Specifying command actions dynamically

You can specify a command action dynamically (as part of function processing) by the use of a dialog variable. A variable action can be used to share commands, such as UP, DOWN, LEFT, and RIGHT, with the DM component. It can also be used to enable or disable commands during certain points in the dialog. Suppose, for example, an application command table includes these entries:

Table 1. Examples of entries in an application command table
ZCTVERB	ZCTTRUNC	ZCTACT
UP	0	&SCRVERT
DOWN	0	&SCRVERT

You can use the variable SCRVERT to dynamically control the action of the UP and DOWN vertical scroll commands as follows:

If SCRVERT is set to NOP, the commands are not available.
If SCRVERT is set to PASSTHRU, the commands are passed to the dialog.
If SCRVERT is set to blank, command scanning continues. In this case, the system definitions for UP and DOWN in the system command table take effect.
If SCRVERT is set to an action that is not valid, the commands are not available, as in NOP.

For this particular example, setting SCRVERT to SETVERB would have the same effect as setting it to blank, because UP and DOWN are defined in the system command table as SETVERB action commands.

If the dialog overrides or shares the use of the scroll commands, it becomes that dialog's responsibility to ensure that the commands have been redefined with an action of blank, or with SETVERB. This must be done before starting any ISPF function that requires View, Browse, Edit, and Table Display. The same rule applies to the RFIND command used by Browse and Edit and the RCHANGE command used by Edit.