COMMAND clause

COMMAND clause is used to specify the name, key, description and help number for a menu option. It also contains the statements that are executed when this option is activated.

Key list	A list of one or more keys that invoke the menu option
MENU option	The clause that contains the name and description of a menu option
HELP clause	The clause which contains help number corresponding to the menu option

COMMAND clause can contain a nested MENU statement.

Menu option

The menu option clause contains the name of the menu option and the description. Both are optional. This clause has the following syntax:

Option	A character variable or a character string used as the name of a menu option
Description	A character variable or a character string used as the description of a menu option
Expression list	A 4GL expression that returns a name or a description of a menu option

 

There are two ways of specifying the option name and the description.

• In the first case where we have no separator between the option name and description:
• Both name and description in this case are optional
• If only one of them is present, it is treated by 4GL as the option name
• Both option name and description can be represented either by a quoted character string (or other constant), or by a variable
• Typically, the variable used is of character data type, though it can be of any other simple or structured data type, provided that it makes sense as a menu option name or description

 

In the second case a comma separator is present between the name and description:

• Both name and description in this case are obligatory
• If only one of them is present a compile-time error occurs
• Both name and description can be represented by a variable, a constant, or a 4GL expression

• If a name or a description is represented by a 4GL expression which consists of more than one variable or has any operators, it should be enclosed in parentheses, e.g.:

  MENU "my_menu"

  COMMAND KEY (F1) (curr_user||status), "Press to change the user"

 

If a COMMAND clause contains no option name and no description, the menu option will not be visible for a user.