the Macro register and execute it
+"      2WS - we have now found the entry in the table, now yank the
+"            next state into the State macro
+"       bX - and yank the action corresponding to this state table entry
+"            into the Macro register
+"      GVJ - on bottom line, create a command to restore the current character
+"       0H - and save the command into the second Macro register
+"     `a@r - go back to the current position and exectute the macro to restore
+"            the current character
+"       @m - execute the action associated with this state
+"        U - and repeat
+map L   QAmaGNB0M0E@m
wX`a@mGT$B$R0M0E@m
2WSbXGVJ0H`a@r@mU
+"
+"================================================================
+" U - no tail recursion allowed in vi macros so cheat and set U = L
+map U   L
+"
+"================================================================
+" S - yank the next two characters into the State register
+map S   "sy2l
+"
+"================================================================
+" Q - save the current character in the Char register
+map Q   "cyl
+"
+"================================================================
+" A - replace the current character with an 'O'
+map A   rO
+"
+"================================================================
+" N - replace this line with the string 'n'
+map N   C/n
+"
+"================================================================
+" B - put the current state
+map B   "sp
+"
+"================================================================
+" M - yank this line into the Macro register
+map M   "my$
+"
+"================================================================
+" E - delete to the end of the line
+map E   d$
+"
+"================================================================
+" X - yank this word into the Macro register
+map X   "myt 
+"
+"================================================================
+" T - replace this line with the string 's'
+map T   C/s
+"
+"================================================================
+" R - put NextChar
+map R   "np
+"
+"================================================================
+" V - add the letter 'r' (the replace vi command)
+map V   ar
+"
+"================================================================
+" J - restore the current character
+map J   "cp
+"
+"================================================================
+" H - yank this line into the second Macro register
+map H   "ry$
+"
+"================================================================
+" F - yank NextChar (this macro is called from the Macro register)
+map F   "nyl
+"
+"================================================================
+" ^ - replace the current character with an 'X'
+map ^   rX
+"
+"================================================================
+" YKeDP - create the state table, NextChar table and initial state
+" Note that you have to escape the bar character, since it is special to
+" the map command (it indicates a new line).
+map Y   osE1  k  N1       sE1_ mm E2       sE2| mm S1       sE2. ll E1
+map K   osW1  j  S1       sW1_ mm W2       sW2| mm N1       sW2. hh W1
+map e   osN1. hh W1       sN1| mm N2       sN2  k  N1       sN2_ mm E1
+map D   osS1. ll E1       sS1| mm S2       sS2  j  S1       sS2_ mm W1
+map P   onE1 kF nE2 lF nW1 G$JF nW2 hF nN1 hF nN2 kF nS1 lF nS2 G$JF 
E1