kalker/README.md

![](logo.png)

Kalker (or "kalk") is a calculator program/website that supports user-defined variables, functions, derivation, and integration. It runs on Windows, macOS, Linux, Android, and in web browsers (with WebAssembly).

[![Crates.io](https://img.shields.io/crates/v/kalker)](https://crates.io/crates/kalker) ![npm](https://img.shields.io/npm/v/@paddim8/kalk) [![GitHub](https://img.shields.io/github/license/PaddiM8/kalk)](https://github.com/PaddiM8/kalker/blob/master/LICENSE) [![Docs.rs](https://docs.rs/kalk/badge.svg)](https://docs.rs/kalk/latest/kalk/) ![Build status](https://img.shields.io/github/workflow/status/PaddiM8/kalker/Rust?event=push&label=build%20%26%20test)

[Kanban](https://kolan.strct.net/Board/4RAdMjLDz) | [Website - Try it out here!](https://kalker.xyz)

<img src="preview.png" width="750">

# Features

* Operators: `+`, `-`, `*`, `/`, `!`
* Groups: `()`, `⌈ceil⌉`, `⌊floor⌋`, `[iverson]`
* [Pre-defined functions and constants](https://github.com/PaddiM8/kalker/blob/master/kalk/src/prelude/mod.rs)
* User-defined functions and variables. `f(x, y) = xy`, `x = 5`
* Derivative of functions (derivatives of noisy functions or of higher order can be a bit inaccurate). `f'(2)`, `sin'(-pi)`
* Integration. `∫(0, pi, sin(x) dx)` or `∫(0, π, sin(x) dx)`, maybe sometimes be slightly off
* Understands fairly ambiguous syntax. Eg. `2sin50 + 2xy`
* Syntax highlighting
* Special-symbol completion on tab. Eg. write `sqrt` and press tab. It will be turned into `√`
* Sum function: `sum(start, to, expression)` Eg. `sum(1, 3, 2n+1)` is the same as `2*1+1 + 2*2+1 + 2*3+1` = `15`
* Piecewise functions: `f(x) = { f(x + 1) if x <= 1; x otherwise }`, pressing enter before typing the final `}` will make a new line without submitting
* Load a file including predefined functions and constants. For example, if you're going to use kalker for physics, you load up your file with physics functions/constants when starting kalker. This is done either using the `-i file` flag or by putting files in a certain directory and then doing `load filename` inside kalker. [More about files here](https://kalker.xyz/#files)
* Different number bases: Either with a format like `0b1101`, `0o5.3`, `0xff` or a format like `1101_2`. The latter does not support letters, as they would be interpreted as variables
* Misc: separate expressions by a semicolon to write them on the same line, use the `ans` variable to get the value of the previously calculated expression

# Installation

## Package managers

### macOS
`brew install kalker`

### Arch Linux
`kalker` in the AUR, eg. `yay -S kalker`

### Nix/NixOS
Kalker is available through [`nixpkgs`](https://search.nixos.org/packages?channel=unstable&show=kalker&from=0&size=50&sort=relevance&type=packages&query=kalker).
The most up to date version is also available as a [`flake`](https://search.nixos.org/flakes?channel=unstable&show=kalker&from=0&size=50&sort=relevance&type=packages&query=kalker).

## Binaries

Pre-compiled binaries for Linux, Windows, and macOS (64-bit) are available in the [releases page](https://github.com/PaddiM8/kalker/releases).

## Compiling

**Minimum rust version: v1.36.0**. Make sure you have `diffutils` `gcc` `make` and `m4` installed. **If you use windows:** [follow the instructions here](https://docs.rs/gmp-mpfr-sys/1.2.3/gmp_mpfr_sys/index.html#building-on-windows) (don't forget to install `mingw-w64-x86_64-rust` in MSYS2).

### Cargo

Run `cargo install kalker`

### Manually

1. Go into the `cli` directory.
2. Run `cargo build --release`
3. Grab the binary from `targets/release`

# Donation

Kalker is completely free and open source. If you wish to support further development of Kalker and contribute towards it one day getting published on the Google Play Store, you can do so here: [PayPal](https://paypal.me/oliverwaldemar)

# Libraries

There are currently three different libraries related to kalker.

* [kalk](https://crates.io/crates/kalk): The Rust crate that powers it all.
* [@paddim8/kalk](https://www.npmjs.com/package/@paddim8/kalk): JavaScript bindings for `kalk`. This lets you use it in the browser thanks to WebAssembly.
* [@paddim8/kalk-component](https://www.npmjs.com/package/@paddim8/kalk-component): A web component that runs `@paddim8/kalk`, which let's you use kalk in the browser with a command line-like interface.

# Syntax

A more complete reference can be found on [the website](https://kalker.xyz)

## Functions

**Defining:** name(parameter1, parameter2, ...) = expression\
**Example:** $ f(x) = 2x+3 $

**Using:** name(argument1, argument2)\
**Example:** $ f(2) $

## Variables

**Defining:** name = expression\
**Example:** $ x = 3 $

**Using:** name\
**Example:** $ x $

# Contributing

## kalk and cli (Rust)

After making changes to the kalk library (in `kalk/`), you can easily try them out by going to the root of the project directory, and doing `cargo run`. This will start kalker (cli), with the new changes. If you're using Windows, you will need to [follow the instructions here](https://docs.rs/gmp-mpfr-sys/1.2.3/gmp_mpfr_sys/index.html#building-on-windows), but also make sure to install `mingw-w64-x86_64-rust` in MSYS2.

All Rust code is expected to be formatted with `rustfmt

## web (Svelte, TypeScript, Sass)

Run:
1. `npm install`  
2. `npm run dev` - this will automatically re-compile the project when changes are made

## mobile (Android)

Run:  
1. `npm install`
2. `npx cap sync`
3. Build the project using Android Studio, or Gradle directly.