prestech/simple_compiler

GUI_Compiler

This is a project on creating a programming language and its own compiler. In this case thE compiler compiles and runs an instruction set (the programming language) for creating a Graphic User Interface; GUI. I will call this language "J-GUI" i.e the set of instuctions targeted by this compiler. The 'J' in J-GUI stands for "Java" since this language and its compiler are written in Java.

J-GUI Syntax via BNF

J-GUI, like any other language, has specific Syntax and Tokens. This syntax is described using BNF as follows

gui ::= Window String '(' NUMBER ', ' NUMBER ')' layout widgets End '-'

layout ::= Layout layout_type ':'

Layout_type ::= Flow | Grid '(' NUMBER ', ' NUMBER ' [ ',' NUMBER ', ' NUMBER ] ')'

widgets ::= widget widgets | widget

widget ::= Button STRING ';' | Group radio_buttons End ';' | Label STRING ';' | Panel layout widgets End ';' | Textfield NUMBER';

radio_buttons ::= radio_button radio_buttons | radio_button

radio_button ::= Radio STRING ';'

Summary Description of the BNF

The the sources code should begin with the Window toke while specifying the name (string), the size of the window and its layout. This is followed by any number of widgets in the syntax specified by J-GUI's BNF (see the examples source code below). The source code is terminated with End. notice the fullstop (.) at the end of "END".

Failure to follow this rule of syntax will lead to a syntax error which will cause your program to throw an Exception and terminate.

Example Source Code

Below is and example source code of a program written in J-GUI to be compiled and run by this compiler (GUI Compiler). Notice that this language does not have support for Comment yet. Commenting capabilties, both inline and block comments, will added in the near future.

Window " Test Program " (500, 500) Layout Flow :

Textfield 20;

Panel Layout Flow : 
Panel Layout Grid ( 4 , 4 ) :
	Button " 1 " ;
	Button " 2 " ;
	Button " 3 " ;
	Button " 4 " ;
	Button " 5 " ;
	Button " 6 " ;
	Button " 7 " ;
	Button " 8 " ;
	Button " 0 " ;
		
 End;
Panel Layout Grid (4 , 4):
	Label "Label1";
	Label "";
	Label "Label3";
	Label "Label4";
	Label "";
	Label "Label6";
	Label "Label7";
	Label "";
	Label "Label0";
		
 End;
Panel Layout Grid ( 4 ,4):
	Group:
	   Radio"1";
	   Radio"2";
	   Radio"3";
	   Radio"4";
	   Radio"5";
	   Radio"6";
	   Radio"7";
	   Radio"8";
	   Radio"0";
	End;
		
 End;
End;

End.

Description of Source Code

Ignore any information after the forward slashes “//” for there are used to explain the source code below. Note that this program cannot process the “//” as a comment specifier so do not copy and paste this code without removing all comments.

[Window "Test Program" (500, 500) Layout Flow:] creates a 500 x 500 window named “Test Program

[Textfield 20;] adds a text field to the window, with sze 20

[Panel Layout Flow] Creates Panel (panel 1) with Flow layout. Notice that this panel contains three child panel; with all having a 4 by 4 grid layout. These child panels can also contain child panels or other widgets with children, and the cycle continues...)

Panel Layout Grid ( 4 , 4 ) : //Creates a Panel 2, nested in panel 1, and with a Grid layout and Button Components
         //The Button can be specified as  {Button " 1 " ;}  or { Button"1";} . The white spaces between are ignored; see the Label components and Radio below.
	Button " 1 " ;
	Button " 2 " ;
	Button " 3 " ;
	Button " 4 " ;
	Button " 5 " ;
	Button " 6 " ;
	Button " 7 " ;
	Button " 8 " ;
	Button " 0 " ;		
 End; //Ends the Panel scope. If this is not specified  a syntax exception will be thrown
Panel Layout Grid (4 , 4): //Creates another Panel, panel 3 nested in panel 1, at the same level with Panel 2. Specify label components to be add to it. 
	Label "Label1";
	Label ""; //A label with an empty string (name) . The Quotes needs to be specified to show that the string is empty
	Label "Label3";
	Label "Label4";
	Label "";
	Label "Label6";
	Label "Label7";
	Label "";
	Label "Label0";		
 End;

Panel Layout Grid ( 4 ,4):  //Creates another Panel, panel 3 nested in panel 1, at the same level with Panel 2. Specify label components to be add to it. 
	Group: //the COLON must be specified as the start of the scope else a SyntaxErrorException will be thrown.
	   Radio"1";
	   Radio"2";
	   Radio"3";
	   Radio"4";
	   Radio"5";
	   Radio"6";
	   Radio"7";
	   Radio"8";
	   Radio"0";
	End;	
 End;

End; End. //The scope of the source code ends with the “END” and a Full stop “.”; if not specified an SyntaxErrorException will be thrown.

Result of the Source Code

Do you really want to see the result of this source code ? All you have to do is download this project and run it.

QUESTIONS? NEED ASSISTANCE?

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