/- 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.Parser.Command import Lean.Meta.Closure import Lean.Meta.SizeOf import Lean.Meta.Injective import Lean.Meta.Structure import Lean.Meta.AppBuilder import Lean.Elab.Command import Lean.Elab.DeclModifiers import Lean.Elab.DeclUtil import Lean.Elab.Inductive import Lean.Elab.DeclarationRange import Lean.Elab.Binders namespace Lean.Elab.Command open Meta /- Recall that the `structure command syntax is ``` leading_parser (structureTk <|> classTk) >> declId >> many Term.bracketedBinder >> optional «extends» >> Term.optType >> optional (" := " >> optional structCtor >> structFields) ``` -/ structure StructCtorView where ref : Syntax modifiers : Modifiers inferMod : Bool -- true if `{}` is used in the constructor declaration name : Name declName : Name structure StructFieldView where ref : Syntax modifiers : Modifiers binderInfo : BinderInfo inferMod : Bool declName : Name name : Name binders : Syntax type? : Option Syntax value? : Option Syntax structure StructView where ref : Syntax modifiers : Modifiers scopeLevelNames : List Name -- All `universe` declarations in the current scope allUserLevelNames : List Name -- `scopeLevelNames` ++ explicit universe parameters provided in the `structure` command isClass : Bool declName : Name scopeVars : Array Expr -- All `variable` declaration in the current scope params : Array Expr -- Explicit parameters provided in the `structure` command parents : Array Syntax type : Syntax ctor : StructCtorView fields : Array StructFieldView inductive StructFieldKind where | newField | fromParent | subobject deriving Inhabited, BEq structure StructFieldInfo where name : Name declName : Name -- Remark: for `fromParent` fields, `declName` is only relevant in the generation of auxiliary "default value" functions. fvar : Expr kind : StructFieldKind inferMod : Bool := false value? : Option Expr := none deriving Inhabited def StructFieldInfo.isFromParent (info : StructFieldInfo) : Bool := match info.kind with | StructFieldKind.fromParent => true | _ => false def StructFieldInfo.isSubobject (info : StructFieldInfo) : Bool := match info.kind with | StructFieldKind.subobject => true | _ => false /- Auxiliary declaration for `mkProjections` -/ structure ProjectionInfo where declName : Name inferMod : Bool structure ElabStructResult where decl : Declaration projInfos : List ProjectionInfo projInstances : List Name -- projections (to parent classes) that must be marked as instances. mctx : MetavarContext lctx : LocalContext localInsts : LocalInstances defaultAuxDecls : Array (Name × Expr × Expr) private def defaultCtorName := `mk /- The structure constructor syntax is ``` leading_parser try (declModifiers >> ident >> optional inferMod >> " :: ") ``` -/ private def expandCtor (structStx : Syntax) (structModifiers : Modifiers) (structDeclName : Name) : TermElabM StructCtorView := do let useDefault := do let declName := structDeclName ++ defaultCtorName addAuxDeclarationRanges declName structStx[2] structStx[2] pure { ref := structStx, modifiers := {}, inferMod := false, name := defaultCtorName, declName } if structStx[5].isNone then useDefault else let optCtor := structStx[5][1] if optCtor.isNone then useDefault else let ctor := optCtor[0] withRef ctor do let ctorModifiers ← elabModifiers ctor[0] checkValidCtorModifier ctorModifiers if ctorModifiers.isPrivate && structModifiers.isPrivate then throwError "invalid 'private' constructor in a 'private' structure" if ctorModifiers.isProtected && structModifiers.isPrivate then throwError "invalid 'protected' constructor in a 'private' structure" let inferMod := !ctor[2].isNone let name := ctor[1].getId let declName := structDeclName ++ name let declName ← applyVisibility ctorModifiers.visibility declName addDocString' declName ctorModifiers.docString? addAuxDeclarationRanges declName ctor[1] ctor[1] pure { ref := ctor, name, modifiers := ctorModifiers, inferMod, declName } def checkValidFieldModifier (modifiers : Modifiers) : TermElabM Unit := do if modifiers.isNoncomputable then throwError "invalid use of 'noncomputable' in field declaration" if modifiers.isPartial then throwError "invalid use of 'partial' in field declaration" if modifiers.isUnsafe then throwError "invalid use of 