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(************************************************************************)
(* v * The Coq Proof Assistant / The Coq Development Team *)
(* <O___,, * INRIA - CNRS - LIX - LRI - PPS - Copyright 1999-2012 *)
(* \VV/ **************************************************************)
(* // * This file is distributed under the terms of the *)
(* * GNU Lesser General Public License Version 2.1 *)
(************************************************************************)
open Pp
open Util
open Compat
open Tok
(* Dictionaries: trees annotated with string options, each node being a map
from chars to dictionaries (the subtrees). A trie, in other words. *)
module CharMap = Map.Make (struct type t = char let compare = compare end)
type ttree = {
node : string option;
branch : ttree CharMap.t }
let empty_ttree = { node = None; branch = CharMap.empty }
let ttree_add ttree str =
let rec insert tt i =
if i == String.length str then
{node = Some str; branch = tt.branch}
else
let c = str.[i] in
let br =
match try Some (CharMap.find c tt.branch) with Not_found -> None with
| Some tt' ->
CharMap.add c (insert tt' (i + 1)) (CharMap.remove c tt.branch)
| None ->
let tt' = {node = None; branch = CharMap.empty} in
CharMap.add c (insert tt' (i + 1)) tt.branch
in
{ node = tt.node; branch = br }
in
insert ttree 0
(* Search a string in a dictionary: raises [Not_found]
if the word is not present. *)
let ttree_find ttree str =
let rec proc_rec tt i =
if i == String.length str then tt
else proc_rec (CharMap.find str.[i] tt.branch) (i+1)
in
proc_rec ttree 0
(* Removes a string from a dictionary: returns an equal dictionary
if the word not present. *)
let ttree_remove ttree str =
let rec remove tt i =
if i == String.length str then
{node = None; branch = tt.branch}
else
let c = str.[i] in
let br =
match try Some (CharMap.find c tt.branch) with Not_found -> None with
| Some tt' ->
CharMap.add c (remove tt' (i + 1)) (CharMap.remove c tt.branch)
| None -> tt.branch
in
{ node = tt.node; branch = br }
in
remove ttree 0
(* Errors occuring while lexing (explained as "Lexer error: ...") *)
module Error = struct
type t =
| Illegal_character
| Unterminated_comment
| Unterminated_string
| Undefined_token
| Bad_token of string
| UnsupportedUnicode of int
exception E of t
let to_string x =
"Syntax Error: Lexer: " ^
(match x with
| Illegal_character -> "Illegal character"
| Unterminated_comment -> "Unterminated comment"
| Unterminated_string -> "Unterminated string"
| Undefined_token -> "Undefined token"
| Bad_token tok -> Format.sprintf "Bad token %S" tok
| UnsupportedUnicode x ->
Printf.sprintf "Unsupported Unicode character (0x%x)" x)
(* Require to fix the Camlp4 signature *)
let print ppf x = Pp.pp_with ppf (Pp.str (to_string x))
end
open Error
let err loc str = Loc.raise (Loc.make_loc loc) (Error.E str)
let bad_token str = raise (Error.E (Bad_token str))
(* Lexer conventions on tokens *)
type token_kind =
| Utf8Token of (Unicode.status * int)
| AsciiChar
| EmptyStream
let error_unsupported_unicode_character n unicode cs =
let bp = Stream.count cs in
err (bp,bp+n) (UnsupportedUnicode unicode)
let error_utf8 cs =
let bp = Stream.count cs in
Stream.junk cs; (* consume the char to avoid read it and fail again *)
err (bp, bp+1) Illegal_character
let utf8_char_size cs = function
(* Utf8 leading byte *)
| '\x00'..'\x7F' -> 1
| '\xC0'..'\xDF' -> 2
| '\xE0'..'\xEF' -> 3
| '\xF0'..'\xF7' -> 4
| _ (* '\x80'..\xBF'|'\xF8'..'\xFF' *) -> error_utf8 cs
let njunk n = Util.repeat n Stream.junk
let check_utf8_trailing_byte cs c =
if Char.code c land 0xC0 <> 0x80 then error_utf8 cs
(* Recognize utf8 blocks (of length less than 4 bytes) *)
(* but don't certify full utf8 compliance (e.g. no emptyness check) *)
let lookup_utf8_tail c cs =
let c1 = Char.code c in
if c1 land 0x40 = 0 or c1 land 0x38 = 0x38 then error_utf8 cs
else
let n, unicode =
if c1 land 0x20 = 0 then
match Stream.npeek 2 cs with
