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[Caml-list] Q: Correct locations for macro camlp4 extensions
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Date: | 2004-08-24 (07:43) |
From: | Marcin 'Qrczak' Kowalczyk <qrczak@k...> |
Subject: | Re: [Caml-list] Q: Correct locations for macro camlp4 extensions |
W li¶cie z pon, 23-08-2004, godz. 19:16 -0400, Michael Alexander Hamburg napisa³: > Another syntax construction that I might write up (which I'm not aware of > in any programming language) would be something like > > (f _ x _ _ y) translates into (fun p1 p2 p3 -> f p1 x p2 p3 y) My language Kogut uses this (along with _ in patterns as in other functional languages). Note: these expressions are evaluated once, not each time the function is applied. http://kokogut.sourceforge.net/kogut.html > When I have n lists of pairs to sort by the > first element of the tuple, or some other function like that, it saves me > a significant amount of programming effort to write > > # let (<-<<) f g a b = f (g a) (g b);; > or > # let sort_by g a b = sort (compare (g a) (g b));; It may be better to perform Schwartzian transform: make a list of (g x, x) pairs, sort it, and extract elements back. It applies g O(N) rather than O(N log N) times. Well, unless g is as simple as fst. -- __("< Marcin Kowalczyk \__/ qrczak@knm.org.pl ^^ http://qrnik.knm.org.pl/~qrczak/ ------------------- To unsubscribe, mail caml-list-request@inria.fr Archives: http://caml.inria.fr Bug reports: http://caml.inria.fr/bin/caml-bugs FAQ: http://caml.inria.fr/FAQ/ Beginner's list: http://groups.yahoo.com/group/ocaml_beginners