ocaml/camlp4/meta/pa_macro.ml

338 lines
10 KiB
OCaml

(* camlp4r *)
(* $Id$ *)
(*
Added statements:
At toplevel (structure item):
DEFINE <uident>
DEFINE <uident> = <expression>
DEFINE <uident> (<parameters>) = <expression>
IFDEF <uident> THEN <structure_items> (END | ENDIF)
IFDEF <uident> THEN <structure_items> ELSE <structure_items> (END | ENDIF)
IFNDEF <uident> THEN <structure_items> (END | ENDIF)
IFNDEF <uident> THEN <structure_items> ELSE <structure_items> (END | ENDIF)
INCLUDE <string>
In expressions:
IFDEF <uident> THEN <expression> ELSE <expression> (END | ENDIF)
IFNDEF <uident> THEN <expression> ELSE <expression> (END | ENDIF)
__FILE__
__LOCATION__
In patterns:
IFDEF <uident> THEN <pattern> ELSE <pattern> (END | ENDIF)
IFNDEF <uident> THEN <pattern> ELSE <pattern> (END | ENDIF)
As Camlp4 options:
-D<uident> define <uident>
-U<uident> undefine it
-I<dir> add <dir> to the search path for INCLUDE'd files
After having used a DEFINE <uident> followed by "= <expression>", you
can use it in expressions *and* in patterns. If the expression defining
the macro cannot be used as a pattern, there is an error message if
it is used in a pattern.
The toplevel statement INCLUDE <string> can be used to include a
file containing macro definitions; note that files included in such
a way can not have any non-macro toplevel items. The included files
are looked up in directories passed in via the -I option, falling
back to the current directory.
The expression __FILE__ returns the current compiled file name.
The expression __LOCATION__ returns the current location of itself.
*)
#load "pa_extend.cmo";
#load "q_MLast.cmo";
open Pcaml;
type item_or_def 'a =
[ SdStr of 'a
| SdDef of string and option (list string * MLast.expr)
| SdUnd of string
| SdITE of string and list (item_or_def 'a) and list (item_or_def 'a)
| SdInc of string ]
;
value rec list_remove x =
fun
[ [(y, _) :: l] when y = x -> l
| [d :: l] -> [d :: list_remove x l]
| [] -> [] ]
;
value defined = ref [];
value is_defined i = List.mem_assoc i defined.val;
value _loc =
let nowhere =
{ (Lexing.dummy_pos) with Lexing.pos_lnum = 1; Lexing.pos_cnum = 0 } in
(nowhere, nowhere);
value subst mloc env =
let rec loop =
fun
[ <:expr< let $opt:rf$ $list:pel$ in $e$ >> ->
let pel = List.map (fun (p, e) -> (p, loop e)) pel in
<:expr< let $opt:rf$ $list:pel$ in $loop e$ >>
| <:expr< if $e1$ then $e2$ else $e3$ >> ->
<:expr< if $loop e1$ then $loop e2$ else $loop e3$ >>
| <:expr< $e1$ $e2$ >> -> <:expr< $loop e1$ $loop e2$ >>
| <:expr< fun $args$ -> $e$ >> -> <:expr< fun $args$ -> $loop e$ >>
| <:expr< fun [ $list: peoel$ ] >> -> <:expr< fun [ $list: (List.map loop_peoel peoel)$ ] >>
| <:expr< $lid:x$ >> | <:expr< $uid:x$ >> as e ->
try <:expr< $anti:List.assoc x env$ >> with
[ Not_found -> e ]
| <:expr< ($list:x$) >> -> <:expr< ($list:List.map loop x$) >>
| <:expr< do {$list:x$} >> -> <:expr< do {$list:List.map loop x$} >>
| <:expr< { $list:pel$ } >> ->
let pel = List.map (fun (p, e) -> (p, loop e)) pel in
