pratt-calc 0.1.5

Arithmetic calculator which uses a Pratt parser

Introduction

An arithmetic expression calculator in Python, demoing the Pratt parsing algorithm.

This takes inspiration from this 2010 blog post by Eli Bendersky, as well as a few other sources:

1. Simple but Powerful Pratt Parsing
2. Pratt Parsers: Expression Parsing Made Easy
3. Compiling Expressions (Chapter 17 of Crafting Interpreters)

Requirements

Requires Python 3.13 or greater.

Installation

pipx install pratt-calc

In some cases it may be necessary to specify the Python version manually:

PIPX_DEFAULT_PYTHON=python3.13 pipx install pratt-calc

Or, if you have uv installed:

uvx pipx install pratt-calc

Contributing

Install uv, then run:

git clone https://github.com/BrandonIrizarry/pratt-calc
cd pratt-calc
uv sync --locked

Usage

pratt-calc $EXPRESSION

Example:

pratt-calc 3-4*5

This should print -17 at the console.