Got an error while parsing grammar 'wrong argument type Class (expected Module)'

[Ivan Lo]

Hi everybody got the following error while parsing grammar. I saw that was similar questions related to this error but from my side I do the stuff right (but as a result it seems i do something wrong)

error that i got

     TypeError:

       wrong argument type Class (expected Module)

     # (eval):93:in `extend'

     # (eval):93:in `_nt_line'

     # (eval):21:in `block in _nt_document'

     # (eval):20:in `loop'

     # (eval):20:in `_nt_document'

     # /Users/gingray/.rvm/gems/ruby-2.2.2/gems/treetop-1.6.8/lib/treetop/runtime/compiled_parser.rb:18:in `parse'

     # ./app/services/parser/chord_parser.rb:8:in `parse'

     # ./spec/services/parser/chord_parser_spec.rb:3:in `block (2 levels) in <top (required)>'

     # ./spec/services/parser/chord_parser_spec.rb:5:in `block (2 levels) in <top (required)>'

     # ./spec/spec_helper.rb:36:in `block (2 levels) in <top (required)>'

my grammar

grammar TreetopChord

  rule document

    (line)*

  end

  rule line

    (text / chord / title ) [\r\n]+ <LineLiteral> / (text / chord / title ) <LineLiteral>

  end

  rule text

    [a-zA-Z0-9,.\s]+ <TextLiteral>

  end

  rule chord

    '{' [0-9#b/]+ '}' <ChordExpression>

  end

  rule title

    '[' [a-z]+ ']' <TitleLiteral>

  end

end

module TreetopChord

  class LineLiteral < Treetop::Runtime::SyntaxNode

  end

  class TextLiteral < Treetop::Runtime::SyntaxNode

  end

  class ChordExpression < Treetop::Runtime::SyntaxNode

  end

  class TitleLiteral < Treetop::Runtime::SyntaxNode

  end

end

I'll really grateful for any help. Thanks in advance.

[mar...@reality.com]

Ivan --

It looks like the error is exactly what it says:

> TypeError:
> wrong argument type Class (expected Module)
> # (eval):93:in `extend'

That is, you are trying to extend with <TextLiteral>:

> [a-zA-Z0-9,.\s]+ <TextLiteral>

...which should be a module, but is actually a class:

> class TextLiteral < Treetop::Runtime::SyntaxNode

And likewise with LineLiteral, ChordExpression, and TitleLiteral.

> I'll really grateful for any help. Thanks in advance.

Hope that helps.

-- Markus

--
Send from PINE (GUI? Phooey!)

[Clifford Heath]

Apparently my reply from this morning did not get posted; thanks Marcus for replying.

You can only use a class on a rule that creates a new node, not on a node that has been returned from another rule.

Parentheses and alternation do not create new nodes, only terminals and sequences.

Clifford Heath.

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