175661b6c3
This PR reorganizes the monad hierarchy for symbolic computation in Lean. ## Motivation We want a clean layering where: 1. A foundational monad (`SymM`) provides maximally shared terms and structural/syntactic `isDefEq` 2. `GrindM` builds on this foundation, adding E-graphs, congruence closure, and decision procedures 3. Symbolic execution / VCGen uses `GrindM` directly without introducing a third monad ## Changes The core symbolic computation layer still lives in `Lean.Meta.Sym`. This monad (`SymM`) provides: - Maximally shared terms with pointer-based equality - Structural/syntactic `isDefEq` and matching (no reduction, predictable cost) - Monotonic local contexts (no `revert` or `clear`), enabling O(1) metavariable validation - Efficient `intro`, `apply`, and `simp` implementations The name "Sym" reflects that this is infrastructure for symbolic computation: symbolic simulation, verification condition generation, and decision procedures. ### Updated hierarchy ``` Lean.Meta.Sym -- SymM: shared terms, syntactic isDefEq, intro, apply, simp Lean.Meta.Grind -- GrindM: E-graphs, congruence closure (extends SymM) ``` Symbolic execution is a usage pattern of `GrindM` operating on `Grind.Goal`, not a separate monad. This keeps the API surface minimal: users learn two monads, and VCGen is "how you use `GrindM`" (for users that want to use `grind`) rather than a third abstraction to understand.
28 lines
543 B
Text
28 lines
543 B
Text
import Lean.Meta.Tactic
|
|
import Lean.Meta.Sym
|
|
|
|
def f (x : Nat) :=
|
|
let y := x + 1
|
|
2*y
|
|
|
|
open Lean Meta Sym
|
|
/--
|
|
info: x : Nat
|
|
⊢ have y := x + 1;
|
|
x ≤ 2 * y
|
|
---
|
|
info: x : Nat
|
|
y : Nat := x + 1
|
|
⊢ x ≤ 2 * y
|
|
-/
|
|
#guard_msgs in
|
|
run_meta SymM.run do
|
|
withLocalDeclD `x Nat.mkType fun x => do
|
|
let m ← mkFreshExprMVar <| mkNatLE x (mkApp (mkConst ``f) x)
|
|
let mvarId := m.mvarId!
|
|
let mvarId ← unfoldTarget mvarId ``f
|
|
let mvarId ← mvarId.liftLets
|
|
logInfo mvarId
|
|
let (_, mvarId) ← intro mvarId `y
|
|
logInfo mvarId
|
|
return ()
|