parse_forest_visitor.rb in rley-0.3.05

- old
+ new
@@ -1,115 +1,113 @@
-module Rley # This module is used as a namespace
-  # A visitor class dedicated in the visit of a parse forest.
-  # It combines the Visitor and Observer patterns.
-  class ParseForestVisitor
-    # Link to the parse forest to visit
-    attr_reader(:pforest)
-
-    # List of objects that subscribed to the visit event notification.
-    attr_reader(:subscribers)
-    
-    # A Hash with pairs of the form: Node => node visit data
-    attr_reader(:agenda)
-    
-    # Indicates the kind of forest traversal to perform: :post_order, :pre-order
-    attr_reader(:traversal)
-
-    # Build a visitor for the given pforest.
-    # @param aParseForest [ParseForest] the parse tree to visit.
-    def initialize(aParseForest, aTraversalStrategy = :post_order)
-      @pforest = aParseForest
-      @subscribers = []
-      @traversal = aTraversalStrategy
-    end
-
-    public
-
-    # Add a subscriber for the visit event notifications.
-    # @param aSubscriber [Object]
-    def subscribe(aSubscriber)
-      subscribers << aSubscriber
-    end
-
-    # Remove the given object from the subscription list.
-    # The object won't be notified of visit events.
-    # @param aSubscriber [Object]
-    def unsubscribe(aSubscriber)
-      subscribers.delete_if { |entry| entry == aSubscriber }
-    end
-
-    # The signal to begin the visit of the parse forest.
-    def start()
-      pforest.accept(self)
-    end
-
-
-    # Visit event. The visitor is about to visit the pforest.
-    # @param aParseForest [ParseForest] the pforest to visit.
-    def start_visit_pforest(aParseForest)
-      broadcast(:before_pforest, aParseForest)
-    end
-
-
-    # Visit event. The visitor is about to visit the given non terminal node.
-    # @param aNonTerminalNode [NonTerminalNode] the node to visit.
-    def visit_nonterminal(aNonTerminalNode)
-      if @traversal == :post_order
-        broadcast(:before_non_terminal, aNonTerminalNode)
-        traverse_children(aNonTerminalNode)
-      else
-        traverse_children(aNonTerminalNode)  
-        broadcast(:before_non_terminal, aNonTerminalNode)
-      end
-      broadcast(:after_non_terminal, aNonTerminalNode)
-    end
-
-    # Visit event. The visitor is visiting the
-    # given terminal node.
-    # @param aTerminalNode [TerminalNode] the terminal to visit.
-    def visit_terminal(aTerminalNode)
-      broadcast(:before_terminal, aTerminalNode)
-      broadcast(:after_terminal, aTerminalNode)
-    end
-
-
-    # Visit event. The visitor has completed its visit of the given 
-    # non-terminal node.
-    # @param aNonTerminalNode [NonTerminalNode] the node to visit.
-    def end_visit_nonterminal(aNonTerminalNode)
-      broadcast(:after_non_terminal, aNonTerminalNode)
-    end
-
-    # Visit event. The visitor has completed the visit of the pforest.
-    # @param aParseForest [ParseForest] the pforest to visit.
-    def end_visit_pforest(aParseForest)
-      broadcast(:after_pforest, aParseForest)
-    end
-
-    private
-    
-    # Visit event. The visitor is about to visit the children of a non 
-    # terminal node.
-    # @param aParentNode [NonTeminalNode] the (non-terminal) parent node.
-    def traverse_children(aParentNode)
-      children = aParentNode.children
-      broadcast(:before_children, aParentNode, children)
-      
-      # Let's proceed with the visit of children
-      children.each { |a_node| a_node.accept(self) }
-      
-      broadcast(:after_children, aParentNode, children)
-    end
-
-    # Send a notification to all subscribers.
-    # @param msg [Symbol] event to notify
-    # @param args [Array] arguments of the notification.
