website/programs/gott.adoc

= gott
apiote <me@apiote.xyz>
v1.1.2 2020-04-24
:toc:

gott is a Railway Oriented Programming library for Go.

[WARNING]
Version 1 of gott is deprecated, please use version 2 which uses generics

In ROP a program is a chain of functions wrapped in blocks resembling track switches. It’s a simplification of an Either monad.

gott provides N types of blocks:

* Bind, which wraps a function that continues on the happy track or switches to the sad track

    >------+-------->
            \
             \
    >---------+----->

* Map, which wraps a function that will alwayc continue on the happy track

    >--------------->
    >--------------->

* Tee, which wraps a function performing side effects and can switch to the sad track

             _
             |
    >--------++----->
               \
                \
    >------------+-->

* SafeTee, which is to Tee what Map is to Bind

             _
             |
    >--------+------>
    >--------------->

* Recover, which wraps a function that tries to return to the happy Path

    >--------+------>
            /
           /
    >-----+--------->

* Catch, which switches to the sad track in case of a panic
* Handle, which does different things depending on which track the processing is

== Usage

Provided functions are methods of `Result` and return `Result` so that they can be chained.

Usage can be seen in tests, the simplest being

    import (
    	"apiote.xyz/p/gott"
    )
    func divide5(by ...interface{}) (interface{}, error) {
    	if b := by[0].(int); b == 0 {
    		return Tuple(by), errors.New("divideByZero")
    	} else {
    		return 5 / b, nil
    	}
    func main() {
    	s, e := NewResult(5).Bind(divide5).Finish()
    	// s == 1; e == nil
    }

== Mirrors

The canonical repository for this project is https://git.apiote.xyz/gott.git it’s mirrored at https://notabug.org/apiote/gott

Mirrors exist solely for the sake of the code and any additional functions provided by third-party services (including but not limited to issues and pull requests) will not be used and will be ignored.

== License

----
This Source Code Form is subject to the terms of the Mozilla Public
License, v. 2.0. If a copy of the MPL was not distributed with this
file, You can obtain one at https://mozilla.org/MPL/2.0/.
----