1------------------------------------------------------------------------------ 2-- -- 3-- GNAT COMPILER COMPONENTS -- 4-- -- 5-- P A R . C H 2 -- 6-- -- 7-- B o d y -- 8-- -- 9-- Copyright (C) 1992-2003 Free Software Foundation, Inc. -- 10-- -- 11-- GNAT is free software; you can redistribute it and/or modify it under -- 12-- terms of the GNU General Public License as published by the Free Soft- -- 13-- ware Foundation; either version 2, or (at your option) any later ver- -- 14-- sion. GNAT is distributed in the hope that it will be useful, but WITH- -- 15-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY -- 16-- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License -- 17-- for more details. You should have received a copy of the GNU General -- 18-- Public License distributed with GNAT; see file COPYING. If not, write -- 19-- to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, -- 20-- MA 02111-1307, USA. -- 21-- -- 22-- GNAT was originally developed by the GNAT team at New York University. -- 23-- Extensive contributions were provided by Ada Core Technologies Inc. -- 24-- -- 25------------------------------------------------------------------------------ 26 27pragma Style_Checks (All_Checks); 28-- Turn off subprogram body ordering check. Subprograms are in order 29-- by RM section rather than alphabetical 30 31separate (Par) 32package body Ch2 is 33 34 -- Local functions, used only in this chapter 35 36 function P_Pragma_Argument_Association return Node_Id; 37 38 --------------------- 39 -- 2.3 Identifier -- 40 --------------------- 41 42 -- IDENTIFIER ::= LETTER {[UNDERLINE] LETTER_OR_DIGIT} 43 44 -- LETTER_OR_DIGIT ::= IDENTIFIER_LETTER | DIGIT 45 46 -- An IDENTIFIER shall not be a reserved word 47 48 -- Error recovery: can raise Error_Resync (cannot return Error) 49 50 function P_Identifier (C : Id_Check := None) return Node_Id is 51 Ident_Node : Node_Id; 52 53 begin 54 -- All set if we do indeed have an identifier 55 56 if Token = Tok_Identifier then 57 Ident_Node := Token_Node; 58 Scan; -- past Identifier 59 return Ident_Node; 60 61 -- If we have a reserved identifier, manufacture an identifier with 62 -- a corresponding name after posting an appropriate error message 63 64 elsif Is_Reserved_Identifier (C) then 65 Scan_Reserved_Identifier (Force_Msg => False); 66 Ident_Node := Token_Node; 67 Scan; -- past the node 68 return Ident_Node; 69 70 -- Otherwise we have junk that cannot be interpreted as an identifier 71 72 else 73 T_Identifier; -- to give message 74 raise Error_Resync; 75 end if; 76 end P_Identifier; 77 78 -------------------------- 79 -- 2.3 Letter Or Digit -- 80 -------------------------- 81 82 -- Parsed by P_Identifier (2.3) 83 84 -------------------------- 85 -- 2.4 Numeric Literal -- 86 -------------------------- 87 88 -- NUMERIC_LITERAL ::= DECIMAL_LITERAL | BASED_LITERAL 89 90 -- Numeric literal is returned by the scanner as either 91 -- Tok_Integer_Literal or Tok_Real_Literal 92 93 ---------------------------- 94 -- 2.4.1 Decimal Literal -- 95 ---------------------------- 96 97 -- DECIMAL_LITERAL ::= NUMERAL [.NUMERAL] [EXPONENT] 98 99 -- Handled by scanner as part of numeric lIteral handing (see 2.4) 100 101 -------------------- 102 -- 2.4.1 Numeral -- 103 -------------------- 104 105 -- NUMERAL ::= DIGIT {[UNDERLINE] DIGIT} 106 107 -- Handled by scanner as part of numeric literal handling (see 2.4) 108 109 --------------------- 110 -- 2.4.1 Exponent -- 111 --------------------- 112 113 -- EXPONENT ::= E [+] NUMERAL | E - NUMERAL 114 115 -- Handled by scanner as part of numeric literal handling (see 2.4) 116 117 -------------------------- 118 -- 2.4.2 Based Literal -- 119 -------------------------- 120 121 -- BASED_LITERAL ::= 122 -- BASE # BASED_NUMERAL [.BASED_NUMERAL] # [EXPONENT] 123 124 -- Handled by scanner as part of numeric literal handling (see 2.4) 125 126 ----------------- 127 -- 2.4.2 Base -- 