Class: RaddDjur::Grammar::Parser

Inherits:
Object
  • Object
show all
Includes:
Immutable, Parsers
Defined in:
lib/radd_djur/grammar.rb

Instance Method Summary collapse

Methods included from Parsers

any_char, char, fail, ret, string

Constructor Details

#initialize(&block) ⇒ Parser

Returns a new instance of Parser.



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# File 'lib/radd_djur/grammar.rb', line 105

def initialize(&block)
  @block = block
end

Instance Method Details

#/(p2) ⇒ Object 



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# File 'lib/radd_djur/grammar.rb', line 132

def /(p2)
  p1 = self
  Parser.new { |d|
    Promise.lazy {
      result = p1.parse(d).force
      if result.succeeded?
        Promise.eager(result)
      else
        p2.to_parser.parse(d)
      end
    }
  }
end

#bind(&f2) ⇒ Object 



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# File 'lib/radd_djur/grammar.rb', line 117

def bind(&f2)
  p1 = self
  Parser.new { |d|
    Promise.lazy {
      result = p1.parse(d).force
      if result.succeeded?
        p2 = f2.call(result.value)
        p2.to_parser.parse(result.remainder)
      else
        Promise.eager(NO_PARSE)
      end
    }
  }
end

#one_or_more ⇒ Object 



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# File 'lib/radd_djur/grammar.rb', line 154

def one_or_more
  bind { |x|
    zero_or_more.bind { |xs|
      ret xs.cons(x)
    }
  }
end

#optional ⇒ Object 



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# File 'lib/radd_djur/grammar.rb', line 146

def optional
  self / ret(nil)
end

#parse(d) ⇒ Object 



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# File 'lib/radd_djur/grammar.rb', line 113

def parse(d)
  @block.call(d)
end

#to_parser ⇒ Object 



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# File 'lib/radd_djur/grammar.rb', line 109

def to_parser
  self
end

#zero_or_more ⇒ Object 



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# File 'lib/radd_djur/grammar.rb', line 150

def zero_or_more
  one_or_more / ret(List.empty)
end