lean4-htt/tests/elab/funind_proof.lean
Garmelon 08eb78a5b2
chore: switch to new test/bench suite (#12590)
This PR sets up the new integrated test/bench suite. It then migrates
all benchmarks and some related tests to the new suite. There's also
some documentation and some linting.

For now, a lot of the old tests are left alone so this PR doesn't become
even larger than it already is. Eventually, all tests should be migrated
to the new suite though so there isn't a confusing mix of two systems.
2026-02-25 13:51:53 +00:00

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inductive Term where
| const : String → Term
| app : String → List Term → Term
namespace Term
mutual
def numConsts : Term → Nat
| const _ => 1
| app _ cs => numConstsLst cs
def numConstsLst : List Term → Nat
| [] => 0
| c :: cs => numConsts c + numConstsLst cs
end
mutual
-- Since #4733 this function can be compiled using structural recursion,
-- but then the construction of the functional induction principle falls over
-- TODO: Fix funind, and then omit the `termination_by` here (or test both variants)
def replaceConst (a b : String) : Term → Term
| const c => if a == c then const b else const c
| app f cs => app f (replaceConstLst a b cs)
termination_by t => sizeOf t
def replaceConstLst (a b : String) : List Term → List Term
| [] => []
| c :: cs => replaceConst a b c :: replaceConstLst a b cs
termination_by ts => sizeOf ts
end
/--
info: Term.replaceConst.induct (a : String) (motive1 : Term → Prop) (motive2 : List Term → Prop)
(case1 : ∀ (a_1 : String), (a == a_1) = true → motive1 (const a_1))
(case2 : ∀ (a_1 : String), ¬(a == a_1) = true → motive1 (const a_1))
(case3 : ∀ (a : String) (cs : List Term), motive2 cs → motive1 (app a cs)) (case4 : motive2 [])
(case5 : ∀ (c : Term) (cs : List Term), motive1 c → motive2 cs → motive2 (c :: cs)) (a✝ : Term) : motive1 a✝
-/
#guard_msgs in
#check replaceConst.induct
theorem numConsts_replaceConst (a b : String) (e : Term) : numConsts (replaceConst a b e) = numConsts e := by
apply replaceConst.induct (a := a)
(motive1 := fun e => numConsts (replaceConst a b e) = numConsts e)
(motive2 := fun es => numConstsLst (replaceConstLst a b es) = numConstsLst es)
case case1 => intro c h; guard_hyp h :ₛ (a == c) = true; simp [replaceConst, numConsts, *]
case case2 => intro c h; guard_hyp h :ₛ ¬(a == c) = true; simp [replaceConst, numConsts, *]
case case3 =>
intro f cs ih
guard_hyp ih :ₛnumConstsLst (replaceConstLst a b cs) = numConstsLst cs
simp [replaceConst, numConsts, *]
case case4 => simp [replaceConstLst, numConstsLst, *]
case case5 =>
intro c cs ih₁ ih₂
guard_hyp ih₁ :ₛ numConsts (replaceConst a b c) = numConsts c
guard_hyp ih₂ :ₛ numConstsLst (replaceConstLst a b cs) = numConstsLst cs
simp [replaceConstLst, numConstsLst, *]
theorem numConsts_replaceConst' (a b : String) (e : Term) : numConsts (replaceConst a b e) = numConsts e := by
apply replaceConst.induct (a := a)
(motive1 := fun e => numConsts (replaceConst a b e) = numConsts e)
(motive2 := fun es => numConstsLst (replaceConstLst a b es) = numConstsLst es)
<;> intros <;> simp [replaceConst, numConsts, replaceConstLst, numConstsLst, *]
theorem numConsts_replaceConst'' (a b : String) (e : Term) : numConsts (replaceConst a b e) = numConsts e := by
induction e using replaceConst.induct (a := a)
(motive2 := fun es => numConstsLst (replaceConstLst a b es) = numConstsLst es) <;>
simp [replaceConst, numConsts, replaceConstLst, numConstsLst, *]
end Term