'unsafe' in field declaration" if modifiers.attrs.size != 0 then throwError "invalid use of attributes in field declaration" /- ``` def structExplicitBinder := leading_parser atomic (declModifiers true >> "(") >> many1 ident >> optional inferMod >> optDeclSig >> optional (Term.binderTactic <|> Term.binderDefault) >> ")" def structImplicitBinder := leading_parser atomic (declModifiers true >> "{") >> many1 ident >> optional inferMod >> declSig >> "}" def structInstBinder := leading_parser atomic (declModifiers true >> "[") >> many1 ident >> optional inferMod >> declSig >> "]" def structSimpleBinder := leading_parser atomic (declModifiers true >> ident) >> optional inferMod >> optDeclSig >> optional (Term.binderTactic <|> Term.binderDefault) def structFields := leading_parser many (structExplicitBinder <|> structImplicitBinder <|> structInstBinder) ``` -/ private def expandFields (structStx : Syntax) (structModifiers : Modifiers) (structDeclName : Name) : TermElabM (Array StructFieldView) := let fieldBinders := if structStx[5].isNone then #[] else structStx[5][2][0].getArgs fieldBinders.foldlM (init := #[]) fun (views : Array StructFieldView) fieldBinder => withRef fieldBinder do let mut fieldBinder := fieldBinder if fieldBinder.getKind == ``Parser.Command.structSimpleBinder then fieldBinder := Syntax.node ``Parser.Command.structExplicitBinder #[ fieldBinder[0], mkAtomFrom fieldBinder "(", mkNullNode #[ fieldBinder[1] ], fieldBinder[2], fieldBinder[3], fieldBinder[4], mkAtomFrom fieldBinder ")" ] let k := fieldBinder.getKind let binfo ← if k == ``Parser.Command.structExplicitBinder then pure BinderInfo.default else if k == ``Parser.Command.structImplicitBinder then pure BinderInfo.implicit else if k == ``Parser.Command.structInstBinder then pure BinderInfo.instImplicit else throwError "unexpected kind of structure field" let fieldModifiers ← elabModifiers fieldBinder[0] checkValidFieldModifier fieldModifiers if fieldModifiers.isPrivate && structModifiers.isPrivate then throwError "invalid 'private' field in a 'private' structure" if fieldModifiers.isProtected && structModifiers.isPrivate then throwError "invalid 'protected' field in a 'private' structure" let inferMod := !fieldBinder[3].isNone let (binders, type?) ← if binfo == BinderInfo.default then let (binders, type?) := expandOptDeclSig fieldBinder[4] let optBinderTacticDefault := fieldBinder[5] if optBinderTacticDefault.isNone then pure (binders, type?) else if optBinderTacticDefault[0].getKind != ``Parser.Term.binderTactic then pure (binders, type?) else let binderTactic := optBinderTacticDefault[0] match type? with | none => throwErrorAt binderTactic "invalid field declaration, type must be provided when auto-param (tactic) is used" | some type => let tac := binderTactic[2] let name ← Term.declareTacticSyntax tac -- The tactic should be for binders+type. -- It is safe to reset the binders to a "null" node since there is no value to be elaborated let type ← `(forall $(binders.getArgs):bracketedBinder*, $type) let type ← `(autoParam $type $(mkIdentFrom tac name)) pure (mkNullNode, some type) else let (binders, type) := expandDeclSig fieldBinder[4] pure (binders, some type) let value? ← if binfo != BinderInfo.default then pure none else let optBinderTacticDefault := fieldBinder[5] -- trace[Elab.struct] ">>> {optBinderTacticDefault}" if optBinderTacticDefault.isNone then pure none else if optBinderTacticDefault[0].getKind == ``Parser.Term.binderTactic then pure none else -- binderDefault := leading_parser " := " >> termParser pure (some optBinderTacticDefault[0][1]) let idents := fieldBinder[2].getArgs idents.foldlM (init := views) fun (views : Array StructFieldView) ident => withRef ident do let name := ident.getId.eraseMacroScopes unless name.isAtomic do throwErrorAt ident "invalid field name '{name.eraseMacroScopes}', field names must be atomic" let declName := structDeclName ++ name let declName ← applyVisibility fieldModifiers.visibility declName addDocString' declName fieldModifiers.docString? return views.push { ref := ident modifiers := fieldModifiers binderInfo := binfo inferMod declName name binders type? value? } private def validStructType (type : Expr) : Bool := match type with | Expr.sort .. => true | _ => false private def findFieldInfo? (infos : Array StructFieldInfo) (fieldName : Name) : Option StructFieldInfo := infos.find? fun info => info.name == fieldName private def containsFieldName (infos : Array StructFieldInfo) (fieldName : Name) : Bool := (findFieldInfo? infos fieldName).isSome register_builtin_option structureDiamondWarning : Bool := { defValue := false descr := "enable/disable warning messages for structure diamonds" } /-- Return `some fieldName` if field `fieldName` of the parent structure `parentStructName` is already in `infos` -/ private def findExistingField? (infos : Array StructFieldInfo) (parentStructName : Name) : CoreM (Option Name) := do let fieldNames := getStructureFieldsFlattened (← getEnv) parentStructName for fieldName in fieldNames do if containsFieldName infos fieldName then return some fieldName return none private partial def processSubfields (structDeclName : Name) (parentFVar : Expr) (parentStructName : Name) (subfieldNames : Array Name) (infos : Array StructFieldInfo) (k : Array StructFieldInfo → TermElabM α) : TermElabM α := go 0 infos where go (i : Nat) (infos : Array StructFieldInfo) := do if h : i < subfieldNames.size then let subfieldName := subfieldNames.get ⟨i, h⟩ if containsFieldName infos subfieldName then throwError "field '{subfieldName}' from '{parentStructName}' has already been declared" let val ← mkProjection parentFVar subfieldName let type ← inferType val withLetDecl subfieldName type val fun subfieldFVar => /- The following `declName` is only used for creating the `_default` auxiliary declaration name when its default value is overwritten in the structure. If the default value is not overwritten, then its value is irrelevant. -/ let declName := structDeclName ++ subfieldName let infos := infos.push { name := subfieldName, declName, fvar := subfieldFVar, kind := StructFieldKind.fromParent } go (i+1) infos else k infos /-- Return `some (structName, fieldName, struct)` if `e` is a projection function application -/ private def isProjFnApp? (e : Expr) : MetaM (Option (Name × Name × Expr)) := do match e.getAppFn with | Expr.const declName .. => match (← getProjectionFnInfo? declName) with | some { ctorName := ctorName, numParams := n, .. } => if declName.isStr && e.getAppNumArgs == n+1 then let ConstantInfo.ctorInfo ctorVal ← getConstInfo ctorName | unreachable! return some (ctorVal.induct, declName.getString!, e.appArg!) else return none | _ => return none | _ => return none /-- Return `some fieldName`, if `e` is an expression that represents an access to field `fieldName` of the structure `s`. The name of the structure type must be `structName`. -/ private partial def isProjectionOf? (e : Expr) (structName : Name) (s : Expr) : MetaM (Option Name) := do if let some (baseStructName, fieldName, e) ← isProjFnApp? e then if let some path ← visit e #[] then if let some path' := getPathToBaseStructure? (← getEnv) baseStructName structName then if path'.toArray == path.reverse then return some fieldName return none where visit (e : Expr) (path : Array Name) : MetaM (Option (Array Name)) := do if e == s then return some path -- Check whether `e` is a `toParent` field if let some (_, _, e') ← isProjFnApp? e then visit e' (path.push e.getAppFn.constName!) else return none private def getFieldType (infos : Array StructFieldInfo) (parentStructName : Name) (parentType : Expr) (fieldName : Name) : MetaM Expr := do withLocalDeclD (← mkFreshId) parentType fun parent => do let proj ← mkProjection parent fieldName let projType ← inferType proj /- Eliminate occurrences of `parent`. This may happen when structure contains dependent fields -/ let visit (e : Expr) : MetaM TransformStep := do if let some fieldName ← isProjectionOf? e parentStructName parent then -- trace[Meta.debug] "field '{fieldName}' of {e}" match (← findFieldInfo? infos fieldName) with | some existingFieldInfo => return TransformStep.done existingFieldInfo.fvar | none => throwError "unexpected field access {indentExpr e}" else return TransformStep.visit e Meta.transform projType (pre := visit) private def toVisibility (fieldInfo : StructureFieldInfo) : CoreM Visibility := do if isProtected (← getEnv) fieldInfo.projFn then return Visibility.protected else if isPrivateName fieldInfo.projFn then return Visibility.private else