3/16/2017 - 1:47 PM

php2rpg.md

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php2rpg

Guide showing you PHP and RPG differences

RPG is strongly typed.
RPG indexes start at 1, where PHP starts at 0.
Variables in PHP start with a Dollar sign. ($)

Typing

RPG does not have strings like PHP. RPG has character fields, which consists of a block of memory. When you refernece the field, it will return every character that was allocated for it - including blanks.
There are more types than shown here.

$x = "Hello world!"; //String
$y = 5985;           //Int
$z = 10.365;         //Float
$a = true;           //Boolean

Dcl-S x Char(12) Inz('Hello world!');
Dcl-S y Int(5)   Inz(5985);
Dcl-S z Float(8) Inz(10.365);
Dcl-S a Ind      Inz(*On);

Options for integer types:

Dcl-S y Int(3|5|10|20) (signed)
- 3: -128 to 127
- 5: -32768 to 32767
- 10: -2147483648 to 2147483647
- 20: -9223372036854775808 to 9223372036854775807
Dcl-S y Unz(3|5|10|20) (unsigned)
- 3: 0 to 255
- 5: 0 to 65535
- 10: 0 to 4294967295
- 20: 0 to 18446744073709551615

Options for decimal types:

Dcl-S z Float(4|8)
Dcl-S z Zoned(length:digits) (zoned decimal)`
Dcl-S z Packed(length:digits) (packed decimal)`
Dcl-S z Bindec(length:digits) (binary decimal)`

Create different variables

$txt = "Hello world!";
$x = 5;
$y = 10.5;

echo $txt;
echo "<br>";
echo $x;
echo "<br>";
echo $y;

Dcl-S txt Char(12)    Inz('Hello world!');
Dcl-S x   Int(3)      Inz(5);
Dcl-S y   Packed(5:1) Inz(10.5);

DSPLY txt;
DSPLY %Char(x);
DSPLY %Char(y);

Arithmetic operators

echo 5 + 5;
echo 5 - 5;
echo 5 / 5;
echo 5 * 5;

Dcl-S Result Int(5); 

Result = 5 + 5;
dsply %char(Result);

Result = 5 - 5;
dsply %char(Result);

Result = 5 / 5;
dsply %char(Result);

Result = 5 * 5;
dsply %char(Result);

Assignment operators

$x = 10; 
$x += 10;
$x -= 10;
$x /= 10;
$x *= 10;

Dcl-S Result Int(5); 

Result  = 10;
Result += 10;
Result -= 10;
Result /= 10;
Result *= 10;

Comparison operators

Booleans in PHP are either true or false
Booleans are called Indicators in RPG
- They are either *On or *Off (the same are true or false)


$varA = 5;
%varB = 10;

$bool = ($varA == 4varB);
$bool = ($varA != $varB);
$bool = ($varA > $varB);
$bool = ($varA < $varB);
$bool = ($varA >= $varB);
$bool = ($varA <= $varB);


Dcl-S bool Ind;
Dcl-S varA Int(3) Inz(5);
Dcl-S varb Int(3) Inz(10);

bool = (varA == varB);
bool = (varA <> varB);
bool = (varA > varB);
bool = (varA < varB);
bool = (varA >= varB);
bool = (varA <= varB);

Logical operators

If ($bool == true && $varA == 5) {
  echo('Hello world.');
]

If ($bool == false || $varA == 5) {
  echo('Hello world.');
]

If ($bool != false) {
  echo('Hello world.');
]

If (bool = *On AND varA = 5);
  dsply ('Hello world.');
Endif;

If (bool = *Off OR varA = 5);
  dsply ('Hello world.');
Endif;

If NOT (bool = *Off);
  dsply ('Hello world.');
Endif;

Arrays

$MyArray = [];
$MyArray[0] = 'Hello';
$MyArray[1] = 'World';
$MyArray[2] = 'How';
$MyArray[3] = 'Are';
$MyArray[4] = 'You?';

echo $MyArray[2];

Dcl-S MyArray Char(5) Dim(10);

MyArray(1) = 'Hello';
MyArray(2) = 'World';
MyArray(3) = 'How';
MyArray(4) = 'Are';
MyArray(5) = 'You?';

dsply (MyArray(3));

