Marcin 'Qrczak' Kowalczyk
2 Mar 2001 18:58:16 GMT
Thu, 1 Mar 2001 12:25:33 +0100, S. Doaitse Swierstra <email@example.com> pisze:
> From the Haskell manual I understand that pattern matching in "let"'s
> should be done lazily, so the addition of a collection of ~'s should
> not make a difference.
Toplevel ~ in let doesn't change anything. But nested ~'s do make
a difference. When a variable of a pattern is evaluated, the whole
pattern is matched. When you protect a subpattern by ~ deferring its
matching and a variable from the subpattern is evaluated, again the
whole subpattern is matched, unless its subsubpatterns are protected
with their own ~'s etc.
__("< Marcin Kowalczyk * firstname.lastname@example.org http://qrczak.ids.net.pl/
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