Make sure default impls for BoundedEnum are TCO'd #37
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The implementations for `defaultCardinality`, `defaultToEnum`, and `defaultFromEnum` don't trigger tail-call optimization, which means that they are quite a bit slower than they could be (and in some cases will produce a stack overflow when they needn't). This commit will also have the fortunate effect that this library won't break if the compiler stops inlining function composition in the (arguably broken) way that it does currently; see purescript/purescript#3439 (comment)
natefaubion
reviewed
Jan 30, 2019
test/Test/Data/Enum.purs
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| -- | A newtype over Int which is supposed to represent Ints bounded between 0 | ||
| -- | and 10,000. Why 10,000? It's just about large enough that we'll most | ||
| -- | likely see stack overflow errors if we've managed to break TCO. | ||
| newtype Upto10k = Upto10k Int |
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I've seen stack-unsafe code work up to 30k iterations in the past. I always do 100k.
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Huh, news to me - good to know, thanks! I'll change this.
natefaubion
approved these changes
Jan 31, 2019
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The implementations for
defaultCardinality,defaultToEnum, anddefaultFromEnumdon't trigger tail-call optimization, which means thatthey are quite a bit slower than they could be (and in some cases will
produce a stack overflow when they needn't).
This commit will also have the fortunate effect that this library won't
break if the compiler stops inlining function composition in the
(arguably broken) way that it does currently; see
purescript/purescript#3439 (comment)