structure Lean.Meta.ElimAltInfo : Type

• name : Name
• declName? : Option Name

  A declaration corresponding to the inductive constructor. (For custom recursors, the alternatives correspond to parameter names in the recursor, so we may not have a declaration to point to.) This is used for go-to-definition on the alternative name.

• numFields : Nat
• provesMotive : Bool

  If provesMotive := true, then this alternative has motive as its conclusion. Only for those alternatives the induction tactic should introduce reverted hypotheses.

instance Lean.Meta.instReprElimAltInfo : Repr ElimAltInfo

instance Lean.Meta.instInhabitedElimAltInfo : Inhabited ElimAltInfo

structure Lean.Meta.ElimInfo : Type

Information about an eliminator as used by induction or cases.

Created from an expression by getElimInfo. This typically contains level metavariables that are instantiated as we go (e.g. in addImplicitTargets), so this is single use.

• elimExpr : Expr
• elimType : Expr
• motivePos : Nat
• targetsPos : Array Nat
• altsInfo : Array ElimAltInfo
• numComplexMotiveArgs : Nat

  Extra arguments to the motive, after the targets, that are instantiated with non-atomic expressions in the goal

instance Lean.Meta.instReprElimInfo : Repr ElimInfo

instance Lean.Meta.instInhabitedElimInfo : Inhabited ElimInfo

def Lean.Meta.altArity (motive : Expr) (n : Nat) : Expr → Nat × Bool

Given the type t of an alternative, determines the number of parameters (.forall and .let)-bound, and whether the conclusion is a motive-application.

def Lean.Meta.getElimExprInfo (elimExpr : Expr) (baseDeclName? : Option Name := none) : MetaM ElimInfo

def Lean.Meta.getElimInfo (elimName : Name) (baseDeclName? : Option Name := none) : MetaM ElimInfo

def Lean.Meta.addImplicitTargets (elimInfo : ElimInfo) (targets : Array Expr) : MetaM (Array Expr)

Eliminators/recursors may have implicit targets. For builtin recursors, all indices are implicit targets. Given an eliminator and the sequence of explicit targets, this methods returns a new sequence containing implicit and explicit targets.

partial def Lean.Meta.addImplicitTargets.collect (elimInfo : ElimInfo) (targets : Array Expr) (type : Expr) (argIdx targetIdx : Nat) (implicits : Array MVarId) (targets' : Array Expr) : MetaM (Array MVarId × Array Expr)

structure Lean.Meta.CustomEliminator : Type

• induction : Bool
• typeNames : Array Name
• elimName : Name

instance Lean.Meta.instInhabitedCustomEliminator : Inhabited CustomEliminator

instance Lean.Meta.instReprCustomEliminator : Repr CustomEliminator

structure Lean.Meta.CustomEliminators : Type

• map : SMap (Bool × Array Name) Name

instance Lean.Meta.instInhabitedCustomEliminators : Inhabited CustomEliminators

instance Lean.Meta.instReprCustomEliminators : Repr CustomEliminators

def Lean.Meta.addCustomEliminatorEntry (es : CustomEliminators) (e : CustomEliminator) : CustomEliminators

opaque Lean.Meta.customEliminatorExt : SimpleScopedEnvExtension CustomEliminator CustomEliminators

def Lean.Meta.mkCustomEliminator (elimName : Name) (induction : Bool) : MetaM CustomEliminator

def Lean.Meta.addCustomEliminator (declName : Name) (attrKind : AttributeKind) (induction : Bool) : MetaM Unit

def Lean.Meta.getCustomEliminators : CoreM CustomEliminators

Gets all the eliminators defined using the @[induction_eliminator] and @[cases_eliminator] attributes.

def Lean.Meta.getCustomEliminator? (targets : Array Expr) (induction : Bool) : MetaM (Option Name)

Gets an eliminator appropriate for the provided array of targets. If induction is true then returns a matching eliminator defined using the @[induction_eliminator] attribute and otherwise returns one defined using the @[cases_eliminator] attribute.

The @[induction_eliminator] attribute is for the induction tactic and the @[cases_eliminator] attribute is for the cases tactic.