Module: Filigree::Visitor

Includes:
ClassMethodsModule
Defined in:
lib/filigree/visitor.rb

Overview

An implementation of the Visitor pattern.

Defined Under Namespace

Modules: ClassMethods

Instance Method Summary collapse

Methods included from ClassMethodsModule

included

Dynamic Method Handling

This class handles dynamic methods through the method_missing method

#method_missing(name, *args) ⇒ Object

This is used to get and set binding names



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# File 'lib/filigree/visitor.rb', line 70

def method_missing(name, *args)
	if args.empty? and @match_bindings.last.respond_to?(name)
		@match_bindings.last.send(name)
	elsif name.to_s[-1] == '=' and args.length == 1
		@match_bindings.last.send(name, *args)
	else
		super(name, *args)
	end
end

Instance Method Details

#visit(*objects) ⇒ Object

Find the correct pattern and execute its block on the provided objects.

Parameters:

  • objects (Object) —

    Objects to pattern match.

Returns:

  • (Object) —

    Result of calling the matched pattern’s block

Raises:

  • (MatchError) —

    Raised when no matching pattern is found and strict matching is enabled.



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# File 'lib/filigree/visitor.rb', line 39

def visit(*objects)
	# FIXME: A dirty hack.  Find a better place to initialize this.
	@match_bindings ||= Array.new

	@match_bindings.push OpenStruct.new

	self.class.patterns.each do |pattern|

		# FIXME: Make these take their arguments in the same order
		if pattern.match?(objects, self)
			result = pattern.(self, objects)
			@match_bindings.pop
			return result
		end
	end

	@match_bindings.pop

	if self.class.strict_match?
		# If we didn't find anything we raise a MatchError.
		raise MatchError
	else
		nil
	end
end