# crow

[![Package Version](https://img.shields.io/hexpm/v/crow)](https://hex.pm/packages/crow)
[![Hex Docs](https://img.shields.io/badge/hex-docs-ffaff3)](https://hexdocs.pm/crow/)

A Gleam project

## Quick start

```sh
gleam run   # Run the project
gleam test  # Run the tests
gleam shell # Run an Erlang shell
```

## Installation

If available on Hex this package can be added to your Gleam project:

```sh
gleam add crow
```

and its documentation can be found at <https://hexdocs.pm/crow>.

## Presentation 

PRESENTATION - Gleam is expressive

Gleam is fairly simple and in some ways syntax is less expressive than what
can be found in erlang or elixir: 

* Lack of literals
* Lack of branching options
* Lack of macro system
* No behaviour or protocol system

But is just as capable of modelling most problem domains:

* "Open" domain through types public types
* Constained set of operations through opaque types
  * Api might be "flexible", next = gamestate -> next -> gamestate
  * Api might be "precise", next = gamestate -> gamestate

May or not require assertion checks when depending on Result types
  * Result types can be composed together
  * But composition can also be achieved with pipes
  * Or a custom mechanism to apply types or functions

We may add to this type through Generics.

TODO: Recover gamestate file here

pub type MoveError {
  NoPath
  OutOfBounds
  Blocked
  NoPiece
}

pub fn move(
  in board: Board,
  from from: Position,
  to to: Position,
) -> Result(Board, MoveError) {
  try Nil = check_bounds(at: from, in: board)
  try Nil = check_bounds(at: to, in: board)
  try Nil = check_piece(at: from, in: board)
  try Nil = check_move(from: from, to: to, in: board)
  Ok(update(at: from, to: to, in: board))
}