274 lines
7.8 KiB
OCaml
274 lines
7.8 KiB
OCaml
(***********************************************************************)
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(* *)
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(* Objective Caml *)
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(* *)
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(* Xavier Leroy, projet Cristal, INRIA Rocquencourt *)
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(* *)
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(* Copyright 1996 Institut National de Recherche en Informatique et *)
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(* en Automatique. All rights reserved. This file is distributed *)
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(* under the terms of the Q Public License version 1.0. *)
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(* *)
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(***********************************************************************)
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(* $Id$ *)
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(* The lexical analyzer for lexer definitions. Bootstrapped! *)
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{
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open Syntax
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open Parser
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(* Auxiliaries for the lexical analyzer *)
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let brace_depth = ref 0
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and comment_depth = ref 0
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let in_pattern () = !brace_depth = 0 && !comment_depth = 0
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exception Lexical_error of string * int * int
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let string_buff = Buffer.create 256
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let reset_string_buffer () = Buffer.clear string_buff
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let store_string_char c = Buffer.add_char string_buff c
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let get_stored_string () = Buffer.contents string_buff
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let char_for_backslash = function
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'n' -> '\n'
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| 't' -> '\t'
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| 'b' -> '\b'
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| 'r' -> '\r'
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| c -> c
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let line_num = ref 1
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let line_start_pos = ref 0
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let handle_lexical_error fn lexbuf =
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let line = !line_num
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and column = Lexing.lexeme_start lexbuf - !line_start_pos + 1 in
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try
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fn lexbuf
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with Lexical_error (msg, 0, 0) ->
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raise(Lexical_error(msg, line, column))
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let get_input_name () = Sys.argv.(Array.length Sys.argv - 1)
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let warning lexbuf msg =
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Printf.eprintf "ocamllex warning:\nFile \"%s\", line %d, character %d: %s.\n"
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(get_input_name ()) !line_num
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(Lexing.lexeme_start lexbuf - !line_start_pos+1) msg;
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flush stderr
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let decimal_code c d u =
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100 * (Char.code c - 48) + 10 * (Char.code d - 48) + (Char.code u - 48)
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let char_for_hexadecimal_code d u =
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let d1 = Char.code d in
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let val1 = if d1 >= 97 then d1 - 87
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else if d1 >= 65 then d1 - 55
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else d1 - 48
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in
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let d2 = Char.code u in
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let val2 = if d2 >= 97 then d2 - 87
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else if d2 >= 65 then d2 - 55
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else d2 - 48
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in
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Char.chr (val1 * 16 + val2)
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}
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let identstart =
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['A'-'Z' 'a'-'z' '_' '\192'-'\214' '\216'-'\246' '\248'-'\255']
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let identbody =
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['A'-'Z' 'a'-'z' '_' '\192'-'\214' '\216'-'\246' '\248'-'\255' '\'' '0'-'9']
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let backslash_escapes =
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['\\' '"' '\'' 'n' 't' 'b' 'r']
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rule main = parse
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[' ' '\013' '\009' '\012' ] +
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{ main lexbuf }
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| '\010'
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{ line_start_pos := Lexing.lexeme_end lexbuf;
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incr line_num;
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main lexbuf }
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| "(*"
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{ comment_depth := 1;
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handle_lexical_error comment lexbuf;
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main lexbuf }
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| '_' { Tunderscore }
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| identstart identbody *
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{ match Lexing.lexeme lexbuf with
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"rule" -> Trule
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| "parse" -> Tparse
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| "shortest" -> Tparse_shortest
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| "and" -> Tand
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| "eof" -> Teof
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| "let" -> Tlet
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| "as" -> Tas
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| s -> Tident s }
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| '"'
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{ reset_string_buffer();
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handle_lexical_error string lexbuf;
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Tstring(get_stored_string()) }
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(* note: ''' is a valid character literall (by contrast with the compiler) *)
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| "'" [^ '\\'] "'"
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{ Tchar(Char.code(Lexing.lexeme_char lexbuf 1)) }
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| "'" '\\' backslash_escapes "'"
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{ Tchar(Char.code(char_for_backslash (Lexing.lexeme_char lexbuf 2))) }
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| "'" '\\' (['0'-'9'] as c) (['0'-'9'] as d) (['0'-'9'] as u)"'"
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{ let v = decimal_code c d u in
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if v > 255 then
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raise
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(Lexical_error
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(Printf.sprintf "illegal escape sequence \\%c%c%c" c d u,
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!line_num, Lexing.lexeme_start lexbuf - !line_start_pos+1))
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else
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Tchar v }
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| "'" '\\' 'x'
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(['0'-'9' 'a'-'f' 'A'-'F'] as d) (['0'-'9' 'a'-'f' 'A'-'F'] as u) "'"
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{ Tchar(Char.code(char_for_hexadecimal_code d u)) }
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| "'" '\\' (_ as c)
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{ raise
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(Lexical_error
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(Printf.sprintf "illegal escape sequence \\%c" c,
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!line_num, Lexing.lexeme_start lexbuf - !line_start_pos+1))
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}
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| '{'
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{ let n1 = Lexing.lexeme_end lexbuf
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and l1 = !line_num
