1 files changed, 29 insertions, 93 deletions
diff --git a/backends/lean/Base/Arith/Arith.lean b/backends/lean/Base/Arith/Arith.lean
index ff628cf3..3557d350 100644
--- a/backends/lean/Base/Arith/Arith.lean
+++ b/backends/lean/Base/Arith/Arith.lean
@@ -230,25 +230,20 @@ def introInstances (declToUnfold : Name) (lookup : Expr → MetaM (Option Expr))
     let type ← inferType e
     let name ← mkFreshUserName `h
     -- Add a declaration
-    let nval ← Utils.addDecl name e type (asLet := false)
+    let nval ← Utils.addDeclTac name e type (asLet := false)
     -- Simplify to unfold the declaration to unfold (i.e., the projector)
-    let simpTheorems ← Tactic.simpOnlyBuiltins.foldlM (·.addConst ·) ({} : SimpTheorems)
-    -- Add the equational theorem for the decl to unfold
-    let simpTheorems ← simpTheorems.addDeclToUnfold declToUnfold
-    let congrTheorems ← getSimpCongrTheorems
-    let ctx : Simp.Context := { simpTheorems := #[simpTheorems], congrTheorems }
-    -- Where to apply the simplifier
-    let loc := Tactic.Location.targets #[mkIdent name] false
-    -- Apply the simplifier
-    let _ ← Tactic.simpLocation ctx (discharge? := .none) loc
+    Utils.simpAt [declToUnfold] [] [] (Tactic.Location.targets #[mkIdent name] false)
     -- Return the new value
     pure nval
 
+def introHasPropInstances : Tactic.TacticM (Array Expr) := do
+  trace[Arith] "Introducing the HasProp instances"
+  introInstances ``HasProp.prop_ty lookupHasProp
+
 -- Lookup the instances of `HasProp for all the sub-expressions in the context,
 -- and introduce the corresponding assumptions
 elab "intro_has_prop_instances" : tactic => do
-  trace[Arith] "Introducing the HasProp instances"
-  let _ ← introInstances ``HasProp.prop_ty lookupHasProp
+  let _ ← introHasPropInstances
 
 example (x y : U32) : x.val ≤ Scalar.max ScalarTy.U32 := by
   intro_has_prop_instances
@@ -258,74 +253,6 @@ example {a: Type} (v : Vec a) : v.val.length ≤ Scalar.max ScalarTy.Usize := by
   intro_has_prop_instances
   simp_all [Scalar.max, Scalar.min]
 
