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|
#!/usr/bin/ruby
# encoding: utf-8
=begin LICENSE
[The "BSD licence"]
Copyright (c) 2009-2010 Kyle Yetter
All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions
are met:
1. Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer in the
documentation and/or other materials provided with the distribution.
3. The name of the author may not be used to endorse or promote products
derived from this software without specific prior written permission.
THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
=end
require 'antlr3'
module ANTLR3
=begin rdoc ANTLR3::AST
Name space containing all of the entities pertaining to tree construction and
tree parsing.
=end
module AST
autoload :Wizard, 'antlr3/tree/wizard'
autoload :Visitor, 'antlr3/tree/visitor'
####################################################################################################
############################################ Tree Parser ###########################################
####################################################################################################
=begin rdoc ANTLR3::AST::TreeParser
= TreeParser
TreeParser is the default base class of ANTLR-generated tree parsers. The class
tailors the functionality provided by Recognizer to the task of tree-pattern
recognition.
== About Tree Parsers
ANTLR generates three basic types of recognizers:
* lexers
* parsers
* tree parsers
Furthermore, it is capable of generating several different flavors of parser,
including parsers that take token input and use it to build Abstract Syntax
Trees (ASTs), tree structures that reflect the high-level syntactic and semantic
structures defined by the language.
You can take the information encapsulated by the AST and process it directly in
a program. However, ANTLR also provides a means to create a recognizer which is
capable of walking through the AST, verifying its structure and performing
custom actions along the way -- tree parsers.
Tree parsers are created from tree grammars. ANTLR-generated tree parsers
closely mirror the general structure of regular parsers and lexers.
For more in-depth coverage of the topic, check out the ANTLR documentation
(http://www.antlr.org).
== The Tree Parser API
Like Parser, the class does not stray too far from the Recognizer API.
Mainly, it customizes a few methods specifically to deal with tree nodes
(instead of basic tokens), and adds some helper methods for working with trees.
Like all ANTLR recognizers, tree parsers contained a shared state structure and
an input stream, which should be a TreeNodeStream. ANTLR intends to keep its
tree features flexible and customizable, and thus it does not make any
assumptions about the class of the actual nodes it processes. One consequence of
this flexibility is that tree parsers also require an extra tree adaptor object,
the purpose of which is to provide a homogeneous interface for handling tree
construction and analysis of your tree nodes.
See Tree and TreeAdaptor for more information.
=end
class TreeParser < Recognizer
def self.main( argv = ARGV, options = {} )
if ::Hash === argv then argv, options = ARGV, argv end
main = ANTLR3::Main::WalkerMain.new( self, options )
block_given? ? yield( main ) : main.execute( argv )
end
def initialize( input, options = {} )
super( options )
@input = input
end
alias tree_node_stream input
alias tree_node_stream= input=
def source_name
@input.source_name
end
def missing_symbol( error, expected_token_type, follow )
name = token_name( expected_token_type ).to_s
text = "<missing " << name << '>'
tk = create_token do |t|
t.text = text
t.type = expected_token_type
end
return( CommonTree.new( tk ) )
end
def match_any( ignore = nil )
@state.error_recovery = false
look, adaptor = @input.look, @input.tree_adaptor
if adaptor.child_count( look ) == 0
@input.consume
return
end
level = 0
while type = @input.peek and type != EOF
#token_type == EOF or ( token_type == UP && level == 0 )
@input.consume
case type
when DOWN then level += 1
when UP
level -= 1
level.zero? and break
end
end
end
def mismatch( input, type, follow = nil )
raise MismatchedTreeNode.new( type, input )
end
def error_header( e )
<<-END.strip!
#{ grammar_file_name }: node from #{
e.approximate_line_info? ? 'after ' : ''
} line #{ e.line }:#{ e.column }
END
end
def error_message( e )
adaptor = e.input.adaptor
e.token = adaptor.token( e.node )
e.token ||= create_token do | tok |
tok.type = adaptor.type_of( e.node )
tok.text = adaptor.text_of( e.node )
end
return super( e )
end
def trace_in( rule_name, rule_index )
super( rule_name, rule_index, @input.look )
end
def trace_out( rule_name, rule_index )
super( rule_name, rule_index, @input.look )
end
end
####################################################################################################
############################################ Tree Nodes ############################################
####################################################################################################
=begin rdoc ANTLR3::AST::Tree
= ANTLR Abstract Syntax Trees
As ANTLR is concerned, an Abstract Syntax Tree (AST) node is an object that
wraps a token, a list of child trees, and some information about the collective
source text embodied within the tree and its children.
