Use UArray instead of Set for builtin availability check#7736
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Use UArray instead of Set for builtin availability check#7736
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The builtin availability check in `scriptCBORDecoder` was using `Set DefaultFun` for O(log n) membership, with a TODO suggesting `IntSet`. A `UArray DefaultFun Bool` is a better fit: since `DefaultFun` derives `Ix`, lookup is a true O(1) unboxed array index with no conversion at the lookup site. The array is built once per call via `runSTUArray`, folding over the `Set` through its `Foldable` instance (no intermediate list). The array covers all ~100 `DefaultFun` constructors.
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Unclear this is an improvement. Try |
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Summary
Addresses the
TODOinSerialisedScript.hs:202suggesting a better data structure for the builtin availability check inscriptCBORDecoder.Previously
checkBuiltindid an O(log n)Set.memberon aSet DefaultFun.DefaultFunalready derivesIx, so aUArray DefaultFun Boolgives a true O(1) unboxed array index with nofromEnum/hash at the lookup site (GHC'sIxinstance handles the offset).