@[notation_class] attribute for @[simps]

This declares the @[notation_class] attribute, which is used to give smarter default projections for @[simps].

We put this in a separate file so that we can already tag some declarations with this attribute in the file where we declare @[simps]. For further documentation, see Tactic.Simps.Basic.

def notation_class : Lean.ParserDescr

The @[notation_class] attribute specifies that this is a notation class, and this notation should be used instead of projections by @[simps].

• This is only important if the projection is written differently using notation, e.g. + uses HAdd.hAdd, not Add.add and 0 uses OfNat.ofNat not Zero.zero. We also add it to non-heterogenous notation classes, like Neg, but it doesn't do much for any class that extends Neg.
• @[notation_class * <projName> Simps.findCoercionArgs] is used to configure the SetLike and DFunLike coercions.
• The first name argument is the projection name we use as the key to search for this class (default: name of first projection of the class).
• The second argument is the name of a declaration that has type findArgType which is defined to be Name → Name → Array Expr → MetaM (Array (Option Expr)). This declaration specifies how to generate the arguments of the notation class from the arguments of classes that use the projection.

def Simps.findArgType : Type

The type of methods to find arguments for automatic projections for simps. We partly define this as a separate definition so that the unused arguments linter doesn't complain.

def Simps.defaultfindArgs : findArgType

Find arguments for a notation class

def Simps.copyFirst : findArgType

Find arguments by duplicating the first argument. Used for pow.

def Simps.copySecond : findArgType

Find arguments by duplicating the first argument. Used for smul.

def Simps.nsmulArgs : findArgType

Find arguments by prepending ℕ and duplicating the first argument. Used for nsmul.

def Simps.zsmulArgs : findArgType

Find arguments by prepending ℤ and duplicating the first argument. Used for zsmul.

def Simps.findZeroArgs : findArgType

Find arguments for the Zero class.

def Simps.findOneArgs : findArgType

Find arguments for the One class.

def Simps.findCoercionArgs : findArgType

Find arguments of a coercion class (DFunLike or SetLike)

structure Simps.AutomaticProjectionData : Type

Data needed to generate automatic projections. This data is associated to a name of a projection in a structure that must be used to trigger the search.

• className : Lean.Name

  className is the name of the class we are looking for.

• isNotation : Bool

  isNotation is a boolean that specifies whether this is notation (false for the coercions DFunLike and SetLike). If this is set to true, we add the current class as hypothesis during type-class synthesis.

• findArgs : Lean.Name

  The method to find the arguments of the class.

instance Simps.instInhabitedAutomaticProjectionData : Inhabited AutomaticProjectionData

opaque Simps.notationClassAttr : Lean.NameMapExtension AutomaticProjectionData

@[notation_class] attribute. Note: this is not a NameMapAttribute because we key on the argument of the attribute, not the declaration name.