( Forth testing harness
"#" means "assert". We stop at first failure, indicating
the failure through IO on port 1 )
: fail SPC ." failed" LF 1 1 PC! BYE ;
: # IF SPC ." pass" LF ELSE fail THEN ;
: #eq 2DUP SWAP . SPC '=' EMIT SPC . '?' EMIT = # ;