| [_;c2] ->
check_utf8_trailing_byte cs c2;
2, (c1 land 0x1F) lsl 6 + (Char.code c2 land 0x3F)
| _ -> error_utf8 cs
else if c1 land 0x10 = 0 then
match Stream.npeek 3 cs with
| [_;c2;c3] ->
check_utf8_trailing_byte cs c2; check_utf8_trailing_byte cs c3;
3, (c1 land 0x0F) lsl 12 + (Char.code c2 land 0x3F) lsl 6 +
(Char.code c3 land 0x3F)
| _ -> error_utf8 cs
else match Stream.npeek 4 cs with
| [_;c2;c3;c4] ->
check_utf8_trailing_byte cs c2; check_utf8_trailing_byte cs c3;
check_utf8_trailing_byte cs c4;
4, (c1 land 0x07) lsl 18 + (Char.code c2 land 0x3F) lsl 12 +
(Char.code c3 land 0x3F) lsl 6 + (Char.code c4 land 0x3F)
| _ -> error_utf8 cs
in
try Unicode.classify unicode, n
with Unicode.Unsupported ->
njunk n cs; error_unsupported_unicode_character n unicode cs
let lookup_utf8 cs =
match Stream.peek cs with
| Some ('\x00'..'\x7F') -> AsciiChar
| Some ('\x80'..'\xFF' as c) -> Utf8Token (lookup_utf8_tail c cs)
| None -> EmptyStream
let unlocated f x =
try f x with Loc.Exc_located (_, exc) -> raise exc
let check_keyword str =
let rec loop_symb = parser
| [< ' (' ' | '\n' | '\r' | '\t' | '"') >] -> bad_token str
| [< s >] ->
match unlocated lookup_utf8 s with
| Utf8Token (_,n) -> njunk n s; loop_symb s
| AsciiChar -> Stream.junk s; loop_symb s
| EmptyStream -> ()
in
loop_symb (Stream.of_string str)
let check_keyword_to_add s =
try check_keyword s
with Error.E (UnsupportedUnicode unicode) ->
Flags.if_verbose msg_warning
(strbrk (Printf.sprintf "Token '%s' contains unicode character 0x%x which will not be parsable." s unicode))
let check_ident str =
let rec loop_id intail = parser
| [< ' ('a'..'z' | 'A'..'Z' | '_'); s >] ->
loop_id true s
| [< ' ('0'..'9' | ''') when intail; s >] ->
loop_id true s
| [< s >] ->
match unlocated lookup_utf8 s with
| Utf8Token (Unicode.Letter, n) -> njunk n s; loop_id true s
| Utf8Token (Unicode.IdentPart, n) when intail -> njunk n s; loop_id true s
| EmptyStream -> ()
| Utf8Token _ | AsciiChar -> bad_token str
in
loop_id false (Stream.of_string str)
let is_ident str =
try let _ = check_ident str in true with Error.E _ -> false
(* Keyword and symbol dictionary *)
let token_tree = ref empty_ttree
let is_keyword s =
try match (ttree_find !token_tree s).node with None -> false | Some _ -> true
with Not_found -> false
let add_keyword str =
if not (is_keyword str) then
begin
check_keyword_to_add str;
token_tree := ttree_add !token_tree str
end
let remove_keyword str =
token_tree := ttree_remove !token_tree str
(* Freeze and unfreeze the state of the lexer *)
type frozen_t = ttree
let freeze () = !token_tree
let unfreeze tt =
token_tree := tt
let init () =
unfreeze empty_ttree
let _ = init()
(* The string buffering machinery *)
let buff = ref (String.create 80)
let store len x =
if len >= String.length !buff then
buff := !buff ^ String.create (String.length !buff);
!buff.[len] <- x;
succ len
let rec nstore n len cs =
if n>0 then nstore (n-1) (store len (Stream.next cs)) cs else len
let get_buff len = String.sub !buff 0 len
(* The classical lexer: idents, numbers, quoted strings, comments *)
let rec ident_tail len = parser
| [< ' ('a'..'z' | 'A'..'Z' | '0'..'9' | ''' | '_' as c); s >] ->
ident_tail (store len c) s
| [< s >] ->
match lookup_utf8 s with
| Utf8Token ((Unicode.IdentPart | Unicode.Letter), n) ->
ident_tail (nstore n len s) s
| _ -> len
let rec number len = parser
| [< ' ('0'..'9' as c); s >] -> number (store len c) s
| [< >] -> len
let rec string in_comments bp len = parser
| [< ''"'; esc=(parser [<''"' >] -> true | [< >] -> false); s >] ->
if esc then string in_comments bp (store len '"') s else len
| [< ''('; s >] ->
(parser
| [< ''*'; s >] ->
string (Option.map succ in_comments) bp (store (store len '(') '*') s
| [< >] ->
string in_comments bp (store len '(') s) s
| [< ''*'; s >] ->
(parser
| [< '')'; s >] ->
if in_comments = Some 0 then
msg_warning (strbrk "Not interpreting \"*)\" as the end of current non-terminated comment because it occurs in a non-terminated string of the comment.");
