README.md

elm-review-pipeline-styles

Provides elm-review rules to forbid pipelines for code-style reasons.

Provided rules

• 🔧 ReviewPipelineStyles - Reports pipelines that are not valid by user-defined rules.

For example, the usage of <| or the usage of excessively-long |> pipelines.

This rule works with the following pipeline types:

• |> -- Right "pizza" pipelines, i.e. right function application, so-called because the operator resembles a slice of pizza 🍕.
• <| -- Left "pizza" pipelines, i.e. left function application, so-called because the operator resembles a slice of pizza 🍕.
• >> -- Right composition pipelines.
• << -- Left composition pipelines.
• foo (bar (baz (i (j k)))) -- Parenthetical application pipelines.

If you don't know where to start, be sure to check out ReviewPipelineStyles.Premade for some ready-made rules, as well as examples of how to construct them.

Configuration

import Review.Rule exposing (Rule)
import ReviewPipelineStyles
import ReviewPipelineStyles.Premade
    exposing
        ( noMultilineLeftPizza
        , noPipelinesWithConfusingNonCommutativeFunctions
        , noPipelinesWithSimpleInputs
        , noRepeatedParentheticalApplication
        , noSemanticallyInfixFunctionsInLeftPipelines
        , noSingleLineRightPizza
        )


config : List Rule
config =
    [ ReviewPipelineStyles.rule <|
        List.concat
            [ noMultilineLeftPizza
            , noSingleLineRightPizza
            , noPipelinesWithSimpleInputs
            , noRepeatedParentheticalApplication
            , noPipelinesWithConfusingNonCommutativeFunctions
            , noSemanticallyInfixFunctionsInLeftPipelines
            ]
    ]

Try it out

You can try the example configuration above out by running the following command:

elm-review --template SiriusStarr/elm-review-pipeline-styles/example

Changelog

• 1.3.9

  • 🚑 Fixed a major regression introduced in 1.3.8 that caused some initial nodes in pipelines to not be checked for subpipelines. It is critical that you upgrade if you are on 1.3.8.

• 1.3.8

  • 🐛 Fixes should no longer generate invalid code due to needing parentheses around a pipeline step.
  • 🐛 Fixes should no longer genereate invalid code due to needing parentheses around the entire pipeline.

• 1.3.7

  • 🐛 No longer report invalid parenthetical pipelines. Previously:

    foo
        (a (b c))
        (d (e f))

    would treat

    foo
        (a (b c))

    as a pipeline, instead of the correct a (b c) (since only the terminal argument can be pipelined).

  • ⚡️ Improve performance by skipping some unnecessary recursion. (Maybe.withDefault's lack of laziness strikes again.)

  • Bump elm-review to v2.13.1 and elm-syntax to v7.3.2.

• 1.3.6 -- Bump elm-review to v2.12.2 for upstream bugfix and improve documentation for adding fixes to rules.

• 1.3.5 -- Bump elm-review to v2.12.1 for upstream bugfix.

• 1.3.4 -- Bump elm-review to v2.11.1 and mark rule as providing fixes, if it does.

• 1.3.3

  • 🐛 aConfusingNonCommutativeFunction no longer flags fully-saturated functions, since they are not actually confusing. For example:

    Set.diff a b -- Passes
        |> Set.toList

    is now allowed, while

    b
        |> Set.diff a -- Fails
        |> Set.toList

    is not. This was not the behavior previously, when both would have been flagged as confusing.

    Non-commutative operator behavior is unchanged, i.e. they are still not allowed in prefix form even when fully-saturated, as they remain confusing. For example:

    xs ++ ys -- Passes
        |> List.map foo

    is still allowed, while

    (++) xs ys -- Fails
        |> List.map foo

    is still not.

• 1.3.2 -- Improve handling of nested pipelines.

  • 🐛 Do not allow fixes that would lead to compilation errors by converting a parenthetical pipeline that is immediately nested within another pipeline to another type.

  • 🚸 noRepeatedParentheticalApplication premade rule will not flag parenthetical application that is immediately nested within another pipeline, as it cannot be readily rewritten as another type. This often occurs with nested maps, for example:

    foo
        |> Maybe.map (Result.map (yi << er))
        |> bar

• 1.3.1 -- 🐛 Fix aSemanticallyInfixFunction. Previously, it did not check how many args were applied, leading to it flagging things as infix that weren't yet infix, because no args had been applied. Now it requires exactly one arg to be applied.

• 1.3.0

  • 🚸 Improved noPipelinesWithSimpleInputs. Now flags all unnecessary left inputs (since the operator does not improve clarity in any way), but only flags simple (non-semantic) right inputs.
  • 🚸 Improved noPipelinesWithConfusingNonCommutativeFunctions. Now only flags all non-commutative functions in right pipelines, whereas only confusing prefix operators are flagged in left/parenthetical pipelines, as the other functions are in the correct argument order.
  • 🚩 Added new StepPredicate: aConfusingNonCommutativePrefixOperator This only flags non-commutative prefix operators rather than also flagging e.g. compare.

• 1.2.0

  • ✨ Added new noMultilineLeftComposition and noSingleLineRightComposition premade rules.
  • 📝 Fix minor doc issues.

• 1.1.0

  • Added premade rules for ease of use! Find them in the ReviewPipelineStyles.Premade module. The documentation for these rules includes the source for how to construct them as a sort of tutorial to learn to create your own.
  • Added StepPredicates. Easily inspect individual steps of pipelines!
  • Updated elm-syntax to avoid mangling fixes involving some lambdas.
  • Minor documentation fixes/clarifications.

• 1.0.0 -- Initial release