Road to Elm - Pipes, Chaining and Nesting
If you're familiar with Linux, you have certainly encountered pipes:
find / -name somename | grep ...
they take the result from one command and pass it to the next function, allowing you to chain multiple command together.
They're helpful and convenient, and take advantage of the compositionality that the language encourages. And you can have them in many FP languages (clojure, F#, Elm, ..)
In Elm:
MarioModel
|> somefunction somearg
|> someother function
|> gravity
-- returns the MarioModel, which has gone through all those functions
As you can see it's quite easy to read, to format, and you can see at a glance what that MarioModel goes through.
Alternative syntaxes:
- nesting
(grav (jump (someother (somefunction MarioModel))))
I'm a LISPer, so I love that. But I can see why people prefer pipes.
- temp vars
var marioModel = { x: 5, y: 8, ... }
var tempMario = somefunction(marioModel);
var finalMario = gravity(tempMario);
would work in the same way, but it doesn't really exist as a standalone concept.
- chainable
The most similar concept, is probably chainable functions, as commonly used in jQuery:
$("#mariomodel").somefunction(2000).gravity(10);
Directions
According to what looks natural to you you might prefer
|>function application forwards, as we saw above, or<|function application backwards, which, for example, looks like this:
leftAligned <| monospace <| fromString "some text"