This section describes the CST-Frame model, which is used to create the sample and generation subprograms for a model. Sample subprograms provide a sample of user exit code and generation subprograms supply code frame parameters.
This section covers the following topics:
Sample subprograms are invoked from a user exit and provide a starting sample to help the developer create user exit code. They can be simple or complicated, depending on the model.
Before invoking the sample subprograms, Natural Construct invokes all maintenance subprograms and the pre-generation subprogram. This ensures that the current specification parameters are valid and the conditions are set.
When creating a sample subprogram, you can include additional parameters to give the developer more control over what is generated into the user exit.
Note:
To pass additional information to the subprogram, use the
CU—PDA.#PDAX-FRAME-PARM variable.
To define a sample subprogram
Type ".E" at the beginning of a user exit line in the Code Frame editor.
Press Enter.
For more information about defining a sample subprogram, see Use Parameters Supplied by User Exits.
Generation subprograms are invoked from a code frame and supply code frame parameters. Because the lengths and contents of some parameters change based on user-supplied input values or information in Predict, these parameters must be supplied by the generation subprograms. The subprograms write statements to the Natural edit buffer, based on the user-supplied input parameters or other calculated values.
To write to the edit buffer, include a DEFINE PRINTER(SRC=1)
OUTPUT 'SOURCE' statement in the subprogram that routes the output to
the source work area. To allow models to be ported to multiple platforms, use
the CU--DFPR copycode member to define the SRC printer.
All WRITE, DISPLAY, and PRINT statement output for your print file is written to the edit buffer. Use the NOTITLE option on each of these statements. If a DISPLAY statement is used in the subprogram, also use the NOHDR option. When trailing blanks should be suppressed in variable names, the PRINT statement can be a useful alternative to the WRITE statement. However, you may want to increase the line length of the edit buffer when using the PRINT statement, so variable names are not split at the hyphen (-).
Because generation logic can be highly complex, these subprograms allow ultimate flexibility. However, they are less maintainable than code frame statements because you must change Natural programs to modify the generated code.
Generation subprograms can also accept the #PDA-FRAME-PARM constant code frame parameter from the CU—PDA common parameter data area. This parameter allows a subprogram to be invoked several times within the generation process. Each time the generation subprogram is invoked, it can use the value of this parameter to determine what to generate.
To invoke a generation subprogram
Specify line type "N" at the > prompt in the Code Frame editor.
Optionally, specify the constant parameter value at this prompt.
For more information about generation subprograms, see Parameters Supplied by Generation Subprograms.
For an example of a generated generation subprogram, refer to CUMNGGL in the SYSCST library.
Use the CST-Frame model to create the generation or sample subprogram. This model has one specification panel, Standard Parameters.
CUGFMA CST-Frame Subprogram CUG-MA0
Mar 30 Standard Parameters 1 of 1
Module name ........ CXMNGGL_
Parameter data area CXMNPDA_ *
Title .............. Frame ...________________
Description ........ This generation/sample subprogram ..___________________
_______________________________________________________
_______________________________________________________
_______________________________________________________
Enter-PF1---PF2---PF3---PF4---PF5---PF6---PF7---PF8---PF9---PF10--PF11--PF12---
help retrn quit userX main |
The input fields on the Standard Parameters panel are:
| Field | Description |
|---|---|
| Module name | Name specified on the Generation main menu. The
name of the subprogram must be alphanumeric and no more than eight characters
in length. Use the following naming conventions:
|
| Parameter data area | Name of the parameter data area (PDA) for your
model. Natural Construct determines the PDA name
based on the Module name specified on the Generation main menu. For example, if
you enter "CXMNGAAA", Natural Construct assumes the
PDA name is CXMNPDA.
Use the following naming convention: CXxxPDA where xx uniquely identifies your model. |
| Title | Title for the generated subprogram. The title identifies the subprogram for the List Generated Modules function on the Generation main menu and is used internally for program documentation. |
| Description | Brief description of the subprogram. The description is inserted in the banner at the beginning of the subprogram and is used internally for program documentation. |
CSGSAMPL CST-Frame Subprogram CSGSM0
Mar 30 User Exits 1 of 1
User Exits Exists Sample Required Conditional
-------------------------------- -------- ---------- -------- ------------
_ CHANGE-HISTORY Subprogram
_ PARAMETER-DATA
_ LOCAL-DATA
_ START-OF-PROGRAM
_ GENERATE-CODE
_ BEFORE-CHECK-ERROR Example
_ ADDITIONAL-INITIALIZATIONS Example
_ END-OF-PROGRAM |
For information about these user exits, see Supplied User Exits. For information about using the User Exit editor, refer to User Exit Editor, Natural Construct Generation.