nathom / expr-parser

LL(1) arithmetic expression parser in Rust

Arithmetic Expression Parser

A dependency-free lexer, parser, and evaluator for integer arithmetic expressions.

It uses predictive, top-down, recursive descent parsing by implementing the LL(1) expression grammar given in Expr.abnf. Thus, with only a single token of lookahead, we are able to evaluate an arbitrary expression with correct rules of precedence.

Usage

Running the program will show the parse tree and result for the input.

cargo run

Type in the input, and hit return.

Run tests

To run all tests, run

cargo test