Pantograph/Pantograph/Frontend/MetaTranslate.lean

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import Lean.Meta
open Lean
namespace Pantograph.Frontend
namespace MetaTranslate
structure Context where
sourceMCtx : MetavarContext := {}
sourceLCtx : LocalContext := {}
abbrev FVarMap := HashMap FVarId FVarId
structure State where
-- Stores mapping from old to new mvar/fvars
mvarMap: HashMap MVarId MVarId := {}
fvarMap: HashMap FVarId FVarId := {}
/-
Monadic state for translating a frozen meta state. The underlying `MetaM`
operates in the "target" context and state.
-/
abbrev MetaTranslateM := ReaderT Context StateRefT State MetaM
def getSourceLCtx : MetaTranslateM LocalContext := do pure (← read).sourceLCtx
def getSourceMCtx : MetaTranslateM MetavarContext := do pure (← read).sourceMCtx
def addTranslatedFVar (src dst: FVarId) : MetaTranslateM Unit := do
modifyGet λ state => ((), { state with fvarMap := state.fvarMap.insert src dst })
def addTranslatedMVar (src dst: MVarId) : MetaTranslateM Unit := do
modifyGet λ state => ((), { state with mvarMap := state.mvarMap.insert src dst })
def saveFVarMap : MetaTranslateM FVarMap := do
return (← get).fvarMap
def restoreFVarMap (map: FVarMap) : MetaTranslateM Unit := do
modifyGet λ state => ((), { state with fvarMap := map })
def resetFVarMap : MetaTranslateM Unit := do
modifyGet λ state => ((), { state with fvarMap := {} })
mutual
private partial def translateExpr (srcExpr: Expr) : MetaTranslateM Expr := do
let sourceMCtx ← getSourceMCtx
let (srcExpr, _) := instantiateMVarsCore (mctx := sourceMCtx) srcExpr
--IO.println s!"Transform src: {srcExpr}"
let result ← Core.transform srcExpr λ e => do
let state ← get
match e with
| .fvar fvarId =>
let .some fvarId' := state.fvarMap.find? fvarId | panic! s!"FVar id not registered: {fvarId.name}"
assert! (← getLCtx).contains fvarId'
return .done $ .fvar fvarId'
| .mvar mvarId => do
assert! !(sourceMCtx.dAssignment.contains mvarId)
assert! !(sourceMCtx.eAssignment.contains mvarId)
match state.mvarMap.find? mvarId with
| .some mvarId' => do
return .done $ .mvar mvarId'
| .none => do
-- Entering another LCtx, must save the current one
let fvarMap ← saveFVarMap
let mvarId' ← translateMVarId mvarId
restoreFVarMap fvarMap
return .done $ .mvar mvarId'
| _ => return .continue
Meta.check result
return result
partial def translateLocalInstance (srcInstance: LocalInstance) : MetaTranslateM LocalInstance := do
return {
className := srcInstance.className,
fvar := ← translateExpr srcInstance.fvar
}
partial def translateLocalDecl (srcLocalDecl: LocalDecl) : MetaTranslateM LocalDecl := do
let fvarId ← mkFreshFVarId
addTranslatedFVar srcLocalDecl.fvarId fvarId
match srcLocalDecl with
| .cdecl index _ userName type bi kind => do
--IO.println s!"[CD] {userName} {toString type}"
return .cdecl index fvarId userName (← translateExpr type) bi kind
| .ldecl index _ userName type value nonDep kind => do
--IO.println s!"[LD] {toString type} := {toString value}"
return .ldecl index fvarId userName (← translateExpr type) (← translateExpr value) nonDep kind
partial def translateLCtx : MetaTranslateM LocalContext := do
resetFVarMap
(← getSourceLCtx).foldlM (λ lctx srcLocalDecl => do
let localDecl ← Meta.withLCtx lctx #[] do translateLocalDecl srcLocalDecl
pure $ lctx.addDecl localDecl
) (← MonadLCtx.getLCtx)
partial def translateMVarId (srcMVarId: MVarId) : MetaTranslateM MVarId := do
if let .some mvarId' := (← get).mvarMap.find? srcMVarId then
return mvarId'
let srcDecl := (← getSourceMCtx).findDecl? srcMVarId |>.get!
let mvar ← withTheReader Context (λ ctx => { ctx with sourceLCtx := srcDecl.lctx }) do
let lctx' ← translateLCtx
let localInstances' ← srcDecl.localInstances.mapM translateLocalInstance
Meta.withLCtx lctx' localInstances' do
let target' ← translateExpr srcDecl.type
Meta.mkFreshExprMVar target' srcDecl.kind srcDecl.userName
addTranslatedMVar srcMVarId mvar.mvarId!
return mvar.mvarId!
end
def translateMVarFromTermInfo (termInfo : Elab.TermInfo) (context? : Option Elab.ContextInfo)
: MetaTranslateM MVarId := do
withTheReader Context (λ ctx => { ctx with
sourceMCtx := context?.map (·.mctx) |>.getD {},
sourceLCtx := termInfo.lctx,
}) do
let type := termInfo.expectedType?.get!
let lctx' ← translateLCtx
let mvar ← Meta.withLCtx lctx' #[] do
let type' ← translateExpr type
Meta.mkFreshExprSyntheticOpaqueMVar type'
return mvar.mvarId!
def translateMVarFromTacticInfoBefore (tacticInfo : Elab.TacticInfo) (_context? : Option Elab.ContextInfo)
: MetaTranslateM (List MVarId) := do
withTheReader Context (λ ctx => { ctx with sourceMCtx := tacticInfo.mctxBefore }) do
tacticInfo.goalsBefore.mapM translateMVarId
end MetaTranslate
export MetaTranslate (MetaTranslateM)
end Pantograph.Frontend