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in reply to Re: Why Perl Is Not My Favourite Functional Programming Language
in thread A mini-language for sequences (part 1)

Have you tried prototypes?

Briefly. I don't fully grok the try/catch example in perldoc perlsub, so I may be missing something, but my failed attempts look like: 

#! /usr/bin/perl

use strict;
use warnings;

sub curry(&@)
{
    my ($fn, @args) = @_;

    return sub {
        $fn->(@args, @_);
    }
}

&curry(+, 2)->();

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which of course does not compile. (There's also the issue that in order to really do higher-order functions with prototypes, I'd need to somehow examine fn's prototype and preserve it in the returned sub.)

I'm thinking that a source filter might help, turning builtins used as values into anonymous subs, but I don't know very much about source filters — I'm not even sure that they do what I think they do.

--
Yours in pedantry,
F o x t r o t U n i f o r m
"Anything you put in comments is not tested and easily goes out of date." -- tye

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Re^3: Why Perl Is Not My Favourite Functional Programming Language
by itub (Priest) on Nov 06, 2004 at 03:46 UTC
    Perhaps I misunderstood what you wanted. While you are certainly in trouble if you want to curry the + operator, I see no problem with a function such as sum. 

    use strict;
use warnings;
use List::Util qw(sum);

sub curry(&@)
{
    my ($fn, @args) = @_;
    return sub {
        $fn->(@args, @_);
    }
}

my $f = curry { sum(@_) } 5;

print $f->(3); # prints 8 (5 + 3)

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Re^3: Why Perl Is Not My Favourite Functional Programming Language
by brian_d_foy (Abbot) on Nov 19, 2004 at 17:56 UTC
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In Section Meditations