utop/syntax/pa_optcomp.ml

710 lines
20 KiB
OCaml

(*
* pa_optcomp.ml
* -------------
* Copyright : (c) 2008, Jeremie Dimino <jeremie@dimino.org>
* Licence : BSD3
*
* This file is a part of optcomp.
*)
open Camlp4.Sig
open Camlp4.PreCast
external filter : 'a Gram.not_filtered -> 'a = "%identity"
external not_filtered : 'a -> 'a Gram.not_filtered = "%identity"
(* Subset of supported caml types *)
type typ =
| Tvar of string
| Tbool
| Tint
| Tchar
| Tstring
| Ttuple of typ list
(* Subset of supported caml values *)
type value =
| Bool of bool
| Int of int
| Char of char
| String of string
| Tuple of value list
type ident = string
(* An identifier. It is either a lower or a upper identifier. *)
module Env = Map.Make(struct type t = ident let compare = compare end)
type env = value Env.t
type directive =
| Dir_let of ident * Ast.expr
| Dir_default of ident * Ast.expr
| Dir_if of Ast.expr
| Dir_else
| Dir_elif of Ast.expr
| Dir_endif
| Dir_include of Ast.expr
| Dir_error of Ast.expr
| Dir_warning of Ast.expr
| Dir_directory of Ast.expr
(* This one is not part of optcomp but this is one of the directives
handled by camlp4 we probably want to use. *)
| Dir_default_quotation of Ast.expr
(* Quotations are evaluated by the token filters, but are expansed
after. Evaluated quotations are kept in this table, which quotation
id to to values: *)
let quotations : (int, value) Hashtbl.t = Hashtbl.create 42
let next_quotation_id =
let r = ref 0 in
fun _ -> incr r; !r
(* +-------------+
| Environment |
+-------------+ *)
let env = ref Env.empty
let define id value = env := Env.add id value !env
let _ =
define "ocaml_version" (Scanf.sscanf Sys.ocaml_version "%d.%d" (fun major minor -> Tuple [Int major; Int minor]))
let dirs = ref []
let add_include_dir dir = dirs := dir :: !dirs
(* +--------------+
| Dependencies |
+--------------+ *)
module String_set = Set.Make(String)
(* All depencies of the file being parsed *)
let dependencies = ref String_set.empty
(* Where to write dependencies *)
let dependency_filename = ref None
(* The file being parsed. This is set when the first (token, location)
pair is fetched. *)
let source_filename = ref None
let write_depencies () =
match !dependency_filename, !source_filename with
| None, _
| _, None ->
()
| Some dependency_filename, Some source_filename ->
let oc = open_out dependency_filename in
if not (String_set.is_empty !dependencies) then begin
output_string oc "# automatically generated by optcomp\n";
output_string oc source_filename;
output_string oc ": ";
output_string oc (String.concat " " (String_set.elements !dependencies));
output_char oc '\n'
end;
close_out oc
(* +----------------------------------------+
| Value to expression/pattern conversion |
+----------------------------------------+ *)
let rec expr_of_value _loc = function
| Bool true -> <:expr< true >>
| Bool false -> <:expr< false >>
| Int x -> <:expr< $int:string_of_int x$ >>
| Char x -> <:expr< $chr:Char.escaped x$ >>
| String x -> <:expr< $str:String.escaped x$ >>
| Tuple [] -> <:expr< () >>
| Tuple [x] -> expr_of_value _loc x
| Tuple l -> <:expr< $tup:Ast.exCom_of_list (List.map (expr_of_value _loc) l)$ >>
let rec patt_of_value _loc = function
| Bool true -> <:patt< true >>
| Bool false -> <:patt< false >>
| Int x -> <:patt< $int:string_of_int x$ >>
| Char x -> <:patt< $chr:Char.escaped x$ >>
| String x -> <:patt< $str:String.escaped x$ >>
| Tuple [] -> <:patt< () >>
| Tuple [x] -> patt_of_value _loc x
