STRUCT |
This command serves two purposes:
You can use it to perform structural indentation of the source code of the Natural object currently in the work area of the editor.
Various display features make the structure of a program clear to you, thus allowing you to detect any structural inconsistencies.
However, since STRUCT processes Natural
sources whether or not they can actually be cataloged, a source will not be
parsed for syntactical correctness. Although in most cases,
STRUCT will deliver nicely structured source lines,
there may be source lines which are ambiguous and which will not be structured
as expected.
The following types of statements are affected by the
STRUCT command:
conditional statement blocks (AT BREAK,
IF,
DECIDE FOR,
etc.),
DO/DOEND statement blocks,
DEFINE
DATA blocks,
inline subroutines.
When you enter the system command STRUCT,
the STRUCT menu will be displayed. It offers the
following functions:
With this function, you can have a source program indented so that the indentation of source-code lines reflects the structure of the program.
This function is the same as that of the editor command
STRUCT.
Indentation will take the source-code line length into consideration; that is, a line to be indented will not be shifted beyond the right margin; if "correct" indentation would require a line to be shifted beyond the right margin, it will only be moved as far to the right as possible, but not beyond the margin.
With the Generate function, you can specify the following options:
| Field | Explanation | |
|---|---|---|
| Source Name | In this field, you enter
the name of the source you wish to be structurally indented. The specified
source will then be read from the system file into the work area and indented.
If you specify no source name, the object currently in the work area of the editor will be indented. If the work area is empty, you must specify a source name. |
|
| Shift setting | In this field, you can enter the number of positions (from 1 to 9) by which source-code lines are to be indented. By default, indentation is by 2 positions. | |
| Align Comments | Y | Each comment line will be indented as far as the statement line above it; except comment lines which begin at the beginning of a line, these will be not be indented. |
| N | Comment lines will not be indented. | |
| L | Comment lines will be aligned left-justified. | |
| Display Messages | Y | A message indicating that the structured program has been generated into the work area and a list of any source-code lines that could not be "correctly" indented (see above) will be displayed. |
| N | No such messages will be displayed. | |
| Return to STRUCT | Y | You will be returned to the
STRUCT menu after the Generate function has been
executed.
|
| N | You will be returned to the screen from
where you issued the STRUCT command after the
Generate function has been executed.
|
|
Note:
Indentation is performed differently for a reporting-mode program
than for a structured-mode program.
You can exclude sections of your program source from structural
indentation by using the special statements /*STRUCT OFF and
/*STRUCT ON. These must be entered at the beginning of a
source-code line. The source-code lines between these two statements will
remain as they are when you execute the Generate
function.
Program before being structurally indented:
DEFINE DATA LOCAL 1 EMPL VIEW OF EMPLOYEES 2 PERSONNEL-ID 2 FULL-NAME 3 FIRST-NAME 3 NAME 1 VEHI VIEW OF VEHICLES 2 PERSONNEL-ID 2 MAKE END-DEFINE FIND EMPL WITH NAME = 'ADKINSON' IF NO RECORDS FOUND WRITE 'NO RECORD FOUND' END-NOREC FIND (1) VEHI WITH PERSONNEL-ID = EMPL.PERSONNEL-ID DISPLAY EMPL.PERSONNEL-ID FULL-NAME MAKE END-FIND END-FIND END
The same program after the function Generate Structured Source has been applied to it:
DEFINE DATA LOCAL
1 EMPL VIEW OF EMPLOYEES
2 PERSONNEL-ID
2 FULL-NAME
3 FIRST-NAME
3 NAME
1 VEHI VIEW OF VEHICLES
2 PERSONNEL-ID
2 MAKE
END-DEFINE
FIND EMPL WITH NAME = 'ADKINSON'
IF NO RECORDS FOUND
WRITE 'NO RECORD FOUND'
END-NOREC
FIND (1) VEHI WITH PERSONNEL-ID = EMPL.PERSONNEL-ID
DISPLAY EMPL.PERSONNEL-ID FULL-NAME MAKE
END-FIND
END-FIND
END
With this function, you can display the source code of an object along with several items of information which make the structure of the object clear.
With the Display function, you have the following options:
| Field | Explanation | |
|---|---|---|
| Source Name | In this field, you enter
the name of the source you wish to be displayed. The specified source will then
be read from the system file and displayed.
If you specify no source name, the object currently in the work area of the editor will be displayed. If the work area is empty, you must specify a source name. |
|
| Display Compressed | Y | Source-code lines on the same structural level will not be displayed. Only those lines will be displayed which cause a change in the structure table on the right-hand side of the screen. From the gap in the sequence of line numbers you can tell how many lines are not shown between two given lines displayed. |
| N | All source-code lines will be displayed. | |
| Return to STRUCT | Y | You will be returned to the
STRUCT menu after the Display function has been
executed.
|
| N | You will be returned to the screen from
where you issued the STRUCT command after the
Display function has been executed.
|
|
The following information is displayed:
| Line Numbers | For every statement which closes a statement block, the source-code line number of the corresponding statement which initiates the statement block will be displayed to the left of the source code. |
| Structure Table | To the right of the source code, a table is displayed, which contains indicators for open statement blocks. For each open statement block, a single letter is displayed. The different letters refer to different types of statements (for an explanation of the letters, press PF1). Any structural inconsistency in the source code is indicated by a message being displayed in the structure table. |
14:17:47 - Structured Source ABC in Library XYZ - 2003-02-04 0010 DEFINE DATA LOCAL *O 0020 1 EMPL VIEW OF EMPLOYEES *O 0030 2 PERSONNEL-ID *O 0040 2 FULL-NAME *O 0050 3 FIRST-NAME *O 0060 3 NAME *O 0070 1 VEHI VIEW OF VEHICLES *O 0080 2 PERSONNEL-ID *O 0090 2 MAKE *O 0100 0010 END-DEFINE *O 0110 FIND EMPL WITH NAME = 'ADKINSON' *F 0120 IF NO RECORDS FOUND *FJ 0130 WRITE 'NO RECORD FOUND' *FJ 0140 0120 END-NOREC *FJ 0150 FIND (1) VEHI WITH PERSONNEL-ID = EMPL.PERSONNEL-I *FF 0160 DISPLAY EMPL.PERSONNEL-ID FULL-NAME MAKE *FF 0170 0150 END-FIND *FF 0180 0110 END-FIND *F 0190 END * PF1=Help, PF2=Menu, PF3=Exit, PF6=Top, PF12=Cancel. |
The current content of the work area is not affected by the displayed source.
With this function, you can print the source code of an object along with its structural information.
The Print function corresponds to the function Display Structure of Source, only the output is not displayed on the screen but sent to a printer.
With the Print function, you have the same options as with the Display function.
With this function, you can read a source from the system file and write it into the editor work area together with its structure information, plus several lines (line numbers 0000) at the beginning of the source, which explain the structure information.
With the Write function, you have the same options as with the function Display Structure of Source, except that you must specify a Source Name.
The source and its structure information are written as text into
the work area, and can be edited with the system command
EDIT.