-    def broadcast(msg, *args)
-      subscribers.each do |a_subscriber|
-        next unless a_subscriber.respond_to?(msg)
-        a_subscriber.send(msg, *args)
-      end
-    end
-  end # class
-end # module
-
-# End of file
\ No newline at end of file
+module Rley # This module is used as a namespace
+  # A visitor class dedicated in the visit of a parse forest.
+  # It combines the Visitor and Observer patterns.
+  class ParseForestVisitor
+    # Link to the parse forest to visit
+    attr_reader(:pforest)
+
+    # List of objects that subscribed to the visit event notification.
+    attr_reader(:subscribers)
+
+    # A Hash with pairs of the form: Node => node visit data
+    attr_reader(:agenda)
+
+    # Indicates the kind of forest traversal to perform: :post_order, :pre-order
+    attr_reader(:traversal)
+
+    # Build a visitor for the given pforest.
+    # @param aParseForest [ParseForest] the parse tree to visit.
+    def initialize(aParseForest, aTraversalStrategy = :post_order)
+      @pforest = aParseForest
+      @subscribers = []
+      @traversal = aTraversalStrategy
+    end
+
+    # Add a subscriber for the visit event notifications.
+    # @param aSubscriber [Object]
+    def subscribe(aSubscriber)
+      subscribers << aSubscriber
+    end
+
+    # Remove the given object from the subscription list.
+    # The object won't be notified of visit events.
+    # @param aSubscriber [Object]
+    def unsubscribe(aSubscriber)
+      subscribers.delete_if { |entry| entry == aSubscriber }
+    end
+
+    # The signal to begin the visit of the parse forest.
+    def start()
+      pforest.accept(self)
+    end
+
+
+    # Visit event. The visitor is about to visit the pforest.
+    # @param aParseForest [ParseForest] the pforest to visit.
+    def start_visit_pforest(aParseForest)
+      broadcast(:before_pforest, aParseForest)
+    end
+
+
+    # Visit event. The visitor is about to visit the given non terminal node.
+    # @param aNonTerminalNode [NonTerminalNode] the node to visit.
+    def visit_nonterminal(aNonTerminalNode)
+      if @traversal == :post_order
+        broadcast(:before_non_terminal, aNonTerminalNode)
+        traverse_children(aNonTerminalNode)
+      else
+        traverse_children(aNonTerminalNode)
+        broadcast(:before_non_terminal, aNonTerminalNode)
+      end
+      broadcast(:after_non_terminal, aNonTerminalNode)
+    end
+
+    # Visit event. The visitor is visiting the
+    # given terminal node.
+    # @param aTerminalNode [TerminalNode] the terminal to visit.
+    def visit_terminal(aTerminalNode)
+      broadcast(:before_terminal, aTerminalNode)
+      broadcast(:after_terminal, aTerminalNode)
+    end
+
+
+    # Visit event. The visitor has completed its visit of the given
+    # non-terminal node.
+    # @param aNonTerminalNode [NonTerminalNode] the node to visit.
+    def end_visit_nonterminal(aNonTerminalNode)
+      broadcast(:after_non_terminal, aNonTerminalNode)
+    end
+
+    # Visit event. The visitor has completed the visit of the pforest.
+    # @param aParseForest [ParseForest] the pforest to visit.
+    def end_visit_pforest(aParseForest)
+      broadcast(:after_pforest, aParseForest)
+    end
+
+    private
+
+    # Visit event. The visitor is about to visit the children of a non
+    # terminal node.
+    # @param aParentNode [NonTeminalNode] the (non-terminal) parent node.
+    def traverse_children(aParentNode)
+      children = aParentNode.children
+      broadcast(:before_children, aParentNode, children)
+
+      # Let's proceed with the visit of children
+      children.each { |a_node| a_node.accept(self) }
+
+      broadcast(:after_children, aParentNode, children)
+    end
+
+    # Send a notification to all subscribers.
+    # @param msg [Symbol] event to notify
+    # @param args [Array] arguments of the notification.
+    def broadcast(msg, *args)
+      subscribers.each do |a_subscriber|
+        next unless a_subscriber.respond_to?(msg)
+        a_subscriber.send(msg, *args)
+      end
+    end
+  end # class
+end # module
+
+# End of file