Wireworld

Wireworld
You are encouraged to solve this task according to the task description, using any language you may know.

Wireworld is a cellular automaton with some similarities to Conway's Game of Life. It is capable of doing sophisticated computations (e.g., calculating primeness!) with appropriate programs, and is much simpler to program for.

A wireworld arena consists of a cartesian grid of cells, each of which can be in one of four states. All cell transitions happen simultaneously. The cell transition rules are this:

Input State	Output State	Condition
empty	empty
electron head	electron tail
electron tail	conductor
conductor	electron head	if 1 or 2 cells in the neighborhood of the cell are in the state “electron head”
conductor	conductor	otherwise

To implement this task, create a program that reads a wireworld program from a file and displays an animation of the processing. Here is a sample description file (using "H" for an electron head, "t" for a tail, "." for a conductor and a space for empty) you may wish to test with, which demonstrates two cycle-3 generators and an inhibit gate:

tH.........
.   .
   ...
.   .
Ht.. ......

While text-only implementations of this task are possible, mapping cells to pixels is advisable if you wish to be able to display large designs. The logic is not significantly more complex.

Ada

<lang Ada>with Ada.Text_IO; use Ada.Text_IO;

procedure Test_Wireworld is

  type Cell is (' ', 'H', 't', '.');
  type Board is array (Positive range <>, Positive range <>) of Cell;
     -- Perform one transition of the cellular automation
  procedure Wireworld (State : in out Board) is
     function "abs" (Left : Cell) return Natural is
     begin
        if Left = 'H' then
           return 1;
        else
           return 0;
        end if;
     end "abs";
     Above   : array (State'Range (2)) of Cell := (others => ' ');
     Left    : Cell := ' '; 
     Current : Cell;
  begin
     for I in State'First (1) + 1..State'Last (1) - 1 loop
        for J in State'First (2) + 1..State'Last (2) - 1 loop
           Current := State (I, J);
           case Current is
              when ' ' =>
                 null;
              when 'H' =>
                 State (I, J) := 't';
              when 't' =>
                 State (I, J) := '.';
              when '.' =>
                 if abs Above (       J - 1) + abs Above (       J) + abs Above (       J + 1) +
                    abs Left                                        + abs State (I,     J + 1) + 
                    abs State (I + 1, J - 1) + abs State (I + 1, J) + abs State (I + 1, J + 1)
                 in 1..2 then
                    State (I, J) := 'H';
                 else
                    State (I, J) := '.';
                 end if;
           end case;
           Above (J - 1) := Left;
           Left := Current;
        end loop;
     end loop;
  end Wireworld;
     -- Print state of the automation
  procedure Put (State : Board) is
  begin
     for I in State'First (1) + 1..State'Last (1) - 1 loop
        for J in State'First (2) + 1..State'Last (2) - 1 loop
           case State (I, J) is
              when ' ' => Put (' ');
              when 'H' => Put ('H');
              when 't' => Put ('t');
              when '.' => Put ('.');
           end case;
        end loop;
        New_Line;
     end loop;
  end Put;
  Oscillator : Board := ("         ", "  tH     ", " .  .... ", "  ..     ", "         ");

begin

  for Step in 0..9 loop
     Put_Line ("Step" & Integer'Image (Step) & " ---------"); Put (Oscillator);
     Wireworld (Oscillator);
  end loop;

end Test_Wireworld;</lang> The solution assumes that the border of the board is empty. When transition is performed these cells are not changed. Automation transition is an in-place operation that allocates memory for to keep one row of the board size.

Step 0 ---------
 tH
.  ....
 ..
Step 1 ---------
 .t
.  H...
 ..
Step 2 ---------
 ..
.  tH..
 .H
Step 3 ---------
 ..
.  .tH.
 Ht
Step 4 ---------
 ..
H  ..tH
 t.
Step 5 ---------
 H.
t  ...t
 ..
Step 6 ---------
 tH
.  ....
 ..
Step 7 ---------
 .t
.  H...
 ..
Step 8 ---------
 ..
.  tH..
 .H
Step 9 ---------
 ..
.  .tH.
 Ht

ALGOL 68

Translation of: python

- note: This specimen retains the original python coding style.

