in reply to converting context free grammar to BNF

I switched to Marpa::R2 instad of Parse::RecDescent. I had to change the grammar a bit to make it work: 
#!/usr/bin/perl
use warnings;
use strict;

use Marpa::R2;
use Data::Dumper;

my $dsl = << '__DSL__';
:default ::= action => [values]
lexeme default = latm => 1

seq     ::= '(' seqstrs ')'
seqstrs ::= seqstr seqstrs | seqstr
seqstr  ::= seq | tagstr
tagstr  ::= OZN seq | OZN rijec

OZN      ~ [A-Z.,?'*:`]+
rijec    ~ [\w\-?,:<*`*]+
space    ~ [\s]+
:discard ~ space
__DSL__

my $grammar = 'Marpa::R2::Scanless::G'->new({ source => \$dsl });

my $input = "(SBARQ (WHNP (WP Who))(SQ (VP (VBZ says)(, ,)(S (SBAR (``
+ ``)(IN If)(S (NP (PRP you))(VP (VBP do)(RB n<t)(VP (VB look)(ADJP (J
+J good)))))(, ,)(S (NP (PRP we))(VP (VBP do)(RB n<t)(VP (VB look)(ADJ
+P (JJ good)('' <<)))))))))(? ?))";

my $result = $grammar->parse(\$input);
print Dumper($result);

[download]

It seems you confused ( and '(' . Marpa doesn't know the (s) , you have to enumerate the alternatives.

Output: 

$VAR1 = \[
            '(',
            [
              [
                [
                  'SBARQ',
                  [
                    '(',
                    [
                      [
                        [
                          'WHNP',
                          [
                            '(',
                            [
                              [
                                [
                                  'WP',
                                  'Who'
                                ]
                              ]
                            ],
                            ')'
                          ]
                        ]
                      ]
                    ],
                    ')'
                  ]
                ]
              ],
              [
                [
                  [
                    '(',
                    [
                      [
                        [
                          'SQ',
                          [
                            '(',
                            [
                              [
                                [
                                  'VP',
                                  [
                                    '(',
                                    [
                                      [
                                        [
                                          'VBZ',
                                          'says'
                                        ]
                                      ]
                                    ],
                                    ')'
                                  ]
                                ]
                              ],
                              [
                                [
                                  [
                                    '(',
                                    [
                                      [
                                        [
                                          ',',
                                          ','
                                        ]
                                      ]
                                    ],
                                    ')'
                                  ]
                                ],
                                [
                                  [
                                    [
                                      '(',
                                      [
                                        [
                                          [
                                            'S',
                                            [
                                              '(',
                                              [
                                                [
                                                  [
                                                    'SBAR',
                                                    [
                                                      '(',
                                                      [
                                                        [
                                                          [
                                                            '``',
                                                            '``'
                                                          ]
                                                        ]
                                                      ],
                                                      ')'
                                                    ]
                                                  ]
                                                ],
                                                [
                                                  [
                                                    [
                                                      '(',
                                                      [
                                                        [
                                                          [
                                                            'IN',
                                                            'If'
                                                          ]
                                                        ]
                                                      ],
                                                      ')'
                                                    ]
                                                  ],
                                                  [
                                                    [
                                                      [
                                                        '(',
                                                        [
                                                          [
                                                            [
                                                              'S',
                                                              [
                                                                '(',
                                                                [
                                                                  [
                                                                    [
                                                                      
+'NP',
                                                                      
+[
                                                                      
+  '(',
                                                                      
+  [
                                                                      
+    [
                                                                      
+      [
                                                                      
+        'PRP',
                                                                      
+        'you'
                                                                      
+      ]
                                                                      
+    ]
                                                                      
+  ],
                                                                      
+  ')'
                                                                      
+]
                                                                    ]
                                                                  ]
                                                                ],
                                                                ')'
                                                              ]
                                                            ]
                                                          ],
                                                          [
                                                            [
                                                              [
                                                                '(',
                                                                [
                                                                  [
                                                                    [
                                                                      