let in_comments = Option.map pred in_comments in
string in_comments bp (store (store len '*') ')') s
| [< >] ->
string in_comments bp (store len '*') s) s
| [< 'c; s >] -> string in_comments bp (store len c) s
| [< _ = Stream.empty >] ep -> err (bp, ep) Unterminated_string
(* Hook for exporting comment into xml theory files *)
let xml_output_comment = ref (fun _ -> ())
let set_xml_output_comment f = xml_output_comment := f
(* Utilities for comments in beautify *)
let comment_begin = ref None
let comm_loc bp = if !comment_begin=None then comment_begin := Some bp
let current = Buffer.create 8192
let between_com = ref true
type com_state = int option * string * bool
let restore_com_state (o,s,b) =
comment_begin := o;
Buffer.clear current; Buffer.add_string current s;
between_com := b
let dflt_com = (None,"",true)
let com_state () =
let s = (!comment_begin, Buffer.contents current, !between_com) in
restore_com_state dflt_com; s
let real_push_char c = Buffer.add_char current c
(* Add a char if it is between two commands, if it is a newline or
if the last char is not a space itself. *)
let push_char c =
if
!between_com || List.mem c ['\n';'\r'] ||
(List.mem c [' ';'\t']&&
(Buffer.length current = 0 ||
not (let s = Buffer.contents current in
List.mem s.[String.length s - 1] [' ';'\t';'\n';'\r'])))
then
real_push_char c
let push_string s = Buffer.add_string current s
let null_comment s =
let rec null i =
i<0 || (List.mem s.[i] [' ';'\t';'\n';'\r'] && null (i-1)) in
null (String.length s - 1)
let comment_stop ep =
let current_s = Buffer.contents current in
if !Flags.xml_export && Buffer.length current > 0 &&
(!between_com || not(null_comment current_s)) then
!xml_output_comment current_s;
(if Flags.do_beautify() && Buffer.length current > 0 &&
(!between_com || not(null_comment current_s)) then
let bp = match !comment_begin with
Some bp -> bp
| None ->
msgerrnl(str"No begin location for comment '"++str current_s ++str"' ending at "++int ep);
ep-1 in
Pp.comments := ((bp,ep),current_s) :: !Pp.comments);
Buffer.clear current;
comment_begin := None;
between_com := false
(* Does not unescape!!! *)
let rec comm_string bp = parser
| [< ''"' >] -> push_string "\""
| [< ''\\'; _ =
(parser [< ' ('"' | '\\' as c) >] ->
if c='"' then real_push_char c;
real_push_char c
| [< >] -> real_push_char '\\'); s >]
-> comm_string bp s
| [< _ = Stream.empty >] ep -> err (bp, ep) Unterminated_string
| [< 'c; s >] -> real_push_char c; comm_string bp s
let rec comment bp = parser bp2
| [< ''(';
_ = (parser
| [< ''*'; s >] -> push_string "(*"; comment bp s
| [< >] -> push_string "(" );
s >] -> comment bp s
| [< ''*';
_ = parser
| [< '')' >] -> push_string "*)";
| [< s >] -> real_push_char '*'; comment bp s >] -> ()
| [< ''"'; s >] ->
if Flags.do_beautify() then (push_string"\"";comm_string bp2 s)
else ignore (string (Some 0) bp2 0 s);
comment bp s
| [< _ = Stream.empty >] ep -> err (bp, ep) Unterminated_comment
| [< 'z; s >] -> real_push_char z; comment bp s
(* Parse a special token, using the [token_tree] *)
(* Peek as much utf-8 lexemes as possible *)
(* and retain the longest valid special token obtained *)
let rec progress_further last nj tt cs =
try progress_from_byte last nj tt cs (List.nth (Stream.npeek (nj+1) cs) nj)
with Failure _ -> last
and update_longest_valid_token last nj tt cs =
match tt.node with
| Some _ as last' ->
stream_njunk nj cs;
progress_further last' 0 tt cs
| None ->
progress_further last nj tt cs
(* nj is the number of char peeked since last valid token *)
(* n the number of char in utf8 block *)
and progress_utf8 last nj n c tt cs =
try
let tt = CharMap.find c tt.branch in
if n=1 then
update_longest_valid_token last (nj+n) tt cs
else
match Util.List.skipn (nj+1) (Stream.npeek (nj+n) cs) with
| l when List.length l = n-1 ->
List.iter (check_utf8_trailing_byte cs) l;
let tt = List.fold_left (fun tt c -> CharMap.find c tt.branch) tt l in
update_longest_valid_token last (nj+n) tt cs
