A tiny Brainfuck interpreter in PostScript

tiny_bf.ps

% A Brainfuck interpreter written in PostScript
% 2023-12-05 Nicolas Seriot https://github.com/nst/bfps
% ps2pdf bf_tiny.ps && open bf_tiny.ps

/P(+[-[<<[+[--->]-[<<<]]]>>>-]>-.---.>..>.<<<<-.<+.>>>>>.>.<<.<-.)def

/Courier findfont 12 scalefont setfont 32 740 moveto

/p 0 def/M 30000 string def/m 0 def/V{M m get}def/j P length array def 0 1 P
length 1 sub{/i exch def/c P i 1 getinterval def c([)eq{i}if c(])eq{/x exch def
j i x put j x i put}if}for/_{V add 255 and M m 3 -1 roll put}def{p P length ge{
exit}if/C P p 1 getinterval def C(+)eq{1 _}if C(-)eq{-1 _}if C(>)eq{/m m 1 add
def}if C(<)eq{/m m 1 sub def}if C([)eq{V 0 eq{/p j p get def}if}if C(])eq{V 0
ne{/p j p get def}if}if C(.)eq{/s 1 string def s 0 V put s show}if C(,)eq{/f
(%lineedit)(r)file def f read pop M m 3 -1 roll put}if/p p 1 add def}loop