Class: Peggy::Builder

Inherits:
Parser
  • Object
show all
Defined in:
lib/builder.rb,
lib/Copy of builder.rb

Overview

Parser builder. The built in methods create syntax elements. Any other method called on this object create references to production, or actual productions, if called at the top level. Todo: Change to a class and separate from Parser.

Direct Known Subclasses

PEG::PEGCompiler, Peggy

Instance Attribute Summary collapse

Attributes inherited from Parser

#debug_flag, #ignore_productions, #parse_results, #source_text

Instance Method Summary collapse

Methods inherited from Parser

#allow?, #check?, #correct_regexp!, #dissallow?, #ignore?, #literal?, #match?, #query?, #regexp?, #string?

Constructor Details

#initialize ⇒ Builder

Returns a new instance of Builder.



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# File 'lib/builder.rb', line 246

def initialize
  @building = true
end

Dynamic Method Handling

This class handles dynamic methods through the method_missing method

#method_missing(name, *args) ⇒ Object

Create a production if at the top level, or a reference to a production a production is being built.



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# File 'lib/builder.rb', line 257

def method_missing name, *args
  if @building
    if @parent
      ref = Reference.new name
      @parent << ref
    elsif block_given?
      @productions = {} unless @productions
      prod = Production.new name
      @parent = prod
      yield
      @parent = nil
      @productions[name] = prod
    else
      super
    end
  else
    prod = @productions[name]
    super unless prod
# puts "matching #{name} at #{args.first}"
    prod.match self, args.first
  end
end

Instance Attribute Details

#parent ⇒ Object (readonly)

Current parent being built



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# File 'lib/builder.rb', line 244

def parent
  @parent
end

#productions ⇒ Object (readonly)

Productions to build



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# File 'lib/builder.rb', line 242

def productions
  @productions
end

Instance Method Details

#[](index) ⇒ Object

Reference a production by its name index.



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# File 'lib/builder.rb', line 251

def [] index
  productions[index]
end

#each(&blk) ⇒ Object Also known as: seq

Add an Sequence element to the parent.



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# File 'lib/builder.rb', line 294

def each &blk
  build_piece Sequence, blk
end

#eof(*args) ⇒ Object 



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# File 'lib/builder.rb', line 287

def eof *args
  if args.length == 1 then super args.first
  else method_missing :eof, *args
  end
end

#lit(*values) ⇒ Object

Add an Literal element to the parent.



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# File 'lib/builder.rb', line 301

def lit *values
  if values.size == 1
    build_piece Literal, nil, values.first
  else
    one{
      for v in values
        build_piece Literal, nil, v
      end
    }
  end
end

#many(&blk) ⇒ Object

Add an AnyNumber element to the parent.



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# File 'lib/builder.rb', line 314

def many &blk
  build_piece AnyNumber, blk
end

#neg(&blk) ⇒ Object 



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# File 'lib/builder.rb', line 328

def neg &blk
  build_piece Negative, blk
end

#one(&blk) ⇒ Object Also known as: alt

Add an Alternatives element to the parent.



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# File 'lib/builder.rb', line 281

def one &blk
  build_piece Alternatives, blk
end

#opt(&blk) ⇒ Object

Add an Optional element to the parent.



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# File 'lib/builder.rb', line 319

def opt &blk
  build_piece Optional, blk
end

#parse?(goal, index = 0) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/builder.rb', line 336

def parse? goal, index=0
  @building = nil
  super
end

#pos(&blk) ⇒ Object 



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# File 'lib/builder.rb', line 332

def pos &blk
  build_piece Positive, blk
end

#reset! ⇒ Object 



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# File 'lib/Copy of builder.rb', line 250

def reset!
  @building = true
  @productions = {}
end

#some(&blk) ⇒ Object

Add an AtLeastOne element to the parent.



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# File 'lib/builder.rb', line 324

def some &blk
  build_piece AtLeastOne, blk
end