Class: Walrus::Grammar::NotPredicate

Inherits:
Predicate
  • Object
show all
Defined in:
lib/walrus/grammar/not_predicate.rb

Instance Attribute Summary

Attributes inherited from Predicate

#hash

Instance Method Summary collapse

Methods inherited from Predicate

#eql?, #initialize, #to_parseable

Methods included from Memoizing

#check_left_recursion, #memoizing_parse

Methods included from ParsletCombining

#&, #>>, #and?, #and_predicate, #choice, #memoizing_parse, #merge, #not!, #not_predicate, #omission, #one_or_more, #optional, #repeat, #repeat_with_default, #repetition, #repetition_with_default, #sequence, #skip, #zero_or_more, #zero_or_one, #|

Constructor Details

This class inherits a constructor from Walrus::Grammar::Predicate

Instance Method Details

#parse(string, options = {}) ⇒ Object

Raises:

  • (ArgumentError) 


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# File 'lib/walrus/grammar/not_predicate.rb', line 22

def parse(string, options = {})
  raise ArgumentError if string.nil?
  catch :ZeroWidthParseSuccess do
    begin
      @parseable.memoizing_parse(string, options)
    rescue ParseError # failed to pass (which is just what we wanted)
      throw :NotPredicateSuccess
    end
  end
  
  # getting this far means that parsing succeeded (not what we wanted)
  raise ParseError.new('predicate not satisfied ("%s" not allowed) while parsing "%s"' % [@parseable.to_s, string],
                       :line_end => options[:line_start], :column_end => options[:column_start])
end