71 lines
2.8 KiB
Text
71 lines
2.8 KiB
Text
/-
|
||
Copyright (c) 2020 Microsoft Corporation. All rights reserved.
|
||
Released under Apache 2.0 license as described in the file LICENSE.
|
||
Authors: Leonardo de Moura
|
||
-/
|
||
import Lean.Meta.KAbstract
|
||
import Lean.Meta.Tactic.Util
|
||
import Lean.Meta.Tactic.Intro
|
||
|
||
namespace Lean.Meta
|
||
|
||
/-- The `generalize` tactic takes arguments of the form `h : e = x` -/
|
||
structure GeneralizeArg where
|
||
expr : Expr
|
||
xName? : Option Name := none
|
||
hName? : Option Name := none
|
||
deriving Inhabited
|
||
|
||
partial def generalize
|
||
(mvarId : MVarId) (args : Array GeneralizeArg)
|
||
(pred : (parent? : Option Expr) → (e : Expr) → MetaM Bool := fun _ _ => return true)
|
||
: MetaM (Array FVarId × MVarId) :=
|
||
withMVarContext mvarId do
|
||
checkNotAssigned mvarId `generalize
|
||
let tag ← getMVarTag mvarId
|
||
let target ← instantiateMVars (← getMVarType mvarId)
|
||
let rec go (i : Nat) : MetaM Expr := do
|
||
if i < args.size then
|
||
let arg := args[i]
|
||
let e ← instantiateMVars arg.expr
|
||
let eType ← instantiateMVars (← inferType e)
|
||
let type ← go (i+1)
|
||
let xName ← if let some xName := arg.xName? then pure xName else mkFreshUserName `x
|
||
return Lean.mkForall xName BinderInfo.default eType (← kabstractWithPred type e pred)
|
||
else
|
||
return target
|
||
let targetNew ← go 0
|
||
unless (← isTypeCorrect targetNew) do
|
||
throwTacticEx `generalize mvarId m!"result is not type correct{indentExpr targetNew}"
|
||
let es := args.map (·.expr)
|
||
if !args.any fun arg => arg.hName?.isSome then
|
||
let mvarNew ← mkFreshExprSyntheticOpaqueMVar targetNew tag
|
||
assignExprMVar mvarId (mkAppN mvarNew es)
|
||
introNP mvarNew.mvarId! args.size
|
||
else
|
||
let (rfls, targetNew) ← forallBoundedTelescope targetNew args.size fun xs type => do
|
||
let rec go' (i : Nat) : MetaM (List Expr × Expr) := do
|
||
if i < xs.size then
|
||
let arg := args[i]
|
||
if let some hName := arg.hName? then
|
||
let xType ← inferType xs[i]
|
||
let e ← instantiateMVars arg.expr
|
||
let eType ← instantiateMVars (← inferType e)
|
||
let (hType, r) ←
|
||
if (← isDefEq xType eType) then
|
||
pure (← mkEq e xs[i], ← mkEqRefl e)
|
||
else
|
||
pure (← mkHEq e xs[i], ← mkHEqRefl e)
|
||
let (rs, type) ← go' (i+1)
|
||
return (r :: rs, mkForall hName BinderInfo.default hType type)
|
||
else
|
||
go' (i+1)
|
||
else
|
||
return ([], type)
|
||
let (rfls, type) ← go' 0
|
||
return (rfls, ← mkForallFVars xs type)
|
||
let mvarNew ← mkFreshExprSyntheticOpaqueMVar targetNew tag
|
||
assignExprMVar mvarId (mkAppN (mkAppN mvarNew es) rfls.toArray)
|
||
introNP mvarNew.mvarId! (args.size + rfls.length)
|
||
|
||
end Lean.Meta
|