The Tree module, like the Token and Stream modules, emulates an abstract base
class for AST classes; it specifies the attributes that are expected of basic
tree nodes as well as the methods trees need to implement.
== Terminology
While much of this terminology is probably familiar to most developers, the
following brief glossary is intended to clarify terminology used in code
throughout the AST library:
[payload] either a token value contained within a node or +nil+
[flat list (nil tree)] a tree node without a token payload, but with more
than one children -- functions like an array of
tree nodes
[root] a top-level tree node, i.e. a node that does not have a parent
[leaf] a node that does not have any children
[siblings] all other nodes sharing the same parent as some node
[ancestors] the list of successive parents from a tree node to the root node
[error node] a special node used to represent an erroneous series of tokens
from an input stream
=end
module Tree
#attr_accessor :parent
attr_accessor :start_index
attr_accessor :stop_index
attr_accessor :child_index
attr_reader :type
attr_reader :text
attr_reader :line
attr_reader :column
#attr_reader :children
attr_reader :token
def root?
parent.nil?
end
alias detached? root?
def root
cursor = self
until cursor.root?
yield( parent_node = cursor.parent )
cursor = parent_node
end
return( cursor )
end
#
def leaf?
children.nil? or children.empty?
end
def has_child?( node )
children and children.include?( node )
end
def depth
root? ? 0 : parent.depth + 1
end
def siblings
root? and return []
parent.children.reject { | c | c.equal?( self ) }
end
def each_ancestor
block_given? or return( enum_for( :each_ancestor ) )
cursor = self
until cursor.root?
yield( parent_node = cursor.parent )
cursor = parent_node
end
return( self )
end
def ancestors
each_ancestor.to_a
end
def walk
block_given? or return( enum_for( :walk ) )
stack = []
cursor = self
while true
begin
yield( cursor )
stack.push( cursor.children.dup ) unless cursor.empty?
rescue StopIteration
# skips adding children to prune the node
ensure
break if stack.empty?
cursor = stack.last.shift
stack.pop if stack.last.empty?
end
end
return self
end
end
=begin rdoc ANTLR3::AST::BaseTree
A base implementation of an Abstract Syntax Tree Node. It mainly defines the
methods and attributes required to implement the parent-node-children
relationship that characterize a tree; it does not provide any logic concerning
a node's token <i>payload</i>.
=end
class BaseTree < ::Array
attr_accessor :parent
extend ClassMacros
include Tree
def initialize( node = nil )
super()
@parent = nil
@child_index = 0
end
def children() self end
alias child at
alias child_count length
def first_with_type( tree_type )
find { | child | child.type == tree_type }
end
def add_child( child_tree )
child_tree.nil? and return
if child_tree.flat_list?
self.equal?( child_tree.children ) and
raise ArgumentError, "attempt to add child list to itself"
child_tree.each_with_index do | child, index |
child.parent = self
child.child_index = length + index
end
concat( child_tree )
else
child_tree.child_index = length
child_tree.parent = self
self << child_tree
end
return( self )
end
def detach
@parent = nil
@child_index = -1
return( self )
end
alias add_children concat
alias each_child each
def set_child( index, tree )
return if tree.nil?
tree.flat_list? and raise ArgumentError, "Can't set single child to a list"
tree.parent = self
tree.child_index = index
self[ index ] = tree
end
def delete_child( index )
killed = delete_at( index ) and freshen( index )
return killed
end
def replace_children( start, stop, new_tree )
start >= length or stop >= length and
raise IndexError, ( <<-END ).gsub!( /^\s+\| /,'' )
| indices span beyond the number of children:
| children.length = #{ length }
| start = #{ start_index.inspect }
| stop = #{ stop_index.inspect }
END
new_children = new_tree.flat_list? ? new_tree : [ new_tree ]
self[ start .. stop ] = new_children
freshen( start_index )
return self
end
def flat_list?
