brainfuck.ps

%!PS-Adobe-3.0

% Brainfuck Implementation in PostScript
% Author : Kazuhiko Sakaguchi (pi8027)
% Date : 2010-07-14

/initArray {
	/size exch def
	/arr size array def
	0 1 size 1 sub {
		arr exch 0 put
	} for
	arr
} def

/run {
	/error exch def
	/output exch def
	/input exch def
	/program exch def
	/mem 4096 initArray def
	1 0
	{
		/po exch def
		/pc exch def
		/instruction program pc get def
		instruction 0 eq {
			exit
		} if
		instruction (+) 0 get eq {
			mem po mem po get 1 add 256 mod put
			pc 1 add po
		} if
		instruction (-) 0 get eq {
			mem po mem po get 255 add 256 mod put
			pc 1 add po
		} if
		instruction (>) 0 get eq {
			pc 1 add po 1 add
		} if
		instruction (<) 0 get eq {
			pc 1 add po 1 sub
		} if
		instruction (.) 0 get eq {
			output mem po get write
			pc 1 add po
		} if
		instruction (,) 0 get eq {
			mem po input read not { 0 } if put
			pc 1 add po
		} if
		instruction ([) 0 get eq {
			mem po get 0 eq {
				pc 0
				{
					/instruction' program 3 index get def
					instruction' ([) 0 get eq {
						1 add
					} if
					instruction' (]) 0 get eq {
						1 sub
					} if
					instruction' 0 eq {
						pop pop false exit % error check
					} if
					dup 0 eq {
						pop po true exit
					} if
					exch 1 add exch
				} loop
				not {
					error (Error!) writestring exit
				} if
			}
			{
				pc 1 add po
			} ifelse
		} if
		instruction (]) 0 get eq {
			mem po get 0 ne {
				pc 0
				{
					/instruction' program 3 index get def
					instruction' ([) 0 get eq {
						1 sub
					} if
					instruction' (]) 0 get eq {
						1 add
					} if
					instruction' 0 eq {
						pop pop false exit % error check
					} if
					dup 0 eq {
						pop po true exit
					} if
					exch 1 sub exch
				} loop
				not {
					error (Error!) writestring exit
				} if
			}
			{
				pc 1 add po
			} ifelse
		} if
		% pointer check
	} loop
} def

/element {
	/elem exch def
	/arr exch def
	false
	0 1 arr length 1 sub {
		exch pop
		arr exch get elem eq {
			true
			exit
		} if
		false
	} for
} def

/readProgram {
	/file exch (r) file def
	64 string dup 1 0 put % buffer
	1 % iterator
	{
		/iter exch def
		iter 64 mod 0 eq {
			/newbuf iter 64 add string def
			newbuf 0 3 2 roll putinterval
			newbuf
		} if
		/buf exch def
		file read {
			/ch exch def
			(+-><.,[]) ch element {
				buf iter ch put
				iter 1 add
			}
			{
				iter
			} ifelse
			buf exch
		}
		{
			buf
			exit
		} ifelse
	} loop
	file closefile
} def

/stdin (%stdin) (r) file def
/stdout (%stdout) (w) file def
/stderr (%stderr) (w) file def

(input.bf) readProgram
stdin stdout stderr run

stdin closefile
stdout closefile
stderr closefile