Cross Ref > Language Basics

Same as standard C++. Both are case sensitive. In C and C++ commands and variable names are case sensitive.

MessageBox::Show("Hello");

messagebox::SHOW("Hello"); //>>>Does not work!

Prism is generally not case sensitive. Commands and variable names are not case sensitive.

Note: Prism (and Delphi for .Net) do not automatically match your typed case with the defined case as C# and VB.Net do within the Visual Studio Shell.

Syntax Example:   The following demonstrates command and variable case insensitiviy. var  FullName: String; begin  fullname := 'Mike Prestwood';  MessageBox.Show(fullNAME);  MESSAGEBOX.SHOW(FULLNAME);  messAGEbox.sHow(fullname); end;

Same as standard C++. For C++, Java, JavaScript, and PHP, 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 more C++ formatted that way.

class Cyborg {
public: System::Void IntroduceYourself() {
    MessageBox::Show("Hi");
  }
};

Same as in Delphi for Win32 but Prism also supports inline variable declaration.

function DoSomething : integer;

var

 a, b : integer;

begin

 a := 1;

 b := 2;

 var c : integer; //Prism allows inline (local) variables.

 c := a + b;

 result := c;

end;

 Delphi Prism Code Blocks (begin..end)

Commenting Code
Same as standard C++. C++ uses "//" for a single line comment and /* */ for a multiple line comment.

//Single line comment in MS (not ANSI compliant so do NOT use).
  

/* ANSI compliant single line comment. */
  

/*
Multiple line
comment.

*/

/*

* This is another popular

* way to write multi-line

* comments.

*/

Commenting Code
Delphi uses // for a single line comment and both {} and (**) for multiple line comments. Although you can nest different types of multiple line comments, it is recommended that you don't.

Compiler Directives - $
A special comment. Delphi compiler directives are in the form of {$DIRECTIVE}. Of interest for comments is using the $IFDEF compiler directive to remark out code.

//This is a single line comment.

 
{

Multiple line

comment.

}

 
(*
This too is a
multiple line comment.
*)

 
{$IFDEF TEMPOUT}
  //...code here
{$ENDIF}

 Delphi Prism Comments (// or { ... } or (* ... *))  

C++/CLI supports the const and static const keywords of standard C++ as well as the new literal keyword. A literal is equivalent to static const in standard C++ and Microsoft's documentation recommends to replace static const with the new literal keyword because a literal is available in metadata; a static const variable is not available in metadata to other compilers.

You can use static const within the class declaration or locally within a method. However, literal is only valid in the class declaration section and const is only valid within a method.

Syntax Example:   //some method { const String^ MyName = "John"; static const Int32 MyAge = 27; //} // public class SomeClass : public Object { public:   literal double Pi = 3.14159;   literal String^ MyName = "Mike";   static const Int32 MyAge = 35; //...

 Ref: http://msdn.microsoft.com/en-us/library/ms235301(VS.80).aspx

In Prism, you define constants similar to how you define variables but use the Const keyword instead of the Var keyword. Specifying the type is optional. If you don't specify the type, the compiler chooses the most appropriate type for you.

Declare class constants as part of the class definitions. Declare local constants above the begin..end. Although Prism support inline variables, inline constants are not supported.

//Specified type:
const
  kFeetToMeter: Double = 3.2808; 

  kMeterToFeet: Double = .3048; 

  kName: String = "Mike";
 
//Unspecified type:

const kPIShort = 3.14;

 Delphi Prism Constants (const kPI: Double=3.1459;)  

Same as standard C++. C++ uses a semicolon ";" as an end of statement specifier and you can put multiple statements on a single line of code if you wish as well as split a single statement into two or more code lines.

//.Net WinForms example.

//Add, using namespace System::Windows::Forms;

MessageBox::Show("Hello1");

MessageBox::Show("Hello2");

MessageBox::Show("Hello3");

MessageBox::Show("Hello4"); MessageBox::Show("Hello5"); 

MessageBox:: 

  Show 

    ("Hello6");

Object Pascal uses a semicolon ";" as an end of statement specifier and you can put multiple statements on a single line of code and put a single statement on two or more code lines if you wish.

Syntax Example:   MessageBox.Show("Hello1"); MessageBox.Show("Hello2"); MessageBox.Show("Hello3"); //Same line works too: MessageBox.Show("Hello4");  MessageBox.Show("Hello5"); //Two or more lines works too: MessageBox.Show ("Hello6");

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

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).

MessageBox::Show("Hello");

MessageBox::Show("Hello \"Mike\".");

//Does ASP evaluate this simple

//floating point math correctly? No! 

if ((.1 + .1 + .1) == 0.3) {
  MessageBox::Show("Correct");
} else {
  MessageBox::Show("Not correct");
}

In Prism, you use either quotes or apostrophes for string literals.

Different than Delphi, you can start floating point literals with a decimal or an integer. For example, to specify a fractional floating point literal between 1 and -1, you can preceed the decimal with a 0 or not.

x := .1 + .1;     //Does work.

x := 0.1 + 0.1;   //Does work.

Syntax Example:   MessageBox.Show('Hello'); MessageBox.Show("Hello"); //Example of embedding quotes and apostropes: MessageBox.Show('He said, "Who''s computer?"'); MessageBox.Show("She said, ""Mike's computer"".");

Prism supports type inference where you just use a variable and the compiler will then choose the lowest type possible (such as an Integer before a LongInt). With Prism, you frequently do not have to use commands to convert from one type to another.

Variable names are not case sensitive. The Prism language offers both old-style declaring variables before the begin as well as in-line variable declaration.

Prism does support variable initialization too.

Prism offers many variable types. Some common variable types include Integer, LongInt, Single, Double, Boolean, and String.

Syntax Example:   var FName: String; //This is old-style. begin FName := "Mike Prestwood"; MessageBox.Show(FName); Var Age: LongInt; //Local variables. Age:=36; MessageBox.Show(Fname + " is " + Age + " years old"); //Assign values too... Var Wife: String:="Lisa"; Var WifeAge: Integer:=32; messagebox.Show(wife + " is " + Wifeage + "."); end;