+'VP',
                                                                      
+[
                                                                      
+  '(',
                                                                      
+  [
                                                                      
+    [
                                                                      
+      [
                                                                      
+        'VBP',
                                                                      
+        'do'
                                                                      
+      ]
                                                                      
+    ]
                                                                      
+  ],
                                                                      
+  ')'
                                                                      
+]
                                                                    ]
                                                                  ],
                                                                  [
                                                                    [
                                                                      
+[
                                                                      
+  '(',
                                                                      
+  [
                                                                      
+    [
                                                                      
+      [
                                                                      
+        'RB',
                                                                      
+        'n<t'
                                                                      
+      ]
                                                                      
+    ]
                                                                      
+  ],
                                                                      
+  ')'
                                                                      
+]
                                                                    ],
                                                                    [
                                                                      
+[
                                                                      
+  [
                                                                      
+    '(',
                                                                      
+    [
                                                                      
+      [
                                                                      
+        [
                                                                      
+          'VP',
                                                                      
+          [
                                                                      
+            '(',
                                                                      
+            [
                                                                      
+              [
                                                                      
+                [
                                                                      
+                  'VB',
                                                                      
+                  'look'
                                                                      
+                ]
                                                                      
+              ]
                                                                      
+            ],
                                                                      
+            ')'
                                                                      
+          ]
                                                                      
+        ]
                                                                      
+      ],
                                                                      
+      [
                                                                      
+        [
                                                                      
+          [
                                                                      
+            '(',
                                                                      
+            [
                                                                      
+              [
                                                                      
+                [
                                                                      
+                  'ADJP',
                                                                      
+                  [
                                                                      
+                    '(',
                                                                      
+                    [
                                                                      
+                      [
                                                                      
+                        [
                                                                      
+                          'JJ',
                                                                      
+                          'good'
                                                                      
+                        ]
                                                                      
+                      ]
                                                                      
+                    ],
                                                                      
+                    ')'
                                                                      
+                  ]
                                                                      
+                ]
                                                                      
+              ]
                                                                      
+            ],
                                                                      
+            ')'
                                                                      
+          ]
                                                                      
+        ]
                                                                      
+      ]
                                                                      
+    ],
                                                                      
+    ')'
                                                                      
+  ]
                                                                      
+]
                                                                    ]
                                                                  ]
                                                                ],
                                                                ')'
                                                              ]
                                                            ]
                                                          ]
                                                        ],
                                                        ')'
                                                      ]
                                                    ],
                                                    [
                                                      [
                                                        [
                                                          '(',
                                                          [
                                                            [
                                                              [
                                                                ',',
                                                                ','
                                                              ]
                                                            ]
                                                          ],
                                                          ')'
                                                        ]
                                                      ],
                                                      [
                                                        [
                                                          [
                                                            '(',
                                                            [
                                                              [
                                                                [
                                                                  'S',
                                                                  [
                                                                    '(
+',
                                                                    [
                                                                      
+[
                                                                      
+  [
                                                                      
+    'NP',
                                                                      
+    [
                                                                      
+      '(',
                                                                      
+      [
                                                                      
+        [
                                                                      
+          [
                                                                      
+            'PRP',
                                                                      
+            'we'
                                                                      
+          ]
                                                                      
+        ]
                                                                      
+      ],
                                                                      
+      ')'
                                                                      
+    ]
                                                                      
+  ]
                                                                      
+]
                                                                    ],
                                                                    ')
+'
                                                                  ]
                                                                ]
                                                              ],
                                                              [
                                                                [
                                                                  [
                                                                    '(
+',
                                                                    [
                                                                      
+[
                                                                      
+  [
                                                                      
+    'VP',
                                                                      
+    [
                                                                      
+      '(',
                                                                      
+      [
                                                                      
+        [
                                                                      
+          [
                                                                      
+            'VBP',
                                                                      
+            'do'
                                                                      
