For every command and every statement with operands there is an operand form listing the associated operands. Depending on the definition in the syntax file, the operands of a structure may, under minimum and medium guidance, either be integrated in the form or listed in a separate subform. If SDF specifies on the form an operand value associated with a structure for which there is a separate subform, an empty set of parentheses following the value draws attention to the existence of the subform. Even where a subform exists, the user may enter the operands of the structure in the higher-ranking form. They should be enclosed in parentheses and placed immediately after the operand value which initiates the structure.
SDF offers the user a form in which to enter the values for the operands of a command or statement. This form is preset with the default values of the optional operands. Once a form has been sent off, SDF either displays another form (subform for a structure) or causes the command or statement to be executed. The user is supplied with an operand form in the following cases:
after selecting a command or statement in a menu
after entering <command>? or <statement>? in unguided dialog or in the NEXT line of a form or menu
after entering !<command>? or !<statement>? in unguided dialog or in the NEXT line of a form or menu
if, in guided dialog, a program expects a specific statement (operand form for a statement)
in program mode after entering a question mark in unguided dialog if the program expects a specific statement for the next processing step
if, in unguided dialog (NO form), a request to correct an errored entry is answered with a question mark
if an incorrect entry is made in guided dialog
If the user sends off an operand form with a question mark instead of an operand value, SDF offers the same form with additional information.
Switchover to a lower-ranking operand form occurs in the following cases:
after entering at least one structure-initiating operand value in the form and entering *CONTINUE in the NEXT line (display of a subform)
after entering a structure-initiating operand value in the form and entering *DOWN(<operand>) in the NEXT line of a form (switch to the subform for an individual structure)
Switchover to a higher-ranking operand form occurs in the following cases:
after entering *UP in the NEXT line of a subform
after entering “
-”in the NEXT line of the first page of the first of a sequence of subforms (or pressing the
key in Styleguide mode) after entering *CANCEL in the NEXT line of a subform (or pressing the
key in Styleguide mode)
The specifications made previously in the subform are retained during switchover with *UP or “-”, but in the case of switchover with *CANCEL they are discarded.