MiniSoft Compiler

A compiler for the MiniSoft language developed with Flex and Bison. This project was created as part of the Compilation course at the University of Science and Technology Houari Boumediene (USTHB).

Project Overview

The MiniSoft compiler implements a complete compilation process for a simple educational programming language. It features:

• Lexical analysis using Flex
• Syntactic analysis using Bison
• Semantic analysis with comprehensive error checking
• Symbol table management
• Detailed error reporting with line and column information

The compiler can detect various errors including:

• Undeclared identifiers
• Duplicate declarations
• Type incompatibilities
• Division by zero (for constant expressions)
• Array index out of bounds
• Attempt to modify constants
• Invalid loop control variables

MiniSoft Language Features

MiniSoft is a simple programming language with the following features:

• Integer and floating-point data types
• Variable and constant declarations
• Array support
• Arithmetic and logical operations
• Control structures (if-else, while loops, for loops)
• Input/output operations
• Single-line and multi-line comments

Sample Program

MainPrgm L3_software;
Var 
    <!- Variable declarations ->
    let x, y, z: Int;
    let a, b: Float;
    let arr: [Int; 10];
    @define Const PI: Float = 3.14;
    @define Const MAX: Int = 100;

BeginPg
{
    {-- Main program body --}
    x := 10;
    y := 20;
    z := x + y;
    
    a := 1.5;
    b := a * PI;
    
    arr[0] := 5;
    
    if (z > MAX) then {
        output("z exceeds maximum");
    } else {
        output("z is within limits: ", z);
    }
    
    for i from 0 to 9 step 1 {
        arr[i] := i * 2;
    }
    
    do {
        x := x - 1;
    } while (x > 0);
    
    input(y);
    output("You entered: ", y);
}
EndPg;

Building and Running

Prerequisites

To build and run the MiniSoft compiler, you need:

• GCC compiler
• Flex lexical analyzer
• Bison parser generator
• Make build system

On Ubuntu/Debian, you can install these with:

sudo apt-get install build-essential flex bison

Build Instructions

1. Clone this repository:

   git clone https://github.com/your-username/minisoft-compiler.git
   cd minisoft-compiler

2. Build the compiler:

   make

3. Clean build files (optional):

   make clean

Running the Compiler

To compile a MiniSoft program:

./compiler test.txt

This will analyze the input file and report any errors found during the compilation process. If compilation is successful, it will output "Program successfully parsed" and display the symbol table.

Project Structure

• lexer.l: Flex specification for lexical analysis
• parser.y: Bison specification for syntactic and semantic analysis
• symtab.h/c: Symbol table implementation
• Makefile: Build configuration
• test.txt: Example MiniSoft program

Implementation Details

The compiler is implemented in three main phases:

1. Lexical Analysis: Identifies tokens, validates identifiers and numeric constants
2. Syntactic Analysis: Validates program structure and builds an abstract syntax tree
3. Semantic Analysis: Performs type checking, validates array accesses, handles constant expressions

Special attention was given to:

• Detecting division by zero in expressions like a := 1 / (7 - 7)
• Preventing modification of constants
• Validating array indices
• Checking loop control variables

Authors

• Hermez Abderrahim
• Belkacemi Abderrahim

License

This project is licensed under the MIT License - see the LICENSE file for details.