gren-lang / gren-lang/compiler

Underscore type params

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language proposal
Dominant language
Haskell
Stars
503
Forks
29
PR merge metrics
No merged PRs in 30d

Description

Allow underscore as a type parameter when we do not need the type parameter to match any thing. It would be analogous to using an underscore for a value parameter that we don't use. For example:

listLength : List _ -> Int

As opposed to

listLength : List a -> Int

I think the underscore more clearly conveys the meaning of "This isn't important".

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First steps

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Research direction

No implementation file, test, or entry point is named in the issue. Start by locating the compiler's type-parameter parsing and inference tests, then verify that List _ -> Int is accepted and that the underscore does not need to match a specific type.

Written by the indexing model from the issue text.

Assessment

Tech stack
haskell
Domain
compilers
Issue type
Feature
Difficulty
5/5
Estimated time
Over a week
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
25/100

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