RosettaCodeData/Task/Wireworld/ALGOL-68/wireworld.alg

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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