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|
open Ppxlib
let extend_list_by name = object
inherit Ast_traverse.map as super
method! expression e =
match e.pexp_desc with
| Pexp_construct ({txt = Lident "[]"; _}, None) -> Ast_builder.Default.elist ~loc:e.pexp_loc [Ast_builder.Default.estring ~loc:e.pexp_loc name]
| _ -> super#expression e
end
[%%expect{|
val extend_list_by : string -> Ast_traverse.map = <fun>
|}]
let () =
let name = "a: instr pos=Before" in
let transform = extend_list_by name in
Driver.(register_transformation ~instrument:(Instrument.make ~position:Before transform#structure) name)
let () =
let name = "b: instr pos=After" in
let transform = extend_list_by name in
Driver.(register_transformation ~instrument:(Instrument.make ~position:After transform#structure) name)
let () =
let name = "c: impl" in
let transform = extend_list_by name in
Driver.register_transformation ~impl:transform#structure name
(* The order of the list should only depend on how the rewriters got registered,
not on the alphabetic order of the names they got registered with. *)
let x = []
[%%expect{|
val x : string list =
["a: instr pos=Before"; "c: impl"; "b: instr pos=After"]
|}]
|