false
end
def freshen( offset = 0 )
for i in offset ... length
node = self[ i ]
node.child_index = i
node.parent = self
end
end
def sanity_check( parent = nil, i = -1 )
parent == @parent or
raise TreeInconsistency.failed_parent_check!( parent, @parent )
i == @child_index or
raise TreeInconsistency.failed_index_check!( i, @child_index )
each_with_index do | child, index |
child.sanity_check( self, index )
end
end
def inspect
empty? and return to_s
buffer = ''
buffer << '(' << to_s << ' ' unless flat_list?
buffer << map { | c | c.inspect }.join( ' ' )
buffer << ')' unless flat_list?
return( buffer )
end
def walk
block_given? or return( enum_for( :walk ) )
stack = []
cursor = self
while true
begin
yield( cursor )
stack.push( Array[ *cursor ] ) unless cursor.empty?
rescue StopIteration
# skips adding children to prune the node
ensure
break if stack.empty?
cursor = stack.last.shift
stack.pop if stack.last.empty?
end
end
return self
end
def prune
raise StopIteration
end
abstract :to_s
#protected :sanity_check, :freshen
def root?() @parent.nil? end
alias leaf? empty?
end
=begin rdoc ANTLR3::AST::CommonTree
The default Tree class implementation used by ANTLR tree-related code.
A CommonTree object is a tree node that wraps a token <i>payload</i> (or a +nil+
value) and contains zero or more child tree nodes. Additionally, it tracks
information about the range of data collectively spanned by the tree node:
* the token stream start and stop indexes of tokens contained throughout
the tree
* that start and stop positions of the character input stream from which
the tokens were defined
Tracking this information simplifies tasks like extracting a block of code or
rewriting the input stream. However, depending on the purpose of the
application, building trees with all of this extra information may be
unnecessary. In such a case, a more bare-bones tree class could be written
(optionally using the BaseTree class or the Token module). Define a customized
TreeAdaptor class to handle tree construction and manipulation for the
customized node class, and recognizers will be able to build, rewrite, and parse
the customized lighter-weight trees.
=end
class CommonTree < BaseTree
def initialize( payload = nil )
super()
@start_index = -1
@stop_index = -1
@child_index = -1
case payload
when CommonTree then # copy-constructor style init
@token = payload.token
@start_index = payload.start_index
@stop_index = payload.stop_index
when nil, Token then @token = payload
else raise ArgumentError,
"Invalid argument type: %s (%p)" % [ payload.class, payload ]
end
end
def initialize_copy( orig )
super
clear
@parent = nil
end
def copy_node
return self.class.new( @token )
end
def flat_list?
@token.nil?
end
def type
@token ? @token.type : 0
end
def text
@token.text rescue nil
end
def line
if @token.nil? or @token.line == 0
return ( empty? ? 0 : first.line )
end
return @token.line
end
def column
if @token.nil? or @token.column == -1
return( empty? ? 0 : first.column )
end
return @token.column
end
def start_index
@start_index == -1 and @token and return @token.index
return @start_index
end
def stop_index
@stop_index == -1 and @token and return @token.index
return @stop_index
end
alias token_start_index= start_index=
alias token_stop_index= stop_index=
alias token_start_index start_index
alias token_stop_index stop_index
def name
@token.name rescue 'INVALID'
end
def token_range
unknown_boundaries? and infer_boundaries
@start_index .. @stop_index
end
def source_range
unknown_boundaries? and infer_boundaries
tokens = map do | node |
tk = node.token and tk.index >= 0 ? tk : nil
end
tokens.compact!
first, last = tokens.minmax_by { |t| t.index }
first.start .. last.stop
end
def infer_boundaries
if empty? and @start_index < 0 || @stop_index < 0
@start_index = @stop_index = @token.index rescue -1
return
end
for child in self do child.infer_boundaries end
return if @start_index >= 0 and @stop_index >= 0
@start_index = first.start_index
@stop_index = last.stop_index
return nil
end
def unknown_boundaries?
