note
educated_foo
<i>You can get pretty much the same techniques out of Haskell, but you'll miss currying.</i>
<p>Huh? Haskell's curried...
<code>
foo a b c = a ++ c ++ b
with_parens a b = foo a b
y = with_parens "<" ">"
</code>
then print (y "banana") prints "<banana>".
BTW, if you haven't, you should <strong>definitely</strong> check out Haskell, as it can be a truly mind-bending experience. It's easy to get up and running with the <a href="http://haskell.org/hugs/">HUGS</a> interpreter, now with delicious readline support.
<p>
/s
<p>
<b>Update:</b> you won't miss the currying anymore...
<code>
use strict;
use Carp;
use Attribute::Handlers;
sub _curry {
my ($n, $func, @args) = @_;
return sub {
my $narg = @args + @_;
if ($narg > $n) {
carp "$narg args to curried function (expects $n).";
} elsif ($narg < $n) {
return _curry($n, $func, @args, @_);
} else {
return &$func(@args, @_);
}
};
}
sub curry : ATTR(CODE) {
my ($package, $symbol, $code, $name, $n) = @_;
confess "Usage: sub mysub : curry(N), where N > 0"
unless $n;
local($^W) = 0;
no strict 'refs';
my $newsub = _curry($n, $code);
*{$package . '::' . *{$symbol}{NAME}} = $newsub;
}
sub foo :curry(3) {
print "foo: @_\n";
}
my $x = foo(1,2);
&$x(3);
&$x(2);
</code>
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