Works with: ALGOL 68G version Any - tested with release 1.18.0-9h.tiny

<lang algol68>CO Wireworld implementation. CO

PROC exception = ([]STRING args)VOID:(

 putf(stand error, ($"Exception"$, $", "g$, args, $l$));
 stop

);

PROC assertion error = (STRING message)VOID:exception(("assertion error", message));

MODE CELL = CHAR; MODE WORLD = FLEX[0, 0]CELL; CELL head="H", tail="t", conductor=".", empty = " "; STRING all states := empty;

BOOL wrap = FALSE; # is the world round? #

STRING nl := REPR 10;

STRING in string :=

 "tH........."+nl+
 ".   ."+nl+
 "   ..."+nl+
 ".   ."+nl+
 "Ht.. ......"+nl

OP +:= = (REF FLEX[]FLEX[]CELL lines, FLEX[]CELL line)VOID:(

     [UPB lines + 1]FLEX[0]CELL new lines;
     new lines[:UPB lines]:=lines;
     lines := new lines;
     lines[UPB lines]:=line

);

PROC read file = (REF FILE in file)WORLD: (

   # file > initial world configuration" #
   FLEX[0]CELL line;
   FLEX[0]FLEX[0]CELL lines;
   INT upb x:=0, upb y := 0;
   BEGIN 
     # on physical file end(in file, exit read line); #
     make term(in file, nl);
     FOR x TO 5 DO
       get(in file, (line, new line));
       upb x := x;
       IF UPB line > upb y THEN upb y := UPB line FI;
       lines +:= line
     OD;
   exit read line: SKIP
   END;
   [upb x, upb y]CELL out;
   FOR x TO UPB out DO
     out[x,]:=lines[x]+" "*(upb y-UPB lines[x])
   OD;
   out

);

PROC new cell = (WORLD current world, INT x, y)CELL: (

   CELL istate := current world[x, y];
   IF INT pos; char in string (istate, pos, all states); pos IS REF INT(NIL) THEN 
       assertion error("Wireworld cell set to unknown value "+istate) FI;
   IF istate = head THEN
       tail
   ELIF istate = tail THEN
       conductor
   ELIF istate = empty THEN
       empty
   ELSE # istate = conductor #
       [][]INT dxy list = ( (-1,-1), (-1,+0), (-1,+1),
                            (+0,-1),          (+0,+1),
                            (+1,-1), (+1,+0), (+1,+1) );
       INT n := 0;
       FOR enum dxy TO UPB dxy list DO
         []INT dxy = dxy list[enum dxy];
         IF wrap THEN
           INT px = ( x + dxy[1] - 1 ) MOD 1 UPB current world + 1;
           INT py = ( y + dxy[2] - 1 ) MOD 2 UPB current world + 1;
           n +:= ABS (current world[px, py] = head)
         ELSE
           INT px = x + dxy[1];
           INT py = y + dxy[2];
           IF px >= 1 LWB current world AND px <= 1 UPB current world AND
              py >= 2 LWB current world AND py <= 2 UPB current world THEN
                n +:= ABS (current world[px, py] = head)
           FI
         FI
       OD;
       IF 1 <= n AND n <= 2 THEN head ELSE conductor FI
   FI

);

PROC next gen = (WORLD world)WORLD:(

   # compute next generation of wireworld #
   WORLD new world := world;
   FOR x TO 1 UPB world DO
       FOR y TO 2 UPB world DO
           new world[x,y] := new cell(world, x, y)
       OD
   OD;
   new world

);

PROC world2string = (WORLD world) STRING:(

   STRING out:="";
   FOR x TO UPB world DO
     out +:= world[x,]+nl
   OD;
   out

);

FILE in file; associate(in file, in string);

WORLD ww := read file(in file); close(in file);

FOR gen TO 10 DO

   printf ( ($lg(-3)" "$, gen-1,  $g$,"="* (2 UPB ww-4), $l$));
   print ( world2string(ww) );
   ww := next gen(ww)

OD</lang>

Output:

  0 =======
tH.........
.   .      
   ...     
.   .      
Ht.. ......

  1 =======
.tH........
H   .      
   ...     
H   .      
t... ......

  2 =======
H.tH.......
t   .      
   ...     
t   .      
.H.. ......

  3 =======
tH.tH......
.   H      
   ...     
.   .      
HtH. ......

  4 =======
.tH.tH.....
H   t      
   HHH     
H   .      
t.tH ......

  5 =======
H.tH.tH....
t   .      
   ttt     
t   .      
.H.t ......

  6 =======
tH.tH.tH...
.   H      
   ...     
.   .      
HtH. ......

  7 =======
.tH.tH.tH..
H   t      
   HHH     
H   .      
t.tH ......

  8 =======
H.tH.tH.tH.
t   .      
   ttt     
t   .      
.H.t ......

  9 =======
tH.tH.tH.tH
.   H      
   ...     
.   .      
HtH. ......