| Tuple l -> <:patt< $tup:Ast.paCom_of_list (List.map (patt_of_value _loc) l)$ >>
(* +-----------------------+
| Expression evaluation |
+-----------------------+ *)
let rec type_of_value = function
| Bool _ -> Tbool
| Int _ -> Tint
| Char _ -> Tchar
| String _ -> Tstring
| Tuple l -> Ttuple (List.map type_of_value l)
let rec string_of_type = function
| Tvar v -> "'" ^ v
| Tbool -> "bool"
| Tint -> "int"
| Tchar -> "char"
| Tstring -> "string"
| Ttuple l -> "(" ^ String.concat " * " (List.map string_of_type l) ^ ")"
let invalid_type loc expected real =
Loc.raise loc (Failure
(Printf.sprintf "this expression has type %s but is used with type %s"
(string_of_type real) (string_of_type expected)))
let type_of_patt patt =
let rec aux (a, n) = function
| <:patt< $tup:x$ >> ->
let l, x = List.fold_left
(fun (l, x) patt -> let t, x = aux x patt in (t :: l, x))
([], (a, n)) (Ast.list_of_patt x []) in
(Ttuple(List.rev l), x)
| _ ->
(Tvar(Printf.sprintf "%c%s"
(char_of_int (Char.code 'a' + a))
(if n = 0 then "" else string_of_int n)),
if a = 25 then (0, n + 1) else (a + 1, n))
in
fst (aux (0, 0) patt)
let rec eval env = function
(* Literals *)
| <:expr< true >> -> Bool true
| <:expr< false >> -> Bool false
| <:expr< $int:x$ >> -> Int(int_of_string x)
| <:expr< $chr:x$ >> -> Char(Camlp4.Struct.Token.Eval.char x)
| <:expr< $str:x$ >> -> String(Camlp4.Struct.Token.Eval.string ~strict:() x)
(* Tuples *)
| <:expr< $tup:x$ >> -> Tuple(List.map (eval env) (Ast.list_of_expr x []))
(* Variables *)
| <:expr@loc< $lid:x$ >>
| <:expr@loc< $uid:x$ >> ->
begin try
Env.find x env
with
Not_found ->
Loc.raise loc (Failure (Printf.sprintf "unbound value %s" x))
end
(* Value comparing *)
| <:expr< $x$ = $y$ >> -> let x, y = eval_same env x y in Bool(x = y)
| <:expr< $x$ < $y$ >> -> let x, y = eval_same env x y in Bool(x < y)
| <:expr< $x$ > $y$ >> -> let x, y = eval_same env x y in Bool(x > y)
| <:expr< $x$ <= $y$ >> -> let x, y = eval_same env x y in Bool(x <= y)
| <:expr< $x$ >= $y$ >> -> let x, y = eval_same env x y in Bool(x >= y)
| <:expr< $x$ <> $y$ >> -> let x, y = eval_same env x y in Bool(x <> y)
(* min and max *)
| <:expr< min $x$ $y$ >> -> let x, y = eval_same env x y in min x y
| <:expr< max $x$ $y$ >> -> let x, y = eval_same env x y in max x y
(* Arithmetic *)
| <:expr< $x$ + $y$ >> -> Int(eval_int env x + eval_int env y)
| <:expr< $x$ - $y$ >> -> Int(eval_int env x - eval_int env y)
| <:expr< $x$ * $y$ >> -> Int(eval_int env x * eval_int env y)
| <:expr< $x$ / $y$ >> -> Int(eval_int env x / eval_int env y)
| <:expr< $x$ mod $y$ >> -> Int(eval_int env x mod eval_int env y)
(* Boolean operations *)
| <:expr< not $x$ >> -> Bool(not (eval_bool env x))
| <:expr< $x$ or $y$ >> -> Bool(eval_bool env x or eval_bool env y)
| <:expr< $x$ || $y$ >> -> Bool(eval_bool env x || eval_bool env y)
| <:expr< $x$ && $y$ >> -> Bool(eval_bool env x && eval_bool env y)
(* String operations *)
| <:expr< $x$ ^ $y$ >> -> String(eval_string env x ^ eval_string env y)
(* Pair operations *)
| <:expr< fst $x$ >> -> fst (eval_pair env x)
| <:expr< snd $x$ >> -> snd (eval_pair env x)
(* Let-binding *)
| <:expr< let $p$ = $x$ in $y$ >> ->
let vx = eval env x in
let env =
try
bind env p vx
with
Exit -> invalid_type (Ast.loc_of_expr x) (type_of_patt p) (type_of_value vx)
in
eval env y
| e -> Loc.raise (Ast.loc_of_expr e) (Stream.Error "expression not supported")
and bind env patt value = match patt with
| <:patt< $lid:id$ >> ->
Env.add id value env
