Qalqulator

A calculator that uses (and outputs) rational numbers wherever possible.

The only operation that causes the output to revert to a floating point is exponentiation with fractional exponents.

Installation

Using Cargo

1. Install Rust.

2. Run the following command in your terminal:

   cargo install qalqulator
   

Using pre-built binaries

Pre-built binaries are available on the releases page.

Example usage

$ qalqulator
>>> 6 * 7
42
>>> (12/11)^(4/2)
144/121
>>> let x = 141 % 100
41
>>> x + 0.5
83/2
>>> to_float(x) + 1/2
41.5
>>> x^(1/2)
6.4031242374328485
>>> exit

Features

• Supports all basic arithmetic operations with operator precedence and parentheses:
  • Addition: +
  • Subtraction (and negation): -
  • Multiplication: *
  • Division: /
  • Remainder (not modulus): %
  • Exponentiation: ^
• Numbers can be entered as integers (42), floating point numbers (42.0), or fractions (42/1) and will be automatically converted to rational numbers.
• Values can be assigned to variable names using the let keyword. For example, let x = 42 will assign the value 42 to the variable x.
• To convert a value to a floating point number manually, use the to_float function. For example, to_float(83/2) will return 41.5.
• To leave qalqulator, use exit or Ctrl+D.

Additional features

This is a toy project that I built for my own needs over the course of a few hours. If you find it useful and would like to see additional features, please open an issue or a pull request.

Name

Qalqulator is a calculator over $\mathbb{Q}$, the set of all rational numbers.