refactor: bundle wn and wr into DivModState
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alexkeizer
commented
Sep 24, 2024
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@bollu I also made some naming changes as I went along, I'm marking them with comments so you know to make those changes to the main PR even if we decide against merging this one
src/Init/Data/BitVec/Bitblast.lean
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| rw [Nat.shiftRight_eq_div_pow] | ||
| apply Nat.div_eq_of_lt n.isLt | ||
| } | ||
| def DivModState.Lawful.init {w : Nat} (args : DivModArgs w) (hd : 0#w < args.d) : |
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| def DivModState.Lawful.init {w : Nat} (args : DivModArgs w) (hd : 0#w < args.d) : | |
| def DivModState.lawful_init {w : Nat} (args : DivModArgs w) (hd : 0#w < args.d) : |
| divRec m args (divSubtractShift args qr) := rfl | ||
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| /-- The output of `divRec` is a lawful state -/ | ||
| theorem lawful_divRec {args : DivModArgs w} {qr : DivModState w} |
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I decided to rename this from the somewhat ambiguous "correct" to "lawful"
src/Init/Data/BitVec/Bitblast.lean
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| @@ -671,13 +690,14 @@ private theorem two_mul_add_sub_lt_of_lt_of_lt_two (h : a < x) (hy : y < 2) : | |||
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| /-- We show that the output of `divSubtractShift` is lawful, which tells us that it | |||
| obeys the division equation. -/ | |||
| def divSubtractShiftProof (qr : DivModState w) (h : qr.Poised wr wn n d) : | |||
| DivModState.Lawful w (wr + 1) (wn - 1) n d (divSubtractShift n d wn qr) := by | |||
| def lawful_divSubtractShift (qr : DivModState w) (h : qr.Poised args) : | |||
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Not a fan of divSubtractShiftProof as a name, so I renamed it to lawful_...
alexkeizer
commented
Sep 24, 2024
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@bollu: I didn't really like how
Lawfulhad so many parameters flying about, and in particular, how it's basically impossible to tell what, say,Lawful w w 0 n d qrmeans.So, I made a refactor to bundle
wnandwras fields of theDivModState(I'm a huge fan of this, it makes stuff much easier to read!), and while I was at it, also bundlednanddinto aDivModArgsstruct (this one I think is an improvement overall, but a much less clearcut one: it does make some call sites look a bit awkward).Anyway, It's a pretty big refactor, hence the PR to your PR (the base branch of this one is the upstream PR).