C

See: Wireworld/C

C++

Library: libggi

(for graphics)

Library: POSIX

(for usleep)

<lang cpp>#include <ggi/ggi.h>

1. include <set>
2. include <map>
3. include <utility>
4. include <iostream>
5. include <fstream>
6. include <string>

1. include <unistd.h> // for usleep

enum cell_type { none, wire, head, tail };

// ***************** // * display class * // *****************

// this is just a small wrapper for the ggi interface

class display { public:

 display(int sizex, int sizey, int pixsizex, int pixsizey,
         ggi_color* colors);
 ~display()
 {
   ggiClose(visual);
   ggiExit();
 }

 void flush();
 bool keypressed() { return ggiKbhit(visual); }
 void clear();
 void putpixel(int x, int y, cell_type c);

private:

 ggi_visual_t visual;
 int size_x, size_y;
 int pixel_size_x, pixel_size_y;
 ggi_pixel pixels[4];

};

display::display(int sizex, int sizey, int pixsizex, int pixsizey,

                ggi_color* colors):
 pixel_size_x(pixsizex),
 pixel_size_y(pixsizey)

{

 if (ggiInit() < 0)
 {
   std::cerr << "couldn't open ggi\n";
   exit(1);
 }

 visual = ggiOpen(NULL);
 if (!visual)
 {
   ggiPanic("couldn't open visual\n");
 }

 ggi_mode mode;
 if (ggiCheckGraphMode(visual, sizex, sizey,
                       GGI_AUTO, GGI_AUTO, GT_4BIT,
                       &mode) != 0)
 {
   if (GT_DEPTH(mode.graphtype) < 2) // we need 4 colors!
     ggiPanic("low-color displays are not supported!\n");
 }
 if (ggiSetMode(visual, &mode) != 0)
 {
   ggiPanic("couldn't set graph mode\n");
 }
 ggiAddFlags(visual, GGIFLAG_ASYNC);

 size_x = mode.virt.x;
 size_y = mode.virt.y;

 for (int i = 0; i < 4; ++i)
   pixels[i] = ggiMapColor(visual, colors+i);

}

void display::flush() {

 // set the current display frame to the one we have drawn to
 ggiSetDisplayFrame(visual, ggiGetWriteFrame(visual));

 // flush the current visual
 ggiFlush(visual);

 // try to set a different frame for drawing (errors are ignored; if
 // setting the new frame fails, the current one will be drawn upon,
 // with the only adverse effect being some flickering).
 ggiSetWriteFrame(visual, 1-ggiGetDisplayFrame(visual));

}

void display::clear() {

 ggiSetGCForeground(visual, pixels[0]);
 ggiDrawBox(visual, 0, 0, size_x, size_y);

}

void display::putpixel(int x, int y, cell_type cell) {

 // this draws a logical pixel (i.e. a rectangle of size pixel_size_x
 // times pixel_size_y), not a physical pixel
 ggiSetGCForeground(visual, pixels[cell]);
 ggiDrawBox(visual,
            x*pixel_size_x, y*pixel_size_y,
            pixel_size_x, pixel_size_y);

}

// ***************** // * the wireworld * // *****************

// initialized to an empty wireworld class wireworld { public:

 void set(int posx, int posy, cell_type type);
 void draw(display& destination);
 void step();

private:

 typedef std::pair<int, int> position;
 typedef std::set<position> position_set;
 typedef position_set::iterator positer;
 position_set wires, heads, tails;

};

void wireworld::set(int posx, int posy, cell_type type) {

 position p(posx, posy);
 wires.erase(p);
 heads.erase(p);
 tails.erase(p);
 switch(type)
 {
 case head:
   heads.insert(p);
   break;
 case tail:
   tails.insert(p);
   break;
 case wire:
   wires.insert(p);
   break;
 }

}

void wireworld::draw(display& destination) {

 destination.clear();
 for (positer i = heads.begin(); i != heads.end(); ++i)
   destination.putpixel(i->first, i->second, head);
 for (positer i = tails.begin(); i != tails.end(); ++i)
   destination.putpixel(i->first, i->second, tail);
 for (positer i = wires.begin(); i != wires.end(); ++i)
   destination.putpixel(i->first, i->second, wire);
 destination.flush();

}

void wireworld::step() {

 std::map<position, int> new_heads;
 for (positer i = heads.begin(); i != heads.end(); ++i)
   for (int dx = -1; dx <= 1; ++dx)
     for (int dy = -1; dy <= 1; ++dy)
     {
       position pos(i->first + dx, i->second + dy);
       if (wires.count(pos))
         new_heads[pos]++;
     }
 wires.insert(tails.begin(), tails.end());
 tails.swap(heads);
 heads.clear();
 for (std::map<position, int>::iterator i = new_heads.begin();
      i != new_heads.end();
      ++i)
 {

// std::cout << i->second;

   if (i->second < 3)
   {
     wires.erase(i->first);
     heads.insert(i->first);
   }
 }