+          ]
                                                                      
+        ]
                                                                      
+      ],
                                                                      
+      ')'
                                                                      
+    ]
                                                                      
+  ]
                                                                      
+],
                                                                      
+[
                                                                      
+  [
                                                                      
+    [
                                                                      
+      '(',
                                                                      
+      [
                                                                      
+        [
                                                                      
+          [
                                                                      
+            'RB',
                                                                      
+            'n<t'
                                                                      
+          ]
                                                                      
+        ]
                                                                      
+      ],
                                                                      
+      ')'
                                                                      
+    ]
                                                                      
+  ],
                                                                      
+  [
                                                                      
+    [
                                                                      
+      [
                                                                      
+        '(',
                                                                      
+        [
                                                                      
+          [
                                                                      
+            [
                                                                      
+              'VP',
                                                                      
+              [
                                                                      
+                '(',
                                                                      
+                [
                                                                      
+                  [
                                                                      
+                    [
                                                                      
+                      'VB',
                                                                      
+                      'look'
                                                                      
+                    ]
                                                                      
+                  ]
                                                                      
+                ],
                                                                      
+                ')'
                                                                      
+              ]
                                                                      
+            ]
                                                                      
+          ],
                                                                      
+          [
                                                                      
+            [
                                                                      
+              [
                                                                      
+                '(',
                                                                      
+                [
                                                                      
+                  [
                                                                      
+                    [
                                                                      
+                      'ADJP',
                                                                      
+                      [
                                                                      
+                        '(',
                                                                      
+                        [
                                                                      
+                          [
                                                                      
+                            [
                                                                      
+                              'JJ',
                                                                      
+                              'good'
                                                                      
+                            ]
                                                                      
+                          ]
                                                                      
+                        ],
                                                                      
+                        ')'
                                                                      
+                      ]
                                                                      
+                    ]
                                                                      
+                  ],
                                                                      
+                  [
                                                                      
+                    [
                                                                      
+                      [
                                                                      
+                        '(',
                                                                      
+                        [
                                                                      
+                          [
                                                                      
+                            [
                                                                      
+                              '\'\'',
                                                                      
+                              '<<'
                                                                      
+                            ]
                                                                      
+                          ]
                                                                      
+                        ],
                                                                      
+                        ')'
                                                                      
+                      ]
                                                                      
+                    ]
                                                                      
+                  ]
                                                                      
+                ],
                                                                      
+                ')'
                                                                      
+              ]
                                                                      
+            ]
                                                                      
+          ]
                                                                      
+        ],
                                                                      
+        ')'
                                                                      
+      ]
                                                                      
+    ]
                                                                      
+  ]
                                                                      
+]
                                                                    ],
                                                                    ')
+'
                                                                  ]
                                                                ]
                                                              ]
                                                            ],
                                                            ')'
                                                          ]
                                                        ]
                                                      ]
                                                    ]
                                                  ]
                                                ]
                                              ],
                                              ')'
                                            ]
                                          ]
                                        ]
                                      ],
                                      ')'
                                    ]
                                  ]
                                ]
                              ]
                            ],
                            ')'
                          ]
                        ]
                      ]
                    ],
                    ')'
                  ]
                ],
                [
                  [
                    [
                      '(',
                      [
                        [
                          [
                            '?',
                            '?'
                          ]
                        ]
                      ],
                      ')'
                    ]
                  ]
                ]
              ]
            ],
            ')'
          ];

[download]

($q=q:Sq=~/;[c](.)(.)/;chr(-||-|5+lengthSq)`"S|oS2"`map{chr |+ord
}map{substrSq`S_+|`|}3E|-|`7**2-3:)=~y+S|`+$1,++print+eval$q,q,a,

[download]

Replies are listed 'Best First'.
Re^2: converting context free grammar to BNF
by nido203 (Novice) on May 31, 2016 at 18:07 UTC

