Simple Imperative Language Compiler (Academic Project)

Compiler made as a final project for academic course - Formal Languages and Techniques of Translation.

Simple usage scenario

Used technologies

• Flex version 2.6.4,
• Bison version 3.0.4,
• g++ version 8.2.0,
• GNU Make version 4.2.1.

Compiler has been written in C++ language with parser and lexer made from Bison and Flex tools.

Compilation

Build process is simplified by GNU make

• make to compile source code. Output ready in bin directory.
• make clean to remove bin directory with whole content.

Uruchamianie kompilatora

To run the compiler you have to type ./compiler filename.imp filename.mr, gdzie:

• filename.imp - filename with input code,
• filename.mr - filename with output code.

If compilation is carried out successfully the output code is produced. In other case warnings and errors are printed.

Interpreter

Interpreter of the output assembly is responsible for executing the code, it was written by our academic teacher - phd. Maciej Gębala. You can find the source code in the interpreter path.

Language grammar

High level language for which compiler was desgined can be described with following grammar:

program      -> DECLARE declarations IN commands END

declarations -> declarations pidentifier;
            | declarations pidentifier(num:num);
            | 

commands     -> commands command
            | command

command      -> identifier := expression;
            | IF condition THEN commands ELSE commands ENDIF
            | IF condition THEN commands ENDIF
            | WHILE condition DO commands ENDWHILE
            | DO commands WHILE condition ENDDO
            | FOR pidentifier FROM value TO value DO commands ENDFOR
            | FOR pidentifier FROM value DOWNTO value DO commands ENDFOR
            | READ identifier;
            | WRITE value;

expression   -> value
            | value + value
            | value - value
            | value * value
            | value / value
            | value % value

condition    -> value = value
            | value != value
            | value < value
            | value > value
            | value <= value
            | value >= value

value        -> num
            | identifier

identifier   -> pidentifier
            | pidentifier(pidentifier)
            | pidentifier(num)

Sample test programme for specified language:

[ Factorization of a number into prime factors ]

DECLARE
    n; m; reszta; potega; dzielnik;
IN
    READ n;
    dzielnik := 2;
    m := dzielnik * dzielnik;
    WHILE n >= m DO
        potega := 0;
        reszta := n % dzielnik;
        WHILE reszta = 0 DO
            n := n / dzielnik;
            potega := potega + 1;
            reszta := n % dzielnik;
        ENDWHILE
        IF potega > 0 THEN [ czy znaleziono dzielnik ]
            WRITE dzielnik;
            WRITE potega;
        ELSE
            dzielnik := dzielnik + 1;
            m := dzielnik * dzielnik;
        ENDIF
    ENDWHILE
    IF n != 1 THEN [ ostatni dzielnik ]
        WRITE n;
        WRITE 1;
    ENDIF
END