martinezdelariva/railway

Railway

, _(*1)

This library is based on a post from (Scott Wlaschin)[https://fsharpforfunandprofit.com/posts/recipe-part2/] in order to bring Railway Oriented Programming to PHP., _(*2)

Installation

Install it using Composer, _(*3)

composer require martinezdelariva/railway 

Motivation

Typically every use case receives a request and produces a response. The use case passes for several steps until gets the final response to be returned. Handle every error scenario could be tedious and difficult to read., _(*4)

Either

In order to have a type that works with any workflow, we borrow the type Either from functional programming:, _(*5)

, _(*6)

This object acts as a switch, where left means failure and the right means success., _(*7)

Railway Naming Convention

Railways have switches ("points" in the UK) for directing trains onto a different track. We can think of these “Success/Failure” functions as railway switches., _(*8)

• One track function: it has 1 input and 1 output.

, _(*9)

• Two track function: it has 2 input (Either) and 2 output (Either).

, _(*10)

• Switch: it has 1 input and 2 output (Either).

, _(*11)

Functions

Please find below the list of functions which connects switch together:, _(*12)

Map

1-1 : 2-2, _(*13)

Converts one track function into two track function., _(*14)

, _(*15)

Lift

Converts one track function into switch., _(*16)

1-1 : 1-2, _(*17)

, _(*18)

Bind

Converts switch into two track function., _(*19)

1-2 : 2-2, _(*20)

, _(*21)

Unite

Join two switches into another switch., _(*22)

1-2 and 1-2 : 1-2, _(*23)

, _(*24)

Tee

Dead-function to one track function., _(*25)

, _(*26)

TryCatch

Handling exceptions. Convert one track function into switch., _(*27)

1-1 : 1-2, _(*28)

, _(*29)

Plus

Combines switch functions in parallel., _(*30)

1-2 + 1-2 : 1-2, _(*31)

, _(*32)

DoubleMap

Handles both tracks, converting one track into two track function., _(*33)

1-1 : 2-2, _(*34)

, _(*35)