Sending messages

To send a message means in our context to invoke the dispatcher of the object passing the message as an argument. This was done by evaluating the expression: (define bal-set(acc1 two)).

Invoking the dispatcher caused the following changes in the diagram below:

• a new envionment frame was created for the dispatcher with the key/value-pair `msg$=>$two' stored in it.
• the new environment frame was linked with the previous one
• the dispatcher interpreted the message `two' and returned a pointer to the method `deposit' to the caller of the function. The call was initiated from the top-level and therefore changed the top-level environment by adding the variable `bal-set' assigning it the value returned by the call.

Georg P. Loczewski 2004-03-05

Impressum und Datenschutz