added tag v1_9_0_4

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/tags/v1_9_0_4@18845 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 70 insertions, 0 deletions

diff --git a/trunk/ext/ripper/lib/ripper/filter.rb b/trunk/ext/ripper/lib/ripper/filter.rb
new file mode 100644
index 0000000000..898501b23c
--- /dev/null
+++ b/trunk/ext/ripper/lib/ripper/filter.rb
@@ -0,0 +1,70 @@
+#
+# $Id$
+#
+# Copyright (c) 2004,2005 Minero Aoki
+#
+# This program is free software.
+# You can distribute and/or modify this program under the Ruby License.
+# For details of Ruby License, see ruby/COPYING.
+#
+
+require 'ripper/lexer'
+
+class Ripper
+
+  # This class handles only scanner events,
+  # and they are dispatched in the `right' order (same with input).
+  class Filter
+
+    def initialize(src, filename = '-', lineno = 1)
+      @__lexer = Lexer.new(src, filename, lineno)
+      @__line = nil
+      @__col = nil
+    end
+
+    # The file name of the input.
+    def filename
+      @__lexer.filename
+    end
+
+    # The line number of the current token.
+    # This value starts from 1.
+    # This method is valid only in event handlers.
+    def lineno
+      @__line
+    end
+
+    # The column number of the current token.
+    # This value starts from 0.
+    # This method is valid only in event handlers.
+    def column
+      @__col
+    end
+
+    # Starts parsing.  _init_ is a data accumulator.
+    # It is passed to the next event handler (as of Enumerable#inject).
+    def parse(init = nil)
+      data = init
+      @__lexer.lex.each do |pos, event, tok|
+        @__line, @__col = *pos
+        data = if respond_to?(event, true)
+               then __send__(event, tok, data)
+               else on_default(event, tok, data)
+               end
+      end
+      data
+    end
+
+    private
+
+    # This method is called when some event handler have not defined.
+    # _event_ is :on_XXX, _token_ is scanned token, _data_ is a data
+    # accumulator.  The return value of this method is passed to the
+    # next event handler (as of Enumerable#inject).
+    def on_default(event, token, data)
+      data
+    end
+
+  end
+
+end