While loop

$num = 0;

while ($num < 5) {
 echo 'number: ' . $num;
 $num++;
}

Dcl-S num Int(3) Inz(0);

Dow (num < 5);
  dsply ('number: ' + %Char(num));
  num += 1;
Enddo;

For loop (Counting up example)

for ($x = 0; $x <= 10; $x++) {
    echo "The number is: " . $x;
}

Dcl-S x Int(3);

For x = 0 to 10;
  dsply ('The number is: ' + %Char(x));
Endfor;

For loop (Counting down example)

for ($x = 10; $x >= 0; $x--) {
    echo "The number is: " . $x;
}

Dcl-S x Int(3);

For x = 10 downto 0;
  dsply ('The number is: ' + %Char(x));
Endfor;

For loop (by amount)

This example prints 0, 2, 4, 6, 8, 10
The RPG for is also writable as For x = 0 to 10 by 2.

for ($x = 0; $x <= 10; $x += 2) {
    echo "The number is: " . $x;
}

For x = 0 by 2 to 10;
  dsply ('The number is: ' + %Char(x));
Endfor;

Function/procedure definition

PHP passes parameters by value always.
RPG passes by reference by default, but will pass by value with the value keyword.
*N in RPG represents 'nothing' - you can optionally put the procedure name (doDivide) in its place.

echo doDivide(10, 2);
return;

function doDivide($numA, $numB) {
    return $numA / $numB;
}

dsply (%Char(doDivide(10, 2)));
*InLR = *On;
Return;

Dcl-Proc doDivide;
  Dcl-Pi *N Int(3);
    numA Int(3) Value;
    numB Int(3) Value;
  End-Pi;
  
  Return numA / numB;
Edn-Proc;

Test global scope (variable in global scope)

$x = 5; // global scope
  
function myTest() {
     // using x inside this function will generate an error
     echo "<p>Variable x inside function is: $x</p>";
} 
myTest();

echo "<p>Variable x outside function is: $x</p>";

Dcl-S x Int(3) Inz(5); //Global scope

myTest();
dsply ('Variable x outside procedure is: ' + %Char(x));

*Inlr = *On;
Return;

Dcl-Proc myTest;
  // using x inside this function will be ok because it's global
  dsply ('Variable x inside procedure is: ' + %Char(x));
End-Proc;

Test local scope (variable inside function)

This is a false program (won't compile) and script: using x outside the function/procedure will stop the compiler/script because x doesn't exist in the global scope.

function myTest() {
     $x = 5; // local scope
     echo "<p>Variable x inside function is: $x</p>";
} 
myTest();

// using x outside the function will generate an error
echo "<p>Variable x outside function is: $x</p>";

myTest();                                                          
dsply ('Variable x outside procedure is: ' + %Char(x)); 
                                                        
*Inlr = *On;                                            
Return;                                                 
                                                        
Dcl-Proc myTest;                                        
  Dcl-S x Int(3) Inz(5);                                
                                                        
  dsply ('Variable x inside procedure is: ' + %Char(x));
End-Proc;

Get the length of a string - %len / %trim

echo strlen("Hello world!");

If you pass in a variable to %len, it will return the length of the variable - this includes the blanks.

//We use %trim to remove the blanks from the character field
// Dcl-S someAlphaVar Char(100) Inz('Hello there world!');
// %len(%trim(someAlphaVar));

//%Char must be used because DSPLY won't except anything other than characters
dsply %char(%len('Hello world!'));

Search for a specific text within a string - %Scan

Both strpos and %scan return the starting index of the string.

echo strpos("Hello world!", "world");

dsply %char(%scan('world':'Hello world!'));

Replace text within a string - %scanrpl

echo str_replace("world", "Barry", "Hello world!");

dsply %scanrpl('world':'Barry':'Hello world!');

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php2rpg.md

php2rpg

Typing

Create different variables

Arithmetic operators

Assignment operators

Comparison operators

Logical operators

Arrays

While loop

For loop (Counting up example)

For loop (Counting down example)

For loop (by amount)

Function/procedure definition

Test global scope (variable in global scope)

Test local scope (variable inside function)

Get the length of a string - %len / %trim

Search for a specific text within a string - %Scan

Replace text within a string - %scanrpl