    Thank you so much guys, I learned some things that were confusing me and turns out that it is ok to just use Parse::RecDescent without BNF. This really helps. I have just one question. As I must use Parse::RecDescent and not Marpa, I need to parse Abstract syntax tree and copy data from dumper to array and then export it to JSON format. The code is this:

    use Parse::RecDescent;
use Data::Dumper;

$::RD_AUTOACTION = q { [ @item ] };


$grammar = q{
start: seq

seq: '(' seqstr(s) ')'

seqstr: seq | tagstr

tagstr: OZN ( seq | rijec )

OZN: /[A-Z.,?'*:`*]+ /
rijec: /[\w-?,:<*`*]+/
};

my $parser=Parse::RecDescent->new($grammar);
my $result = $parser->start("(SBARQ (WHADVP (WRB Where))(SQ (VBZ is)(N
+P (NNP Inoco))(VP (VBN based)))(. ?))");
print Dumper($result);

    [download]
[reply]
[d/l]

      Hi nido203,

      export it to JSON format

      With one of the JSON modules this is as simple as:

      use JSON::MaybeXS;
print encode_json($result);

      [download]

      Hope this helps,
      -- Hauke D

[reply]
[d/l]

        Hi! thanks for the reply but now there is another problem. It works now and it exports to json but it looks like this:

        ["start",["seq","(",[["seqstr",["tagstr",["OZN","SBARQ "],["_alternati
+on_1_of_production_1_of_rule_tagstr",["seq","(",[["seqstr",["tagstr",
+["OZN","WHADVP "],["_alternation_1_of_production_1_of_rule_tagstr",["
+seq","(",[["seqstr",["tagstr",["OZN","WRB "],["_alternation_1_of_prod
+uction_1_of_rule_tagstr",["rijec","Where"]]]]],")"]]]]],")"]]]],["seq
+str",["seq","(",[["seqstr",["tagstr",["OZN","SQ "],["_alternation_1_o
+f_production_1_of_rule_tagstr",["seq","(",[["seqstr",["tagstr",["OZN"
+,"VBZ "],["_alternation_1_of_production_1_of_rule_tagstr",["rijec","i
+s"]]]]],")"]]]],["seqstr",["seq","(",[["seqstr",["tagstr",["OZN","NP 
+"],["_alternation_1_of_production_1_of_rule_tagstr",["seq","(",[["seq
+str",["tagstr",["OZN","NNP "],["_alternation_1_of_production_1_of_rul
+e_tagstr",["rijec","Inoco"]]]]],")"]]]]],")"]],["seqstr",["seq","(",[
+["seqstr",["tagstr",["OZN","VP "],["_alternation_1_of_production_1_of
+_rule_tagstr",["seq","(",[["seqstr",["tagstr",["OZN","VBN "],["_alter
+nation_1_of_production_1_of_rule_tagstr",["rijec","based"]]]]],")"]]]
+]],")"]]],")"]],["seqstr",["seq","(",[["seqstr",["tagstr",["OZN",". "
+],["_alternation_1_of_production_1_of_rule_tagstr",["rijec","?"]]]]],
+")"]]],")"]]

        [download]

        It should actually look like this example bellow, I mean with curly brackets (not square) and colons instead of comma:

        {"firstName": "John",
"lastName" : "Smith",
"age"          : 25,
"address"   :
{"streetAdr
”
: "21 2nd Street",
"city"         : "New York",
"state"       : "NY",
”
zip"          : "10021"},
"phoneNumber":
[{"type"  : "home",
"number": "212 555
-
1234"},
{"type"  : "fax",
"number
”
: "646 555
-
4567"}]
}

        [download]

        I tried using <autotree> directive and it won't even export to json (shows message:"encountered object 'start=HASH(0x89d0d08)', but neither allow_blessed nor convert_blessed settings are enabled at gramatika.txt line 31.") Is there another way to get desired shape? Thanks!

[reply]
[d/l]
[select]

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