Class: LinkParser

Inherits:
Object show all
Includes:
Log4r
Defined in:
lib/linkparser.rb,
lib/linkparser/log.rb,
lib/linkparser/word.rb,
lib/linkparser/utils.rb,
lib/linkparser/linkage.rb,
lib/linkparser/sentence.rb,
lib/linkparser/connector.rb,
lib/linkparser/connection.rb,
lib/linkparser/definition.rb,
lib/linkparser/dictionary.rb

Overview

connection.rb - this file contains the class declarations for the LinkParser::Connection class.

Synopsis

Rcsid

$Id: connection.rb,v 1.3 2003/06/08 03:53:27 stillflame Exp $

Authors

Martin Chase <[email protected]>

:include: COPYRIGHT

Please see the file COPYRIGHT for licensing details.

Defined Under Namespace

Classes: Connection, Connector, Definition, Dictionary, Linkage, ParseError, ParseState, Sentence, Word

Constant Summary collapse

LEFT_MODE = 
1
RIGHT_MODE = 
2
INNER_MODE = 
4
OUTER_MODE = 
8
FORCE_MODE = 
16
UNSATISFIED = 
nil
Log = 
Logger::new( "LinkParser" )

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(dict_opts, parse_opts) ⇒ LinkParser

Initializes a new parser, using the option hashes given



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# File 'lib/linkparser.rb', line 66

def initialize( dict_opts, parse_opts )
		@dictionary = LinkParser::Dictionary::new(dict_opts)
		@parseOptions = parse_opts
end

Instance Attribute Details

#dictionary ⇒ Object (readonly)

the dictionary



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# File 'lib/linkparser.rb', line 426

def dictionary
  @dictionary
end

#parseOptions ⇒ Object (readonly)

the options for parsing



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# File 'lib/linkparser.rb', line 429

def parseOptions
  @parseOptions
end

Instance Method Details

#add_connection(ps) ⇒ Object

With a connection having been found between two words, or assumed to be so, create it if possible, recurse where needed, and combine it all into the results. The “force” modes are where no actual connection has been made, but recursion is still needed to connect the words inbetween the inner word under consideration and both edge words.



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# File 'lib/linkparser.rb', line 242

def add_connection(ps)
	if (ps.mode & INNER_MODE).nonzero?
		if (ps.mode & FORCE_MODE).nonzero?
			r = inner_force_recursion(ps)
			# Log.debug( "inner_force_recursion finished" )
			r
		else
			r = inner_add_connection(ps)
			# Log.debug( "inner_add_connection finished" )
			r
		end
	elsif (ps.mode & FORCE_MODE).nonzero?
		r = outer_force_recursion(ps)
		# Log.debug( "outer_force_recursion finished" )
		r
	else
		r = outer_add_connection(ps)
		# Log.debug( "outer_add_connection finished" )
		r
	end
end

#create_connection(sentence, left, right, left_conn, right_conn) ⇒ Object

Makes the Word and Connection objects out of the Sentence, indicies and Connectors.



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# File 'lib/linkparser.rb', line 394

def create_connection(sentence, left, right, left_conn, right_conn)
	left_word = Word::new(sentence, left)
	right_word = Word::new(sentence, right)
	connection = Connection::new(left_conn, right_conn, left_word, right_word)
	left_word.right << connection
	right_word.left << connection
	return [left_word, right_word, connection]
end

#find_linkages(sentence) ⇒ Object

Finds all valid linkages in the sentence



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# File 'lib/linkparser.rb', line 110

