1.28.1 Send methods

code ->_execute:

This method is redefined by the various subclasses of class code and does the actual execution of the code object.

Bugs: Its implementation must be in the C-language, which makes it impossible for the application programmer to create new code classes.

code ->debug_class: {user,service}

If service, execution happens in service mode, hiding it from the XPCE and Prolog debuggers. This mechanism is used by the Visual Hierarchy and Inspector tools to hide change-tracking from the debugger.

code ->execute:

Execute the code object. This method is redefined by all procedure type code object (returning success or failure). The method at this level invokes code<-execute if the code object is an instance of a subclass of class function and returns success if the function executes successfully. This makes functions available as procedures too.

See also

class-execute_function

code ->forward: any ...

This is the common way to activate code objects. It binds the predefined var objects @arg1 ... @arg10 to the arguments provided to this message and then invokes code->execute on itself. Example:

new(@m, message(@pce, write_ln, @arg1, @arg2)),
send(@m, forward, hello, world).

will print

hello world

code->forward pushes a variable-binding frame, thus limiting the scope of local assignments to var objects (see class assign and var->assign.

See also

- code->forward_vector
- code<-forward

code ->forward_vars: assign ...

Makes the assignments from the given list and then code->execute’s the code object. The scope of the assignments is limited to the execution of the code object. Suppose @client is defined as a global var object reflecting a notion of current client. The following example executes the code object while binding @client to the value of the Prolog variable Client:

send(Code, forward_vars, assign(@client, Client)).

This interface should be considered experimental and equivalent to the following (recall that code->forward limits the scope of local assignments to var objects):

send(and(assign(@client, Client), Code), forward)

See also class assign and class var.

code ->forward_vector: any ...

The actual argument syntax is:

code ->forward_vector: any ..., vector, [int]

Bind @arg1 ... from the concatenation of the leading arguments and the vector with the first [int] elements skipped and then invokes code->execute. See object->send_vector

See also

- code->forward
- object->send_vector