@start_index < 0 or @stop_index < 0
end
def to_s
flat_list? ? 'nil' : @token.text.to_s
end
def pretty_print( printer )
text = @token ? @token.text : 'nil'
text =~ /\s+/ and
text = text.dump
if empty?
printer.text( text )
else
endpoints = @token ? [ "(#{ text }", ')' ] : [ '', '' ]
printer.group( 1, *endpoints ) do
for child in self
printer.breakable
printer.pp( child )
end
end
end
end
end
=begin rdoc ANTLR3::AST::CommonErrorNode
Represents a series of erroneous tokens from a token stream input
=end
class CommonErrorNode < CommonTree
include ANTLR3::Error
include ANTLR3::Constants
attr_accessor :input, :start, :stop, :error
def initialize( input, start, stop, error )
super( nil )
stop = start if stop.nil? or
( stop.token_index < start.token_index and stop.type != EOF )
@input = input
@start = start
@stop = stop
@error = error
end
def flat_list?
return false
end
def type
INVALID_TOKEN_TYPE
end
def text
case @start
when Token
i = @start.token_index
j = ( @stop.type == EOF ) ? @input.size : @stop.token_index
@input.to_s( i, j ) # <- the bad text
when Tree
@input.to_s( @start, @stop ) # <- the bad text
else
"<unknown>"
end
end
def to_s
case @error
when MissingToken
"<missing type: #{ @error.missing_type }>"
when UnwantedToken
"<extraneous: #{ @error.token.inspect }, resync = #{ text }>"
when MismatchedToken
"<mismatched token: #{ @error.token.inspect }, resync = #{ text }>"
when NoViableAlternative
"<unexpected: #{ @error.token.inspect }, resync = #{ text }>"
else "<error: #{ text }>"
end
end
end
Constants::INVALID_NODE = CommonTree.new( ANTLR3::INVALID_TOKEN )
####################################################################################################
########################################### Tree Adaptors ##########################################
####################################################################################################
=begin rdoc ANTLR3::AST::TreeAdaptor
Since a tree can be represented by a multitude of formats, ANTLR's tree-related
code mandates the use of Tree Adaptor objects to build and manipulate any actual
trees. Using an adaptor object permits a single recognizer to work with any
number of different tree structures without adding rigid interface requirements
on customized tree structures. For example, if you want to represent trees using
simple arrays of arrays, you just need to design an appropriate tree adaptor and
provide it to the parser.
Tree adaptors are tasked with:
* copying and creating tree nodes and tokens
* defining parent-child relationships between nodes
* cleaning up / normalizing a full tree structure after construction
* reading and writing the attributes ANTLR expects of tree nodes
* providing node access and iteration
=end
module TreeAdaptor
include TokenFactory
include Constants
include Error
def add_child( tree, child )
tree.add_child( child ) if tree and child
end
def child_count( tree )
tree.child_count
end
def child_index( tree )
tree.child_index rescue 0
end
def child_of( tree, index )
tree.nil? ? nil : tree.child( index )
end
def copy_node( tree_node )
tree_node and tree_node.dup
end
def copy_tree( tree, parent = nil )
tree or return nil
new_tree = copy_node( tree )
set_child_index( new_tree, child_index( tree ) )
set_parent( new_tree, parent )
each_child( tree ) do | child |
new_sub_tree = copy_tree( child, new_tree )
add_child( new_tree, new_sub_tree )
end
return new_tree
end
def delete_child( tree, index )
tree.delete_child( index )
end
def each_child( tree )
block_given? or return enum_for( :each_child, tree )
for i in 0 ... child_count( tree )
yield( child_of( tree, i ) )
end
return tree
end
def each_ancestor( tree, include_tree = true )
block_given? or return enum_for( :each_ancestor, tree, include_tree )
if include_tree
begin yield( tree ) end while tree = parent_of( tree )
else
while tree = parent_of( tree ) do yield( tree ) end
end
end
def flat_list?( tree )
tree.flat_list?
end
def empty?( tree )
child_count( tree ).zero?
end
def parent( tree )
tree.parent
end
def replace_children( parent, start, stop, replacement )
parent and parent.replace_children( start, stop, replacement )
end
def rule_post_processing( root )
if root and root.flat_list?
case root.child_count
when 0 then root = nil
when 1
root = root.child( 0 ).detach
end
end
return root
end
def set_child_index( tree, index )
tree.child_index = index
end
def set_parent( tree, parent )
tree.parent = parent
end
def set_token_boundaries( tree, start_token = nil, stop_token = nil )
return unless tree
start = stop = 0
start_token and start = start_token.index
stop_token and stop = stop_token.index
tree.start_index = start
tree.stop_index = stop
return tree
end
def text_of( tree )
tree.text rescue nil
end
def token( tree )
CommonTree === tree ? tree.token : nil
end
def token_start_index( tree )
tree ? tree.token_start_index : -1
end
def token_stop_index( tree )
tree ? tree.token_stop_index : -1
end
def type_name( tree )
tree.name rescue 'INVALID'
end
def type_of( tree )
tree.type rescue INVALID_TOKEN_TYPE
end
def unique_id( node )
node.hash
end
end
=begin rdoc ANTLR3::AST::CommonTreeAdaptor
The default tree adaptor used by ANTLR-generated tree code. It, of course,
builds and manipulates CommonTree nodes.
