This might sound kind of dumb, but since I've never used C before, how can I modify the given interpreter (sange.fi/~atehwa/small-esoteric/iag.c) to take programmes from stdin, instead of from a programme file?
@EdgyNerd I can't test it at the moment, but shouldn't be too hard: in the main function remove the lines between char *progp = prog; and the while loop, then within the while loop change fgetc(pfile) to getc(). It'd be pretty simplistic, but it should work.