add equal function #4
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Contributor
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This looks good, but I wonder if we should add this now, or try to figure out how to add this to Prelude as an |
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Author
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I could move this over to a Prelude PR once things are in place there |
src/Data/Record.purs
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| , RowCons name ty tailRow row | ||
| , EqualFields tail row | ||
| ) => EqualFields (Cons name ty tail) row where | ||
| equalFields _ a b = get' a == get' b && rest |
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hey @justinwoo! I think it might be more efficient to use an if expression to make this short-circuit:
equalFields _ a b =
if get' a == get' b
then equalRest a b -- evaluate this fully only inside the true branch
else false
where
get' = get (SProxy :: SProxy name)
equalRest = equalFields (RLProxy :: RLProxy tail)(I think the strictness means that the rest of the record would be compared before being passed to &&)
Member
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get' a == get' b && equalRest a b would also short circuit :)
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Oh, okay! Sometimes I forget we have compiler magic – thanks! :)
Contributor
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@justinwoo Could you please rebase this? |
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Author
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rebased! |
Contributor
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Thanks! |
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I realized that I need this function but we don't seem to have it yet