| <:patt< $tup:patts$ >> ->
let patts = Ast.list_of_patt patts [] in
begin match value with
| Tuple values when List.length values = List.length patts ->
List.fold_left2 bind env patts values
| _ ->
raise Exit
end
| _ ->
Loc.raise (Ast.loc_of_patt patt) (Stream.Error "pattern not supported")
and eval_same env ex ey =
let vx = eval env ex and vy = eval env ey in
let tx = type_of_value vx and ty = type_of_value vy in
if tx = ty then
(vx, vy)
else
invalid_type (Ast.loc_of_expr ey) tx ty
and eval_int env e = match eval env e with
| Int x -> x
| v -> invalid_type (Ast.loc_of_expr e) Tint (type_of_value v)
and eval_bool env e = match eval env e with
| Bool x -> x
| v -> invalid_type (Ast.loc_of_expr e) Tbool (type_of_value v)
and eval_string env e = match eval env e with
| String x -> x
| v -> invalid_type (Ast.loc_of_expr e) Tstring (type_of_value v)
and eval_pair env e = match eval env e with
| Tuple [x; y] -> (x, y)
| v -> invalid_type (Ast.loc_of_expr e) (Ttuple [Tvar "a"; Tvar "b"]) (type_of_value v)
(* +-----------------------+
| Parsing of directives |
+-----------------------+ *)
let rec skip_space stream = match Stream.peek stream with
| Some((BLANKS _ | COMMENT _), _) ->
Stream.junk stream;
skip_space stream
| _ ->
()
let parse_equal stream =
skip_space stream;
match Stream.next stream with
| KEYWORD "=", _ -> ()
| _, loc -> Loc.raise loc (Stream.Error "'=' expected")
let rec parse_eol stream =
let tok, loc = Stream.next stream in
match tok with
| BLANKS _ | COMMENT _ ->
parse_eol stream
| NEWLINE | EOI ->
()
| _ ->
Loc.raise loc (Stream.Error "end of line expected")
(* Return wether a keyword can be interpreted as an identifier *)
let keyword_is_id str =
let rec aux i =
if i = String.length str then
true
else
match str.[i] with
| 'A' .. 'Z' | 'a' .. 'z' | '0' .. '9' ->
aux (i + 1)
| _ ->
false
in
aux 0
let parse_ident stream =
skip_space stream;
let tok, loc = Stream.next stream in
begin match tok with
| LIDENT id | UIDENT id ->
id
| KEYWORD kwd when keyword_is_id kwd ->
kwd
| _ ->
Loc.raise loc (Stream.Error "identifier expected")
end
let parse_expr stream =
(* Lists of opened brackets *)
let opened_brackets = ref [] in
(* Return the next token of [stream] until all opened parentheses
have been closed and a newline is reached *)
let rec next_token _ =
Some(match Stream.next stream, !opened_brackets with
| (NEWLINE, loc), [] ->
EOI, loc
| (KEYWORD("(" | "[" | "{" as b), _) as x, l ->
opened_brackets := b :: l;
x
| (KEYWORD ")", loc) as x, "(" :: l ->
opened_brackets := l;
x
| (KEYWORD "]", loc) as x, "[" :: l ->
opened_brackets := l;
x
| (KEYWORD "}", loc) as x, "{" :: l ->
opened_brackets := l;
x
| x, _ ->
x)
in
Gram.parse_tokens_before_filter Syntax.expr_eoi
(not_filtered (Stream.from next_token))
let parse_directive stream = match Stream.peek stream with
| Some(KEYWORD "#", loc) ->
Stream.junk stream;
(* Move the location to the beginning of the line *)
let (file_name,
start_line, start_bol, start_off,
stop_line, stop_bol, stop_off,
ghost) = Loc.to_tuple loc in
let loc = Loc.of_tuple (file_name,
start_line, start_bol, start_bol,
start_line, start_bol, start_bol,
ghost) in
begin match parse_ident stream with
| "let" ->
let id = parse_ident stream in
parse_equal stream;
let expr = parse_expr stream in
Some(Dir_let(id, expr), loc)
| "let_default" ->
let id = parse_ident stream in
parse_equal stream;
let expr = parse_expr stream in
Some(Dir_default(id, expr), loc)
(* For compatibility *)
| "define" ->
