perform
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    The perform message sends a specified message to the target object.
    The message to be sent is specified by an object of class Symbol.  A
    Symbol object must be the first parameter to the perform message.
    All following parameters are passed to the invoked method as is.

    For example, the following code fragment creates a Symbol object
    referring to the move message and sends it to the object obj,
    using the perform message.

        LOCAL oSym := Symbol():new( "move" )
        obj:perform( oSym, 15 )

    This has the effect of sending the move message to obj.  The
    second parameter passed to perform above, 15, will be passed to the
    move method as its first parameter.