SneakyDave.com

If you’re a developer, you know most languages aren’t that much different from each other, it’s just learning how to implement the current function or feature you’re looking for that’s the hard part.

I was reading this article on COBOL still accounting for 80% of business code in the world, and thought about how languages aren’t really that different from each other. For example, I’ll document some common and routine snippets of code from COBOL and PHP. It isn’t the language that’s hard to learn, it’s simple syntax, but the hard part is finding out how to get your favorite language to do what you want.

To simplify things, I’m using PHP’s alternative syntax, which means that, similar to COBOL, you don’t use { and } to enclose some statements, you use statements such as ENDIF and ENDFOR, which is how I learned it.

These should work if you’re using PHP5 and PHP4. PHP’s Object Oriented structure isn’t described here. The COBOL examples are strictly IBM z/OS COBOL, old school, no OOP required, or desired.

One thing to understand about PHP, as this is different from some other languages, is it will do a fairly good job of determining if your variable is a string or numeric, so you don’t see a lot of “wrong type” errors in PHP.

Maybe another day, or another life time, I’ll write about the similarities of CICS and PHP/Apache. They both are stateless protocols, in which in CICS you need a COMMUNICATIONS AREA to or a DATA MAP to hold variables you want to keep, and with PHP, you’d probably use a session to do the same thing. A CICS MAP isn’t a lot different from defining an HTML FORM to a user.

I haven’t included the WORKING STORAGE of the definitions of these COBOL variables, to save space, but they shouldn’t matter very much for these examples. You can define variables in PHP “on the fly”, but you may get syntax notification warnings in PHP if you try to use a variable before its definition.

If you’re a COBOL developer interested in PHP, the best place to learn it is on http://php.net, search or browse through some functions to see some of the things you work with today that could work in PHP. For instance, search for the “Date” function, and browse the pages on arrays to get a feel for how those topics are presented. Each function has user contributed notes too for code tidbits or gotchas

Then, download some PHP code, and see what it’s doing. Try to avoid Object Oriented PHP code unless you’re familiar with those types of structures.

These examples below are pretty simple, if you need more complex ones, let me know. No questions about how to convert any Cobol ’74 Report-Writer or internal sorts to PHP though!

(btw, in the CNET article, it describes PHP being a “new” language, and Java and .NET, as well as COBOL, as older languages. PHP itself has been around longer than .NET, but what do you expect, it’s CNET).

Conditional Statements

COBOL

IF EMP-NO = '228A'
    COMPUTE EMP-RAISE = EMP-SALARY * .05
ELSE
    COMPUTE EMP-RAISE = 0
END-IF

PHP

if ($emp_no == '228A'):
    $emp_raise = $emp_salary * .05;
else:
    $emp_raise = 0;
endif;

Case/Switch/Evaluate

COBOL

EVALUATE ERR_CODE
    WHEN 00
        DISPLAY 'ROW FOUND'
    WHEN +100
        DISPLAY 'ROW NOT FOUND'
    WHEN OTHER
        DISPLAY 'WHAT HAPPENED?'
END-EVALUATE

PHP

switch ($err_code) {
    case 0:
        echo "Row Found";
        break;
    case 100:
        echo "Row not found";
        break;
    default:
        echo "What happened?";
}

Loops

COBOL

COUNTER = 1
PERFORM UNTIL COUNTER > 5000
    DISPLAY 'COUNTER = ' COUNTER
    COUNTER = COUNTER + 1
END-PERFORM

PHP

for($counter = 1; $counter <= 5000; $counter++):
    echo "counter = ".$counter;
endfor;

Code Reuse / Copying

COBOL

COPY ILXAN001.

