let step k st outs ins =
if st <> T.OO then k st outs ins else
match ins with
+ | "stream_eq" :: tl -> k T.OK ("stream_eq" :: outs) tl
| "ctc" :: tl -> k T.OK ("ctc" :: outs) tl
| "contextual" :: "transitive" :: "closure" :: tl -> k T.OK ("ctc" :: outs) tl
| "compose" :: tl -> k T.OK ("compose" :: outs) tl