Talk:STXTRM

While the  command would seem to make STXTRM easier to program than MSM, I suspect the fact that non-instructions are not copied from the bottom to the top any longer will make   hard to use without losing the rest of the stack data, at least without combining it cleverly with. Also, I think there is no way to get the equivalent of Underload's a command, not that it is needed for Turing completeness. --Ørjan (talk) 01:02, 12 August 2013 (UTC)

Oh, I think I was wrong about this. I just realized you can use  and   to get hold of raw   and   characters even if in a literally balanced subprogram. From this it's not so hard to implement the analogy of Underload's  command: :,.:/,/. This followed by  gives you a command to preserve a (balanced) string for one iteration, and you can "quine" this to preserve indefinitely, thus getting around the non-copying of non-commands part: [ ; :,.:/,/. ./ :,.:/,/. .: ] ; :,.:/,/. ./ :,.:/,/. .: This makes me convinced that STXTRM is Turing-complete even without. You still cannot use  directly for Underload , though, because it messes up the order of evaluation.

With the help of  I think you can simulate most Underload commands more directly, with a slightly more complicated encoding of Underload  : [ |: [ A ] ] :| will run subprogram  immediately. --Ørjan (talk) 19:11, 27 August 2013 (UTC)

Oh hm that is wrong, I forgot that just reversing  makes it hit a   first. Should be fixable though. --Ørjan (talk) 23:50, 28 August 2013 (UTC) [ [|:], A [] ] :,| should work. --Ørjan (talk) 23:56, 28 August 2013 (UTC)

Argh no, that of course breaks if A contains any  characters. Looking awkward now. :( --Ørjan (talk) 23:58, 28 August 2013 (UTC)