metaperl has asked for the wisdom of the Perl Monks concerning the following question:

I have a subroutine which returns a word based on the results of applying a closure to a test value: 
sub morf {

    my($tester, $testval, $true_word, $false_word)=@_;
    $tester->($testval) ? $true_word : $false_word ;

}

[download]
Now, I want to curry string equal so that my function morf returns 'Male' if the $testval is 'M' and otherwise female: 
sub se {
    my ($val) = @_;

    sub { $_[0] eq $val } ;
}

[download]
morf(se('M'), $driver->{gender}, 'Male', 'Female') ;

[download]
How can this be done?

Replies are listed 'Best First'.
Re: currying CORE functions into closures?
by roboticus (Chancellor) on May 01, 2009 at 22:35 UTC
    metaperl:

    Doesn't it just work?

    roboticus@swill
$ cat 761397.pl
#!/usr/bin/perl -w
use strict;
use warnings;

sub morf {
        my ($tester, $testval, $true_word, $false_word) = @_;
        $tester->($testval) ? $true_word : $false_word;
}

sub se {
        my ($val) = @_;
        sub { $_[0] eq $val}
}

my $fr = se('M');

for my $FL (split /|/, "MNLOP") {
        print "FL=$FL, MORF=", morf($fr, $FL, 'Male', 'Female'), "\n";
}
roboticus@swill
$ ./761397.pl
FL=M, MORF=Male
FL=N, MORF=Female
FL=L, MORF=Female
FL=O, MORF=Female
FL=P, MORF=Female
Male
Female
Male

    [download]
    ...roboticus
[reply]
[d/l]
Re: currying CORE functions into closures?
by revdiablo (Prior) on May 01, 2009 at 21:13 UTC

    Maybe I don't understand your question, but aren't you already doing that with se?

[reply]
[d/l]

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