Promotion (stanc.Frontend.Promotion)

module UnsizedType = Middle.UnsizedType

type t =

| NoPromotion
| IntToReal
| ToVar
| ToComplexVar
| IntToComplex
| RealToComplex
| TuplePromotion of t list

Type to represent promotions in the typechecker. This can be used to return information about how to promote expressions for use in Ast.Promotion

val t_of_sexp : Sexplib0.Sexp.t -> t

val sexp_of_t : t -> Sexplib0.Sexp.t

val scalarize : UnsizedType.t -> UnsizedType.t

Our promotion nodes only store the scalar type to promote, e.g to promote a tuple(array int) to a tuple(array real), we store tuple(real), not tuple(array real)

val promote_unsized_type : 
  UnsizedType.t ->
  UnsizedType.autodifftype ->
  t ->
  UnsizedType.t * UnsizedType.autodifftype

Get the UnsizedType.t which is the result of promoting a given type. See promote for the version which promotes expressions directly.

val promote_inner : 
  Ast.typed_expression ->
  t ->
  (Ast.typed_expr_meta, Ast.fun_kind) Ast.expr_with

val promote : 
  (Ast.typed_expr_meta, Ast.fun_kind) Ast.expr_with ->
  t ->
  (Ast.typed_expr_meta, Ast.fun_kind) Ast.expr_with

val promote_list : 
  (Ast.typed_expr_meta, Ast.fun_kind) Ast.expr_with list ->
  t list ->
  (Ast.typed_expr_meta, Ast.fun_kind) Ast.expr_with list

val get_type_promotion_exn : 
  (UnsizedType.autodifftype * UnsizedType.t) ->
  (UnsizedType.autodifftype * UnsizedType.t) ->
  t

Get the promotion needed to make the second type into the first. Types NEED to have previously been checked to be promotable or else a fatal error will be thrown.

val promotion_cost : t -> Core.Int.t

Calculate the "cost"/number of promotions performed. Used to disambiguate function signatures