def find_linkages(sentence)
	# Log.debug( "find_linkages start" )
	ps = ParseState::new
	ps.sentence = sentence
	# :MC: To be used for pruning, but not until profiling/benchmarking is
	# done.  The idea will be to check each <side>_conn to see if it has any
	# chance of connecting, and if not, skipping the entire set.
	ps.all_connectors = make_connector_hash(ps.sentence)
	# Log.debug( "Connector hash created => #{ps.all_connectors.inspect}" )
	ps.results = []
	ps.left = 0
	ps.right = sentence.definitions.length - 1
	satisfied = false
	for ps.right_set in ps.sentence.definitions[ps.right].connector_sets do
		next unless ps.right_set.right.all_pass?(:optional?)
		# :MC: For pruning.
		next if ps.right_set.find {|c| (! c.optional?) and (ps.all_connectors[c].empty? or c.cost > 0)}
		for ps.left_set in ps.sentence.definitions[ps.left].connector_sets do
			next unless ps.left_set.left.all_pass?(:optional?)
			# :MC: For pruning.
			next if ps.left_set.find {|c| (! c.optional?) and (ps.all_connectors[c].empty? or c.cost > 0)}
			matched = false
			for ps.right_conn in ps.right_set.left do
				for ps.left_conn in ps.left_set.right do
					if ps.left_conn.match(ps.right_conn)
						matched = true
						ps.mode = OUTER_MODE
						flag = add_connection(ps)
						satisfaction = true unless flag == UNSATISFIED
					end
				end
			end
			unless matched
				ps.right_conn = ps.left_conn = nil
				ps.mode = OUTER_MODE | FORCE_MODE
				flag = add_connection(ps)
				satisfaction = true unless flag == UNSATISFIED
			end
		end
	end
	ps.results = ps.results.find_all {|linkage|
		linkage.valid? && linkage.connected?
	}
	ps.results.uniq!
	if satisfaction
		# Log.debug( "find_linkages finished - %d results" % ps.results.length )
	else
		# Log.debug( "find_linkages finished - unsatisfied" )
	end
	return ps.results
end

#inner_add_connection(ps) ⇒ Object

Inside of recursion, create the connection, recurse on either side, combine the results of each. This mostly just rearranges the parse state for the recursions to follow.



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# File 'lib/linkparser.rb', line 342

def inner_add_connection(ps)
	new_ps = ParseState::new(*ps.to_a)
	new_ps.inner_set = new_ps.inner = new_ps.inner_conn = nil
	if (ps.mode & RIGHT_MODE).nonzero?
		left, right, ps.left_word, ps.right_word, ps.connection =
			ps.inner, ps.right,
			*create_connection(ps.sentence, ps.inner, ps.right,
							   ps.inner_conn, ps.right_conn)
		new_ps.update({	:results =>		[],
						:left =>		ps.inner,
					  })
		if ps.inner_conn.multiple?
			new_ps.update({:left_set =>	ps.inner_set})
		else
			new_ps.update({:left_set =>	ps.inner_set - [ps.inner_conn]})
		end
		new_ps.update({:right_set =>	ps.right_set - [ps.right_conn]}) unless
			ps.right_conn.multiple?
	else # LEFT_MODE
		left, right, ps.left_word, ps.right_word, ps.connection =
			ps.left, ps.inner,
			*create_connection(ps.sentence, ps.left, ps.inner,
							   ps.left_conn, ps.inner_conn)
		new_ps.update({	:results =>		[],
						  :right =>		ps.inner,
					  })
		new_ps.update({:left_set =>	ps.left_set - [ps.left_conn]}) unless
			ps.left_conn.multiple?
		if ps.inner_conn.multiple?
			new_ps.update({:right_set =>	ps.inner_set})
		else
			new_ps.update({:right_set =>	ps.inner_set - [ps.inner_conn]})
		end
	end
	# Log.debug( "inner_add_connection start with %s" % ps.connection )
	results = re_find_linkages(new_ps)
	if results == UNSATISFIED
		# Log.debug( "re_find_linkages(%d, %d) end - unsatisfied" %
#					  [new_ps.left, new_ps.right])
		return results
	end
	# Log.debug("re_find_linkages(%d, %d) end - %d results" %
#				  [new_ps.left, new_ps.right, results.length])
	results << Linkage::new(ps.sentence.names.map{nil}) if results.empty?
	ps.results += results.collect {|linkage|
		linkage.insert(ps.connection, left, right,
					   ps.left_word, ps.right_word)
	}
end

#inner_force_recursion(ps) ⇒ Object

Inside of a recurse, pretend there is a connection between two words to find any connections that may exist to the words in between, and if those connections are enough to satisfy the conditions of connectivity and satisfaction.



