ocaml/camlp4/examples/macros.ml

68 lines
2.0 KiB
OCaml

open Camlp4.PreCast;;
let foldr_funs = ref [];;
let foldl_funs = ref [];;
AstFilters.register_str_item_filter begin
Ast.map_expr begin function
| <:expr@loc< def_foldr $lid:name$ $e$ >> ->
foldr_funs := (name, e) :: !foldr_funs; <:expr@loc<()>>
| <:expr@loc< def_foldl $lid:name$ $e$ >> ->
foldl_funs := (name, e) :: !foldl_funs; <:expr@loc<()>>
| e -> e
end
end#str_item;;
AstFilters.register_str_item_filter begin
Ast.map_expr begin function
| <:expr@loc< $lid:name$($tup:e$) >> when List.mem_assoc name !foldl_funs ->
let op = List.assoc name !foldl_funs in
let rec foldl =
function
| [] -> assert false
| [x] -> x
| x :: xs -> <:expr@loc< $op$ $foldl xs$ $x$ >>
in foldl (List.rev (Ast.list_of_expr e []))
| <:expr@loc< $lid:name$($tup:e$) >> when List.mem_assoc name !foldr_funs ->
let op = List.assoc name !foldr_funs in
let rec foldr =
function
| [] -> assert false
| [x] -> x
| x :: xs -> <:expr@loc< $op$ $x$ $foldr xs$ >>
in foldr (Ast.list_of_expr e [])
| e -> e
end
end#str_item;;
(*
AstFilters.register_str_item_filter begin
Ast.map_expr begin function
| <:expr@loc< foldl($lid:op$, $e$) >> ->
let rec foldl =
function
| [] -> assert false
| [x] -> x
| x :: xs -> <:expr@loc< $lid:op$ $foldl xs$ $x$ >>
in foldl (List.rev (Ast.list_of_expr e []))
| <:expr@loc< foldr($lid:op$, $e$) >> ->
let rec foldr =
function
| [] -> assert false
| [x] -> x
| x :: xs -> <:expr@loc< $lid:op$ $x$ $foldr xs$ >>
in foldr (Ast.list_of_expr e [])
| e -> e
end
end#str_item;;
AstFilters.register_str_item_filter begin
Ast.map_expr begin function
| <:expr@loc< \!+ ($tup:e$) >> ->
begin match Ast.list_of_expr e [] with
| [] | [_] -> assert false
| x :: xs -> List.fold_left (fun acc x -> <:expr@loc< $acc$ + $x$ >>) x xs
end
| <:expr< \!+ $e$ >> -> e
| e -> e
end
end#str_item;;
*)