MiniCompiler

Compiler for my own programming language.

Language specification:

Language elements:

Language contains following terminals:

• keywords: program if else while read write return int double bool true false
• operators and special symbols: = || && | & == != > >= < <= + - * / ! ~ ( ) { } ;
• identifiers and numbers

Identifier is string containing letters and digits, starting with letter. Both upper and lowercase letters are allowed and are distinguishable. Floating point number is string of digits meaning integer part of a number, dot and fractional part. Starting zero is allowed only when it is the only digit of integer part. Integer number is string of digits.

Additionally, all white characters (spaces, tabulators, new lines) are ignored, but separate elements.

Language allow comments starting with //. All characters in line after comment symbol are ignored. String is any text in " " and can be used only in write instruction.

Program

Program starts with program keyword followed by set of declarations and instructions in brackets.

Declarations

Single declaration contains type, identifier and semicolon. Allowed types are: int, double and bool. All variables are initialized by default values (zero or false).

Use of undeclared variable causes compilation error with "undeclared variable" message. All identifiers must be unique.

Instructions

Language contains 7 instructions:

• block statement { code }
• expression
• conditional statement
• while loop
• read
• write
• return

Example programs

program {
	write (5 + 5) * 2.5 - 18 == (int) 7.35;
	write 1 / 2 == (double) 1 / 2;
	write (double) 64 / 2 / 2 / 2 / 2 / 2 / 2;
	write (4 - 2 - 1) * (5 - 3 - 1) * ((-2 + 3) + 1 - (int)!(true == false)); 
	write 2 + 3 * 3 + 5 + 10 / 2 - 6;
	write 1.5 * 1.5 * 1.5 * 1.5 * 1.5 * 1.5 * 1.5;
}

Output:

True
False
1.000000
1
15
17.085938

program {
	bool b;
	bool c;
	int cnt;
	int cntTemp;
	b = c = true;
	cnt = 3;
	while (b || c) {
		cntTemp = cnt;
		while(b == true && c == true && cntTemp > 0){
			write --cntTemp;
			write " ";
			cntTemp = cntTemp - 1;
		}	
		if(cnt == 1)
			b = false;
		if(cnt == 0) {
			write "end";
			return;
		}
		cnt = cnt - 1;
	}
}

Output:

3 2 1 2 1 1 end

program	{
	int i;
	double d;
	bool b;
	i = 5;
	d = 123.456;
	b = true;
	write i;
	write "\n";
	write d;
	write "\n";
	write b;
	write "\n";
}

Output:

5
123.456000
True

program {
	int a;
	int b;
	a = 10;
	b = -21;
	if(a < b)
		write "FAIL\n";
	if(a <b) {
		write "FAIL";
		write "FAIL";
	}
	write "OK\n";
	if(a >b) {
		write "OK";
		write "OK";
	}
	write "OK\n";
	if (a <b) {
		write "FAIL";
		write "FAIL";
	}
	else {
		write "OK";
		write "OK";
	}
	write "OK";
	if (a <b)
		write "FAIL";
	else
		write "OK";
	write "FINISH";
}

Output:

OK
OKOKOK
OKOKOKOKFINISH

program {
	int a;
	int b;
	bool c;
	a = 10;
	b = 11;
	c = false;
	if (a==b && (a=20)>0) {}
	if (20 == a)
		write "FAIL";
	c = 15 != 41 || (a = -1) == 5;
	if (a == -1)
		write "FAIL";
	c = 15 != 41 || 21 == 21 || (a = 0) == 2;
	if (a == 0)
		write "FAIL";
	c = 15 == 41 || 21 == 20 || (a = 10) == 5;
	if (a != 10)
		write "FAIL";
	write "OK";
}

Output:

OK

program {
	if ( true )
		if ( true )
			write "poo\n";
		else
			write "boo\n";
	if ( true )
		if ( false )
			write "too\n";
		else
			write "doo\n";
	if ( false )
		if ( true )
			write "goo\n";
		else
			write "koo\n";
	if ( false )
		if ( false )
			write "woo\n";
		else
			write "foo\n";
}

Output:

poo
doo

Running program

To build compiler run following command in main project folder:

gplex /out:lexer.cs kompilator.lex
gppg /gplex /out:parser.cs kompilator.y

Move file with source code to bin/Debug folder. Run project and type its name from keyboard. After successful compilation, .il file is generated in bin/Debug folder. You can make .exe file using ilasm program.