parser.rb in hexapdf-0.12.0

- old
+ new

@@ -2,11 +2,11 @@
 #
 #--
 # This file is part of HexaPDF.
 #
 # HexaPDF - A Versatile PDF Creation and Manipulation Library For Ruby
-# Copyright (C) 2014-2019 Thomas Leitner
+# Copyright (C) 2014-2020 Thomas Leitner
 #
 # HexaPDF is free software: you can redistribute it and/or modify it
 # under the terms of the GNU Affero General Public License version 3 as
 # published by the Free Software Foundation with the addition of the
 # following permission added to Section 15 as permitted in Section 7(a):
@@ -160,15 +160,28 @@
     # To parse some contents the #parse method needs to be called with the contents to be parsed
     # and a Processor object which is used for processing the parsed operators.
     class Parser
 
       # Creates a new Parser object and calls #parse.
-      def self.parse(contents, processor)
-        new.parse(contents, processor)
+      def self.parse(contents, processor = nil, &block)
+        new.parse(contents, processor, &block)
       end
 
-      # Parses the contents and calls the processor object for each parsed operator.
-      def parse(contents, processor)
+      # Parses the contents and calls the processor object or the given block for each parsed
+      # operator.
+      #
+      # If a full-blown Processor is not needed (e.g. because the graphics state doesn't need to be
+      # maintained), one can use the block form to handle the parsed objects and their parameters.
+      #
+      # Note: The parameters array is reused for each processed operator, so duplicate it if
+      # necessary.
+      def parse(contents, processor = nil, &block) #:yields: object, params
+        raise ArgumentError, "Argument processor or block is needed" if processor.nil? && block.nil?
+        if processor.nil?
+          block.singleton_class.alias_method(:process, :call)
+          processor = block
+        end
+
         tokenizer = Tokenizer.new(contents, raise_on_eos: true)
         params = []
         loop do
           obj = tokenizer.next_object(allow_keyword: true)
           if obj.kind_of?(Tokenizer::Token)