Interpreter in Go

A simple interpreter for the Monkey programming language, written in Go, based on Thorsten Ball’s book How to Write an Interpreter in Go.

📚 About

This project implements a fully working interpreter for a Lisp-like language called Monkey, as described in the book. It's built from scratch using idiomatic Go and includes all major components of an interpreter:

• A lexer that tokenizes the source code
• A Pratt parser to generate the abstract syntax tree (AST)
• An evaluator that walks the AST and executes the code
• A basic object system (integers, booleans, strings, functions, closures)
• Support for let-bindings, conditionals, first-class functions, and a REPL

🧠 Learning Goals

This project is a great foundation for understanding:

• Lexing and parsing theory
• Interpreter architecture
• Scope and closures
• Functional programming concepts in a small language

🚀 Features

• REPL for interactive programming
• Lexical scoping and closures
• Built-in functions (e.g., len, first, last, push, etc.)
• Error handling and runtime type checking

🛠️ Getting Started

Prerequisites

• Go (version 1.18+ recommended)

Clone and Run

git clone https://github.com/your-username/monkey-interpreter.git
cd monkey-interpreter
go run main.go

## 🧪 REPL Example

```text
>> let add = fn(a, b) { a + b; };
>> add(2, 3);
5
>> let twice = fn(f, x) { f(f(x)); };
>> twice(fn(x) { x + 1; }, 5);
7