The concept of ACTION is specific to instrumentation tasks (see SUN/134). The task is capable of obeying or cancelling a number of distinct commands known as actions. It does this, for example, in response to the ICL command:
where context
is OBEY
or CANCEL
.
Actions have to be declared in the Interface File, following the parameter declarations. The Action Specification is of the form:
Where actionname
is a character string specifying a valid action name. The same rules should be
applied to action names as are applied to parameter names (see Appendix A.1).
The Context Specifications allow command-line parameter positions to be allocated differently for different actions and contexts of the task. The Context Specification is of the form:
where context
is OBEY
or CANCEL
.
The order of the NEEDS fields within the Context Specification defines the order in which parameters may be specified on the command line for this particular action and context.
If no NEEDS list is specified, positions will default to those specified in the Parameter Specification.
For historical reasons, NEEDS specifications can have RANGE or IN constraints but these have no effect.
This field specifies the name by which the action is known to the person running the I-task.
The field is of the form:
where name
is a character string specifying a valid keyword. The same rules should be applied to
action keywords as are applied to parameter keywords (see Appendix A.1).
This field is used to specify the word that the user uses to communicate with a particular action. Thus the user could specify:
As can be seen, this completes the separation between the program’s view of actions and the user’s view of them. It is possible for the programmer to re-write the program using completely different action names, but the user command could be kept the same by just changing the ACTION statements in the Interface File. Similarly the user’s view of the program can be changed by just changing the action KEYWORD fields.
If the KEYWORD field is not specified for an action, then the system will use the action name as the keyword.
This field is used to specify some help text for an action. No current user interfaces make use of this.
The field is of the form:
where help-text
is a character string giving help information about the action.