=end
class CommonTreeAdaptor
extend ClassMacros
include TreeAdaptor
include ANTLR3::Constants
def initialize( token_class = ANTLR3::CommonToken )
@token_class = token_class
end
def create_flat_list
return create_with_payload( nil )
end
alias create_flat_list! create_flat_list
def become_root( new_root, old_root )
new_root = create( new_root ) if new_root.is_a?( Token )
old_root or return( new_root )
new_root = create_with_payload( new_root ) unless CommonTree === new_root
if new_root.flat_list?
count = new_root.child_count
if count == 1
new_root = new_root.child( 0 )
elsif count > 1
raise TreeInconsistency.multiple_roots!
end
end
new_root.add_child( old_root )
return new_root
end
def create_from_token( token_type, from_token, text = nil )
from_token = from_token.dup
from_token.type = token_type
from_token.text = text.to_s if text
tree = create_with_payload( from_token )
return tree
end
def create_from_type( token_type, text )
from_token = create_token( token_type, DEFAULT_CHANNEL, text )
create_with_payload( from_token )
end
def create_error_node( input, start, stop, exc )
CommonErrorNode.new( input, start, stop, exc )
end
def create_with_payload( payload )
return CommonTree.new( payload )
end
def create( *args )
n = args.length
if n == 1 and args.first.is_a?( Token ) then create_with_payload( args[ 0 ] )
elsif n == 2 and Integer === args.first and String === args[ 1 ]
create_from_type( *args )
elsif n >= 2 and Integer === args.first
create_from_token( *args )
else
sig = args.map { |f| f.class }.join( ', ' )
raise TypeError, "No create method with this signature found: (#{ sig })"
end
end
creation_methods = %w(
create_from_token create_from_type
create_error_node create_with_payload
create
)
for method_name in creation_methods
bang_method = method_name + '!'
alias_method( bang_method, method_name )
deprecate( bang_method, "use method ##{ method_name } instead" )
end
def rule_post_processing( root )
if root and root.flat_list?
if root.empty? then root = nil
elsif root.child_count == 1 then root = root.first.detach
end
end
return root
end
def empty?( tree )
tree.empty?
end
def each_child( tree )
block_given? or return enum_for( :each_child, tree )
tree.each do | child |
yield( child )
end
end
end
####################################################################################################
########################################### Tree Streams ###########################################
####################################################################################################
=begin rdoc ANTLR3::AST::TreeNodeStream
TreeNodeStreams flatten two-dimensional tree structures into one-dimensional
sequences. They preserve the two-dimensional structure of the tree by inserting
special +UP+ and +DOWN+ nodes.
Consider a hypothetical tree:
[A]
+--[B]
| +--[C]
| `--[D]
`--[E]
`--[F]
A tree node stream would serialize the tree into the following sequence:
A DOWN B DOWN C D UP E DOWN F UP UP EOF
Other than serializing a tree into a sequence of nodes, a tree node stream
operates similarly to other streams. They are commonly used by tree parsers as
the main form of input. #peek, like token streams, returns the type of the token
of the next node. #look returns the next full tree node.
=end
module TreeNodeStream
extend ClassMacros
include Stream
include Constants
abstract :at
abstract :look
abstract :tree_source
abstract :token_stream
abstract :tree_adaptor
abstract :unique_navigation_nodes=
abstract :to_s
abstract :replace_children
end
=begin rdoc ANTLR3::AST::CommonTreeNodeStream
An implementation of TreeNodeStream tailed for streams based on CommonTree
objects. CommonTreeNodeStreams are the default input streams for tree parsers.