}

ggi_color colors[4] =

 {{ 0x0000, 0x0000, 0x0000 },  // background: black
  { 0x8000, 0x8000, 0x8000 },  // wire: white
  { 0xffff, 0xffff, 0x0000 },  // electron head: yellow
  { 0xffff, 0x0000, 0x0000 }}; // electron tail: red

int main(int argc, char* argv[]) {

 int display_x = 800;
 int display_y = 600;
 int pixel_x = 5;
 int pixel_y = 5;

 if (argc < 2)
 {
   std::cerr << "No file name given!\n";
   return 1;
 }

 // assume that the first argument is the name of a file to parse
 std::ifstream f(argv[1]);
 wireworld w;
 std::string line;
 int line_number = 0;
 while (std::getline(f, line))
 {
   for (int col = 0; col < line.size(); ++col)
   {
     switch (line[col])
     {
     case 'h': case 'H':
       w.set(col, line_number, head);
       break;
     case 't': case 'T':
       w.set(col, line_number, tail);
       break;
     case 'w': case 'W': case '.':
       w.set(col, line_number, wire);
       break;
     default:
       std::cerr << "unrecognized character: " << line[col] << "\n";
       return 1;
     case ' ':
       ; // no need to explicitly set this, so do nothing
     }
   }
   ++line_number;
 }

 display d(display_x, display_y, pixel_x, pixel_y, colors);

 w.draw(d);

 while (!d.keypressed())
 {
   usleep(100000);
   w.step();
   w.draw(d);
 }
 std::cout << std::endl;

}</lang>

Common Lisp

<lang lisp>(defun electron-neighbors (wireworld row col)

 (destructuring-bind (rows cols) (array-dimensions wireworld)
   (loop   for off-row from (max 0 (1- row)) to (min (1- rows) (1+ row)) sum
     (loop for off-col from (max 0 (1- col)) to (min (1- cols) (1+ col)) count
       (and (not (and (= off-row row) (= off-col col)))
            (eq 'electron-head (aref wireworld off-row off-col)))))))

(defun wireworld-next-generation (wireworld)

 (destructuring-bind (rows cols) (array-dimensions wireworld)
   (let ((backing (make-array (list rows cols))))
     (do ((c 0 (if (= c (1- cols)) 0 (1+ c)))
          (r 0 (if (= c (1- cols)) (1+ r) r)))
         ((= r rows))
       (setf (aref backing r c) (aref wireworld r c)))
     (do ((c 0 (if (= c (1- cols)) 0 (1+ c)))
          (r 0 (if (= c (1- cols)) (1+ r) r)))
         ((= r rows))
       (setf (aref wireworld r c)
             (case (aref backing r c)
               (electron-head 'electron-tail)
               (electron-tail 'conductor)
               (conductor (case (electron-neighbors backing r c)
                            ((1 2) 'electron-head)
                            (otherwise 'conductor)))
               (otherwise nil)))))))

(defun print-wireworld (wireworld)

 (destructuring-bind (rows cols) (array-dimensions wireworld)
   (do ((r 0 (1+ r)))
       ((= r rows))
     (do ((c 0 (1+ c)))
         ((= c cols))
       (format t "~C" (case (aref wireworld r c)
                        (electron-head #\H)
                        (electron-tail #\t)
                        (conductor #\.)
                        (otherwise #\Space))))
     (format t "~&"))))

(defun wireworld-show-gens (wireworld n)

 (dotimes (m n)
   (terpri)
   (wireworld-next-generation wireworld)
   (print-wireworld wireworld)))

(defun ww-char-to-symbol (char)

 (ecase char
   (#\Space 'nil)
   (#\.     'conductor)
   (#\t     'electron-tail)
   (#\H     'electron-head)))

(defun make-wireworld (image)

 "Make a wireworld grid from a list of strings (rows) of equal length

(columns), each character being ' ', '.', 'H', or 't'."

 (make-array (list (length image) (length (first image)))
             :initial-contents
             (mapcar (lambda (s) (map 'list #'ww-char-to-symbol s)) image)))

(defun make-rosetta-wireworld ()

 (make-wireworld '("tH........."
                   ".   .      "
                   "   ...     "
                   ".   .      "
                   "Ht.. ......")))</lang>

Output:

CL-USER> (wireworld-show-gens (make-rosetta-wireworld) 12)

.tH........
H   .      
   ...     
H   .      
t... ......

H.tH.......
t   .      
   ...     
t   .      
.H.. ......

tH.tH......
.   H      
   ...     
.   .      
HtH. ......

.tH.tH.....
H   t      
   HHH     
H   .      
t.tH ......

H.tH.tH....
t   .      
   ttt     
t   .      
.H.t ......

tH.tH.tH...
.   H      
   ...     
.   .      
HtH. ......

.tH.tH.tH..
H   t      
   HHH     
H   .      
t.tH ......