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# File 'lib/linkparser.rb', line 314

def inner_force_recursion(ps)
	# Log.debug( "inner_force_recursion start" )
	new_ps = ParseState::new(*ps.to_a)
	if (ps.mode & RIGHT_MODE).nonzero?
		left, right = ps.inner, ps.right
		new_ps.update({	:results =>		[],
						:left =>		ps.inner,
					  })
	else # LEFT_MODE
		left, right = ps.left, ps.inner
		new_ps.update({	:results =>		[],
						:right =>		ps.inner,
					  })
	end
	results = re_find_linkages(new_ps)
	if results == UNSATISFIED
		# Log.debug( "re_find_linkages(%d, %d) end - unsatisfied" %
		#		  [new_ps.left, new_ps.right])
	else
		# Log.debug("re_find_linkages(%d, %d) end - %d results" %
		#		  [new_ps.left, new_ps.right, results.length])
	end
	return results
end

#make_connector_hash(sentence) ⇒ Object

Creates a hash of connectors to the words that have matching connectors.



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# File 'lib/linkparser.rb', line 404

def make_connector_hash( sentence )
	connectors = {}
	sentence.definitions.each {|word|
		word.connector_sets.each {|set|
			set.each {|connector|
				# :TODO: add in pruning somewhere around here
				connectors[connector] = nil
			}
		}
	}
	connectors.each {|connector,val|
		connectors[connector] = connectors.keys.find_all {|conn| conn.match(connector)}
	}
	return connectors
end

#outer_add_connection(ps) ⇒ Object

In the outer call of find_linkages, a connection has been found, so create it and recurse into the inner words.



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# File 'lib/linkparser.rb', line 266

def outer_add_connection(ps)
	ps.left_word, ps.right_word, ps.connection =
		create_connection( ps.sentence, ps.left, ps.right, ps.left_conn,
						   ps.right_conn )
	# Log.debug( "outer_add_connection with %s." % ps.connection )
	new_ps = ParseState::new(*ps.to_a)
	new_ps.update( {:results =>		[]} )
	new_ps.update( {:left_set =>	ps.left_set - [ps.left_conn]} ) unless
		ps.left_conn.multiple?
	new_ps.update( {:right_set =>	ps.right_set - [ps.right_conn]} ) unless
		ps.right_conn.multiple?
	results = re_find_linkages(new_ps)
	if results == UNSATISFIED
		# Log.debug("re_find_linkages(%d, %d) end - unsatisfied" %
		#		  [new_ps.left, new_ps.right])
		return results
	end
	# Log.debug("re_find_linkages(%d, %d) end - %d results" %
	#				[new_ps.left, new_ps.right, results.length])
	results << Linkage::new(ps.sentence.names.map{nil}) if results.empty?
	ps.results += results.collect {|linkage|
		linkage.insert(ps.connection, ps.left, ps.right,
					   ps.left_word, ps.right_word)
	}
end

#outer_force_recursion(ps) ⇒ Object

In the outer call of find_linkages, no connection was found between a pair of sets, but recurse anyway into the inner words.



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# File 'lib/linkparser.rb', line 294

def outer_force_recursion(ps)
	# Log.debug( "outer_force_recursion on '%s' and '%s'" %
	#				[ps.left_set, ps.right_set] )
	new_ps = ParseState::new(*ps.to_a)
	new_ps.results = []
	results = re_find_linkages(new_ps)
	if results == UNSATISFIED
		# Log.debug( "re_find_linkages(%d, %d) end - unsatisfied" %
		#		   [new_ps.left, new_ps.right])
		return results
	end
	# Log.debug( "re_find_linkages(%d, %d) end - %d results" %
	#		   [new_ps.left, new_ps.right, new_ps.results.length] )
	ps.results += results
end

#parse(string) ⇒ Object

Takes a string and tries to parse it into a Sentence object

Raises:



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# File 'lib/linkparser.rb', line 72

def parse( string )
		raise ParseError.new("Unable to parse nothing.") unless
			string && !string.empty?
		words = string.split
		
		words = @dictionary.affix(words)
		
