elm-review/tests/NoFullyAppliedPrefixOperator.elm
2020-04-05 09:57:34 +02:00

64 lines
1.3 KiB
Elm

module NoFullyAppliedPrefixOperator exposing (rule)
{-|
@docs rule
-}
import Elm.Syntax.Expression as Expression exposing (Expression)
import Elm.Syntax.Node as Node exposing (Node)
import Elm.Syntax.Range exposing (Range)
import Review.Rule as Rule exposing (Error, Rule)
{-| Reports when an operator is used as a prefix operator and all the operands are already given.
config =
[ NoFullyAppliedPrefixOperator.rule
]
## Fail
_ =
(+) 1 2
## Success
_ =
1 + 2
_ =
(+) 1
_ =
(+)
-}
rule : Rule
rule =
Rule.newModuleRuleSchema "NoFullyAppliedPrefixOperator" ()
|> Rule.withSimpleExpressionVisitor expressionVisitor
|> Rule.fromModuleRuleSchema
error : Range -> Error {}
error range =
Rule.error
{ message = "Prefer using the infix form (`a + b`) over the prefix form (`(+) a b`) when possible"
, details = [ "The prefix form is generally harder to read over the infix form." ]
}
range
expressionVisitor : Node Expression -> List (Error {})
expressionVisitor node =
case Node.value node of
Expression.Application [ Node.Node range (Expression.PrefixOperator _), _, _ ] ->
[ error range ]
_ ->
[]