las-span.pl

use 5.010;
use strict;
use warnings;

use Data::Dumper;

use Marpa::R2;

my $g = Marpa::R2::Scanless::G->new( { 
    source => \(<<'END_OF_SOURCE'),
:default ::= action => [name, value]
lexeme default = action => [name, value]

    All ::= Span
    Span ::= Closed_Span | Open_Span
    Closed_Span ::= Abbreviation
    Closed_Span ::= Closed_Syllable
    Closed_Span ::= Span Closed_Syllable
    Closed_Span ::= Closed_Span Abbreviation
    Open_Span ::= Span Open_Syllable
    Open_Span ::= Open_Syllable
    Abbreviation ::= C
    Closed_Syllable ::= C V C
    Open_Syllable ::= C V

    C ~ [bcdfghjklmnpqrstvwxyz]
    V ~ [aeiou]

:discard ~ whitespace
whitespace ~ [\s]+
END_OF_SOURCE
} );

my $input = <<EOI;
mat
m
EOI

my $r = Marpa::R2::Scanless::R->new( { grammar => $g } );
eval {$r->read(\$input)} || die "Parse failure, progress report is:\n" . $r->show_progress;

if ( $r->ambiguity_metric() > 1 ){
    say "Ambiguous parse, use Marpa::R2::ASF, now dumping alternatives:" ;
    while (my $v = $r->value){
        say Dumper $v;
    }
}
else{
    say Dumper ${ $r->value };
}

$VAR1 = [
          'All',
          [
            'Span',
            [
              'Closed_Span',
              [
                'Closed_Span',
                [
                  'Closed_Syllable',
                  [
                    'C',
                    'm'
                  ],
                  [
                    'V',
                    'a'
                  ],
                  [
                    ${\$VAR1->[1][1][1][1][1][0]},
                    't'
                  ]
                ]
              ],
              [
                'Abbreviation',
                [
                  ${\$VAR1->[1][1][1][1][1][0]},
                  'm'
                ]
              ]
            ]
          ]
        ];