Re: [Factor-talk] Rosettacode and amb
> "Sam" == Samuel Tardieu writes: Sam> - no more macro: "select" recursively builds a candidate using Sam> "amb" And as Jon noticed (in a private chat session), "select" is best defined as : select ( seq -- seq' ) [ amb-lazy ] map ; rather than using the constructive recursive version. Sam -- Samuel Tardieu -- s...@rfc1149.net -- http://www.rfc1149.net/ -- Return on Information: Google Enterprise Search pays you back Get the facts. http://p.sf.net/sfu/google-dev2dev ___ Factor-talk mailing list Factor-talk@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/factor-talk
[Factor-talk] Doctext for map-reduce needs fixing
Hi there,
by sheer luck I stumbled across a mistake in the map-reduce
documentation. It says:
"Unclips the first element of the sequence, calls map-quot on that
element, and proceeds like a reduce, where the calculated element is
the identity element and the rest of the sequence is the sequence to
reduce."
Alright, example:
{ 1 3 5 } [ sq ] [ + ] map-reduce
"Unclips the first element of the sequence,"
{ 1 3 } 5 [ sq ] [ + ] map-reduce
"calls map-quot on that element, and proceeds like a reduce, where the
calculated element is the identity element and the rest of the
sequence is the sequence to reduce."
{ 1 3 } 25 [ + ] reduce
=> 29
Maybe better to say:
"Calls map with map-quot on the complete sequence, then unclips the
first element and proceeds like a reduce..."
same thing in 2map-reduce
Cheers,
Ben
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Re: [Factor-talk] Rosettacode and amb
> "Jon" == Jon Harper writes: Jon> Hi everyone, I wanted to use amb (one the of problems of Jon> rosettacode.org) in factor, but I'm not sure if the solution I came Jon> up with is good. Could you give some feedback ? Is there a Jon> easier/more efficient way than the "macro-map" macro I wrote ? I added an annotation with a simpler (IMO) version: - no more macro: "select" recursively builds a candidate using "amb" - use "2all?" instead of your convoluted reduce (you could have used "2map-reduce" but "2all?" will probably use shortcuts) - use "CONSTANT:" instead of an inlined word Jon> The code is here (only the annotation) : Jon> http://paste.factorcode.org/paste?id=1053#568 Also, as a personal style preference, I dislike words that do something useful *and* print the result unless a non-printing variant exist. I would have written something like: : search ( -- str ) words select dup sentence-match? [ fail ] unless " " join ; : search. ( -- ) search . ; MAIN: search. Amongst other things, this eases testing (although one can argue that redirecting standard output into a string is damn easy in Factor :-). Sam -- Samuel Tardieu -- s...@rfc1149.net -- http://www.rfc1149.net/ -- Return on Information: Google Enterprise Search pays you back Get the facts. http://p.sf.net/sfu/google-dev2dev ___ Factor-talk mailing list Factor-talk@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/factor-talk
