Python Interpreter for a Simple Programming Language

Project Overview

This project implements a fully functional Python-based interpreter for a simplified programming language. The interpreter processes source code by tokenizing input, building an Abstract Syntax Tree (AST), and executing the parsed instructions. It provides a hands-on understanding of core interpreter concepts, including lexical analysis, parsing, and AST-based execution.

The project is being developed as part of the CS 609: Final Project Assignment Southeast Missouri State University and adheres to the requirements outlined in the project guidelines.

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Features

1. Variable Assignments

   • Supports declaring and initializing variables.
   • Example:

     let a = 5;
     let b = a + 3;

2. Arithmetic Operations

   • Handles addition (+), subtraction (-), multiplication (*), and division (/).
   • Example:

     let c = a * b;

3. Output Printing

   • Prints variable values using the print statement.
   • Example:

     print(a);
     print(c);

4. Sequential Statements

   • Parses and executes multiple statements in order.
   • Example:

     let x = 10;
     let y = x * 2;
     print(x);
     print(y);

5. Whitespace and Semicolon Handling

   • Ignores whitespace and requires semicolons (;) to separate statements.

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Project Structure

1. lexer.py
   • Tokenizes the source code into meaningful symbols such as keywords, identifiers, numbers, and operators.
2. parser.py
   • Builds an Abstract Syntax Tree (AST) from tokens to represent the program's hierarchical structure.
3. ast_nodes.py
   • Defines classes for AST nodes, including AssignNode, BinOpNode, and PrintNode.
4. interpreter.py
   • Traverses the AST and executes operations such as variable assignments, arithmetic computations, and print commands.
5. examples/
   • Contains sample programs and test cases demonstrating the interpreter’s functionality.

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How to Run

Prerequisites

• Python 3.7 or higher.

Installation

1. Clone this repository:

   git clone https://github.com/parastiware/Interpreter.git
   cd interpreter

2. Write a sample program in the input format, such as:

   let x = 10 + 5;
   let y = x * 2;
   print(x);
   print(y);

   Save it in a file (e.g., program.txt).
3. Run the interpreter:

   python main.py program.txt