H.tH.tH.tH.
t   .      
   ttt     
t   .      
.H.t ......

tH.tH.tH.tH
.   H      
   ...     
.   .      
HtH. ......

.tH.tH.tH.t
H   t      
   HHH     
H   .      
t.tH ......

H.tH.tH.tH.
t   .      
   ttt     
t   .      
.H.t ......

tH.tH.tH.tH
.   H      
   ...     
.   .      
HtH. ......

Forth

<lang forth>16 constant w

8 constant h

rows w * 2* ;

1 rows constant row h rows constant size

create world size allot world value old old w + value new

init world size erase ;

age new old to new to old ;

foreachrow ( xt -- )

 size 0 do  I over execute  row +loop drop ;

0 constant EMPTY 1 constant HEAD 2 constant TAIL 3 constant WIRE create cstate bl c, char H c, char t c, char . c,

showrow ( i -- ) cr

 old + w over + swap do I c@ cstate + c@ emit loop ;

show ['] showrow foreachrow  ;

line ( row addr len -- )

 bounds do
   i c@
   case
   bl of EMPTY over c! endof
   'H of HEAD  over c! endof
   't of TAIL  over c! endof
   '. of WIRE  over c! endof
   endcase
   1+
 loop drop ;

load ( filename -- )

 r/o open-file throw
 init  old row + 1+  ( file row )
 begin  over pad 80 rot read-line throw
 while  over pad rot line
        row +
 repeat
 2drop close-file throw
 show cr ;

+head ( sum i -- sum )

 old + c@ HEAD = if 1+ then ;

conductor ( i WIRE -- i HEAD|WIRE )

 drop 0
 over 1- row - +head
 over    row - +head
 over 1+ row - +head
 over 1-       +head
 over 1+       +head
 over 1- row + +head
 over    row + +head
 over 1+ row + +head
 1 3 within if HEAD else WIRE then ;

\ before: empty head tail wire

create transition ' noop , ' 1+ , ' 1+ , ' conductor ,

\ after: empty tail wire head|wire

new-state ( i -- )

 dup  old + c@
 dup cells transition + @ execute
 swap new + c! ;

newrow ( i -- )

 w over + swap do I new-state loop ;

gen ['] newrow foreachrow age ;

wireworld begin gen 0 0 at-xy show key? until ;</lang>

Output:

s" wireworld.diode" load
                
        ..      
 tH...... .Ht   
        ..      
                
                
                
                
 ok
gen show                
                
        ..      
 .tH..... Ht.   
        ..      
                
                
                
                 ok
gen show 
                
        .H      
 ..tH.... t..   
        .H      
                
                
                
                 ok
gen show 
                
        Ht      
 ...tH..H ...   
        Ht      
                
                
                
                 ok
gen show 
                
        t.      
 ....tH.t ...   
        t.      
                
                
                
                 ok
gen show 
                
        ..      
 .....tH. ...   
        ..      
                
                
                
                 ok
gen show 
                
        H.      
 ......tH ...   
        H.      
                
                
                
                 ok
gen show 
                
        tH      
 .......t ...   
        tH      
                
                
                
                 ok
gen show 
                
        .t      
 ........ H..   
        .t      
                
                
                
                 ok
gen show 
                
        ..      
 ........ tH.   
        ..      
                
                
                
                 ok
gen show 
                
        ..      
 ........ .tH   
        ..      
                
                
                
                 ok
gen show 
                
        ..      
 ........ ..t   
        ..      
                
                
                
                 ok
gen show 
                
        ..      
 ........ ...   
        ..      
                
                
                
                 ok

Haskell

<lang Haskell>import Data.List import Control.Monad import Control.Arrow import Data.Maybe

states=" Ht." shiftS=" t.."

borden bc xs = bs: (map (\x -> bc:(x++[bc])) xs) ++ [bs]

  where r = length $ head xs
        bs = replicate (r+2) bc

take3x3 = ap ((.). taken. length) (taken. length. head) `ap` borden '*'

  where taken n =  transpose. map (take n.map (take 3)).map tails

nwState xs | e =='.' && noH>0 && noH<3 = 'H'

          | otherwise = shiftS !! (fromJust $ elemIndex e states) 
  where e = xs!!1!!1
        noH = length $ filter (=='H') $ concat xs

runCircuit = iterate (map(map nwState).take3x3)</lang> Example executed in GHCi: <lang Haskell>oscillator= [" tH ",

            ".  ....",
            " ..    "
           ]

example = mapM_ (mapM_ putStrLn) .map (borden ' ').take 9 $ runCircuit oscillator</lang> Ouptput:

*Main> example

  tH
 .  ....
  ..


  .t
 .  H...
  ..