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and s1 = !line_start_pos in
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brace_depth := 1;
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let n2 = handle_lexical_error action lexbuf in
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Taction({start_pos = n1; end_pos = n2;
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start_line = l1; start_col = n1 - s1}) }
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| '=' { Tequal }
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| '|' { Tor }
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| '[' { Tlbracket }
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| ']' { Trbracket }
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| '*' { Tstar }
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| '?' { Tmaybe }
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| '+' { Tplus }
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| '(' { Tlparen }
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| ')' { Trparen }
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| '^' { Tcaret }
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| '-' { Tdash }
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| eof { Tend }
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| _
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{ raise(Lexical_error
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("illegal character " ^ String.escaped(Lexing.lexeme lexbuf),
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!line_num, Lexing.lexeme_start lexbuf - !line_start_pos+1)) }
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(* String parsing comes from the compiler lexer *)
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and string = parse
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'"'
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{ () }
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| '\\' ("\010" | "\013" | "\013\010") [' ' '\009'] *
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{ line_start_pos := Lexing.lexeme_end lexbuf;
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incr line_num;
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string lexbuf }
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| '\\' (backslash_escapes as c)
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{ store_string_char(char_for_backslash c);
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string lexbuf }
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| '\\' (['0'-'9'] as c) (['0'-'9'] as d) (['0'-'9'] as u)
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{ let v = decimal_code c d u in
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if in_pattern () && v > 255 then
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warning lexbuf
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(Printf.sprintf
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"illegal backslash escape in string: `\\%c%c%c'" c d u) ;
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store_string_char (Char.chr v);
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string lexbuf }
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| '\\' 'x' (['0'-'9' 'a'-'f' 'A'-'F'] as d) (['0'-'9' 'a'-'f' 'A'-'F'] as u)
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{ store_string_char (char_for_hexadecimal_code d u) ;
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string lexbuf }
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| '\\' (_ as c)
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{if in_pattern () then
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warning lexbuf
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(Printf.sprintf "illegal backslash escape in string: `\\%c'" c) ;
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store_string_char '\\' ;
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store_string_char c ;
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string lexbuf }
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| eof
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{ raise(Lexical_error("unterminated string", 0, 0)) }
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| '\010'
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{ store_string_char '\010';
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line_start_pos := Lexing.lexeme_end lexbuf;
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incr line_num;
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string lexbuf }
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| _ as c
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{ store_string_char c;
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string lexbuf }
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(*
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Lexers comment and action are quite similar,
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they should lex both strings and characters,
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in order not to be confused by what is inside then
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*)
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and comment = parse
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"(*"
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{ incr comment_depth; comment lexbuf }
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| "*)"
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{ decr comment_depth;
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if !comment_depth = 0 then () else comment lexbuf }
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| '"'
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{ reset_string_buffer();
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string lexbuf;
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reset_string_buffer();
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comment lexbuf }
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| "'"
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{ skip_char lexbuf ;
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comment lexbuf }
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| eof
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{ raise(Lexical_error("unterminated comment", 0, 0)) }
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| '\010'
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{ line_start_pos := Lexing.lexeme_end lexbuf;
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incr line_num;
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comment lexbuf }
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| _
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{ comment lexbuf }
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and action = parse
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'{'
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{ incr brace_depth;
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action lexbuf }
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| '}'
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{ decr brace_depth;
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if !brace_depth = 0 then Lexing.lexeme_start lexbuf else action lexbuf }
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| '"'
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{ reset_string_buffer();
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handle_lexical_error string lexbuf;
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reset_string_buffer();
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action lexbuf }
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| "'"
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{ skip_char lexbuf ;
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action lexbuf }
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| "(*"
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{ comment_depth := 1;
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comment lexbuf;
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action lexbuf }
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| eof
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{ raise (Lexical_error("unterminated action", 0, 0)) }
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| '\010'
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{ line_start_pos := Lexing.lexeme_end lexbuf;
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incr line_num;
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action lexbuf }
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| _
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{ action lexbuf }
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and skip_char = parse
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| '\\'? '\010' "'"
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{ line_start_pos := Lexing.lexeme_end lexbuf;
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incr line_num }
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| [^ '\\' '\''] "'" (* regular character *)
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(* one character and numeric escape sequences *)
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| '\\' _ "'"
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| '\\' ['0'-'9'] ['0'-'9'] ['0'-'9'] "'"
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| '\\' 'x' ['0'-'9' 'a'-'f' 'A'-'F'] ['0'-'9' 'a'-'f' 'A'-'F'] "'"
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{()}
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(* A dieu va ! *)
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| "" {()}
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