Class: Metrocot::CompositePattern

Inherits:
BasePattern show all
Defined in:
lib/metrocot.rb

Overview

Matches a series of patterns

Instance Attribute Summary collapse

Attributes inherited from BasePattern

#matched, #metrocot, #name, #node_scraper, #pattern_no, #pred, #source, #succ

Instance Method Summary collapse

Methods inherited from BasePattern

#default_scanner, #dump_match_map, #log, #log_match_data, #optional, parse, #priority, #with_scanned_match_data

Constructor Details

#initialize(parts = nil) ⇒ CompositePattern

Returns a new instance of CompositePattern.



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# File 'lib/metrocot.rb', line 736

def initialize( parts = nil )
	super(nil)
	@parts = if parts.nil?
		[]
	else
		parts.clone
	end
	succ_pred = nil
	@parts.each { |part| 
		part.pred = succ_pred
		succ_pred.succ = part unless succ_pred.nil?
		succ_pred = part
	}
end

Instance Attribute Details

#parts ⇒ Object (readonly)

Returns the value of attribute parts.



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# File 'lib/metrocot.rb', line 734

def parts
  @parts
end

Instance Method Details

#description ⇒ Object 



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# File 'lib/metrocot.rb', line 876

def description
	"comp ##{pattern_no}"
end

#dump(level, out) ⇒ Object 



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# File 'lib/metrocot.rb', line 752

def dump( level, out ) 
	out << "  " * level + "composite p=#{priority} [\n"
	@parts.each { |part|
		part.dump( level + 1, out )
	}
	out << "  " * level + "]\n"
end

#each_match(match_range, match_map) ⇒ Object 



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# File 'lib/metrocot.rb', line 843

def each_match( match_range, match_map )  

	@parts.each { |part| part.matched = nil }
	
	super(match_range, match_map)

	# find the hightest priority part and divine up the children 

	parts_by_priority = @parts.sort_by { |part| 0 - part.priority }
	each_split_match( match_range, {}, parts_by_priority, 0, {} ) { |last_match_range, last_match_map|
		comp_match_range = nil
		@parts.each { |part|
			next unless part.matched
			if ! comp_match_range
				comp_match_range = part.matched
				next
			end
			comp_match_range = comp_match_range.extend(part.matched)
		}
		result = with_scanned_match_data( match_map, last_match_map ) { |match_map|
			log_match_data("comp match trying", comp_match_range, match_map)
			yield( comp_match_range, match_map )
		}
		if result
			log("comp match done, returning: #{result}")
			return result 
		else
			log("comp match not done")
		end
	}

end

#each_split_match(comp_match_range, match_map, parts_by_priority, ppx, part_matches) ⇒ Object 



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# File 'lib/metrocot.rb', line 761

def each_split_match( comp_match_range, match_map, parts_by_priority, ppx, part_matches ) 

	pattern = nil

	while (ppx < parts_by_priority.size)
		pattern = parts_by_priority[ppx]
		break unless pattern.optional 
		break unless pattern.pred && ! pattern.pred.matched
		log("skipping optional #{pattern.description}")
		ppx += 1
	end

	if ppx >= parts_by_priority.size
		log("comp nothing left to do")
		return yield( comp_match_range, match_map ) 
	end


	match_range = comp_match_range
	log("comp matching sub-pattern #{pattern.description} within #{match_range.describe}")

	#
	# figure out which gap this pattern is supposed to fill
	#

	matched_on_right = pattern.succ

	while matched_on_right && ! matched_on_right.matched
		matched_on_right = matched_on_right.succ
	end

	if matched_on_right
		log("comp matching must be left of #{matched_on_right.description}")
		match_range = match_range.head(matched_on_right.matched.start_index, matched_on_right.matched.start_offset) 
	end

	matched_on_left = pattern.pred

	while matched_on_left && ! matched_on_left.matched
		matched_on_left = matched_on_left.pred
	end

	if matched_on_left
		log("comp matching must be right of #{matched_on_left.description}")
		match_range = match_range.tail(matched_on_left.matched.end_index, matched_on_left.matched.end_offset) 
	elsif matched_on_right
		right_node = match_range.hnodes[matched_on_right.matched.start_index]
		parent_of_right_node = right_node && right_node.parent
		parent_ix_of_right_node = parent_of_right_node && node_scraper.hnode_index[parent_of_right_node]
		if parent_ix_of_right_node && parent_ix_of_right_node >= match_range.start_index 
			match_range = match_range.tail(parent_ix_of_right_node + 1, 0)
			log("restricting left boundary to #{match_range} because would otherwise include subtree with right peer")
		end
	end

	log("comp matching sub-pattern #{pattern.description} at #{match_range.describe}")

	pattern.each_match( match_range, match_map ) { |part_match_range, match_map| 

		pattern.matched = part_match_range

		log("found sub-pattern #{pattern.description} at #{part_match_range.describe}")

		result = each_split_match( comp_match_range, match_map, parts_by_priority, ppx + 1, part_matches ) { |sub_match_range, sub_match_map|
			yield( sub_match_range, match_map )
		}

		pattern.matched = nil

		if result
			log("comp done, returning: #{result}")
			return result 
		else
			log("comp not done")
		end
	}

	return nil

end