VAR...[IS...] TO

 Synopsis

         Forward variable's messages (assign and access)

 Syntax

         VAR <variable name> [IS <target name>]
              TO <target variable>

 Arguments

         <variable name> is the name of the 'variable' being declared.
         In fact, this command does not declare a variable but rather
         allows access to a variable in another object.

         <target name> is the name of the variable, in the target
         class, which <variable name>  will be mapped to. This argument
         should be omitted if its value is the same as <variable name>.

         <target variable> is the name of the instance variable that
         the variable messages being declared will be forwarded to. The
         target variable must be a member of the current class or of a
         superclass. Two special keywords can be used instead of specifying
         a target variable: CLASS <className> and SENDER. Their use
         is described in the entry for the MESSAGE...[IS...] TO
         command.

 Description

         This command causes the specified variable's access and assignment
         messages to be forwarded to the object contained in the specified
         target variable. This makes it appear as though the variable
         exists in the class in which this command is used.

 Example

           CLASS Graph
              VAR oWin // refers to Window object
           EXPORT:
              VAR nGraphTop IS nTop TO oWin
              // ...
           END CLASS

         This class specification will cause instances of the Graph class,
         upon receiving the nGraphTop message for access or assign, to
         respond by sending the equivalent nTop message to the object
         referred to by the instance variable oWin. Thus, for example,
         the following code has the ultimate effect of assigning the number
         5 to the nTop variable in the Window object contained in the Graph
         object oGraph.

           LOCAL oGraph := Graph():new(...)
           oGraph:nGraphTop := 5
           ? oGraph:nGraphTop

 See Also

         MESSAGE...[IS...] TO, Message Forwarding