foldingStartMarker = '\b(proc|domain|case|if|%if|for|while|repeat|axiom|category)\b'; foldingStopMarker = '\b(end|end_proc|end_domain|end_case|end_if|end_for|end_while| end_repeat|end_axiom|end_category)\b';
You could do for instance...
'[^#]*?\b(proc|domain|case|if|%if|for|while|repeat|axiom|category)\b'
Provided your comment char is # that is, basically whatever it is look for it preceding the keyword to negate the entire rule.