README

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.

Installation

Install it using Composer

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.

Either

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

This object acts as a switch, where left means failure and the right means success.

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.

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

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

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

Functions

Please find below the list of functions which connects switch together:

Map

1-1 : 2-2

Converts one track function into two track function.

Lift

Converts one track function into switch.

1-1 : 1-2

Bind

Converts switch into two track function.

1-2 : 2-2

Unite

Join two switches into another switch.

1-2 and 1-2 : 1-2

Tee

Dead-function to one track function.

TryCatch

Handling exceptions. Convert one track function into switch.

1-1 : 1-2

Plus

Combines switch functions in parallel.

1-2 + 1-2 : 1-2

DoubleMap

Handles both tracks, converting one track into two track function.

1-1 : 2-2