alternation.pm

来自「这是一个DFA简化和生成LL(1)分析表的程序,自动生成表格及图形」· PM 代码 · 共 54 行

#: Kid/AST/alternation.pm - generated from template/leftop.pm.tt

package alternation;

use strict;
use warnings;
#use Data::Dumper::Simple;

sub alternation {
    my $self = shift;
    if (!exists $self->{alternation}) {
        my $rlist = $self->{'concat(s)'};
        return nil->new if not $rlist;
        my @concats = @$rlist;
        my $concat = pop @concats;
        my $alternation;
        if (@concats) {
            $alternation = bless {'concat(s)' => \@concats}, ref $self;
        } else {
            $alternation = nil->new;
        }
        $self->{alternation} = $alternation;
        $self->{concat} = $concat;
        #delete $self->{'concat(s)'};
        #warn Dumper($self);
    }
    return $self->{alternation};
}

sub concat {
    my $self = shift;
    if (!exists $self->{concat}) {
        $self->alternation;
    }
    if (@_) {
        $self->{concat} = shift;
    } else {
        $self->{concat} || nil->new;
    }
}

sub get_all {
    my $list = shift;
    my @elems;
    while (ref $list eq 'alternation') {
        unshift @elems, $list->concat;
        $list = $list->alternation;
    }
    @elems;
}


1;