package Regexp::Common::list;

use 5.10.0;

use strict;
use warnings;
no  warnings 'syntax';

use Regexp::Common qw /pattern clean no_defaults/;

our $VERSION = '2017060201';

sub gen_list_pattern {
    my ($pat, $sep, $lsep) = @_;
    $lsep = $sep unless defined $lsep;
    return "(?k:(?:(?:$pat)(?:$sep))*(?:$pat)(?k:$lsep)(?:$pat))";
}

my $defpat = '.*?\S';
my $defsep = '\s*,\s*';

pattern name   => ['list', "-pat=$defpat", "-sep=$defsep", '-lastsep'],
        create => sub {gen_list_pattern (@{$_[1]}{-pat, -sep, -lastsep})},
        ;

pattern name   => ['list', 'conj', '-word=(?:and|or)'],
        create => sub {gen_list_pattern($defpat, $defsep,
                                        '\s*,?\s*'.$_[1]->{-word}.'\s*');
                  },
        ;

pattern name   => ['list', 'and'],
        create => sub {gen_list_pattern ($defpat, $defsep, '\s*,?\s*and\s*')},
        ;

pattern name   => ['list', 'or'],
        create => sub {gen_list_pattern ($defpat, $defsep, '\s*,?\s*or\s*')},
        ;


1;

__END__

=pod

=head1 NAME

Regexp::Common::list -- provide regexes for lists

=head1 SYNOPSIS

    use Regexp::Common qw /list/;

    while (<>) {
        /$RE{list}{-pat => '\w+'}/          and print "List of words";
        /$RE{list}{-pat => $RE{num}{real}}/ and print "List of numbers";
    }


=head1 DESCRIPTION

Please consult the manual of L<Regexp::Common> for a general description
of the works of this interface.

Do not use this module directly, but load it via I<Regexp::Common>.

=head2 C<$RE{list}{-pat}{-sep}{-lastsep}>

Returns a pattern matching a list of (at least two) substrings.

If C<-pat=I<P>> is specified, it defines the pattern for each substring
in the list. By default, I<P> is C<qr/.*?\S/>. In Regexp::Common 0.02
or earlier, the default pattern was C<qr/.*?/>. But that will match
a single space, causing unintended parsing of C<a, b, and c> as a
list of four elements instead of 3 (with C<-word> being C<(?:and)>).
One consequence is that a list of the form "a,,b" will no longer be
parsed. Use the pattern C<qr /.*?/> to be able to parse this, but see
the previous remark.

If C<-sep=I<P>> is specified, it defines the pattern I<P> to be used as
a separator between each pair of substrings in the list, except the final two.
By default I<P> is C<qr/\s*,\s*/>.

If C<-lastsep=I<P>> is specified, it defines the pattern I<P> to be used as
a separator between the final two substrings in the list.
By default I<P> is the same as the pattern specified by the C<-sep> flag.

For example:

      $RE{list}{-pat=>'\w+'}                # match a list of word chars
      $RE{list}{-pat=>$RE{num}{real}}       # match a list of numbers
      $RE{list}{-sep=>"\t"}                 # match a tab-separated list
      $RE{list}{-lastsep=>',\s+and\s+'}     # match a proper English list

Under C<-keep>:

=over 4

=item $1

captures the entire list

=item $2

captures the last separator

=back

=head2 C<$RE{list}{conj}{-word=I<PATTERN>}>

An alias for C<< $RE{list}{-lastsep=>'\s*,?\s*I<PATTERN>\s*'} >>

If C<-word> is not specified, the default pattern is C<qr/and|or/>.

For example:

      $RE{list}{conj}{-word=>'et'}        # match Jean, Paul, et Satre
      $RE{list}{conj}{-word=>'oder'}      # match Bonn, Koln oder Hamburg

=head2 C<$RE{list}{and}>

An alias for C<< $RE{list}{conj}{-word=>'and'} >>

=head2 C<$RE{list}{or}>

An alias for C<< $RE{list}{conj}{-word=>'or'} >>

=head1 SEE ALSO

L<Regexp::Common> for a general description of how to use this interface.

=head1 AUTHOR

Damian Conway (damian@conway.org)

=head1 MAINTENANCE

This package is maintained by Abigail S<(I<regexp-common@abigail.be>)>.

=head1 BUGS AND IRRITATIONS

Bound to be plenty.

For a start, there are many common regexes missing.
Send them in to I<regexp-common@abigail.be>.

=head1 LICENSE and COPYRIGHT

This software is Copyright (c) 2001 - 2017, Damian Conway and Abigail.

This module is free software, and maybe used under any of the following
licenses:

 1) The Perl Artistic License.     See the file COPYRIGHT.AL.
 2) The Perl Artistic License 2.0. See the file COPYRIGHT.AL2.
 3) The BSD License.               See the file COPYRIGHT.BSD.
 4) The MIT License.               See the file COPYRIGHT.MIT.

=cut
