diff options
Diffstat (limited to 'ocaml-binary-annot/testsuite/tests/tool-lexyacc/lexgen.ml')
| -rw-r--r-- | ocaml-binary-annot/testsuite/tests/tool-lexyacc/lexgen.ml | 266 |
1 files changed, 266 insertions, 0 deletions
diff --git a/ocaml-binary-annot/testsuite/tests/tool-lexyacc/lexgen.ml b/ocaml-binary-annot/testsuite/tests/tool-lexyacc/lexgen.ml new file mode 100644 index 0000000000..05cb3c0333 --- /dev/null +++ b/ocaml-binary-annot/testsuite/tests/tool-lexyacc/lexgen.ml @@ -0,0 +1,266 @@ +(***********************************************************************) +(* *) +(* Objective Caml *) +(* *) +(* Xavier Leroy, projet Cristal, INRIA Rocquencourt *) +(* *) +(* Copyright 1996 Institut National de Recherche en Informatique et *) +(* en Automatique. All rights reserved. This file is distributed *) +(* under the terms of the Q Public License version 1.0. *) +(* *) +(***********************************************************************) + +(* $Id: lexgen.ml,v 1.5 2000/12/28 13:06:39 weis Exp $ *) + +(* Compiling a lexer definition *) + +open Syntax + +(* Deep abstract syntax for regular expressions *) + +type regexp = + Empty + | Chars of int + | Action of int + | Seq of regexp * regexp + | Alt of regexp * regexp + | Star of regexp + +(* From shallow to deep syntax *) + +(*** + +let print_char_class c = + let print_interval low high = + prerr_int low; + if high - 1 > low then begin + prerr_char '-'; + prerr_int (high-1) + end; + prerr_char ' ' in + let rec print_class first next = function + [] -> print_interval first next + | c::l -> + if char.code c = next + then print_class first (next+1) l + else begin + print_interval first next; + print_class (char.code c) (char.code c + 1) l + end in + match c with + [] -> prerr_newline() + | c::l -> print_class (char.code c) (char.code c + 1) l; prerr_newline() + + +let rec print_regexp = function + Empty -> prerr_string "Empty" + | Chars n -> prerr_string "Chars "; prerr_int n + | Action n -> prerr_string "Action "; prerr_int n + | Seq(r1,r2) -> print_regexp r1; prerr_string "; "; print_regexp r2 + | Alt(r1,r2) -> prerr_string "("; print_regexp r1; prerr_string " | "; print_regexp r2; prerr_string ")" + | Star r -> prerr_string "("; print_regexp r; prerr_string ")*" + +***) + +let chars = ref ([] : char list list) +let chars_count = ref 0 +let actions = ref ([] : (int * location) list) +let actions_count = ref 0 + +let rec encode_regexp = function + Epsilon -> Empty + | Characters cl -> + let n = !chars_count in +(*** prerr_int n; prerr_char ' '; print_char_class cl; ***) + chars := cl :: !chars; + chars_count := !chars_count + 1; + Chars(n) + | Sequence(r1,r2) -> + Seq(encode_regexp r1, encode_regexp r2) + | Alternative(r1,r2) -> + Alt(encode_regexp r1, encode_regexp r2) + | Repetition r -> + Star (encode_regexp r) + + +let encode_casedef = + List.fold_left + (fun reg (expr,act) -> + let act_num = !actions_count in + actions_count := !actions_count + 1; + actions := (act_num, act) :: !actions; + Alt(reg, Seq(encode_regexp expr, Action act_num))) + Empty + + +let encode_lexdef (Lexdef(_, ld)) = + chars := []; + chars_count := 0; + actions := []; + actions_count := 0; + let name_regexp_list = + List.map (fun (name, casedef) -> (name, encode_casedef casedef)) ld in +(* List.iter print_char_class chars; *) + let chr = Array.of_list (List.rev !chars) + and act = !actions in + chars := []; + actions := []; + (chr, name_regexp_list, act) + + +(* To generate directly a NFA from a regular expression. + Confer Aho-Sethi-Ullman, dragon book, chap. 3 *) + +type transition = + OnChars of int + | ToAction of int + + +let rec merge_trans l1 l2 = + match (l1, l2) with + ([], s2) -> s2 + | (s1, []) -> s1 + | ((OnChars n1 as t1) :: r1 as s1), ((OnChars n2 as t2) :: r2 as s2) -> + if n1 = n2 then t1 :: merge_trans r1 r2 else + if n1 < n2 then t1 :: merge_trans r1 s2 else + t2 :: merge_trans s1 r2 + | ((ToAction n1 as t1) :: r1 as s1), ((ToAction n2 as t2) :: r2 as s2) -> + if n1 = n2 then t1 :: merge_trans r1 r2 else + if n1 < n2 then t1 :: merge_trans r1 s2 else + t2 :: merge_trans s1 r2 + | ((OnChars n1 as t1) :: r1), ((ToAction n2) :: r2 as s2) -> + t1 :: merge_trans r1 s2 + | ((ToAction n1) :: r1 as s1), ((OnChars n2 as t2) :: r2) -> + t2 :: merge_trans s1 r2 + + +let rec nullable = function + Empty -> true + | Chars _ -> false + | Action _ -> false + | Seq(r1,r2) -> nullable r1 && nullable r2 + | Alt(r1,r2) -> nullable r1 || nullable r2 + | Star r -> true + + +let rec firstpos = function + Empty -> [] + | Chars pos -> [OnChars pos] + | Action act -> [ToAction act] + | Seq(r1,r2) -> if nullable r1 + then merge_trans (firstpos r1) (firstpos r2) + else firstpos r1 + | Alt(r1,r2) -> merge_trans (firstpos r1) (firstpos r2) + | Star r -> firstpos r + + +let rec lastpos = function + Empty -> [] + | Chars pos -> [OnChars pos] + | Action act -> [ToAction act] + | Seq(r1,r2) -> if nullable r2 + then merge_trans (lastpos r1) (lastpos r2) + else lastpos r2 + | Alt(r1,r2) -> merge_trans (lastpos r1) (lastpos r2) + | Star r -> lastpos r + + +let followpos size name_regexp_list = + let v = Array.create size [] in + let fill_pos first = function + OnChars pos -> v.(pos) <- merge_trans first v.(pos); () + | ToAction _ -> () in + let rec fill = function + Seq(r1,r2) -> + fill r1; fill r2; + List.iter (fill_pos (firstpos r2)) (lastpos r1) + | Alt(r1,r2) -> + fill r1; fill r2 + | Star r -> + fill r; + List.iter (fill_pos (firstpos r)) (lastpos r) + | _ -> () in + List.iter (fun (name, regexp) -> fill regexp) name_regexp_list; + v + + +let no_action = 0x3FFFFFFF + +let split_trans_set = + List.fold_left + (fun (act, pos_set as act_pos_set) trans -> + match trans with + OnChars pos -> (act, pos :: pos_set) + | ToAction act1 -> if act1 < act then (act1, pos_set) + else act_pos_set) + (no_action, []) + + +let memory = (Hashtbl.create 131 : (transition list, int) Hashtbl.t) +let todo = ref ([] : (transition list * int) list) +let next = ref 0 + +let get_state st = + try + Hashtbl.find memory st + with Not_found -> + let nbr = !next in + next := !next + 1; + Hashtbl.add memory st nbr; + todo := (st, nbr) :: !todo; + nbr + +let rec map_on_states f = + match !todo with + [] -> [] + | (st,i)::r -> todo := r; let res = f st in (res,i) :: map_on_states f + +let number_of_states () = !next + +let goto_state = function + [] -> Backtrack + | ps -> Goto (get_state ps) + + +let transition_from chars follow pos_set = + let tr = Array.create 256 [] + and shift = Array.create 256 Backtrack in + List.iter + (fun pos -> + List.iter + (fun c -> + tr.(Char.code c) <- + merge_trans tr.(Char.code c) follow.(pos)) + chars.(pos)) + pos_set; + for i = 0 to 255 do + shift.(i) <- goto_state tr.(i) + done; + shift + + +let translate_state chars follow state = + match split_trans_set state with + n, [] -> Perform n + | n, ps -> Shift( (if n = no_action then No_remember else Remember n), + transition_from chars follow ps) + + +let make_dfa lexdef = + let (chars, name_regexp_list, actions) = + encode_lexdef lexdef in +(** + List.iter (fun (name, regexp) -> prerr_string name; prerr_string " = "; print_regexp regexp; prerr_newline()) name_regexp_list; +**) + let follow = + followpos (Array.length chars) name_regexp_list in + let initial_states = + List.map (fun (name, regexp) -> (name, get_state(firstpos regexp))) + name_regexp_list in + let states = + map_on_states (translate_state chars follow) in + let v = + Array.create (number_of_states()) (Perform 0) in + List.iter (fun (auto, i) -> v.(i) <- auto) states; + (initial_states, v, actions) + |
