package Text::Abbrev;
require 5.005; # Probably works on earlier versions too.
require Exporter;

our $VERSION = '1.01';

=head1 NAME

abbrev - create an abbreviation table from a list

=head1 SYNOPSIS

use Text::Abbrev;
abbrev $hashref, LIST


=head1 DESCRIPTION

Stores all unambiguous truncations of each element of LIST
as keys in the associative array referenced by C<$hashref>.
The values are the original list elements.

=head1 EXAMPLE

$hashref = abbrev qw(list edit send abort gripe);

%hash = abbrev qw(list edit send abort gripe);

abbrev $hashref, qw(list edit send abort gripe);

abbrev(*hash, qw(list edit send abort gripe));

=cut

@ISA = qw(Exporter);
@EXPORT = qw(abbrev);

# Usage:
# abbrev \%foo, LIST;
# ...
# $long = $foo{$short};

sub abbrev {
my ($word, $hashref, $glob, %table, $returnvoid);

@_ or return; # So we don't autovivify onto @_ and trigger warning
if (ref($_[0])) { # hash reference preferably
$hashref = shift;
$returnvoid = 1;
} elsif (ref \$_[0] eq 'GLOB') { # is actually a glob (deprecated)
$hashref = \%{shift()};
$returnvoid = 1;
}
%{$hashref} = ();

WORD: foreach $word (@_) {
for (my $len = (length $word) - 1; $len > 0; --$len) {
my $abbrev = substr($word,0,$len);
my $seen = ++$table{$abbrev};
if ($seen == 1) { # We're the first word so far to have
# this abbreviation.
$hashref->{$abbrev} = $word;
} elsif ($seen == 2) { # We're the second word to have this
# abbreviation, so we can't use it.
delete $hashref->{$abbrev};
} else { # We're the third word to have this
# abbreviation, so skip to the next word.
next WORD;
}
}
}
# Non-abbreviations always get entered, even if they aren't unique
foreach $word (@_) {
$hashref->{$word} = $word;
}
return if $returnvoid;
if (wantarray) {
%{$hashref};
} else {
$hashref;
}
}

1;