use Perl

• Making it even more compact... (Score:1)

  by amahabal (8575)

  I don't know how to do this, but I am sure Patrick or Jonathan can do this quickly... In the code above, there is still repetition: all entries in %op_dispatch_table are nearly identical, differing only depending on the arity. We could replace that with something generic which is passed a sub, it pops as many elements as the arity of the passed sub and pushes back the value of applying the sub to the reverse of this list. I was unable to do this myself because I could not get from the name of the sub to t
  • Re:Making it even more compact... (Score:2)

    by pmichaud (6013) on 2009.03.03 10:09 (#67673) Homepage Journal

    Yes, it could potentially be made slightly shorter... but I like the straightforward clarity of the above. An advantage of the above approach is that it would work for almost any stack pattern -- including things that don't fit the ".push( fn(.pop) )" model. For example, to add a 'say' operator that displays the top value of the stack (without removing it):

        'say' => { .[*-1].say }

    I can also imagine functions that rotate or swap the top N operands, or the like. Trying to wedge those into a standard .push/.pop sequence seems a little less straightforward than what we have above.

    I'd still be interested in seeing the solution you have in mind, even if Rakudo doesn't compile/run it yet. In fact, we'd be a bit more likely to make it do that if we had an example to work to. :-)

    Thanks!

    Pm

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    • Re: (Score:1)

      by amahabal (8575)

      I have one version here: http://use.perl.org/~amahabal/journal/38583 [perl.org] Thanks to your suggestion, I added 'say' and 'rotate3'. I will try my original idea next, for which I need to go from a name (such as 'double') to a callable object (&double). Not sure yet what I'd do with multis and such, but I will see how far I get.