asciimath-rs

Parses mathematical (infix) expressions into an Abstract Syntax Tree using Dijkstra's "shunting yard" algorithm.

Simple, bare-bones, and efficient.

Features

• evaluation
  • compile the expression just once, evaluate with a different set of variables
• support for variables and custom functions
• implicit multiplication

High-Level Goals

Ease of use

This means that e.g. passing in variables to expressions and defining custom functions must be possible with minimum knowledge of this library's internals and abstractions. Errors must be helpful and relevant.

Minimalism

Focusing just on mathematical expressions will make it easy for this library to remain slim and deliver superior ergonomics.

Accuracy

Extensive testing and maximum precision must be a part of all the modules to prevent bugs and ensure consistency.

Immediate Roadmap

• Embedded constants like pi and e
• More built-in functions
• Support for word-variables (right now only single-letter variables are supported)
• Thorough documentation
  • basic use
  • available functions

Future

The items below will be considered after ABI stabilization:

• Non-mathematical expressions, like strings
• More operators (e.g. ternary ? : )
• Ability to simplify expressions
• Derivatives, incl. second-order and third-order
• Integration
• Partial differentiation
• Vector calculus
• Matrices and vector spaces

Non-goals

• php-esque abominations like a=func(x) && b=func(y) && 'what'

Motivation

Created for the University of Toronto Mathematical Assessment Tool, to facilitate generation of randomized tests and quizzes which are then automatically graded.

While some great libraries aiming for similar goals do exist, they wouldn't reward me with such a fruitful Rust learning experience and imo sorely lack ergonomics.