Method: Packr::RegexpGroup::Item#initialize

Defined in:
lib/packr/regexp_group.rb

#initialize(expression, replacement = nil) ⇒ Item

Returns a new instance of Item.



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# File 'lib/packr/regexp_group.rb', line 66

def initialize(expression, replacement = nil)
  @expression = expression
  
  if replacement.nil?
    replacement = IGNORE
  elsif replacement.respond_to?(:replacement)
    replacement = replacement.replacement
  elsif !replacement.is_a?(Proc)
    replacement = replacement.to_s
  end
  
  # does the pattern use sub-expressions?
  if replacement.is_a?(String) and replacement =~ LOOKUP
    # a simple lookup? (e.g. "\2")
    if replacement.gsub(/\n/, " ") =~ LOOKUP_SIMPLE
      # store the index (used for fast retrieval of matched strings)
      replacement = replacement[1..-1].to_i
    else # a complicated lookup (e.g. "Hello \2 \1")
      # build a function to do the lookup
      # Improved version by Alexei Gorkov:
      q = '"'
      replacement_string = replacement.
          gsub(/\\/, "\\\\").
          gsub(/"/, "\\x22").
          gsub(/\n/, "\\n").
          gsub(/\r/, "\\r").
          gsub(/\\(\d+)/, q + "+(args[\\1]||" + q+q + ")+" + q).
          gsub(/(['"])\1\+(.*)\+\1\1$/, '\1')
      replacement = lambda { |*args| eval(q + replacement_string + q) }
      
      # My old crappy version:
      # q = (replacement.gsub(/\\./, "") =~ /'/) ? '"' : "'"
      # replacement = replacement.gsub(/\r/, "\\r").gsub(/\\(\d+)/,
      #     q + "+(args[\\1]||" + q+q + ")+" + q)
      # replacement_string = q + replacement.gsub(/(['"])\1\+(.*)\+\1\1$/, '\1') + q
      # replacement = lambda { |*args| eval(replacement_string) }
    end
  end
  
  @length = RegexpGroup.count(@expression)
  @replacement = replacement
end