let id = parse_ident stream in
let expr = parse_expr stream in
Some(Dir_let(id, expr), loc)
(* For compatibility *)
| "default" ->
let id = parse_ident stream in
let expr = parse_expr stream in
Some(Dir_default(id, expr), loc)
| "if" ->
Some(Dir_if(parse_expr stream), loc)
| "else" ->
parse_eol stream;
Some(Dir_else, loc)
| "elif" ->
Some(Dir_elif(parse_expr stream), loc)
| "endif" ->
parse_eol stream;
Some(Dir_endif, loc)
| "include" ->
Some(Dir_include(parse_expr stream), loc)
| "directory" ->
Some(Dir_directory(parse_expr stream), loc)
| "error" ->
Some(Dir_error(parse_expr stream), loc)
| "warning" ->
Some(Dir_warning(parse_expr stream), loc)
| "default_quotation" ->
Some(Dir_default_quotation(parse_expr stream), loc)
| dir ->
Loc.raise loc (Stream.Error (Printf.sprintf "bad directive ``%s''" dir))
end
| _ ->
None
let parse_command_line_define str =
match Gram.parse_string Syntax.expr (Loc.mk "<command line>") str with
| <:expr< $lid:id$ = $e$ >>
| <:expr< $uid:id$ = $e$ >> -> define id (eval !env e)
| _ -> invalid_arg str
(* +----------------+
| BLock skipping |
+----------------+ *)
let rec skip_line stream =
match Stream.next stream with
| NEWLINE, _ -> ()
| EOI, loc -> Loc.raise loc (Stream.Error "#endif missing")
| _ -> skip_line stream
let rec next_directive stream = match parse_directive stream with
| Some dir -> dir
| None -> skip_line stream; next_directive stream
let rec next_endif stream =
let dir, loc = next_directive stream in
match dir with
| Dir_if _ -> skip_if stream; next_endif stream
| Dir_else
| Dir_elif _
| Dir_endif -> dir
| _ -> next_endif stream
and skip_if stream =
let dir, loc = next_directive stream in
match dir with
| Dir_if _ ->
skip_if stream;
skip_if stream
| Dir_else ->
skip_else stream
| Dir_elif _ ->
skip_if stream
| Dir_endif ->
()
| _ -> skip_if stream
and skip_else stream =
let dir, loc = next_directive stream in
match dir with
| Dir_if _ ->
skip_if stream;
skip_else stream
| Dir_else ->
Loc.raise loc (Stream.Error "#else without #if")
| Dir_elif _ ->
Loc.raise loc (Stream.Error "#elif without #if")
| Dir_endif ->
()
| _ ->
skip_else stream
(* +-----------------+
| Token filtering |
+-----------------+ *)
type context = Ctx_if | Ctx_else
(* State of the token filter *)
type state = {
stream : (Gram.Token.t * Loc.t) Stream.t;
(* Input stream *)
mutable bol : bool;
(* Wether we are at the beginning of a line *)
mutable stack : context list;
(* Nested contexts *)
on_eoi : Gram.Token.t * Loc.t -> Gram.Token.t * Loc.t;
(* Eoi handler, it is used to restore the previous sate on #include
directives *)
}
(* Read and return one token *)
let really_read state =
let tok, loc = Stream.next state.stream in
state.bol <- tok = NEWLINE;
match tok with
| QUOTATION ({ q_name = "optcomp" } as quot) ->
let id = next_quotation_id () in
Hashtbl.add quotations id (eval !env (Gram.parse_string
Syntax.expr_eoi
(Loc.move `start quot.q_shift loc)
quot.q_contents));
(* Replace the quotation by its id *)
(QUOTATION { quot with q_contents = string_of_int id }, loc)
| EOI ->
(* If end of input is reached, we call the eoi handler. It may
continue if we were parsing an included file *)
if state.stack <> [] then
Loc.raise loc (Stream.Error "#endif missing");
state.on_eoi (tok, loc)
| _ ->
(tok, loc)
(* Return the next token from a stream, interpreting directives. *)
let rec next_token state_ref =
let state = !state_ref in
if state.bol then
match parse_directive state.stream, state.stack with