  ..
 .  tH..
  .H


  ..
 .  .tH.
  Ht


  ..
 H  ..tH
  t.


  H.
 t  ...t
  ..


  tH
 .  ....
  ..


  .t
 .  H...
  ..


  ..
 .  tH..
  .H

(0.01 secs, 541764 bytes)

J

The example circuit:<lang J>circ0=:}: ] ;. _1 LF, 0 : 0 tH........ . .

  ...    

. . Ht.. ..... )</lang> A 'boarding' verb board and the next cell state verb nwS: <lang J>board=: ' ' ,.~ ' ' ,. ' ' , ' ' ,~ ]

nwS=: 3 : 0

 e=. (<1 1){y
 if. ('.'=e)*. e.&1 2 +/'H'=,y do. 'H' return. end.
 ' t..' {~ ' Ht.' i. e

)</lang> The 'most' powerful part is contained in the following iterating sentence, namely the dyad cut ;. [1]. In this way verb nwS can work on all the 3x3 matrices containing each cell surrounded by its 8 relevant neighbors. <lang J> (3 3 nwS;. _3 board)^: (<10) circuit</lang> Example run:

   (3 3 nwS;. _3 board)^: (<10) circ0
tH........
.   .     
   ...    
.   .     
Ht.. .....

.tH.......
H   .     
   ...    
H   .     
t... .....

H.tH......
t   .     
   ...    
t   .     
.H.. .....

tH.tH.....
.   H     
   ...    
.   .     
HtH. .....

.tH.tH....
H   t     
   HHH    
H   .     
t.tH .....

H.tH.tH...
t   .     
   ttt    
t   .     
.H.t .....

tH.tH.tH..
.   H     
   ...    
.   .     
HtH. .....

.tH.tH.tH.
H   t     
   HHH    
H   .     
t.tH .....

H.tH.tH.tH
t   .     
   ttt    
t   .     
.H.t .....

tH.tH.tH.t
.   H     
   ...    
.   .     
HtH. .....

Java

See: Wireworld/Java

OCaml

<lang ocaml>let w = [|

   "  ......tH              ";
   " .        ......        ";
   "  ...Ht...      .       ";
   "               ....     ";
   "               .  ..... ";
   "               ....     ";
   "  tH......      .       ";
   " .        ......        ";
   "  ...Ht...              ";
 |]

let is_head w x y =

 try if w.(x).[y] = 'H' then 1 else 0
 with _ -> 0

let neighborhood_heads w x y =

 let n = ref 0 in
 for _x = pred x to succ x do
   for _y = pred y to succ y do
     n := !n + (is_head w _x _y)
   done;
 done;
 (!n)

let step w =

 let n = Array.init (Array.length w) (fun i -> String.copy w.(i)) in
 let width = Array.length w
 and height = String.length w.(0)
 in
 for x = 0 to pred width do
   for y = 0 to pred height do
     n.(x).[y] <- (
       match w.(x).[y] with
       | ' ' -> ' '
       | 'H' -> 't'
       | 't' -> '.'
       | '.' ->
           (match neighborhood_heads w x y with
           | 1 | 2 -> 'H'
           | _ -> '.')
       | _ -> assert false)
   done;
 done;
 (n)

let print = (Array.iter print_endline)

let () =

 let rec aux w =
   Unix.sleep 1;
   let n = step w in
   print n;
   aux n
 in
 aux w</lang>

Oz

Includes a simple animation, using a text widget. <lang oz>declare

 Rules =
 [rule(&  & )
  rule(&H &t)
  rule(&t &.)
  rule(&. &H when:fun {$ Neighbours}
                     fun {IsHead X} X == &H end
                     Hs = {Filter Neighbours IsHead}
                     Len = {Length Hs}
                  in
                     Len == 1 orelse Len == 2
                  end)
  rule(&. &.)]

 Init = ["tH........."
         ".   .      "
         "   ...     "
         ".   .      "
         "Ht.. ......"]

 MaxGen = 100

 %% G(i) -> G(i+1)
 fun {Evolve Gi}
    fun {Get X#Y}
       Row = {CondSelect Gi Y unit}
    in
       {CondSelect Row X & } %% cells beyond boundaries are empty
    end
    fun {GetNeighbors X Y}
       {Map [X-1#Y-1  X#Y-1  X+1#Y-1
             X-1#Y           X+1#Y
             X-1#Y+1  X#Y+1  X+1#Y+1]
        Get}
    end
 in
    {Record.mapInd Gi
     fun {$ Y Row}
        {Record.mapInd Row
         fun {$ X C}
            for Rule in Rules return:Return do
               if C == Rule.1 then

