122 lines
2.8 KiB
OCaml
122 lines
2.8 KiB
OCaml
(*
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Cours "Sémantique et Application à la Vérification de programmes"
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Antoine Miné 2015
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Marc Chevalier 2018
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Josselin Giet 2021
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Ecole normale supérieure, Paris, France / CNRS / INRIA
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*)
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(*
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Lexer for a very simple C-like "curly bracket" language.
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This version has local variables, function calls, and returns.
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*)
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{
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open Lexing
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open Parser
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(* keyword table *)
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let kwd_table = Hashtbl.create 10
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let _ =
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List.iter (fun (a,b) -> Hashtbl.add kwd_table a b)
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[
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(* types *)
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"void", TOK_VOID;
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"int", TOK_INT;
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(* constants *)
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"true", TOK_TRUE;
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"false", TOK_FALSE;
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(* expression operators *)
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"rand", TOK_RAND;
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"brand", TOK_BRAND;
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(* control flow *)
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"for", TOK_FOR;
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"while", TOK_WHILE;
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"return", TOK_RETURN;
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"break", TOK_BREAK;
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"if", TOK_IF;
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"else", TOK_ELSE;
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"goto", TOK_GOTO;
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(* special statements *)
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"assert", TOK_ASSERT;
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]
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}
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(* special character classes *)
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let space = [' ' '\t' '\r']+
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let newline = "\n" | "\r" | "\r\n"
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(* utilities *)
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let digit = ['0'-'9']
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let digit_ = ['0'-'9' '_']
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(* integers *)
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let int_dec = digit digit_*
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let int_bin = ("0b" | "0B") ['0'-'1'] ['0'-'1' '_']*
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let int_oct = ("0o" | "0O") ['0'-'7'] ['0'-'7' '_']*
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let int_hex = ("0x" | "0X") ['0'-'9' 'a'-'f' 'A'-'F'] ['0'-'9' 'a'-'f' 'A'-'F' '_']*
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let const_int = int_bin | int_oct | int_dec | int_hex
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(* tokens *)
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rule token = parse
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(* identifier (TOK_id) or reserved keyword *)
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| ['a'-'z' 'A'-'Z' '_'] ['a'-'z' 'A'-'Z' '0'-'9' '_']* as id
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{ try Hashtbl.find kwd_table id with Not_found -> TOK_id id }
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(* symbols *)
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| "(" { TOK_LPAREN }
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| ")" { TOK_RPAREN }
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| "{" { TOK_LCURLY }
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| "}" { TOK_RCURLY }
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| "*" { TOK_STAR }
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| "+" { TOK_PLUS }
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| "-" { TOK_MINUS }
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| "!" { TOK_EXCLAIM }
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| "/" { TOK_DIVIDE }
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| "%" { TOK_PERCENT }
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| "<" { TOK_LESS }
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| ">" { TOK_GREATER }
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| "<=" { TOK_LESS_EQUAL }
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| ">=" { TOK_GREATER_EQUAL }
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| "==" { TOK_EQUAL_EQUAL }
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| "!=" { TOK_NOT_EQUAL }
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| "&&" { TOK_AND_AND }
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| "||" { TOK_BAR_BAR }
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| ";" { TOK_SEMICOLON }
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| ":" { TOK_COLON }
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| "," { TOK_COMMA }
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| "=" { TOK_EQUAL }
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| "++" { TOK_PLUS_PLUS }
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| "--" { TOK_MINUS_MINUS }
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| "+=" { TOK_PLUS_EQUAL }
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| "-=" { TOK_MINUS_EQUAL }
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| "*=" { TOK_STAR_EQUAL }
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| "/=" { TOK_DIVIDE_EQUAL }
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| "%=" { TOK_PERCENT_EQUAL }
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(* literals *)
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| const_int as c { TOK_int c }
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(* spaces, comments *)
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| "/*" { comment lexbuf; token lexbuf }
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| "//" [^ '\n' '\r']* { token lexbuf }
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| newline { new_line lexbuf; token lexbuf }
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| space { token lexbuf }
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(* end of files *)
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| eof { TOK_EOF }
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(* nested comments (handled recursively) *)
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and comment = parse
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| "*/" { () }
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| [^ '\n' '\r'] { comment lexbuf }
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| newline { new_line lexbuf; comment lexbuf }
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