1324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver#!/usr/bin/ruby 2324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver# encoding: utf-8 3324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver 4324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver=begin LICENSE 5324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver 6324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver[The "BSD licence"] 7324c4644fee44b9898524c09511bd33c3f12e2dfBen GruverCopyright (c) 2009-2010 Kyle Yetter 8324c4644fee44b9898524c09511bd33c3f12e2dfBen GruverAll rights reserved. 9324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver 10324c4644fee44b9898524c09511bd33c3f12e2dfBen GruverRedistribution and use in source and binary forms, with or without 11324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruvermodification, are permitted provided that the following conditions 12324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruverare met: 13324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver 14324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver 1. Redistributions of source code must retain the above copyright 15324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver notice, this list of conditions and the following disclaimer. 16324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver 2. Redistributions in binary form must reproduce the above copyright 17324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver notice, this list of conditions and the following disclaimer in the 18324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver documentation and/or other materials provided with the distribution. 19324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver 3. The name of the author may not be used to endorse or promote products 20324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver derived from this software without specific prior written permission. 21324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver 22324c4644fee44b9898524c09511bd33c3f12e2dfBen GruverTHIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 23324c4644fee44b9898524c09511bd33c3f12e2dfBen GruverIMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 24324c4644fee44b9898524c09511bd33c3f12e2dfBen GruverOF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 25324c4644fee44b9898524c09511bd33c3f12e2dfBen GruverIN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 26324c4644fee44b9898524c09511bd33c3f12e2dfBen GruverINCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 27324c4644fee44b9898524c09511bd33c3f12e2dfBen GruverNOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 28324c4644fee44b9898524c09511bd33c3f12e2dfBen GruverDATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 29324c4644fee44b9898524c09511bd33c3f12e2dfBen GruverTHEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 30324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 31324c4644fee44b9898524c09511bd33c3f12e2dfBen GruverTHIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 32324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver 33324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver=end 34324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver 35324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruvermodule ANTLR3 36324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruvermodule AST 37324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver 38324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver=begin rdoc ANTLR3::AST::Visitor 39324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver 40324c4644fee44b9898524c09511bd33c3f12e2dfBen GruverAST::Visitor is an extra utility class for working with tree objects. Visitor 41324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruverobjects are similar to plain vanilla iterators, but provide two action hooks, 42324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruverinstead a standard single iteration block. The <tt>visit(tree)</tt> method walks 43324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruverthrough each node of the tree (top-down left-to-right). If +pre_action+ is 44324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruverdefined, a node is yielded to the block when it has been initially entered. If 45324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver+post_action+ is defined, a node is yielded to the block after all of its 46324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruverchildren have been visited. 47324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver 48324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver=end 49324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver 50324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruverclass Visitor 51324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver def initialize( adaptor = nil ) 52324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver @adaptor = adaptor || CommonTreeAdaptor.new() 53324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver @pre_action = nil 54324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver @post_action = nil 55324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver block_given? and yield( self ) 56324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver end 57324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver 58324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver def pre_action( &block ) 59324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver block_given? and @pre_action = block 60324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver return @pre_action 61324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver end 62324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver 63324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver def post_action( &block ) 64324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver block_given? and @post_action = block 65324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver return @post_action 66324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver end 67324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver 68324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver def visit( tree, pre_action = nil, post_action = nil ) 69324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver flat = @adaptor.flat_list?( tree ) 70324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver before = pre_action || @pre_action 71324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver after = post_action || @post_action 72324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver 73324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver tree = before.call( tree ) unless before.nil? or flat 74324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver @adaptor.child_count( tree ).times do |index| 75324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver child = @adaptor.child_of( tree, index ) 76324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver visit( child, pre_action, post_action ) 77324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver end 78324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver tree = after.call( tree ) unless after.nil? or flat 79324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver 80324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver return tree 81324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver end 82324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruverend 83324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruverend 84324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruverend 85