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#
# $Id$
#
# 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,
# which are dispatched in the 'right' order (same with input).
class Filter
# Creates a new Ripper::Filter instance, passes parameters +src+,
# +filename+, and +lineno+ to Ripper::Lexer.new
#
# The lexer is for internal use only.
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 the parser.
# +init+ is a data accumulator and 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 is undefined.
# +event+ is :on_XXX, +token+ is the scanned token, and +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
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