# Sample usage:
    my @array= ( [ 'a'..'c',undef ], [ 1..7 ], [ 'A'..'E' ] );
    my @trans= mapcar { [@_] } @array;
#   @transpose is now ( ['a',1,'A'],['b',2,'B'],['c',3,'C'],
#                       [undef,4,'D'],[5,'E'],[6] )
    my @transpose= mapcaru { [@_] } @array;
#   @trans is now ( ['a',1,'A'],['b',2,'B'],['c',3,'C'],
#                   [undef,4,'D'],[undef,5,'E'],[undef,6,undef] )

##</code><code>##

#!/usr/bin/perl -w

package mapcar;
use strict;
require Exporter;
use vars qw( $VERSION @EXPORT @ISA );
BEGIN {
    $VERSION= 1.01;
    @EXPORT= qw( mapcar mapcaru );
    @ISA= qw( Exporter );
}

sub mapcaru (&@)
{
    my $sub= shift;
    if(  ! @_  ) {
        require Carp;
        Carp::croak( "mapcaru: Nothing to map" );
    }
    my $max= 0;
    for my $av (  @_  ) {
        if(  ! UNIVERSAL::isa( $av, "ARRAY" )  ) {
            require Carp;
            Carp::croak( "mapcaru: Not an array reference (",
                ref($av) ? ref($av) : $av, ")" );
        }
        $max= @$av   if  $max < @$av;
    }
    my @ret;
    for(  my $i= 0;  $i < $max;  $i++  ) {
        push @ret, &$sub( map { $_->[$i] } @_ );
    }
    return wantarray ? @ret : \@ret;
}

sub mapcar (&@)
{
    my $sub= shift;
    if(  ! @_  ) {
        require Carp;
        Carp::croak( "mapcar: Nothing to map" );
    }
    my $max= 0;
    for my $av (  @_  ) {
        if(  ! UNIVERSAL::isa( $av, "ARRAY" )  ) {
            require Carp;
            Carp::croak( "mapcar: Not an array reference (",
                ref($av) ? ref($av) : $av, ")" );
        }
        $max= @$av   if  $max < @$av;
    }
    my @ret;
    for(  my $i= 0;  $i < $max;  $i++  ) {
        push @ret, &$sub( map { $i < @$_ ? $_->[$i] : () } @_ );
    }
    return wantarray ? @ret : \@ret;
}

1;