		# Create LinkParser::Word objects out of the words and their definitions
		sentence = Sentence::new
# 		if @dictionary.has_key?('LEFT-WALL')
# 			sentence.definitions << @dictionary['LEFT-WALL']
# 			sentence.names << 'LEFT-WALL'
# 		end
		words.each {|word|
			# :!: This should be doing something to incorporate all the different "word.*"'s :!:
#if(found = @dictionary.dict.find {|w,d| %r$#{word}(\.\w)?$.match(w)})
			#	sentence.definitions << found[1]
			if @dictionary.has_key?(word)
sentence.definitions << @dictionary[word]
sentence.names << word
			else
#				raise ParseError::new("The word '#{word}' is not in the dictionary.")
			sentence.definitions << @dictionary["UNKNOWN"]
sentence.names << "UNKNOWN"
end
		}
# 		if @dictionary.has_key?('RIGHT-WALL')
# 			sentence.definitions << @dictionary['RIGHT-WALL']
# 			sentence.names << 'RIGHT-WALL'
# 		end
		
		# Find the linkages
		sentence.linkages = find_linkages(sentence)
		
		return sentence
end

#postProcess(sentence) ⇒ Object

does post-processing of a sentence



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# File 'lib/linkparser.rb', line 421

def postProcess( sentence )
		sentence #:TODO:
end

#re_find_linkages(ps) ⇒ Object

Recursive body of the find_linkages method. See presentation for a general algorithm explaination.



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# File 'lib/linkparser.rb', line 165

def re_find_linkages(ps)
	# Log.debug("re_find_linkages(%d, %d) start - (%s, %s)" % [
	#			  ps.left, ps.right, ps.left_set.right, ps.right_set.left])
	# test for stopping recursion.
	if(ps.left == (ps.right - 1))
		if( ! (ps.left_set.right.all_pass?(:optional?) and
			   ps.right_set.left.all_pass?(:optional?)) )
			return UNSATISFIED
		else
			return []
		end
	end
	results = []
	ps.right_conn = ps.left_conn = ps.inner_conn = nil
	satisfied = false
	for ps.inner in (ps.left+1)..(ps.right-1) do
		for ps.inner_set in ps.sentence.definitions[ps.inner].connector_sets do
			# :MC: For pruning.
			next if ps.inner_set.find {|c| (! c.optional?) and (ps.all_connectors[c].empty? or c.cost > 0)}
			for ps.inner_conn in ps.inner_set.left do
				for ps.left_conn in ps.left_set.right do
					if ps.inner_conn.match(ps.left_conn)
						# Log.debug( "(left)Connecting %s and %s" % [ps.left_conn, ps.inner_conn])
						ps.mode = LEFT_MODE | INNER_MODE
						# in the following call to add_connection, ps is
						# modified to include all the valid partial linkages
						# on this particular connection made using one of
						# the inner word's connectors on the left side.
						satisfied = true unless add_connection(ps) == UNSATISFIED
					end
				end
			end
			lefties = ps.results
			# check for needed recursion.
			if( lefties.empty? and (ps.inner != ps.left + 1) and
			   ( ! (ps.left_set.right.all_pass?(:optional?) and
					ps.inner_set.left.all_pass?(:optional?) ) ) )
				ps.mode = LEFT_MODE | INNER_MODE | FORCE_MODE
				lefties = add_connection(ps)
			end
			ps.results = []
			ps.left_conn = nil
			for ps.inner_conn in ps.inner_set.right do
				for ps.right_conn in ps.right_set.left do
					if ps.inner_conn.match(ps.right_conn)
						# Log.debug( "(right)Connecting %s and %s" % [ps.inner_conn, ps.right_conn] )
						ps.mode = RIGHT_MODE | INNER_MODE
						# add_conneciton here makes ps.results include all
						# valid partial linkages between the inner word and
						# the right side word.
						satisfied = true unless add_connection(ps) == UNSATISFIED
					end
				end
			end
			righties = ps.results
			# check for needed recursion.
			if( righties.empty? and (ps.inner != ps.right - 1) and
			   ( ! (ps.inner_set.right.all_pass?(:optional?) and
					ps.right_set.left.all_pass?(:optional?)) ) )
				ps.mode = RIGHT_MODE | INNER_MODE | FORCE_MODE
				righties = add_connection(ps)
			end
			ps.results = []
			unless( (lefties == UNSATISFIED) or (righties == UNSATISFIED) )
				results += lefties.set_combine(righties)
			end
		end
	end
	return UNSATISFIED unless satisfied
	return ps.results = results
end