return Visibility.regular private partial def copyNewFieldsFrom (structDeclName : Name) (infos : Array StructFieldInfo) (parentType : Expr) (k : Array StructFieldInfo → TermElabM α) : TermElabM α := do copyFields infos parentType k where copyFields (infos : Array StructFieldInfo) (parentType : Expr) (k : Array StructFieldInfo → TermElabM α) : TermElabM α := do let parentStructName ← getStructureName parentType let fieldNames := getStructureFields (← getEnv) parentStructName let rec copy (i : Nat) (infos : Array StructFieldInfo) : TermElabM α := do if h : i < fieldNames.size then let fieldName := fieldNames.get ⟨i, h⟩ let fieldType ← getFieldType infos parentStructName parentType fieldName match (← findFieldInfo? infos fieldName) with | some existingFieldInfo => let existingFieldType ← inferType existingFieldInfo.fvar unless (← isDefEq fieldType existingFieldType) do throwError "parent field type mismatch, field '{fieldName}' from parent '{parentStructName}' {← mkHasTypeButIsExpectedMsg fieldType existingFieldType}" -- TODO: if new field has a default value, it should probably override the default at `infos` (if it has one) copy (i+1) infos | none => let some fieldInfo ← getFieldInfo? (← getEnv) parentStructName fieldName | unreachable! let addNewField : TermElabM α := do /- TODO: we are ignoring the following information from the `fieldName` declaraion at `parentStructName`. - Default value. -/ withLocalDecl fieldName fieldInfo.binderInfo fieldType fun fieldFVar => do -- trace[Meta.debug] "copying field {fieldName} : {← inferType fieldFVar}" let fieldDeclName := structDeclName ++ fieldName let fieldDeclName ← applyVisibility (← toVisibility fieldInfo) fieldDeclName let infos := infos.push { name := fieldName, declName := fieldDeclName, fvar := fieldFVar, value? := none, kind := StructFieldKind.newField, inferMod := fieldInfo.inferMod } copy (i+1) infos if fieldInfo.subobject?.isSome then let fieldParentStructName ← getStructureName fieldType if (← findExistingField? infos fieldParentStructName).isSome then copyFields infos fieldType (fun infos => copy (i+1) infos) else addNewField else addNewField else k infos copy 0 infos private def mkToParentName (parentStructName : Name) : Name := Name.mkSimple $ "to" ++ parentStructName.eraseMacroScopes.getString! -- erase macro scopes? private partial def withParents (view : StructView) (k : Array StructFieldInfo → Array Expr → TermElabM α) : TermElabM α := do go 0 #[] #[] where go (i : Nat) (infos : Array StructFieldInfo) (copiedParents : Array Expr) : TermElabM α := do if h : i < view.parents.size then let parentStx := view.parents.get ⟨i, h⟩ withRef parentStx do let parentType ← Term.elabType parentStx let parentStructName ← getStructureName parentType if let some existingFieldName ← findExistingField? infos parentStructName then if structureDiamondWarning.get (← getOptions) then logWarning s!"field '{existingFieldName}' from '{parentStructName}' has already been declared" copyNewFieldsFrom view.declName infos parentType fun infos => go (i+1) infos (copiedParents.push parentType) -- TODO: if `class`, then we need to create a let-decl that stores the local instance for the `parentStructure` else let toParentName := mkToParentName parentStructName if containsFieldName infos toParentName then throwErrorAt parentStx "field '{toParentName}' has already been declared" let env ← getEnv let binfo := if view.isClass && isClass env parentStructName then BinderInfo.instImplicit else BinderInfo.default withLocalDecl toParentName binfo parentType fun parentFVar => let infos := infos.push { name := toParentName, declName := view.declName ++ toParentName, fvar := parentFVar, kind := StructFieldKind.subobject } let subfieldNames := getStructureFieldsFlattened env parentStructName processSubfields view.declName parentFVar parentStructName subfieldNames infos fun infos => go (i+1) infos copiedParents else k infos copiedParents private def elabFieldTypeValue (view : StructFieldView) : TermElabM (Option Expr × Option Expr) := do Term.withAutoBoundImplicit <| Term.elabBinders view.binders.getArgs fun params => do match view.type? with | none => match view.value? with | none => return (none, none) | some valStx => Term.synthesizeSyntheticMVarsNoPostponing let params ← Term.addAutoBoundImplicits params let value ← Term.elabTerm valStx none let value ← mkLambdaFVars params value return (none, value) | some typeStx => let type ← Term.elabType typeStx Term.synthesizeSyntheticMVarsNoPostponing let params ← Term.addAutoBoundImplicits params match view.value? with | none => let type ← mkForallFVars params type return (type, none) | some valStx => let value ← Term.elabTermEnsuringType valStx type Term.synthesizeSyntheticMVarsNoPostponing let type ← mkForallFVars params type let value ← mkLambdaFVars params value return (type, value) private partial def withFields (views : Array StructFieldView) (i : Nat) (infos : Array StructFieldInfo) (k : Array StructFieldInfo → TermElabM α) : TermElabM α := do if h : i < views.size then let view := views.get ⟨i, h⟩ withRef view.ref $ match findFieldInfo? infos view.name with | none => do let (type?, value?) ← elabFieldTypeValue view match type?, value? with | none, none => throwError "invalid field, type expected" | some type, _ => withLocalDecl view.name view.binderInfo type fun fieldFVar => let infos := infos.push { name := view.name, declName := view.declName, fvar := fieldFVar, value? := value?, kind := StructFieldKind.newField, inferMod := view.inferMod } withFields views (i+1) infos k | none, some value => let type ← inferType value withLocalDecl view.name view.binderInfo type fun fieldFVar => let infos := infos.push { name := view.name, declName := view.declName, fvar := fieldFVar, value? := value, kind := StructFieldKind.newField, inferMod := view.inferMod } withFields views (i+1) infos k | some info => match info.kind with | StructFieldKind.newField => throwError "field '{view.name}' has already been declared" | StructFieldKind.fromParent => match view.value? with | none => throwError "field '{view.name}' has been declared in parent structure" | some valStx => do if let some type := view.type? then throwErrorAt type "omit field '{view.name}' type to set default value" else let mut valStx := valStx if view.binders.getArgs.size > 0 then valStx ← `(fun $(view.binders.getArgs)* => $valStx:term) let fvarType ← inferType info.fvar let value ← Term.elabTermEnsuringType valStx fvarType let infos := infos.push { info with value? := value } withFields views (i+1) infos k | StructFieldKind.subobject => unreachable! else k infos private def getResultUniverse (type : Expr) : TermElabM Level := do let type ← whnf type match type with | Expr.sort u _ => pure u | _ => throwError "unexpected structure resulting type" private def collectUsed (params : Array Expr) (fieldInfos : Array StructFieldInfo) : StateRefT CollectFVars.State MetaM Unit := do params.forM fun p => do let type ← inferType p Term.collectUsedFVars type fieldInfos.forM fun info => do let fvarType ← inferType info.fvar Term.collectUsedFVars fvarType match info.value? with | none => pure () | some value => Term.collectUsedFVars value private def removeUnused (scopeVars : Array Expr) (params : Array Expr) (fieldInfos : Array StructFieldInfo) : TermElabM (LocalContext × LocalInstances × Array Expr) := do let (_, used) ← (collectUsed params fieldInfos).run {} Term.removeUnused scopeVars used private def withUsed {α} (scopeVars : Array Expr) (params : Array Expr) (fieldInfos : Array StructFieldInfo) (k : Array Expr → TermElabM α) : TermElabM α := do let (lctx, localInsts, vars) ← removeUnused scopeVars params fieldInfos withLCtx lctx localInsts <| k vars private def levelMVarToParamFVar (fvar : Expr) : StateRefT Nat TermElabM Unit := do let type ← inferType fvar discard <| Term.levelMVarToParam' type private def levelMVarToParamFVars (fvars : Array Expr) : StateRefT Nat TermElabM Unit := fvars.forM levelMVarToParamFVar private def levelMVarToParamAux (scopeVars : Array Expr) (params : Array Expr) (fieldInfos : Array StructFieldInfo) : StateRefT Nat TermElabM (Array StructFieldInfo) := do levelMVarToParamFVars scopeVars levelMVarToParamFVars params fieldInfos.mapM fun info => do levelMVarToParamFVar info.fvar match info.value? with | none => pure info | some value => let value ← Term.levelMVarToParam' value pure { info with value? := value } private def levelMVarToParam (scopeVars : Array Expr) (params : Array Expr) (fieldInfos : Array StructFieldInfo) : TermElabM (Array