Cross Ref > Language Basics

PHP is case sensitive with variable names but not with commands. Although commands are case incenstive, I prefer to use all lowercase because it's easy to type and that's what I see most PHP coders doing and I see it on PHP.Net.

echo "hello<br>";

ECHO "hello<br>";

Echo "hello<br>";

eCHo "hello<br>";

$fullname = "Mike Prestwood"; //These are two...

$FullName = "Wes Peterson";   //separate varialbes.

ObjectPAL is not case sensitive. My preference for ObjectPAL is to follow the camel casing promoted in the examples and help files originally developed by Borland.

Syntax Example:   All of the following are equivalent: msgInfo "", "Hello" MsgInfo "", "Hello" msginfo "", "Hello" MSGINFO "", "Hello" Variables are not case sensitive. Var FullName String endVar fullname="Mike Prestwood" msgInfo("", fullNAME)

 Camel Casing

In .PHP html pages, you embed PHP code between <?PHP and ?>.

For PHP, JavaScript, Java,and C++, I prefer to put the first { at the end of the first line of the code block as in the example above because I see morePHP codeformatted that way (and on PHP.Net).

PHP Alternative Syntax

Although I don't like to use it, PHP offers an alternative syntax for if, while, for, foreach, and switch. These code blocks are surrounded by statement ending keywords that all use End with camel caps such as endif, endwhile, endfor, endforeach,and endswitch.

<?PHP

$x = "Yes";

//Simple if

If ($x == "Yes")
  echo "hello world";

//If with a block of code.

If ($x == "Yes") {
  echo "Hello world";

  echo "I am a PHP coder!";

}

?>

ObjectPAL code blocks are surrounded by statement ending keywords that all use End with camel caps such as endMethod, endVar, endIf, endSwitch, and endTry.

method

endMethod

var

endVar

if

endIf

switch

endSwitch

try

endTry

Commenting Code
Use the multi-line to comment out large blocks of code and to write multiple line comments.

#This is a comment in PHP.

//This is too!
 

/*

This is a multi-line

comment.

*/

Commenting Code
ObjectPAL uses ; for a single line comment and { } for a multiple line comment.

Syntax Example:   ;Single line comment. { Multiple line comment. }

In PHP, you declare constants using the define keyword:

define("CONST_NAME", "Value");

Constants in PHP are case sensitive. A common standard in PHP is to use all-uppercase letters, with underscores to separate words within the name.

define('FULL_NAME', 'Mike Prestwood');
define("AGE", 25);

echo "Your name is " . FULL_NAME . ".";
echo "You are " . AGE . ".";

 PHP Constants (define)

In ObjectPAL, you declare one or more constant values within a const..endConst block. Optionally, you can specify the dataType by casting the value as part of the declaration.

If you do not specify the data type, the data type is inferred from the value as either a LongInt, a Number, a SmallInt, or a String.

As with variables, the const..endConst block can come within a method or procedure as the first bit of code, or in the Const window. Putting it above the method or procedure is allowed but has no significance so don't.

const
  kFeetToMeter = Number(3.2808)
  kMeterToFeet = Number(.3048)
  kName = String("Mike")

  kCA = "California"     ;String inferred.
endConst

 ObjectPAL Constants (const..endConst)  

ObjectPAL is a bit unique in that it doesn't use a semicolon nor a return to mark the end of a line, it uses whitespace which can be a return, space, or tab. This is a bit unusual but does allow for some nice formatting of code.

Syntax Example:   msgInfo("", "Hello1") msgInfo("", "Hello2") msgInfo("", "Hello3") ;The following single line of code also works. msgInfo("", "Hello4") msgInfo("", "Hello5") ;Two or more works too: msgInfo ("", "Hello6")

In PHP you can use quotes, or apostrophes as in "Prestwood", and 'Prestwood' for string literals. Use a slash in front of a quote or apostrophe to embed same type as in \' and \".

To specify a floating point literal between 1 and -1, you can preceed the decimal with a 0 or not (both work). In other words, preceding and following decimals are allowed (both .1 and 0.1). Trailing decimals are also allowed (1, 1., and 1.0 are all equivalent and allowed).

echo "Mike's drums are over there.<br>";
echo 'Mike said, "hi!"<br>';

//Does PHP evaluate this simple

//floating point math correctly? No! 

If ((.1 + .1 + .1) == .3) {
 Echo "Correct";
} Else {
 Echo "Not correct";
}

 PHP Literals (quote or apostrophe)

String literals are quoted as in "Prestwood". If you need to embed a quote use a slash in front of the quote as in \".

In ObjectPAL, string literals are limited to 255 characters but there's nothing preventing you from using multiple string literals together as in:

msgInfo("", "You can " + " add literals together in ObjectPAL") 

To specify a floating point literal between 1 and -1, you can preceed the decimal with a 0 or not (both work). In other words, preceding and following decimals are allowed (both .1 and 0.1). Trailing decimals are also allowed (1, 1., and 1.0 are all equivalent and allowed).

Syntax Example:   msgInfo("", "Hello") msgInfo("", "Hello \"Mike\".") ;Does ObjectPAL evaluate this simple ;floating point math correctly? No! If (.1 + .1 + .1) = .3 Then  msgInfo("", "Correct") Else  msgInfo("", "Not correct") EndIf

PHP is a loosely typed language. No variable types in PHP. Declaring and using variables are a bit different than in other languages. In PHP, you identify and use a variable with a $ even within strings!

You assign by reference with & as in &$MyVar.

$fullname = 'Mike Prestwood';
$FullName = 'Wes Peterson';   //This is a different variable!
$Age = 38;
$Weight = 162.4;

 

echo "Your name is $fullname.
";
echo "You are $Age and weigh $Weight.
";

 PHP Variables ($x = 0;)

Declaring variables is optional unless you click Program | Compiler Warnings while in the ObjectPAL editor for every form, script, and library you create. Using Compiler Warnings is strongly recommended to avoid incorrectly typing an existing variable and to avoid any confusion about variable scope. Also recommended is turning on Compile with Debug for every form, script, and library too for tighter, cleaner code.

Undeclared variables are AnyType variables. Common data types include Currency, Date, Datetime, Logical, LongInt, Number, SmallInt, String, and Time.

var
    FullName String
    Age SmallInt
    Weight Number

endVar

FullName = "Mike Prestwood"
Age = 32
Weight =154.4

msgInfo("", FullName + ", age=" + String(Age) 

             + ", weight=" + String(Weight))

 ObjectPAL Variables (var x SmallInt endVar)