Tiny Interpreter

A tiny interpreter written in C++ to explore tokenization, lexer design, recursive descent parsing, expression evaluation and interpreter architecture.

Features

• Lexer for tokenizing source input
• Recursive descent parser for expression evaluation
• Arithmetic operations with operator precedence
• Parentheses support for grouped expressions
• Variable assignment and storage
• Comparison operators:
  • <
  • >
  • <=
  • >=
  • !=
• Multi-character token handling
• Token stream debugging output

Structure

• token.hpp - Defines token types and token metadata
• lexer.cpp/hpp - Handles lexical analysis and token generation
• parser.cpp/hpp - Handles recursive descent parsing and expression evaluation

Project Goals

• Build a small interpreted language from scratch in C++

• Explore:

  • Lexer
  • Parser
  • Runtime architecture

• Experiment with features:

  • Abstract Syntax Trees (AST)
  • Functions
  • Logical operators

Working Example

    std::string input1 = "x = (10.0 + 10.0) * 2.5 + 5 / 6";
    std::vector<Token> token1 = tokenize(input1);
    display_token(token1);

    parse(token1);

        --- Token ---
        x : IDENT
        = : ASSIGN
        ( : LEFT_PAREN
        10.0 : NUMBER
        + : PLUS
        10.0 : NUMBER
        ) : RIGHT_PAREN
        * : STAR
        2.5 : NUMBER
        + : PLUS
        5 : NUMBER
        / : SLASH
        6 : NUMBER

        output:
        x = 50.8333