#!/usr/bin/perl
  use strict;
  use warnings;

  use lib '.';

  use Stream qw/node list_to_stream/;
  use Parser ':all';
    
  use Test::More 'no_plan';

  my @tokens = ( 
    node( OP  => '+' ),
    node( VAR => 'x' ), 
    node( VAL =>  3  )
  );  
  my $stream = list_to_stream(@tokens);

  my $parser = concatenate( 
    lookfor('OP'), 
    lookfor('VAR'),
  );
  my ( $parsed, $remainder ) = $parser->($stream);
  is_deeply $parsed, [qw/+ x/],
    'concatenate should return the parsed values';
  is_deeply $remainder, [ VAL => 3 ],
    '... and the rest of the stream';

  # the next test fails ...
  $parser = concatenate(
    lookfor('OP'),
    lookfor('VAR'),
    lookfor('VAL'),
  );
  ( $parsed, $remainder ) = $parser->($stream);
  is_deeply $parsed, [qw/+ x 3/],
    'concatenate should return the parsed values';
  ok !defined $remainder,
    '... and the remaining stream should be empty';