package ppxlib

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Build Ast helpers with the location argument factorized.

Parameters

module Loc : Loc

Signature

module Located : sig ... end
include sig ... end
val loc : Location.t
val ptyp_var : string -> Astlib.Ast_412.Parsetree.core_type
val pdir_int : string -> char option -> Astlib.Ast_412.Parsetree.directive_argument
val include_infos : 'a -> 'a Astlib.Ast_412.Parsetree.include_infos
val location : start:Stdlib.Lexing.position -> end_:Stdlib.Lexing.position -> ghost:bool -> Astlib.Location.t
val ppat_unpack : string option Astlib.Location.loc -> Astlib.Ast_412.Parsetree.pattern
val position : fname:string -> lnum:int -> bol:int -> cnum:int -> Stdlib.Lexing.position
val value_description : name:string Astlib.Location.loc -> type_:Astlib.Ast_412.Parsetree.core_type -> prim:string list -> Astlib.Ast_412.Parsetree.value_description
val estring : string -> Astlib.Ast_412.Parsetree.expression
val enativeint : nativeint -> Astlib.Ast_412.Parsetree.expression
val pstring : string -> Astlib.Ast_412.Parsetree.pattern
val pfloat : string -> Astlib.Ast_412.Parsetree.pattern
val pint32 : int32 -> Astlib.Ast_412.Parsetree.pattern
val pint64 : int64 -> Astlib.Ast_412.Parsetree.pattern
val pnativeint : nativeint -> Astlib.Ast_412.Parsetree.pattern

evar id produces a Pexp_ident _ expression, it parses its input so you can pass any dot-separated identifier, for instance: evar ~loc "Foo.bar".

pstr_value_list ~loc rf vbs = pstr_value ~loc rf vbs if vbs <> [], [] otherwise.

  • deprecated [since 2016-10] use Nonrecursive on the P(str|sig)_type instead
val unapplied_type_constr_conv : Longident.t Loc.t -> f:(string -> string) -> Astlib.Ast_412.Parsetree.expression

unapplied_type_constr_conv is the standard way to map identifiers to conversion fonctions, for preprocessor that creates values that follow the structure of types. More precisely, path_conv path (sprintf "sexp_of_%s") is:

  • sexp_of_t if path is "t"
  • A.B.sexp_of_foo if path is "A.B.foo"
  • A.B.sexp_of_f__foo (module A1) (module A2) if path is "A.B.F(A1)(A2).foo" type_constr_conv also applies it to a list of expression, which both prevents the compiler from allocating useless closures, and almost always what is needed, since type constructors are always applied.
val type_constr_conv : Longident.t Loc.t -> f:(string -> string) -> Astlib.Ast_412.Parsetree.expression list -> Astlib.Ast_412.Parsetree.expression

Tries to simplify fun v1 v2 .. -> f v1 v2 .. into f. Only works when f is a path, not an arbitrary expression as that would change the meaning of the code. This can be used either for cleaning up the generated code, or to reduce allocation if f is a local variable (the compiler won't optimize the allocation of the closure).

Eta-reduction can change the types/behavior in some corner cases that are unlikely to show up in generated code:

  • if f has optional arguments, eta-expanding f can drop them
  • because labels commute, it can change the type of an expression: $ let f ~x y = x + y let f2 = fun x -> add x;; val f : x:int -> int -> int = <fun> val f2 : int -> x:int -> int = <fun> In fact, if f does side effects before receiving all its arguments, and if the eta-expansion is partially applied, eta-reducing could change behavior.

eta_reduce_if_possible_and_nonrec is meant for the case where the resulting expression is going to be bound in a potentially recursive let-binding, where we have to keep the eta-expansion when rec_flag is Recursive to avoid a compile error.

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