lean4-htt/tests/elab/grind_ite_trace.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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module
public import Std.Data.HashMap
public import Std.Data.TreeMap
inductive IfExpr
| lit : Bool → IfExpr
| var : Nat → IfExpr
| ite : IfExpr → IfExpr → IfExpr → IfExpr
deriving DecidableEq
namespace IfExpr
def hasNestedIf : IfExpr → Bool
| lit _ => false
| var _ => false
| ite (ite _ _ _) _ _ => true
| ite _ t e => t.hasNestedIf || e.hasNestedIf
def hasConstantIf : IfExpr → Bool
| lit _ => false
| var _ => false
| ite (lit _) _ _ => true
| ite i t e => i.hasConstantIf || t.hasConstantIf || e.hasConstantIf
def hasRedundantIf : IfExpr → Bool
| lit _ => false
| var _ => false
| ite i t e => t == e || i.hasRedundantIf || t.hasRedundantIf || e.hasRedundantIf
def vars : IfExpr → List Nat
| lit _ => []
| var i => [i]
| ite i t e => i.vars ++ t.vars ++ e.vars
def _root_.List.disjoint {α} [DecidableEq α] : List α → List α → Bool
| [], _ => true
| x::xs, ys => x ∉ ys && xs.disjoint ys
def disjoint : IfExpr → Bool
| lit _ => true
| var _ => true
| ite i t e =>
i.vars.disjoint t.vars && i.vars.disjoint e.vars && i.disjoint && t.disjoint && e.disjoint
def normalized (e : IfExpr) : Bool :=
!e.hasNestedIf && !e.hasConstantIf && !e.hasRedundantIf && e.disjoint
def eval (f : Nat → Bool) : IfExpr → Bool
| lit b => b
| var i => f i
| ite i t e => bif i.eval f then t.eval f else e.eval f
end IfExpr
def IfNormalization : Type := { Z : IfExpr → IfExpr // ∀ e, (Z e).normalized ∧ (Z e).eval = e.eval }
namespace IfExpr
@[simp] def normSize : IfExpr → Nat
| lit _ => 0
| var _ => 1
| .ite i t e => 2 * normSize i + max (normSize t) (normSize e) + 1
def normalize (assign : Std.HashMap Nat Bool) : IfExpr → IfExpr
| lit b => lit b
| var v =>
match assign[v]? with
| none => var v
| some b => lit b
| ite (lit true) t _ => normalize assign t
| ite (lit false) _ e => normalize assign e
| ite (ite a b c) t e => normalize assign (ite a (ite b t e) (ite c t e))
| ite (var v) t e =>
match assign[v]? with
| none =>
let t' := normalize (assign.insert v true) t
let e' := normalize (assign.insert v false) e
if t' = e' then t' else ite (var v) t' e'
| some b => normalize assign (ite (lit b) t e)
termination_by e => e.normSize
-- We tell `grind` to unfold our definitions above.
attribute [local grind] normalized hasNestedIf hasConstantIf hasRedundantIf disjoint vars eval List.disjoint
theorem normalize_spec (assign : Std.HashMap Nat Bool) (e : IfExpr) :
(normalize assign e).normalized
∧ (∀ f, (normalize assign e).eval f = e.eval fun w => assign[w]?.getD (f w))
∧ ∀ (v : Nat), v ∈ vars (normalize assign e) → ¬ v ∈ assign := by
fun_induction normalize
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example (assign : Std.HashMap Nat Bool) (e : IfExpr) :
(normalize assign e).normalized
∧ (∀ f, (normalize assign e).eval f = e.eval fun w => assign[w]?.getD (f w))
∧ ∀ (v : Nat), v ∈ vars (normalize assign e) → assign.contains v = false := by
fun_induction normalize
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