| Some(Dir_if e, _), _ ->
let rec aux e =
if eval_bool !env e then begin
state.stack <- Ctx_if :: state.stack;
next_token state_ref
end else
match next_endif state.stream with
| Dir_else ->
state.stack <- Ctx_else :: state.stack;
next_token state_ref
| Dir_elif e ->
aux e
| Dir_endif ->
next_token state_ref
| _ ->
assert false
in
aux e
| Some(Dir_else, loc), ([] | Ctx_else :: _) ->
Loc.raise loc (Stream.Error "#else without #if")
| Some(Dir_elif _, loc), ([] | Ctx_else :: _) ->
Loc.raise loc (Stream.Error "#elif without #if")
| Some(Dir_endif, loc), [] ->
Loc.raise loc (Stream.Error "#endif without #if")
| Some(Dir_else, loc), Ctx_if :: l ->
skip_else state.stream;
state.stack <- l;
next_token state_ref
| Some(Dir_elif _, loc), Ctx_if :: l ->
skip_if state.stream;
state.stack <- l;
next_token state_ref
| Some(Dir_endif, loc), _ :: l ->
state.stack <- l;
next_token state_ref
| Some(Dir_let(id, e), _), _ ->
define id (eval !env e);
next_token state_ref
| Some(Dir_default(id, e), _), _ ->
if not (Env.mem id !env) then
define id (eval !env e);
next_token state_ref
| Some(Dir_include e, _), _ ->
let fname = eval_string !env e in
(* Try to looks up in all include directories *)
let fname =
try
List.find (fun dir -> Sys.file_exists (Filename.concat dir fname)) !dirs
with
(* Just try in the current directory *)
Not_found -> fname
in
dependencies := String_set.add fname !dependencies;
let ic = open_in fname in
let nested_state = {
stream = Gram.Token.Filter.filter (Gram.get_filter ()) (filter (Gram.lex (Loc.mk fname) (Stream.of_channel ic)));
bol = true;
stack = [];
on_eoi = (fun _ ->
(* Restore previous state and close channel on
eoi *)
state_ref := state;
close_in ic;
next_token state_ref)
} in
(* Replace current state with the new one *)
state_ref := nested_state;
next_token state_ref
| Some(Dir_directory e, loc), _ ->
let dir = eval_string !env e in
add_include_dir dir;
next_token state_ref
| Some(Dir_error e, loc), _ ->
Loc.raise loc (Failure (eval_string !env e))
| Some(Dir_warning e, loc), _ ->
Syntax.print_warning loc (eval_string !env e);
next_token state_ref
| Some(Dir_default_quotation e, loc), _ ->
Syntax.Quotation.default := eval_string !env e;
next_token state_ref
| None, _ ->
really_read state
else
really_read state
let stream_filter filter stream =
(* Set the source filename *)
begin match !source_filename with
| Some _ ->
()
| None ->
match Stream.peek stream with
| None ->
()
| Some(tok, loc) ->
source_filename := Some(Loc.file_name loc)
end;
let state_ref = ref { stream = stream;
bol = true;
stack = [];
on_eoi = (fun x -> x) } in
filter (Stream.from (fun _ -> Some(next_token state_ref)))
(* +----------------------+
| Quotations expansion |
+----------------------+ *)
let expand f loc _ contents =
try
f loc (Hashtbl.find quotations (int_of_string contents))
with
exn -> Loc.raise loc (Failure "fatal error in optcomp!")
(* +--------------+
| Registration |
+--------------+ *)
let _ =
Camlp4.Options.add "-let" (Arg.String parse_command_line_define)
"<string> Binding for a #let directive.";
Camlp4.Options.add "-depend"
(Arg.String (fun filename -> dependency_filename := Some filename))
"<file> Write dependencies to <file>.";
Pervasives.at_exit write_depencies;
Syntax.Quotation.add "optcomp" Syntax.Quotation.DynAst.expr_tag (expand expr_of_value);
Syntax.Quotation.add "optcomp" Syntax.Quotation.DynAst.patt_tag (expand patt_of_value);
Gram.Token.Filter.define_filter (Gram.get_filter ()) stream_filter