128 ----------------- 129 130 -- BASE ::= NUMERAL 131 132 -- Handled by scanner as part of numeric literal handling (see 2.4) 133 134 -------------------------- 135 -- 2.4.2 Based Numeral -- 136 -------------------------- 137 138 -- BASED_NUMERAL ::= 139 -- EXTENDED_DIGIT {[UNDERLINE] EXTENDED_DIGIT} 140 141 -- Handled by scanner as part of numeric literal handling (see 2.4) 142 143 --------------------------- 144 -- 2.4.2 Extended Digit -- 145 --------------------------- 146 147 -- EXTENDED_DIGIT ::= DIGIT | A | B | C | D | E | F 148 149 -- Handled by scanner as part of numeric literal handling (see 2.4) 150 151 ---------------------------- 152 -- 2.5 Character Literal -- 153 ---------------------------- 154 155 -- CHARACTER_LITERAL ::= ' GRAPHIC_CHARACTER ' 156 157 -- Handled by the scanner and returned as Tok_Character_Literal 158 159 ------------------------- 160 -- 2.6 String Literal -- 161 ------------------------- 162 163 -- STRING LITERAL ::= "{STRING_ELEMENT}" 164 165 -- Handled by the scanner and returned as Tok_Character_Literal 166 -- or if the string looks like an operator as Tok_Operator_Symbol. 167 168 ------------------------- 169 -- 2.6 String Element -- 170 ------------------------- 171 172 -- STRING_ELEMENT ::= "" | non-quotation_mark_GRAPHIC_CHARACTER 173 174 -- A STRING_ELEMENT is either a pair of quotation marks ("), 175 -- or a single GRAPHIC_CHARACTER other than a quotation mark. 176 177 -- Handled by scanner as part of string literal handling (see 2.4) 178 179 ------------------ 180 -- 2.7 Comment -- 181 ------------------ 182 183 -- A COMMENT starts with two adjacent hyphens and extends up to the 184 -- end of the line. A COMMENT may appear on any line of a program. 185 186 -- Handled by the scanner which simply skips past encountered comments 187 188 ----------------- 189 -- 2.8 Pragma -- 190 ----------------- 191 192 -- PRAGMA ::= pragma IDENTIFIER 193 -- [(PRAGMA_ARGUMENT_ASSOCIATION {, PRAGMA_ARGUMENT_ASSOCIATION})]; 194 195 -- The caller has checked that the initial token is PRAGMA 196 197 -- Error recovery: cannot raise Error_Resync 198 199 -- One special piece of processing is needed in this routine. As described 200 -- in the section on "Handling semicolon used in place of IS" in module 201 -- Parse, the parser detects the case of missing subprogram bodies to 202 -- allow recovery from this syntactic error. Pragma INTERFACE (and, for 203 -- Ada 95, pragma IMPORT) can appear in place of the body. The parser must 204 -- recognize the use of these two pragmas in this context, otherwise it 205 -- will think there are missing bodies, and try to change ; to IS, when 206 -- in fact the bodies ARE present, supplied by these pragmas. 207 208 function P_Pragma return Node_Id is 209 210 Interface_Check_Required : Boolean := False; 211 -- Set True if check of pragma INTERFACE is required 212 213 Import_Check_Required : Boolean := False; 214 -- Set True if check of pragma IMPORT is required 215 216 Arg_Count : Int := 0; 217 -- Number of argument associations processed 218 219 Pragma_Node : Node_Id; 220 Pragma_Name : Name_Id; 221 Semicolon_Loc : Source_Ptr; 222 Ident_Node : Node_Id; 223 Assoc_Node : Node_Id; 224 Result : Node_Id; 225 226 procedure Skip_Pragma_Semicolon; 227 -- Skip past semicolon at end of pragma 228 229 --------------------------- 230 -- Skip_Pragma_Semicolon -- 231 --------------------------- 232 233 procedure Skip_Pragma_Semicolon is 234 begin 235 if Token /= Tok_Semicolon then 236 T_Semicolon; 237 Resync_Past_Semicolon; 238 else 239 Scan; -- past semicolon 240 end if; 241 end Skip_Pragma_Semicolon; 242 243 -- Start of processing for P_Pragma 244 245 begin 246 Pragma_Node := New_Node (N_Pragma, Token_Ptr); 247 Scan; -- past PRAGMA 248 Pragma_Name := Token_Name; 249 250 if Style_Check then 251 Style.Check_Pragma_Name; 252 end if; 253 254 Ident_Node := P_Identifier; 255 Set_Chars (Pragma_Node, Pragma_Name); 256 