Create a gist now

Instantly share code, notes, and snippets.

What would you like to do?
Marpa parse for subset of bird language
#!/usr/bin/perl
use 5.010;
use strict;
use warnings;
use Data::Dumper;
use English qw( -no_match_vars );
use Test::More tests => 6;
use Marpa::R2 2.090;
my $dsl = <<'END_OF_DSL';
:default ::= action => [name,values]
lexeme default = latm => 1
S ::= ABC
S ::= D
S ::= ABC D
S ::= D ABC
ABC ~ 'abc'
D ~ 'd'
:discard ~ whitespace
whitespace ~ [\s]+
END_OF_DSL
my @ex = ('abc d',
'd abc',
'd abc d',
'd',
'abc',
'abc d d'
);
my $grammar = Marpa::R2::Scanless::G->new( { source => \$dsl } );
TEST: for my $ix (0 .. $#ex)
{
my $input = \($ex[$ix]);
my $i = $ix + 1;
say "** Test #$i: ", ${$input};
my $recce = Marpa::R2::Scanless::R->new( { grammar => $grammar } );
my $value_ref;
my $eval_ok = eval { $value_ref = doit( $recce, $input ); 1; };
if ( !$eval_ok ) {
Test::More::fail("Example $i failed");
Test::More::diag($EVAL_ERROR);
next TEST;
}
say flatten($value_ref);
Test::More::pass( "Example $i OK" );
} ## end TEST:
sub flatten {
my ($tree) = @_;
if ( ref $tree eq 'REF' ) { return flatten( ${$tree} ); }
if ( ref $tree eq 'ARRAY' ) {
return join " ", map { flatten($_) } @{$tree};
}
return $tree;
} ## end sub flatten
sub doit {
my ( $recce, $input ) = @_;
my $input_length = ${$input};
my $length_read = $recce->read($input);
if ( $length_read != length $input_length ) {
die "read() ended prematurely\n",
" input length = $input_length\n",
" length read = $length_read\n",
" the cause may be an unexpected event";
} ## end if ( $length_read != length $input_length )
my $value_ref = $recce->value();
if ( !$value_ref ) {
die "input read, but there was no parse";
}
return $value_ref;
} ## end sub doit
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment