The 'Execute' method

Argument: Character vector
Result: None

Valid for: APL (child task) object

The Execute method allows the parent to cause the child task to execute an APL expression or system command. It takes as an argument a character string which is the command to be executed (or passed as input to ⍞ or ⎕).

The child task should be awaiting input (you can tell whether this is the case by reading the status property, or by using the onReady callback). If it is not, the command will be placed in a buffer and will be executed when the child task next asks for input. However, there is no queue of commands held; any existing command already in the buffer will be over-written if the child task has not yet executed it. The Execute method returns immediately; it does not wait for the command to complete.

In this example, the child task is initially ready for input. It then executes the )LOAD command, and is busy for a short time (status property is 0). The status property then changes back to 1 when it is ready for further input:

      ChildTask.status
1
      ChildTask.Execute ')LOAD 10 SAMPLEEXCEL'
      ChildTask.status
0
      ChildTask.status
1

Note that in a real multi-tasking APLX application you would typically use the Signal method and onSignal events to allow the parent and child tasks to communicate with each other and synchronize their operations. The Execute method would typically be used only when starting up the child task.