| _ ->
error_utf8 cs
with Not_found ->
last
and progress_from_byte last nj tt cs c =
progress_utf8 last nj (utf8_char_size cs c) c tt cs
let find_keyword id s =
let tt = ttree_find !token_tree id in
match progress_further tt.node 0 tt s with
| None -> raise Not_found
| Some c -> KEYWORD c
(* Must be a special token *)
let process_chars bp c cs =
let t = progress_from_byte None (-1) !token_tree cs c in
let ep = Stream.count cs in
match t with
| Some t -> (KEYWORD t, (bp, ep))
| None ->
let ep' = bp + utf8_char_size cs c in
njunk (ep' - ep) cs;
err (bp, ep') Undefined_token
let token_of_special c s = match c with
| '$' -> METAIDENT s
| '.' -> FIELD s
| _ -> assert false
(* Parse what follows a dot / a dollar *)
let parse_after_special c bp =
parser
| [< ' ('a'..'z' | 'A'..'Z' | '_' as d); len = ident_tail (store 0 d) >] ->
token_of_special c (get_buff len)
| [< s >] ->
match lookup_utf8 s with
| Utf8Token (Unicode.Letter, n) ->
token_of_special c (get_buff (ident_tail (nstore n 0 s) s))
| AsciiChar | Utf8Token _ | EmptyStream -> fst (process_chars bp c s)
(* Parse what follows a question mark *)
let parse_after_qmark bp s =
match Stream.peek s with
| Some ('a'..'z' | 'A'..'Z' | '_') -> LEFTQMARK
| None -> KEYWORD "?"
| _ ->
match lookup_utf8 s with
| Utf8Token (Unicode.Letter, _) -> LEFTQMARK
| AsciiChar | Utf8Token _ | EmptyStream -> fst (process_chars bp '?' s)
let blank_or_eof cs =
match Stream.peek cs with
| None -> true
| Some (' ' | '\t' | '\n' |'\r') -> true
| _ -> false
(* Parse a token in a char stream *)
let rec next_token = parser bp
| [< '' ' | '\t' | '\n' |'\r' as c; s >] ->
comm_loc bp; push_char c; next_token s
| [< ''$' as c; t = parse_after_special c bp >] ep ->
comment_stop bp; (t, (ep, bp))
| [< ''.' as c; t = parse_after_special c bp; s >] ep ->
comment_stop bp;
(* We enforce that "." should either be part of a larger keyword,
for instance ".(", or followed by a blank or eof. *)
if t = KEYWORD "." then begin
if not (blank_or_eof s) then err (bp,ep+1) Undefined_token;
if Flags.do_beautify() then between_com := true;
end;
(t, (bp,ep))
| [< ''?'; s >] ep ->
let t = parse_after_qmark bp s in comment_stop bp; (t, (ep, bp))
| [< ' ('a'..'z' | 'A'..'Z' | '_' as c);
len = ident_tail (store 0 c); s >] ep ->
let id = get_buff len in
comment_stop bp;
(try find_keyword id s with Not_found -> IDENT id), (bp, ep)
| [< ' ('0'..'9' as c); len = number (store 0 c) >] ep ->
comment_stop bp;
(INT (get_buff len), (bp, ep))
| [< ''\"'; len = string None bp 0 >] ep ->
comment_stop bp;
(STRING (get_buff len), (bp, ep))
| [< ' ('(' as c);
t = parser
| [< ''*'; s >] ->
comm_loc bp;
push_string "(*";
comment bp s;
next_token s
| [< t = process_chars bp c >] -> comment_stop bp; t >] ->
t
| [< s >] ->
match lookup_utf8 s with
| Utf8Token (Unicode.Letter, n) ->
let len = ident_tail (nstore n 0 s) s in
let id = get_buff len in
let ep = Stream.count s in
comment_stop bp;
(try find_keyword id s with Not_found -> IDENT id), (bp, ep)
| AsciiChar | Utf8Token ((Unicode.Symbol | Unicode.IdentPart), _) ->
let t = process_chars bp (Stream.next s) s in
comment_stop bp; t
| EmptyStream ->
comment_stop bp; (EOI, (bp, bp + 1))
(* (* Debug: uncomment this for tracing tokens seen by coq...*)
let next_token s =
let (t,(bp,ep)) = next_token s in Printf.eprintf "[%s]\n%!" (Tok.to_string t);
(t,(bp,ep))
*)
(* Location table system for creating tables associating a token count
to its location in a char stream (the source) *)
let locerr () = invalid_arg "Lexer: location function"
let loct_create () = Hashtbl.create 207
let loct_func loct i =
try Hashtbl.find loct i with Not_found -> locerr ()
let loct_add loct i loc = Hashtbl.add loct i loc
let current_location_table = ref (loct_create ())
type location_table = (int, CompatLoc.t) Hashtbl.t
let location_table () = !current_location_table
let restore_location_table t = current_location_table := t
(** {6 The lexer of Coq} *)
(** Note: removing a token.