<:expr< { $list:pel$ } >>
| <:expr< match $e$ with [ $list:peoel$ ] >> ->
<:expr< match $loop e$ with [ $list: (List.map loop_peoel peoel)$ ] >>
| <:expr< try $e$ with [ $list:pel$ ] >> ->
let loop' = fun
[ (p, Some e1, e2) -> (p, Some (loop e1), loop e2)
| (p, None, e2) -> (p, None, loop e2) ] in
<:expr< try $loop e$ with [ $list: (List.map loop' pel)$ ] >>
| e -> e ]
and loop_peoel =
fun
[ (p, Some e1, e2) -> (p, Some (loop e1), loop e2)
| (p, None, e2) -> (p, None, loop e2) ]
in loop
;
value substp mloc env =
loop where rec loop =
fun
[ <:expr< $e1$ $e2$ >> -> <:patt< $loop e1$ $loop e2$ >>
| <:expr< $lid:x$ >> ->
try <:patt< $anti:List.assoc x env$ >> with
[ Not_found -> <:patt< $lid:x$ >> ]
| <:expr< $uid:x$ >> ->
try <:patt< $anti:List.assoc x env$ >> with
[ Not_found -> <:patt< $uid:x$ >> ]
| <:expr< $int:x$ >> -> <:patt< $int:x$ >>
| <:expr< $str:s$ >> -> <:patt< $str:s$ >>
| <:expr< ($list:x$) >> -> <:patt< ($list:List.map loop x$) >>
| <:expr< { $list:pel$ } >> ->
let ppl = List.map (fun (p, e) -> (p, loop e)) pel in
<:patt< { $list:ppl$ } >>
| x ->
Stdpp.raise_with_loc mloc
(Failure
"this macro cannot be used in a pattern (see its definition)") ]
;
value incorrect_number loc l1 l2 =
Stdpp.raise_with_loc loc
(Failure
(Printf.sprintf "expected %d parameters; found %d"
(List.length l2) (List.length l1)))
;
value define eo x =
do {
match eo with
[ Some ([], e) ->
EXTEND
expr: LEVEL "simple"
[ [ UIDENT $x$ -> Pcaml.expr_reloc (fun _ -> _loc) (fst _loc) e ] ]
;
patt: LEVEL "simple"
[ [ UIDENT $x$ ->
let p = substp _loc [] e in
Pcaml.patt_reloc (fun _ -> _loc) (fst _loc) p ] ]
;
END
| Some (sl, e) ->
EXTEND
expr: LEVEL "apply"
[ [ UIDENT $x$; param = SELF ->
let el =
match param with
[ <:expr< ($list:el$) >> -> el
| e -> [e] ]
in
if List.length el = List.length sl then
let env = List.combine sl el in
let e = subst _loc env e in
Pcaml.expr_reloc (fun _ -> _loc) (fst _loc) e
else
incorrect_number _loc el sl ] ]
;
patt: LEVEL "simple"
[ [ UIDENT $x$; param = SELF ->
let pl =
match param with
[ <:patt< ($list:pl$) >> -> pl
| p -> [p] ]
in
if List.length pl = List.length sl then
let env = List.combine sl pl in
let p = substp _loc env e in
Pcaml.patt_reloc (fun _ -> _loc) (fst _loc) p
else
incorrect_number _loc pl sl ] ]
;
END
| None -> () ];
defined.val := [(x, eo) :: defined.val];
}
;
value undef x =
try
do {
let eo = List.assoc x defined.val in
match eo with
[ Some ([], _) ->
do {
DELETE_RULE expr: UIDENT $x$ END;
DELETE_RULE patt: UIDENT $x$ END;
}
| Some (_, _) ->
do {
DELETE_RULE expr: UIDENT $x$; SELF END;
DELETE_RULE patt: UIDENT $x$; SELF END;
}
| None -> () ];
defined.val := list_remove x defined.val;
}
with
[ Not_found -> () ]
;
(* This is a list of directories to search for INCLUDE statements. *)
value include_dirs = ref []
;
(* Add something to the above, make sure it ends with a slash. *)
value add_include_dir str =
if str <> "" then
let str =
if String.get str ((String.length str)-1) = '/'
then str else str ^ "/"