PHP

include ("ilxan0001");

(or)

require ("ilxan001");

Find/Replace

COBOL

INSPECT BAD-DATA REPLACING ALL 'XXX' BY 'YYY' TALLYING THE-COUNT
MOVE BAD-DATA TO GOOD-DATA
DISPLAY 'GOOD-DATA = ' GOOD-DATA ', NUMBER OF REPLACEMENTS - '
    THE-COUNT

PHP

$good_data = str_replace('XXX','YYY',$bad_data, $the_count);
echo "Good Data = ".$good_data.", Number of replacements - ".$the_count;

File access (sequential)

COBOL

(Assumes one record in the file)
OPEN INPUT IN-FILE
OPEN OUTPUT OUT-FILE
READ IN-FILE INTO IN-REC
WRITE OUT-REC FROM IN-REC
CLOSE IN-FILE OUT-FILE

(Multiple records)

OPEN INPUT IN-FILE
PERFORM UNTIL END-OF-INPUT = 'Y'
    READ IN-FILE INTO THE-RECORD
        AT END MOVE 'Y' TO END-OF-INPUT
    DISPLAY 'THE RECORD = ' THE-RECORD
END-PERFORM
CLOSE IN-FILE

PHP

(Assumes whole input file should be read and written)

$in_rec = file_get_contents('input.txt');
$out_file = fopen('output.txt', 'w');
fwrite($out_file, $in_rec);
fclose($out_file);

(Reading individual records)

$in-file = fopen('input.txt', 'r');
$contents = '';
while (!feof($in-file)) {
    $the_record = fread($in-file, 8192); // max size of record
    echo "The Record = ".$the_record
}
fclose($in-file);

Currrent Date

COBOL

ACCEPT SYSTEM-LONG-DATE FROM DATE YYYYMMDD.
DISPLAY 'DATE = ' SYSTEM-LONG-DATE

PHP

$system_long_date = Date("Ymd");
echo "Date = ".$system_long_date;

Boolean Switches

COBOL

SET DEBUG-ON TO TRUE
IF DEBUG-ON
    DISPLAY 'THIS IS A DEBUG STATEMENT'
END-IF

PHP

$debug = TRUE;
if ($debug):
    echo "This is a debug statement";
endif;

Arrays

COBOL

ARRAY-MAX = 10
PERFORM UNTIL SUB > ARRAY-MAX
    MOVE 'XXX' TO WS-TABLE-ROW(SUB)
    ADD 1 TO SUB
END-PERFORM

NOTE: Array index starts at 1. There are 10 elements in this array.

PHP

$array_max = 10;
$table_rows = array($array_max);
foreach($table_rows as $a_row){
    $a_row = 'XXX';
}

NOTE: Array index starts at 0. There are 11 elements in this array.

Subroutines

COBOL

    MOVE 'HI THERE' TO THING-TO-DISPLAY
    PERFORM AAAA-DISPLAY-SOMETHING

AAAA-BUILD-SOMETHING.
    DISPLAY THING-TO-DISPLAY

PHP

function DisplaySomething($thing_to_display) {
    echo $thing_to_display;
}

DisplaySomething("Hi There");

Concatenation

COBOL

STRING EMP-ID
       ', '
       EMP_NO
           DELIMITED BY SIZE INTO EMP-DETAILS
END-STRING
DISPLAY 'DETAILS = ' EMP-DETAILS

Unstring / Explode example

MOVE '123,456,789' TO THE-DATA
MOVE ',' TO DELIM
UNSTRING THE-DATA DELIMITED BY DELIM
    INTO DATA1, DATA2, DATA3
END-UNSTRING
DISPLAY 'DATA 1' DATA1
DISPLAY 'DATA 2' DATA2
DISPLAY 'DATA 3' DATA3

PHP

$emp_details = $emp-id.", ".$emp-no;
echo "Details = ".$emp_details

Unstring / Explode example

$the-data = '123,456,789';
$the-array = explode(",",$the_data);
echo "Data 1".$the-array[0];
echo "Data 1".$the-array [0];
echo "Data 1".$the-array [0];

Comments

COBOL

(Remember, COLUMN 8!!)

* THESE ARE SOME COMMENTS IN COBOL
* THEY ARE PRETTY

PHP

/**
* These are some comments in PHP
* They are pretty
*/

(or)

// These are some comments in PHP
// They are pretty