SimpL (sim-l)

A tiny Rust REPL that parses and evaluates arithmetic expressions.

Features

• Supports +, -, *, / with standard precedence
• Parentheses for grouping
• Floating-point numbers
• Simple interactive REPL

Getting started

Build and run:

cargo run

You should see a prompt like:

========== SimpL: Simple expression evaluator ===========
Enter arithmetic expressions like: 2 + 3 * 4
Type 'quit' or 'q' to exit

>>

Example

>> (2 + 3) * 4
 Parsed: ((2 + 3) * 4)
 = 20

More examples are in examples/ with sample inputs and expected outputs.

Notes

• Whitespace is optional around operators.
• Unary minus (e.g. -3) is not supported yet; use 0 - 3 instead.
• Division by zero returns an error.

Project layout

• src/main.rs - REPL loop and I/O
• src/parser.rs - tokenizer and recursive-descent parser
• src/expr.rs - expression tree and evaluator