When = {CondSelect Rule when {Const true}} in if {When {GetNeighbors X Y}} then {Return Rule.2} end end end

         end}
     end}
 end

 %% Create an arena from a list of strings.
 fun {ReadArena LinesList}
    {List.toTuple '#'
     {Map LinesList
      fun {$ Line}
         {List.toTuple row Line}
      end}}
 end

 %% Converts an arena to a virtual string
 fun {ShowArena G}
    {Record.map G
     fun {$ L} {Record.toList L}#"\n" end}
 end

 %% helpers
 fun lazy {Iterate F V} V|{Iterate F {F V}} end
 fun {Const X} fun {$ _} X end end
 
 %% prepare GUI
 [QTk]={Module.link ["x-oz://system/wp/QTk.ozf"]}
 GenDisplay
 Field
 GUI = td(label(handle:GenDisplay)
          label(handle:Field font:{QTk.newFont font(family:'Courier')})
         )
 {{QTk.build GUI} show}

 G0 = {ReadArena Init}
 Gn = {Iterate Evolve G0}

in

 for
    Gi in Gn
    I in 0..MaxGen
 do
    {GenDisplay set(text:"Gen. "#I)}
    {Field set(text:{ShowArena Gi})}
    {Delay 500}
 end</lang>

PureBasic

<lang PureBasic>Enumeration

  #Empty     
  #Electron_head
  #Electron_tail
  #Conductor

EndEnumeration

1. Delay=100
2. XSize=23
3. YSize=12

Procedure Limit(n, min, max)

 If n<min
   n=min
 ElseIf n>max
   n=max
 EndIf
 ProcedureReturn n

EndProcedure

Procedure Moore_neighborhood(Array World(2),x,y)

 Protected cnt=0, i, j
 For i=Limit(x-1, 0, #XSize) To Limit(x+1, 0, #XSize)
   For j=Limit(y-1, 0, #YSize) To Limit(y+1, 0, #YSize) 
     If World(i,j)=#Electron_head
       cnt+1
     EndIf
   Next
 Next
 ProcedureReturn cnt

EndProcedure

Procedure PresentWireWorld(Array World(2))

 Protected x,y
 ;ClearConsole()
 For y=0 To #YSize
   For x=0 To #XSize
     ConsoleLocate(x,y)
     Select World(x,y)
       Case #Electron_head
         ConsoleColor(12,0): Print("#")
       Case #Electron_tail
         ConsoleColor(4,0): Print("#")
       Case #Conductor
         ConsoleColor(6,0): Print("#")
       Default
         ConsoleColor(15,0): Print(" ")
     EndSelect
   Next
   PrintN("")
 Next

EndProcedure

Procedure UpdateWireWorld(Array World(2))

 Dim NewArray(#XSize,#YSize)
 Protected i, j
 For i=0 To #XSize
   For j=0 To #YSize
     Select World(i,j)
       Case #Electron_head
         NewArray(i,j)=#Electron_tail
       Case #Electron_tail
         NewArray(i,j)=#Conductor
       Case #Conductor
         Define m=Moore_neighborhood(World(),i,j)
         If m=1 Or m=2
           NewArray(i,j)=#Electron_head
         Else
           NewArray(i,j)=#Conductor
         EndIf
       Default ; e.g. should be Empty
         NewArray(i,j)=#Empty
     EndSelect
   Next
 Next
 CopyArray(NewArray(),World())

EndProcedure

If OpenConsole()

 EnableGraphicalConsole(#True)
 ConsoleTitle("XOR() WireWorld")
 ;- Set up the WireWorld
 Dim WW.i(#XSize,#YSize)
 Define x, y
 Restore StartWW
 For y=0 To #YSize
   For x=0 To #XSize
     Read.i WW(x,y)
   Next
 Next
 
 ;- Start the WireWorld simulation
 Repeat
   PresentWireWorld(WW())
   UpdateWireWorld(WW())
   Delay(#Delay)
 ForEver

EndIf

DataSection

 StartWW:
 Data.i  0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
 Data.i  0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
 Data.i  0,0,0,3,3,3,3,2,1,3,3,0,0,0,0,0,0,0,0,0,0,0,0,0
 Data.i  0,0,1,0,0,0,0,0,0,0,0,3,3,3,3,3,3,0,0,0,0,0,0,0
 Data.i  0,0,0,2,3,3,3,3,3,3,3,0,0,0,0,0,0,3,0,0,0,0,0,0
 Data.i  0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,3,3,3,3,0,0,0,0
 Data.i  0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,3,0,0,3,3,3,3,3
 Data.i  0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,3,3,3,3,0,0,0,0
 Data.i  0,0,0,3,3,3,3,3,3,3,3,0,0,0,0,0,0,3,0,0,0,0,0,0
 Data.i  0,0,1,0,0,0,0,0,0,0,0,3,3,3,3,3,3,0,0,0,0,0,0,0
 Data.i  0,0,0,2,3,3,3,3,1,2,3,0,0,0,0,0,0,0,0,0,0,0,0,0
 Data.i  0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
 Data.i  0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0

EndDataSection</lang>

Python

<lang python> Wireworld implementation.

from io import StringIO from collections import namedtuple from pprint import pprint as pp import copy

WW = namedtuple('WW', 'world, w, h') head, tail, conductor, empty = allstates = 'Ht. '

infile = StringIO(\ tH......... . .

