An elixir library/livebook plugin/app that combines the simplicity of note-taking with the robust power of computer language and spreadsheet concepts. Exrow allows users to write math equations and expressions using a markdown-like syntax, providing an intuitive and expressive way to work with mathematical concepts.

Obs: This project doesn't want to be a complete CAS but a calculator with steroids.

Status

This project is in the early stages, so there's little to see. For now, you can download the source and run the tests:

$ mix deps.get
$ mix test

A basic version of the parse and runtime are ready, so a calculation can be done by calling it from the iex:

$ iex -S mix
iex(1)> Exrow.Runtime.calculate("var = 1234 * (10 pow -3)\nvar + 2")
[1.234, 3.234]

Packages

This project has three parts:

• exrow-core: parser and runtime library
• exrow-livebook: a plugin to use exrow as livebook's block
• exrow-app: A desktop app for multiple OS, package with burrito and tauri

Technology details

• NimbleParsec to implement a math language parse.
• Phoenix LiveView and [monaco-editor] to create a interactive experience for users, providing a text editor with syntax highlighting and autocompletion.
• GenServer and Task to handle with async values, for example: to update the currency rates on open exchange rates service.

Usage

The basis of ☴ Exrow is: write one math expression by line, for every valid math expression, a result will show up on the right side of the editor:

## An example
price_hour = $100                                                      = $ 100
hours_worked = 72                                                      = 72
price_hour * hours_worked                                              = $ 7200
_ in EUR                                                               = € 7200

Invalid lines will be ignored, so you can use them as notes or comments.

Numbers

You can express numbers in decimal 10 or 12.34, binary 0b00, octal 0o23478 or hexadecimal 0xFF. Long numbers can be written with _ in the middle to make it more transparent, like 1_000_000_000 (the character _ will be ignored).

Nerd info: exrow is strongly inspired by Elixir arithmetic, so numbers are represented similarly.

Units

All the values can be expressed in units. We can use many units: Angular, Area, CSS, Currency, Data, Date and Time, Length, Scales, Temperature, Volume and Weight. You'll see details about each in the following sections, but before that, you need to know you can use the operators in (or the variants into, as, to) to convert between units.

0b101010 in hex
10 meters in centimetres
2h * 2 to minutes

Arithmetic operations

Arithmetic operations can be made with sign or word operators. Expressions can be separated by parentheses or stacked together; parentheses after another will be interpreted as a multiple expression:

10 + 1
10 times 10
(10 + 2) * 10
(10 + 3)(10 * 3) # same as (10 + 3) * (10 * 3)

Operation	Sign	Sample
Addition	+	plus, and, with
Subtraction	-	minus, subtract, without
Multiplication	*	times, multiplied by, mul
Division	/	divide, divide by
Exponent	^	pow
Modulo		rem, mod

Bitwise operations

A set of operators that perform calculations on bits.

Operation	Sign
Bitwise And	&
Bitwise Or	|
Bitwise Xor	xor
Left Shift	<<
Right Shift	>>

Length units

Supported units: meter, mil, points, lines, inch, hand, foot, yard, rod, chain, furlong, mile, cable, nautical mile, league.

Css units

Supported units: px (pixel), pt (point), inch

TODO

• Define the language and implement the parse

  • Numbers
    • Negative numbers
  • Operations
  • Bitwise
  • Parentheses
  • Variables
  • Labels
  • Units
    • Angular
    • Area
    • CSS
    • Currency
    • Data
    • Date and Time
    • Length: meter, mil, points, lines, inch, hand, foot, yard, rod, chain, furlong, mile, cable, nautical mile, league
    • Scales
    • Velocity: km, knot
    • Temperature
    • Volume
    • Weight
  • Function call sum(10, 2) | (sum 10, 2) + 3
  • Percentage
  • Formula support
    • Starting with =?
  • Lambda support
  • Array, rages and matrix
    • Matrix operations

• Implement a runtime

  • Arithmetic
    • Basic operations
    • All operations
  • Variables
  • Units
    • Adjust precision
    • Length
    • [-] Css
  • Currency
  • Lambda

• Livebook plugin

  • Split the project into package
  • Understand how to implement a livebook plugin

• UI

  • Basic Editor
  • Result panel
  • File manager
  • Syntax highlighting
  • Autocomplete

• Documentation

  • Improve the readme
  • Document language usage
  • Apply logo and colours