Editing COBOL (section)

====Report writer====
The report writer is a [[declarative programming|declarative facility]] for creating reports. The programmer need only specify the report layout and the data required to produce it, freeing them from having to write code to handle things like page breaks, data formatting, and headings and footings.{{sfn|ISO/IEC JTC 1/SC 22/WG 4|2014|p=855}}

Reports are associated with report files, which are files which may only be written to through report writer statements.

<syntaxhighlight lang="cobol">
       FD  report-out REPORT sales-report.
</syntaxhighlight>

Each report is defined in the report section of the data division. A report is split into report groups which define the report's headings, footings and details. Reports work around hierarchical ''{{dfn|control breaks}}''. Control breaks occur when a key variable changes it value; for example, when creating a report detailing customers' orders, a control break could occur when the program reaches a different customer's orders. Here is an example report description for a report which gives a salesperson's sales and which warns of any invalid records:

<syntaxhighlight lang="cobol">
       RD  sales-report
           PAGE LIMITS 60 LINES
           FIRST DETAIL 3
           CONTROLS seller-name.

       01  TYPE PAGE HEADING.
           03  COL 1                    VALUE "Sales Report".
           03  COL 74                   VALUE "Page".
           03  COL 79                   PIC Z9 SOURCE PAGE-COUNTER.

       01  sales-on-day TYPE DETAIL, LINE + 1.
           03  COL 3                    VALUE "Sales on".
           03  COL 12                   PIC 99/99/9999 SOURCE sales-date.
           03  COL 21                   VALUE "were".
           03  COL 26                   PIC $$$$9.99 SOURCE sales-amount.

       01  invalid-sales TYPE DETAIL, LINE + 1.
           03  COL 3                    VALUE "INVALID RECORD:".
           03  COL 19                   PIC X(34) SOURCE sales-record.

       01  TYPE CONTROL HEADING seller-name, LINE + 2.
           03  COL 1                    VALUE "Seller:".
           03  COL 9                    PIC X(30) SOURCE seller-name.
</syntaxhighlight>

The above report description describes the following layout:
<pre>
Sales Report                                                             Page  1

Seller: Howard Bromberg
  Sales on 10/12/2008 were $1000.00
  Sales on 12/12/2008 were    $0.00
  Sales on 13/12/2008 were   $31.47
  INVALID RECORD: Howard Bromberg             XXXXYY

Seller: Howard Discount
...
Sales Report                                                            Page 12

  Sales on 08/05/2014 were  $543.98
  INVALID RECORD: William Selden      12052014FOOFOO
  Sales on 30/05/2014 were    $0.00
</pre>

Four statements control the report writer: {{code|INITIATE}}, which prepares the report writer for printing; {{code|GENERATE}}, which prints a report group; {{code|SUPPRESS}}, which suppresses the printing of a report group; and {{code|TERMINATE}}, which terminates report processing. For the above sales report example, the procedure division might look like this:

<syntaxhighlight lang="cobol">
           OPEN INPUT sales, OUTPUT report-out
           INITIATE sales-report
 
           PERFORM UNTIL 1 <> 1
               READ sales
                   AT END
                       EXIT PERFORM
               END-READ
 
               VALIDATE sales-record
               IF valid-record
                   GENERATE sales-on-day
               ELSE
                   GENERATE invalid-sales
               END-IF
           END-PERFORM
 
           TERMINATE sales-report
           CLOSE sales, report-out
           .
</syntaxhighlight>

Use of the Report Writer facility tends to vary considerably; some organizations use it extensively and some not at all.{{sfn|McCracken|1976|p=338}} In addition, implementations of Report Writer ranged in quality, with those at the lower end sometimes using excessive amounts of memory at runtime.{{sfn|McCracken|1976|p=338}}