=end
class CommonTreeNodeStream
include TreeNodeStream
attr_accessor :token_stream
attr_reader :adaptor, :position
def initialize( *args )
options = args.last.is_a?( ::Hash ) ? args.pop : {}
case n = args.length
when 1
@root = args.first
@token_stream = @adaptor = @nodes = @down = @up = @eof = nil
when 2
@adaptor, @root = args
@token_stream = @nodes = @down = @up = @eof = nil
when 3
parent, start, stop = *args
@adaptor = parent.adaptor
@root = parent.root
@nodes = parent.nodes[ start ... stop ]
@down = parent.down
@up = parent.up
@eof = parent.eof
@token_stream = parent.token_stream
when 0
raise ArgumentError, "wrong number of arguments (0 for 1)"
else raise ArgumentError, "wrong number of arguments (#{ n } for 3)"
end
@adaptor ||= options.fetch( :adaptor ) { CommonTreeAdaptor.new }
@token_stream ||= options[ :token_stream ]
@down ||= options.fetch( :down ) { @adaptor.create_from_type( DOWN, 'DOWN' ) }
@up ||= options.fetch( :up ) { @adaptor.create_from_type( UP, 'UP' ) }
@eof ||= options.fetch( :eof ) { @adaptor.create_from_type( EOF, 'EOF' ) }
@nodes ||= []
@unique_navigation_nodes = options.fetch( :unique_navigation_nodes, false )
@position = -1
@last_marker = nil
@calls = []
end
def fill_buffer( tree = @root )
@nodes << tree unless nil_tree = @adaptor.flat_list?( tree )
unless @adaptor.empty?( tree )
add_navigation_node( DOWN ) unless nil_tree
@adaptor.each_child( tree ) { | c | fill_buffer( c ) }
add_navigation_node( UP ) unless nil_tree
end
@position = 0 if tree == @root
return( self )
end
def node_index( node )
@position == -1 and fill_buffer
return @nodes.index( node )
end
def add_navigation_node( type )
navigation_node =
case type
when DOWN
has_unique_navigation_nodes? ? @adaptor.create_from_type( DOWN, 'DOWN' ) : @down
else
has_unique_navigation_nodes? ? @adaptor.create_from_type( UP, 'UP' ) : @up
end
@nodes << navigation_node
end
def at( index )
@position == -1 and fill_buffer
@nodes.at( index )
end
def look( k = 1 )
@position == -1 and fill_buffer
k == 0 and return nil
k < 0 and return self.look_behind( -k )
absolute = @position + k - 1
@nodes.fetch( absolute, @eof )
end
def current_symbol
look
end
def look_behind( k = 1 )
k == 0 and return nil
absolute = @position - k
return( absolute < 0 ? nil : @nodes.fetch( absolute, @eof ) )
end
def tree_source
@root
end
def source_name
self.token_stream.source_name
end
def tree_adaptor
@adaptor
end
def has_unique_navigation_nodes?
return @unique_navigation_nodes
end
attr_writer :unique_navigation_nodes
def consume
@position == -1 and fill_buffer
node = @nodes.fetch( @position, @eof )
@position += 1
return( node )
end
def peek( i = 1 )
@adaptor.type_of look( i )
end
alias >> peek
def <<( k )
self >> -k
end
def mark
@position == -1 and fill_buffer
@last_marker = @position
return @last_marker
end
def release( marker = nil )
