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.

Install it using Composer

composer require martinezdelariva/railway 

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.

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.

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).

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

1-1 : 2-2

Converts one track function into two track function.

Converts one track function into switch.

1-1 : 1-2

Converts switch into two track function.

1-2 : 2-2

Join two switches into another switch.

1-2 and 1-2 : 1-2

Dead-function to one track function.

Handling exceptions. Convert one track function into switch.

1-1 : 1-2

Combines switch functions in parallel.

1-2 + 1-2 : 1-2

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

1-1 : 2-2