We do nothing because [remove_token] is called only when removing a grammar
rule with [Grammar.delete_rule]. The latter command is called only when
unfreezing the state of the grammar entries (see GRAMMAR summary, file
env/metasyntax.ml). Therefore, instead of removing tokens one by one,
we unfreeze the state of the lexer. This restores the behaviour of the
lexer. B.B. *)
IFDEF CAMLP5 THEN
type te = Tok.t
(** Names of tokens, for this lexer, used in Grammar error messages *)
let token_text = function
| ("", t) -> "'" ^ t ^ "'"
| ("IDENT", "") -> "identifier"
| ("IDENT", t) -> "'" ^ t ^ "'"
| ("INT", "") -> "integer"
| ("INT", s) -> "'" ^ s ^ "'"
| ("STRING", "") -> "string"
| ("EOI", "") -> "end of input"
| (con, "") -> con
| (con, prm) -> con ^ " \"" ^ prm ^ "\""
let func cs =
let loct = loct_create () in
let ts =
Stream.from
(fun i ->
let (tok, loc) = next_token cs in
loct_add loct i (make_loc loc); Some tok)
in
current_location_table := loct;
(ts, loct_func loct)
let lexer = {
Token.tok_func = func;
Token.tok_using =
(fun pat -> match Tok.of_pattern pat with
| KEYWORD s -> add_keyword s
| _ -> ());
Token.tok_removing = (fun _ -> ());
Token.tok_match = Tok.match_pattern;
Token.tok_comm = None;
Token.tok_text = token_text }
ELSE (* official camlp4 for ocaml >= 3.10 *)
module M_ = Camlp4.ErrorHandler.Register (Error)
module Loc = CompatLoc
module Token = struct
include Tok (* Cf. tok.ml *)
module Loc = CompatLoc
module Error = Camlp4.Struct.EmptyError
module Filter = struct
type token_filter = (Tok.t * Loc.t) Stream.t -> (Tok.t * Loc.t) Stream.t
type t = unit
let mk _is_kwd = ()
let keyword_added () kwd _ = add_keyword kwd
let keyword_removed () _ = ()
let filter () x = x
let define_filter () _ = ()
end
end
let mk () _init_loc(*FIXME*) cs =
let loct = loct_create () in
let rec self =
parser i
[< (tok, loc) = next_token; s >] ->
let loc = make_loc loc in
loct_add loct i loc;
[< '(tok, loc); self s >]
| [< >] -> [< >]
in current_location_table := loct; self cs
END
(** Terminal symbols interpretation *)
let is_ident_not_keyword s =
is_ident s && not (is_keyword s)
let is_number s =
let rec aux i =
String.length s = i or
match s.[i] with '0'..'9' -> aux (i+1) | _ -> false
in aux 0
let strip s =
let len =
let rec loop i len =
if i = String.length s then len
else if s.[i] == ' ' then loop (i + 1) len
else loop (i + 1) (len + 1)
in
loop 0 0
in
if len == String.length s then s
else
let s' = String.create len in
let rec loop i i' =
if i == String.length s then s'
else if s.[i] == ' ' then loop (i + 1) i'
else begin s'.[i'] <- s.[i]; loop (i + 1) (i' + 1) end
in
loop 0 0
let terminal s =
let s = strip s in
if s = "" then failwith "empty token";
if is_ident_not_keyword s then IDENT s
else if is_number s then INT s
else KEYWORD s
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