StructFieldInfo) := (levelMVarToParamAux scopeVars params fieldInfos).run' 1 private partial def collectUniversesFromFields (r : Level) (rOffset : Nat) (fieldInfos : Array StructFieldInfo) : TermElabM (Array Level) := do fieldInfos.foldlM (init := #[]) fun (us : Array Level) (info : StructFieldInfo) => do let type ← inferType info.fvar let u ← getLevel type let u ← instantiateLevelMVars u accLevelAtCtor u r rOffset us private def updateResultingUniverse (fieldInfos : Array StructFieldInfo) (type : Expr) : TermElabM Expr := do let r ← getResultUniverse type let rOffset : Nat := r.getOffset let r : Level := r.getLevelOffset match r with | Level.mvar mvarId _ => let us ← collectUniversesFromFields r rOffset fieldInfos let rNew := mkResultUniverse us rOffset assignLevelMVar mvarId rNew instantiateMVars type | _ => throwError "failed to compute resulting universe level of structure, provide universe explicitly" private def collectLevelParamsInFVar (s : CollectLevelParams.State) (fvar : Expr) : TermElabM CollectLevelParams.State := do let type ← inferType fvar let type ← instantiateMVars type return collectLevelParams s type private def collectLevelParamsInFVars (fvars : Array Expr) (s : CollectLevelParams.State) : TermElabM CollectLevelParams.State := fvars.foldlM collectLevelParamsInFVar s private def collectLevelParamsInStructure (structType : Expr) (scopeVars : Array Expr) (params : Array Expr) (fieldInfos : Array StructFieldInfo) : TermElabM (Array Name) := do let s := collectLevelParams {} structType let s ← collectLevelParamsInFVars scopeVars s let s ← collectLevelParamsInFVars params s let s ← fieldInfos.foldlM (init := s) fun s info => collectLevelParamsInFVar s info.fvar return s.params private def addCtorFields (fieldInfos : Array StructFieldInfo) : Nat → Expr → TermElabM Expr | 0, type => pure type | i+1, type => do let info := fieldInfos[i] let decl ← Term.getFVarLocalDecl! info.fvar let type ← instantiateMVars type let type := type.abstract #[info.fvar] match info.kind with | StructFieldKind.fromParent => let val := decl.value addCtorFields fieldInfos i (type.instantiate1 val) | _ => addCtorFields fieldInfos i (mkForall decl.userName decl.binderInfo decl.type type) private def mkCtor (view : StructView) (levelParams : List Name) (params : Array Expr) (fieldInfos : Array StructFieldInfo) : TermElabM Constructor := withRef view.ref do let type := mkAppN (mkConst view.declName (levelParams.map mkLevelParam)) params let type ← addCtorFields fieldInfos fieldInfos.size type let type ← mkForallFVars params type let type ← instantiateMVars type let type := type.inferImplicit params.size !view.ctor.inferMod -- trace[Meta.debug] "ctor type {type}" pure { name := view.ctor.declName, type } @[extern "lean_mk_projections"] private constant mkProjections (env : Environment) (structName : Name) (projs : List ProjectionInfo) (isClass : Bool) : Except KernelException Environment private def addProjections (structName : Name) (projs : List ProjectionInfo) (isClass : Bool) : TermElabM Unit := do let env ← getEnv match mkProjections env structName projs isClass with | Except.ok env => setEnv env | Except.error ex => throwKernelException ex private def registerStructure (structName : Name) (infos : Array StructFieldInfo) : TermElabM Unit := do let fields ← infos.filterMapM fun info => do if info.kind == StructFieldKind.fromParent then return none else return some { fieldName := info.name projFn := info.declName inferMod := info.inferMod binderInfo := (← getFVarLocalDecl info.fvar).binderInfo subobject? := if info.kind == StructFieldKind.subobject then match (← getEnv).find? info.declName with | some (ConstantInfo.defnInfo val) => match val.type.getForallBody.getAppFn with | Expr.const parentName .. => some parentName | _ => panic! "ill-formed structure" | _ => panic! "ill-formed environment" else none } modifyEnv fun env => Lean.registerStructure env { structName, fields } private def mkAuxConstructions (declName : Name) : TermElabM Unit := do let env ← getEnv let hasUnit := env.contains `PUnit let hasEq := env.contains `Eq let hasHEq := env.contains `HEq mkRecOn declName if hasUnit then mkCasesOn declName if hasUnit && hasEq && hasHEq then mkNoConfusion declName private def addDefaults (lctx : LocalContext) (defaultAuxDecls : Array (Name × Expr × Expr)) : TermElabM Unit := do let localInsts ← getLocalInstances withLCtx lctx localInsts do defaultAuxDecls.forM fun (declName, type, value) => do let value ← instantiateMVars value if value.hasExprMVar then throwError "invalid default value for field, it contains metavariables{indentExpr value}" /- The identity function is used as "marker". -/ let value ← mkId value discard <| mkAuxDefinition declName type value (zeta := true) setReducibleAttribute declName private partial def mkCoercionToCopiedParent (levelParams : List Name) (params : Array Expr) (view : StructView) (parentType : Expr) : MetaM Unit := do let env ← getEnv let structName := view.declName let sourceFieldNames := getStructureFieldsFlattened env structName let structType ← mkAppN (Lean.mkConst structName (levelParams.map mkLevelParam)) params let Expr.const parentStructName us _ ← pure parentType.getAppFn | unreachable! let binfo := if view.isClass && isClass env parentStructName then BinderInfo.instImplicit else BinderInfo.default withLocalDecl `self binfo structType fun source => do let declType ← instantiateMVars (← mkForallFVars params (← mkForallFVars #[source] parentType)) let declType := declType.inferImplicit params.size true let rec copyFields (parentType : Expr) : MetaM Expr := do let Expr.const parentStructName us _ ← pure parentType.getAppFn | unreachable! let parentCtor := getStructureCtor env parentStructName let mut result := mkAppN (mkConst parentCtor.name us) parentType.getAppArgs for fieldName in getStructureFields env parentStructName do if sourceFieldNames.contains fieldName then let fieldVal ← mkProjection source fieldName result := mkApp result fieldVal else -- fieldInfo must be a field of `parentStructName` let some fieldInfo ← getFieldInfo? env parentStructName fieldName | unreachable! if fieldInfo.subobject?.isNone then throwError "failed to build coercion to parent structure" let resultType ← whnfD (← inferType result) unless resultType.isForall do throwError "failed to build coercion to parent structure, unexpect type{indentExpr resultType}" let fieldVal ← copyFields resultType.bindingDomain! result := mkApp result fieldVal return result let declVal ← instantiateMVars (← mkLambdaFVars params (← mkLambdaFVars #[source] (← copyFields parentType))) let declName := structName ++ mkToParentName (← getStructureName parentType) if env.contains declName then throwError "failed to create coercion '{declName}' to parent structure '{parentStructName}', environment already contains a declaration with the same name" addAndCompile <| Declaration.defnDecl { name := declName levelParams := levelParams type := declType value := declVal hints := ReducibilityHints.abbrev safety := if view.modifiers.isUnsafe then DefinitionSafety.unsafe else DefinitionSafety.safe } if binfo.isInstImplicit then addInstance declName AttributeKind.global (eval_prio default) else setReducibleAttribute declName private def elabStructureView (view : StructView) : TermElabM Unit := do view.fields.forM fun field => do if field.declName == view.ctor.declName then throwErrorAt field.ref "invalid field name '{field.name}', it is equal to structure constructor name" addAuxDeclarationRanges field.declName field.ref field.ref let numExplicitParams := view.params.size let type ← Term.elabType view.type unless validStructType type do throwErrorAt view.type "expected Type" withRef view.ref do withParents view fun fieldInfos copiedParents => do withFields view.fields 0 fieldInfos fun fieldInfos => do Term.synthesizeSyntheticMVarsNoPostponing let u ← getResultUniverse type let inferLevel ← shouldInferResultUniverse u withUsed view.scopeVars view.params fieldInfos fun scopeVars => do let numParams := scopeVars.size + numExplicitParams let fieldInfos ← levelMVarToParam scopeVars view.params fieldInfos let type ← withRef view.ref do if inferLevel then updateResultingUniverse fieldInfos type else checkResultingUniverse (← getResultUniverse type) pure type trace[Elab.structure] "type: {type}" let usedLevelNames ← collectLevelParamsInStructure type scopeVars view.params fieldInfos match sortDeclLevelParams view.scopeLevelNames view.allUserLevelNames usedLevelNames with | Except.error msg => withRef view.ref <| throwError msg | Except.ok levelParams => let params := scopeVars ++ view.params let ctor ← mkCtor view levelParams params fieldInfos let type ← mkForallFVars params type let type ← instantiateMVars type let indType := { name := view.declName, type := type, ctors := [ctor] : InductiveType } let decl := Declaration.inductDecl levelParams params.size [indType] view.modifiers.isUnsafe Term.ensureNoUnassignedMVars decl addDecl decl let projInfos := (fieldInfos.filter fun (info : StructFieldInfo) => !info.isFromParent).toList.map fun (info : StructFieldInfo) => { declName := info.declName, inferMod := info.inferMod : ProjectionInfo } addProjections view.declName projInfos view.isClass registerStructure view.declName fieldInfos mkAuxConstructions view.declName let instParents ← fieldInfos.filterM fun info => do let decl ← Term.getFVarLocalDecl! info.fvar pure (info.isSubobject && decl.binderInfo.isInstImplicit) let projInstances := instParents.toList.map fun info => info.declName Term.applyAttributesAt view.declName view.modifiers.attrs AttributeApplicationTime.afterTypeChecking projInstances.forM fun declName => addInstance declName AttributeKind.global (eval_prio default) copiedParents.forM fun parent => mkCoercionToCopiedParent levelParams params view parent let lctx ← getLCtx let fieldsWithDefault := fieldInfos.filter fun info => info.value?.isSome let defaultAuxDecls ← fieldsWithDefault.mapM fun info => do let type ← inferType info.fvar pure (mkDefaultFnOfProjFn info.declName, type, info.value?.get!) /- The `lctx` and `defaultAuxDecls` are used to create the auxiliary "default value" declarations The parameters `params` for these definitions must be marked as implicit, and all others as explicit. -/ let lctx := params.foldl (init := lctx) fun (lctx : LocalContext) (p : Expr) => lctx.setBinderInfo p.fvarId! BinderInfo.implicit let lctx := fieldInfos.foldl (init := lctx) fun (lctx : LocalContext) (info : StructFieldInfo) => if info.isFromParent then lctx -- `fromParent` fields are elaborated as let-decls, and are zeta-expanded when creating "default value" auxiliary functions else lctx.setBinderInfo info.fvar.fvarId! BinderInfo.default addDefaults lctx defaultAuxDecls /- leading_parser (structureTk <|> classTk) >> declId >> many Term.bracketedBinder >> optional «extends» >> Term.optType >> " := " >> optional structCtor >> structFields >> optDeriving where def «extends» := leading_parser " extends " >> sepBy1 termParser ", " def typeSpec := leading_parser " : " >> termParser def optType : Parser := optional typeSpec def structFields := leading_parser many (structExplicitBinder <|> structImplicitBinder <|> structInstBinder) def structCtor := leading_parser try (declModifiers >> ident >> optional inferMod >> " :: ") -/ def elabStructure (modifiers : Modifiers) (stx : Syntax) : CommandElabM Unit := do checkValidInductiveModifier modifiers let isClass := stx[0].getKind == ``Parser.Command.classTk let modifiers := if isClass then modifiers.addAttribute { name := `class } else modifiers let declId := stx[1] let params := stx[2].getArgs let exts := stx[3] let parents := if exts.isNone then #[] else exts[0][1].getSepArgs let optType := stx[4] let derivingClassViews ← getOptDerivingClasses stx[6] let type ← if optType.isNone then `(Sort _) else pure optType[0][1] let declName ← runTermElabM none fun scopeVars => do let scopeLevelNames ← Term.getLevelNames let ⟨name, declName, allUserLevelNames⟩ ← Elab.expandDeclId (← getCurrNamespace) scopeLevelNames declId modifiers addDeclarationRanges declName stx Term.withDeclName declName do let ctor ← expandCtor stx modifiers declName let fields ← expandFields stx modifiers declName Term.withLevelNames allUserLevelNames <| Term.withAutoBoundImplicit <| Term.elabBinders params fun params => do Term.synthesizeSyntheticMVarsNoPostponing let params ← Term.addAutoBoundImplicits params let allUserLevelNames ← Term.getLevelNames elabStructureView { ref := stx modifiers scopeLevelNames allUserLevelNames declName isClass scopeVars params parents type ctor fields } unless isClass do mkSizeOfInstances declName mkInjectiveTheorems declName return declName derivingClassViews.forM fun view => view.applyHandlers #[declName] builtin_initialize registerTraceClass `Elab.structure end Lean.Elab.Command