Creating operators in the flavor of map & grep...

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

We're all familiar with the perl operators map and grep...

map { ...code here... } @array
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I'd like to create a similar function called &partition that accepts a block of code and acts on an array in similar fashion. I've tried several approaches, most promising of which was

# Predeclaration
sub partition($\@);

...

sub partition($\@){

    my ($coderef, @array) = @_;

    # Do something with these variables

}
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Unfortunately, this doesn't work - typing partition {...} @a just generates a syntax error.
Is what I'm attempting impossible, or am I just not seeing something?
Chris Luka

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Re: Creating operators in the flavor of map & grep... by DamnDirtyApe (Curate) on Sep 04, 2002 at 23:55 UTC
I asked the same question a while back in How do I write subs that take bare blocks as args?, and got many helpful responses. _______________ DamnDirtyApe Those who know that they are profound strive for clarity. Those who would like to seem profound to the crowd strive for obscurity. --Friedrich Nietzsche	[reply]
Re: Creating operators in the flavor of map & grep... by shotgunefx (Parson) on Sep 04, 2002 at 23:49 UTC
The prototype should be partition(&\@) and the array will be passed by ref so it should be my ($coderef,$arrarref) = @_; -Lee "To be civilized is to deny one's nature."	[reply]
Re: Re: Creating operators in the flavor of map & grep... by flounder99 (Friar) on Sep 05, 2002 at 11:58 UTC
I would recommend using (&@) as a prototype. That way you can use a list for other arguments. If you use ($\@) your second argument must be an array. `use strict; use Data::Dumper; sub takes_coderef (&@); takes_coderef {print "I'm a code ref called with (", join(", ", @_), " +)\n"} "first", 2, 3; sub takes_coderef (&@) { my $coderef = shift; my @otherargs = @_; &$coderef(@otherargs); print Data::Dumper->Dump([\@otherargs], ["*otherargs"]); } ___OUTPUT___ I'm a code ref called with (first, 2, 3) @otherargs = ( 'first', 2, 3 );` [download] See this thread about prototypes and especially Tom Christiansen's Prototypes in Perl for a very in-depth discussion of prototypes. -- flounder	[reply] [d/l]
Re: Re: Re: Creating operators in the flavor of map & grep... by shotgunefx (Parson) on Sep 05, 2002 at 13:35 UTC
For most purposes your probably right. Myself, I've mainly written map\|grep like functions for lazy iteration so I've needed the reference to the data. -Lee "To be civilized is to deny one's nature."	[reply]