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, MatchError

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

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
    MatchError
  end
end