f89ed40618
This introduces the `ArgsPacker` module and abstraction, to replace the exising `PackDomain`/`PackMutual` code. The motivation was that we now have more uses besides `Fix.lean` (`GuessLex` and `FunInd`), and the code was spread in various places. The goals are * consistent function naming withing the the `PSigma` handling, the `PSum` handling, and the combined interface * avoid taking a type apart just based on the `PSigma`/`PSum` nesting, to be robust in case the user happens to be using `PSigma`/`PSum` somewhere. Therefore, always pass an `arity` or `numFuncs` or `varNames` around. * keep all the `PSigma`/`PSum` encoding logic contained within one module (`ArgsPacker`), and keep that module independent of its users (so no `EqnInfos` visible here). * pick good variable names when matching on a packed argument * the unary function now is either called `fun1._unary` or `fun1._mutual`, never `fun1._unary._mutual`. This file has less heavy dependencies than `PackMutual` had, so build parallelism is improved as well.
33 lines
1.2 KiB
Text
33 lines
1.2 KiB
Text
set_option autoImplicit false
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def ackermann : Nat → Nat → Nat
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| 0, m => m + 1
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| n+1, 0 => ackermann n 1
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| n+1, m+1 => ackermann n (ackermann (n + 1) m)
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derive_functional_induction ackermann
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/--
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info: ackermann.induct (motive : Nat → Nat → Prop) (case1 : ∀ (m : Nat), motive 0 m)
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(case2 : ∀ (n : Nat), motive n 1 → motive (Nat.succ n) 0)
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(case3 : ∀ (n m : Nat), motive (n + 1) m → motive n (ackermann (n + 1) m) → motive (Nat.succ n) (Nat.succ m)) :
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∀ (a a_1 : Nat), motive a a_1
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-/
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#guard_msgs in
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#check ackermann.induct
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-- TODO: Remove when `List.attach` is upstreamed from std
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def List.attach {α} : (l : List α) → List {x // x ∈ l}
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| [] => []
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| x::xs => ⟨x, List.mem_cons_self _ _⟩ :: xs.attach.map (fun ⟨y, hy⟩ => ⟨y, mem_cons_of_mem _ hy⟩)
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inductive Tree | node : List Tree → Tree
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def Tree.rev : Tree → Tree | node ts => .node (ts.attach.map (fun ⟨t, _ht⟩ => t.rev) |>.reverse)
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derive_functional_induction Tree.rev
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/--
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info: Tree.rev.induct (motive : Tree → Prop)
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(case1 : ∀ (ts : List Tree), (∀ (t : Tree), t ∈ ts → motive t) → motive (Tree.node ts)) (x : Tree) : motive x
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-/
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#guard_msgs in
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#check Tree.rev.induct
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