--- Tactic to split on a disjunction.
--- The expression `h` should be an fvar.
-def splitDisj (h : Expr) (kleft kright : Tactic.TacticM Unit) : Tactic.TacticM Unit := do
-  trace[Arith] "assumption on which to split: {h}"
-  -- Retrieve the main goal
-  Tactic.withMainContext do
-  let goalType ← Tactic.getMainTarget
-  let hDecl := (← getLCtx).get! h.fvarId!
-  let hName := hDecl.userName
-  -- Case disjunction
-  let hTy ← inferType h
-  hTy.withApp fun f xs => do
-  trace[Arith] "as app: {f} {xs}"
-  -- Sanity check
-  if ¬ (f.isConstOf ``Or ∧ xs.size = 2) then throwError "Invalid argument to splitDisj"
-  let a := xs.get! 0
-  let b := xs.get! 1
-  -- Introduce the new goals
-  -- Returns:
-  -- - the match branch
-  -- - a fresh new mvar id
-  let mkGoal (hTy : Expr) (nGoalName : String) : MetaM (Expr × MVarId) := do
-    -- Introduce a variable for the assumption (`a` or `b`). Note that we reuse
-    -- the name of the assumption we split.
-    withLocalDeclD hName hTy fun var => do
-    -- The new goal
-    let mgoal ← mkFreshExprSyntheticOpaqueMVar goalType (tag := Name.mkSimple nGoalName)
-    -- Clear the assumption that we split
-    let mgoal ← mgoal.mvarId!.tryClearMany #[h.fvarId!]
-    -- The branch expression
-    let branch ← mkLambdaFVars #[var] (mkMVar mgoal)
-    pure (branch, mgoal)
-  let (inl, mleft) ← mkGoal a "left"
-  let (inr, mright) ← mkGoal b "right"
-  trace[Arith] "left: {inl}: {mleft}"
-  trace[Arith] "right: {inr}: {mright}"
-  -- Create the match expression
-  withLocalDeclD (← mkFreshUserName `h) hTy fun hVar => do
-  let motive ← mkLambdaFVars #[hVar] goalType
-  let casesExpr ← mkAppOptM ``Or.casesOn #[a, b, motive, h, inl, inr]
-  let mgoal ← Tactic.getMainGoal
-  trace[Arith] "goals: {← Tactic.getUnsolvedGoals}"
-  trace[Arith] "main goal: {mgoal}"
-  mgoal.assign casesExpr
-  let goals ← Tactic.getUnsolvedGoals
-  -- Focus on the left
-  Tactic.setGoals [mleft]
-  kleft
-  let leftGoals ← Tactic.getUnsolvedGoals
-  -- Focus on the right
-  Tactic.setGoals [mright]
-  kright
-  let rightGoals ← Tactic.getUnsolvedGoals
-  -- Put all the goals back
-  Tactic.setGoals (leftGoals ++ rightGoals ++ goals)
-  trace[Arith] "new goals: {← Tactic.getUnsolvedGoals}"
-
-elab "split_disj " n:ident : tactic => do
-  Tactic.withMainContext do
-  let decl ← Lean.Meta.getLocalDeclFromUserName n.getId
-  let fvar := mkFVar decl.fvarId
-  splitDisj fvar (fun _ => pure ()) (fun _ => pure ())
-
-example (x y : Int) (h0 : x ≤ y ∨ x ≥ y) : x ≤ y ∨ x ≥ y := by
-  split_disj h0
-  . left; assumption
-  . right; assumption
-
 -- Lookup the instances of `PropHasImp for all the sub-expressions in the context,
 -- and introduce the corresponding assumptions
 elab "intro_prop_has_imp_instances" : tactic => do
@@ -357,7 +284,7 @@ def intTacPreprocess : Tactic.TacticM Unit := do
     | [] => pure ()
     | asm :: asms =>
       let k := splitOnAsms asms
-      splitDisj asm k k
+      Utils.splitDisjTac asm k k
   -- Introduce
   let asms ← introInstances ``PropHasImp.concl lookupPropHasImp
   -- Split
@@ -403,18 +330,27 @@ example (x y : Int) (h0: 0 ≤ x) (h1: x ≠ 0) (h2 : 0 ≤ y) (h3 : y ≠ 0) :
   int_tac
 
 -- A tactic to solve linear arithmetic goals in the presence of scalars
-syntax "scalar_tac" : tactic
-macro_rules
-  | `(tactic| scalar_tac) =>
-    `(tactic|
-      intro_has_prop_instances;
-      have := Scalar.cMin_bound ScalarTy.Usize;
-      have := Scalar.cMin_bound ScalarTy.Isize;
-      have := Scalar.cMax_bound ScalarTy.Usize;
-      have := Scalar.cMax_bound ScalarTy.Isize;
-      -- TODO: not too sure about that
-      simp only [*, Scalar.max, Scalar.min, Scalar.cMin, Scalar.cMax] at *;
-      int_tac)
+def scalarTac : Tactic.TacticM Unit := do
+  Tactic.withMainContext do
+  -- Introduce the scalar bounds
+  let _ ← introHasPropInstances
+  Tactic.allGoals do
+  -- Inroduce the bounds for the isize/usize types
+  let add (e : Expr) : Tactic.TacticM Unit := do
+    let ty ← inferType e
+    let _ ← Utils.addDeclTac (← mkFreshUserName `h) e ty (asLet := false)
+  add (← mkAppM ``Scalar.cMin_bound #[.const ``ScalarTy.Usize []])
+  add (← mkAppM ``Scalar.cMin_bound #[.const ``ScalarTy.Isize []])
+  add (← mkAppM ``Scalar.cMax_bound #[.const ``ScalarTy.Usize []])
+  add (← mkAppM ``Scalar.cMax_bound #[.const ``ScalarTy.Isize []])
+  -- Reveal the concrete bounds - TODO: not too sure about that.
+  -- Maybe we should reveal the "concrete" bounds (after normalization)
+  Utils.simpAt [``Scalar.max, ``Scalar.min, ``Scalar.cMin, ``Scalar.cMax] [] [] .wildcard
+  -- Apply the integer tactic
+  intTac
+
+elab "scalar_tac" : tactic =>
+  scalarTac
 
 example (x y : U32) : x.val ≤ Scalar.max ScalarTy.U32 := by
   scalar_tac