# do nothing?
end
alias index position
def rewind( marker = @last_marker, release = true )
seek( marker )
end
def seek( index )
@position == -1 and fill_buffer
@position = index
end
def push( index )
@calls << @position
seek( index )
end
def pop
pos = @calls.pop and seek( pos )
return pos
end
def reset
@position = 0
@last_marker = 0
@calls = []
end
def replace_children( parent, start, stop, replacement )
parent and @adaptor.replace_children( parent, start, stop, replacement )
end
def size
@position == -1 and fill_buffer
return @nodes.length
end
def inspect
@position == -1 and fill_buffer
@nodes.map { |nd| @adaptor.type_name( nd ) }.join( ' ' )
end
def extract_text( start = nil, stop = nil )
start.nil? || stop.nil? and return nil
@position == -1 and fill_buffer
if @token_stream
from = @adaptor.token_start_index( start )
to =
case @adaptor.type_of( stop )
when UP then @adaptor.token_stop_index( start )
when EOF then to = @nodes.length - 2
else @adaptor.token_stop_index( stop )
end
return @token_stream.extract_text( from, to )
end
buffer = ''
for node in @nodes
if node == start ... node == stop # <-- hey look, it's the flip flop operator
buffer << @adaptor.text_of( node ) #|| ' ' << @adaptor.type_of( node ).to_s )
end
end
return( buffer )
end
def each
@position == -1 and fill_buffer
block_given? or return enum_for( :each )
for node in @nodes do yield( node ) end
self
end
include Enumerable
def to_a
return @nodes.dup
end
def extract_text( start = nil, stop = nil )
@position == -1 and fill_buffer
start ||= @nodes.first
stop ||= @nodes.last
if @token_stream
case @adaptor.type_of( stop )
when UP
stop_index = @adaptor.token_stop_index( start )
when EOF
return extract_text( start, @nodes[ - 2 ] )
else
stop_index = @adaptor.token_stop_index( stop )
end
start_index = @adaptor.token_start_index( start )
return @token_stream.extract_text( start_index, stop_index )
else
start_index = @nodes.index( start ) || @nodes.length
stop_index = @nodes.index( stop ) || @nodes.length
return(
@nodes[ start_index .. stop_index ].map do | n |
@adaptor.text_of( n ) or " " + @adaptor.type_of( n ).to_s
end.join( '' )
)
end
end
alias to_s extract_text
#private
#
# def linear_node_index( node )
# @position == -1 and fill_buffer
# @nodes.each_with_index do |n, i|
# node == n and return(i)
# end
# return -1
# end
end
=begin rdoc ANTLR3::AST::RewriteRuleElementStream
Special type of stream that is used internally by tree-building and tree-
rewriting parsers.
=end
class RewriteRuleElementStream # < Array
extend ClassMacros
include Error
def initialize( adaptor, element_description, elements = nil )
@cursor = 0
@single_element = nil
@elements = nil
@dirty = false
@element_description = element_description
@adaptor = adaptor
if elements.instance_of?( Array )
@elements = elements
else
add( elements )
end
end
def reset
@cursor = 0
@dirty = true
end
def add( el )
return( nil ) unless el
case
when ! el then return( nil )
when @elements then @elements << el
when @single_element.nil? then @single_element = el
else
@elements = [ @single_element, el ]
@single_element = nil
return( @elements )
end
end
def next_tree
if @dirty or @cursor >= length && length == 1
return dup( __next__ )
end
__next__
end
abstract :dup
def to_tree( el )
return el
end
def has_next?
return( @single_element && @cursor < 1 or
@elements && @cursor < @elements.length )
end
def size
@single_element and return 1
@elements and return @elements.length
return 0
end
alias length size
private
def __next__
l = length
case
when l.zero?
raise Error::RewriteEmptyStream.new( @element_description )
when @cursor >= l
l == 1 and return to_tree( @single_element )
raise RewriteCardinalityError.new( @element_description )
when @single_element
@cursor += 1
return( to_tree( @single_element ) )
else
out = to_tree( @elements.at( @cursor ) )
@cursor += 1
return( out )
end
end
end
=begin rdoc ANTLR3::AST::RewriteRuleTokenStream
Special type of stream that is used internally by tree-building and tree-
rewriting parsers.
=end
class RewriteRuleTokenStream < RewriteRuleElementStream
def next_node
return @adaptor.create_with_payload( __next__ )
end
alias :next :__next__
public :next
def dup( el )
raise TypeError, "dup can't be called for a token stream"
end
end
=begin rdoc ANTLR3::AST::RewriteRuleSubtreeStream
Special type of stream that is used internally by tree-building and tree-
rewriting parsers.
=end
class RewriteRuleSubtreeStream < RewriteRuleElementStream
def next_node
if @dirty or @cursor >= length && length == 1
return @adaptor.copy_node( __next__ )
end
return __next__
end
def dup( el )
@adaptor.copy_tree( el )
end
end
=begin rdoc ANTLR3::AST::RewriteRuleNodeStream
Special type of stream that is used internally by tree-building and tree-
rewriting parsers.
=end
class RewriteRuleNodeStream < RewriteRuleElementStream
alias next_node __next__
public :next_node
def to_tree( el )
@adaptor.copy_node( el )
end
def dup( el )
raise TypeError, "dup can't be called for a node stream"
end
end
end
include AST
end
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