in include_dirs.val := include_dirs.val @ [str]
else ()
;
value smlist = Grammar.Entry.create Pcaml.gram "smlist"
;
value parse_include_file =
let dir_ok file dir = Sys.file_exists (dir ^ file) in
fun file ->
let file =
try (List.find (dir_ok file) (include_dirs.val @ ["./"])) ^ file
with [ Not_found -> file ]
in
let st = Stream.of_channel (open_in file) in
let old_input = Pcaml.input_file.val in
do {
Pcaml.input_file.val := file;
let items = Grammar.Entry.parse smlist st in
do { Pcaml.input_file.val := old_input; items } }
;
value rec execute_macro = fun
[ SdStr i -> [i]
| SdDef x eo -> do { define eo x; [] }
| SdUnd x -> do { undef x; [] }
| SdITE i l1 l2 ->
execute_macro_list (if is_defined i then l1 else l2)
| SdInc f -> execute_macro_list (parse_include_file f) ]
and execute_macro_list = fun
[ [] -> []
| [hd::tl] -> (* The evaluation order is important here *)
let il1 = execute_macro hd in
let il2 = execute_macro_list tl in
il1 @ il2 ]
;
EXTEND
GLOBAL: expr patt str_item sig_item smlist;
str_item: FIRST
[ [ x = macro_def ->
match execute_macro x with
[ [si] -> si
| sil -> <:str_item< declare $list:sil$ end >> ] ] ]
;
macro_def:
[ [ "DEFINE"; i = uident; def = opt_macro_value -> SdDef i def
| "UNDEF"; i = uident -> SdUnd i
| "IFDEF"; i = uident; "THEN"; dl = smlist; _ = endif ->
SdITE i dl []
| "IFDEF"; i = uident; "THEN"; dl1 = smlist; "ELSE";
dl2 = smlist; _ = endif ->
SdITE i dl1 dl2
| "IFNDEF"; i = uident; "THEN"; dl = smlist; _ = endif ->
SdITE i [] dl
| "IFNDEF"; i = uident; "THEN"; dl1 = smlist; "ELSE";
dl2 = smlist; _ = endif ->
SdITE i dl2 dl1
| "INCLUDE"; fname = STRING -> SdInc fname ] ]
;
smlist:
[ [ sml = LIST1 str_item_or_macro -> sml ] ]
;
endif:
[ [ "END" -> ()
| "ENDIF" -> () ] ]
;
str_item_or_macro:
[ [ d = macro_def -> d
| si = str_item -> SdStr si ] ]
;
opt_macro_value:
[ [ "("; pl = LIST1 LIDENT SEP ","; ")"; "="; e = expr -> Some (pl, e)
| "="; e = expr -> Some ([], e)
| -> None ] ]
;
expr: LEVEL "top"
[ [ "IFDEF"; i = uident; "THEN"; e1 = expr; "ELSE"; e2 = expr; _ = endif ->
if is_defined i then e1 else e2
| "IFNDEF"; i = uident; "THEN"; e1 = expr; "ELSE"; e2 = expr; _ = endif ->
if is_defined i then e2 else e1 ] ]
;
expr: LEVEL "simple"
[ [ LIDENT "__FILE__" -> <:expr< $str:Pcaml.input_file.val$ >>
| LIDENT "__LOCATION__" ->
let bp = string_of_int ((fst _loc).Lexing.pos_cnum) in
let ep = string_of_int ((snd _loc).Lexing.pos_cnum) in
<:expr< ($int:bp$, $int:ep$) >> ] ]
;
patt:
[ [ "IFDEF"; i = uident; "THEN"; p1 = patt; "ELSE"; p2 = patt; _ = endif ->
if is_defined i then p1 else p2
| "IFNDEF"; i = uident; "THEN"; p1 = patt; "ELSE"; p2 = patt; _ = endif ->
if is_defined i then p2 else p1 ] ]
;
uident:
[ [ i = UIDENT -> i ] ]
;
END;
Pcaml.add_option "-D" (Arg.String (define None))
"<string> Define for IFDEF instruction."
;
Pcaml.add_option "-U" (Arg.String undef)
"<string> Undefine for IFDEF instruction."
;
Pcaml.add_option "-I" (Arg.String add_include_dir)
"<string> Add a directory to INCLUDE search path."
;