  ...

. . Ht.. ......\ )

def readfile(f):

   'file > initial world configuration'
   world  = f.readlines()
   world  = [row.rstrip('\r\n') for row in world]
   height = len(world)
   width  = max(len(row) for row in world)
   # fill right and frame in empty cells
   nonrow = [ " %*s " % (-width, "") ]
   world  = ( nonrow
              + [ " %*s " % (-width, row) for row in world ]
              + nonrow[:] )    
   world = [list(row) for row in world]
   return WW(world, width, height)

def newcell(currentworld, x, y):

   istate = currentworld[y][x]
   assert istate in allstates, 'Wireworld cell set to unknown value "%s"' % istate
   if istate == head:
       ostate = tail
   elif istate == tail:
       ostate = conductor
   elif istate == empty:
       ostate = empty
   else: # istate == conductor
       n = sum( currentworld[y+dy][x+dx] == head
                for dx,dy in ( (-1,-1), (-1,+0), (-1,+1),
                               (+0,-1),          (+0,+1),
                               (+1,-1), (+1,+0), (+1,+1) ) )
       ostate = head if 1 <= n <= 2 else conductor
   return ostate

def nextgen(ww):

   'compute next generation of wireworld'
   world, width, height = ww
   newworld = copy.deepcopy(world)
   for x in range(1, width+1):
       for y in range(1, height+1):
           newworld[y][x] = newcell(world, x, y)
   return WW(newworld, width, height)

def world2string(ww):

   return '\n'.join( .join(row[1:-1]).rstrip() for row in ww.world[1:-1] )

ww = readfile(infile) infile.close()

for gen in range(10):

   print ( ("\n%3i " % gen) + '=' * (ww.w-4) + '\n' )
   print ( world2string(ww) )
   ww = nextgen(ww)</lang>

Sample Output

  0 =======

tH.........
.   .
   ...
.   .
Ht.. ......

  1 =======

.tH........
H   .
   ...
H   .
t... ......

  2 =======

H.tH.......
t   .
   ...
t   .
.H.. ......

  3 =======

tH.tH......
.   H
   ...
.   .
HtH. ......

  4 =======

.tH.tH.....
H   t
   HHH
H   .
t.tH ......

  5 =======

H.tH.tH....
t   .
   ttt
t   .
.H.t ......

  6 =======

tH.tH.tH...
.   H
   ...
.   .
HtH. ......

  7 =======

.tH.tH.tH..
H   t
   HHH
H   .
t.tH ......

  8 =======

H.tH.tH.tH.
t   .
   ttt
t   .
.H.t ......

  9 =======

tH.tH.tH.tH
.   H
   ...
.   .
HtH. ......

Ruby

See: Wireworld/Ruby

Tcl

See: Wireworld/Tcl

Ursala

The board is represented as a list of character strings, and the neighborhoods function uses the swin library function twice to construct a two dimensional 3 by 3 sliding window. The rule function maps a pair (cell,neighborhood) to a new cell. <lang Ursala>#import std

rule = case~&l\~&l {`H: `t!, `t: `.!,`.: @r ==`H*~; {'H','HH'}?</`H! `.!}

neighborhoods = ~&thth3hthhttPCPthPTPTX**K7S+ swin3**+ swin3@hNSPiCihNCT+ --<0>*+ 0-*

evolve "n" = @iNC ~&x+ rep"n" ^C\~& rule**+ neighborhoods@h</lang> test program: <lang Ursala>diode =

<

  '        ..   ',
  'tH....... .Ht',
  '        ..   '>

1. show+

example = mat0 evolve13 diode</lang> output:

        ..   
tH....... .Ht
        ..   

        ..   
.tH...... Ht.
        ..   

        .H   
..tH..... t..
        .H   

        Ht   
...tH...H ...
        Ht   

        t.   
....tH..t ...
        t.   

        ..   
.....tH.. ...
        ..   

        ..   
......tH. ...
        ..   

        H.   
.......tH ...
        H.   

        tH   
........t ...
        tH   

        .t   
......... H..
        .t   

        ..   
......... tH.
        ..   

        ..   
......... .tH
        ..   

        ..   
......... ..t
        ..   

        ..   
......... ...
        ..