Chris@909: module CodeRay
Chris@909:   
Chris@909:   # = WordList
Chris@909:   # 
Chris@909:   # <b>A Hash subclass designed for mapping word lists to token types.</b>
Chris@909:   # 
Chris@909:   # Copyright (c) 2006-2011 by murphy (Kornelius Kalnbach) <murphy rubychan de>
Chris@909:   #
Chris@909:   # License:: LGPL / ask the author
Chris@909:   # Version:: 2.0 (2011-05-08)
Chris@909:   #
Chris@909:   # A WordList is a Hash with some additional features.
Chris@909:   # It is intended to be used for keyword recognition.
Chris@909:   #
Chris@909:   # WordList is optimized to be used in Scanners,
Chris@909:   # typically to decide whether a given ident is a special token.
Chris@909:   #
Chris@909:   # For case insensitive words use WordList::CaseIgnoring.
Chris@909:   #
Chris@909:   # Example:
Chris@909:   #
Chris@909:   #  # define word arrays
Chris@909:   #  RESERVED_WORDS = %w[
Chris@909:   #    asm break case continue default do else
Chris@909:   #  ]
Chris@909:   #  
Chris@909:   #  PREDEFINED_TYPES = %w[
Chris@909:   #    int long short char void
Chris@909:   #  ]
Chris@909:   #  
Chris@909:   #  # make a WordList
Chris@909:   #  IDENT_KIND = WordList.new(:ident).
Chris@909:   #    add(RESERVED_WORDS, :reserved).
Chris@909:   #    add(PREDEFINED_TYPES, :predefined_type)
Chris@909:   #  
Chris@909:   #  ...
Chris@909:   #  
Chris@909:   #  def scan_tokens tokens, options
Chris@909:   #    ...
Chris@909:   #    
Chris@909:   #    elsif scan(/[A-Za-z_][A-Za-z_0-9]*/)
Chris@909:   #      # use it
Chris@909:   #      kind = IDENT_KIND[match]
Chris@909:   #      ...
Chris@909:   class WordList < Hash
Chris@909:     
Chris@909:     # Create a new WordList with +default+ as default value.
Chris@909:     def initialize default = false
Chris@909:       super default
Chris@909:     end
Chris@909:     
Chris@909:     # Add words to the list and associate them with +value+.
Chris@909:     # 
Chris@909:     # Returns +self+, so you can concat add calls.
Chris@909:     def add words, value = true
Chris@909:       words.each { |word| self[word] = value }
Chris@909:       self
Chris@909:     end
Chris@909:     
Chris@909:   end
Chris@909:   
Chris@909:   
Chris@909:   # A CaseIgnoring WordList is like a WordList, only that
Chris@909:   # keys are compared case-insensitively (normalizing keys using +downcase+).
Chris@909:   class WordList::CaseIgnoring < WordList
Chris@909:     
Chris@909:     def [] key
Chris@909:       super key.downcase
Chris@909:     end
Chris@909:     
Chris@909:     def []= key, value
Chris@909:       super key.downcase, value
Chris@909:     end
Chris@909:     
Chris@909:   end
Chris@909:   
Chris@909: end