PL-TP2 - Custom Programming Language Compiler

Description

This project is a custom programming language compiler developed as part of a university course on "Processamento de Linguagens (PL)". The goal was to design a language with specific features and implement a compiler that translates the language into stack-based virtual machine code.

Features of the Language

1. Imperative Programming: The language supports an imperative programming paradigm.
2. Variable Declaration: Variables must be declared before use and cannot be redeclared. The language supports:
   • Integer variables
   • Arrays of integers
3. Control Structures:
   • while loops with nested support
   • repeat loops with a fixed number of iterations
   • if-else conditional statements
4. Input/Output Operations:
   • read for input
   • print for integer output
   • printS for string output
5. Error Handling:
   • Lexical errors
   • Syntax errors with suggestions
   • Semantic errors for variable and conditional misuse

Key Objectives

• Gain experience in language engineering and generative programming.
• Develop grammar rules for context-free and translator grammars.
• Implement a compiler using Python's PLY (Python Lex-Yacc).
• Generate code for a stack-based virtual machine (VM).

Project Structure

1. Lexical Analysis:
   • Recognizes tokens like keywords, identifiers, and operators.
   • Implements error handling for illegal characters.
2. Syntax Analysis:
   • Uses grammar rules defined in YACC to parse valid programs.
   • Provides detailed feedback for syntax errors.
3. Semantic Analysis:
   • Ensures proper use of variables and control structures.
4. Code Generation:
   • Translates source code into VM assembly instructions.
5. Examples:
   • Programs demonstrating use cases like finding the LCM of two numbers, drawing a triangle, and identifying square sides.

Usage Examples

LCM Calculation

int NumOne, NumTwo, maxValue;
start
printS ("Please Enter two integer Values\n")
read(NumOne)
read(NumTwo)

if (NumOne > NumTwo) {
    maxValue = NumOne;
} else {
    maxValue = NumTwo;
}

while(! (maxValue % NumOne == 0 && maxValue % NumTwo == 0)) {
    maxValue++;
}

printS ("LCM = " + maxValue);

Output VM Code

PUSHN 4
START
PUSHS "Please Enter two integer Values\n"
WRITES
READ
ATOI
STOREG 0
...
STOP

Getting Started

1. Install Python with the PLY library.
2. Run the compiler with a source code file:

   python compiler.py source.txt

3. The compiler will generate VM code in a .vm file.