[Haskell-cafe] trivial function application question
jules at jellybean.co.uk
Fri Jan 5 06:55:03 EST 2007
> So the core question (speaking as a perler) is how do you write
> my $s= 'abcdefg';
> $s =~ s/a/z/g;
> $s =~ s/b/y/g;
> print "$s\n";
> in haskell? There are various haskell regex libraries out there,
But that's such a perler attitude. When all you have is a regex,
everything looks like a s///!
This really doesn't look like much of a regex question to me. A more
haskelly answer might be as simple as:
m 'a' = 'z'
m 'b' = 'y'
m x = x
test1 = map m "abcdefg"
...which is general in the sense that 'm' can be an arbitrary function
from Char -> Char, and avoids the 'overlapping replace' behaviour
alluded to elsewhere in this thread, but is limited if you wanted to do
To do string-based replacement you do have to think careful about what
semantics you're expecting though (w.r.t. overlapping matches, repeated
matches, priority of conflicting matches).
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