elm-review-noleftpizza

Prohibits (redundant/all) use of the left pizza (<|) operator and helps rewriting expressions that use them.

Redundant application of <| adds visual noise and may make things harder to read. For some people, it might act as a visual separator, which is completely fine!

Configuration

To allow <| only when extra parentheses would need to be added in order to remove <| - in other words, to only flag redundant left pizzas, pass the NoLeftPizza.Redundant flag to the rule:

import NoLeftPizza
import Review.Rule exposing (Rule)

config : List Rule
config =
    [ NoLeftPizza.rule NoLeftPizza.Redundant
    ]

If you wish to go all in and remove any and all left pizza's, you can pass NoLeftPizza.Any instead:

import NoLeftPizza
import Review.Rule exposing (Rule)

config : List Rule
config =
    [ NoLeftPizza.rule NoLeftPizza.Any
    ]

Rationale for NoLeftPizza.Any

Our team writes vastly more application code than we write test code. Within our application code, we have - for quite a long time - enforced the rule that <| left pizza is a sad pizza. The one and only exception is in test code, where we prefer to stick to the generally accepted style (test "description" <| \_ -> ...).

So, this is an interesting case. The docs call out this specific example as the type of rule that would need very careful consideration before inclusion. And considered, we have. Carefully, too!

For our specific codebase, we choose to remove noise from our code reviews and automate that part of the process by enforcing a NoLeftPizza rule, for everything other than tests.

You should likely very carefully consider and evaluate the pros and cons before enabling this rule on your codebase.

Like any stylistic choice, it is not for everyone.