Delete_Node (Ident_Node); 257 258 -- See if special INTERFACE/IMPORT check is required 259 260 if SIS_Entry_Active then 261 Interface_Check_Required := (Pragma_Name = Name_Interface); 262 Import_Check_Required := (Pragma_Name = Name_Import); 263 else 264 Interface_Check_Required := False; 265 Import_Check_Required := False; 266 end if; 267 268 -- Scan arguments. We assume that arguments are present if there is 269 -- a left paren, or if a semicolon is missing and there is another 270 -- token on the same line as the pragma name. 271 272 if Token = Tok_Left_Paren 273 or else (Token /= Tok_Semicolon 274 and then not Token_Is_At_Start_Of_Line) 275 then 276 Set_Pragma_Argument_Associations (Pragma_Node, New_List); 277 T_Left_Paren; 278 279 loop 280 Arg_Count := Arg_Count + 1; 281 Assoc_Node := P_Pragma_Argument_Association; 282 283 if Arg_Count = 2 284 and then (Interface_Check_Required or else Import_Check_Required) 285 then 286 -- Here is where we cancel the SIS active status if this pragma 287 -- supplies a body for the currently active subprogram spec. 288 289 if Nkind (Expression (Assoc_Node)) in N_Direct_Name 290 and then Chars (Expression (Assoc_Node)) = Chars (SIS_Labl) 291 then 292 SIS_Entry_Active := False; 293 end if; 294 end if; 295 296 Append (Assoc_Node, Pragma_Argument_Associations (Pragma_Node)); 297 exit when Token /= Tok_Comma; 298 Scan; -- past comma 299 end loop; 300 301 -- If we have := for pragma Debug, it is worth special casing 302 -- the error message (it is easy to think of pragma Debug as 303 -- taking a statement, and an assignment statement is the most 304 -- likely candidate for this error) 305 306 if Token = Tok_Colon_Equal and then Pragma_Name = Name_Debug then 307 Error_Msg_SC ("argument for pragma Debug must be procedure call"); 308 Resync_To_Semicolon; 309 310 -- Normal case, we expect a right paren here 311 312 else 313 T_Right_Paren; 314 end if; 315 end if; 316 317 Semicolon_Loc := Token_Ptr; 318 319 -- Now we have two tasks left, we need to scan out the semicolon 320 -- following the pragma, and we have to call Par.Prag to process 321 -- the pragma. Normally we do them in this order, however, there 322 -- is one exception namely pragma Style_Checks where we like to 323 -- skip the semicolon after processing the pragma, since that way 324 -- the style checks for the scanning of the semicolon follow the 325 -- settings of the pragma. 326 327 -- You might think we could just unconditionally do things in 328 -- the opposite order, but there are other pragmas, notably the 329 -- case of pragma Source_File_Name, which assume the semicolon 330 -- is already scanned out. 331 332 if Chars (Pragma_Node) = Name_Style_Checks then 333 Result := Par.Prag (Pragma_Node, Semicolon_Loc); 334 Skip_Pragma_Semicolon; 335 return Result; 336 else 337 Skip_Pragma_Semicolon; 338 return Par.Prag (Pragma_Node, Semicolon_Loc); 339 end if; 340 341 exception 342 when Error_Resync => 343 Resync_Past_Semicolon; 344 return Error; 345 346 end P_Pragma; 347 348 -- This routine is called if a pragma is encountered in an inappropriate 349 -- position, the pragma is scanned out and control returns to continue. 350 351 -- The caller has checked that the initial token is pragma 352 353 -- Error recovery: cannot raise Error_Resync 354 355 procedure P_Pragmas_Misplaced is 356 begin 357 while Token = Tok_Pragma loop 358 Error_Msg_SC ("pragma not allowed here"); 359 Discard_Junk_Node (P_Pragma); 360 end loop; 361 end P_Pragmas_Misplaced; 362 363 -- This function is called to scan out an optional sequence of pragmas. 364 -- If no pragmas are found, then No_List is returned. 365 366 -- Error recovery: Cannot raise Error_Resync 367 368 function P_Pragmas_Opt return List_Id is 369 L : List_Id; 370 371 begin 372 if Token = Tok_Pragma then 373 L := New_List; 374 P_Pragmas_Opt (L); 375 return L; 376 377 else 378 return No_List; 379 end if; 380 end P_Pragmas_Opt; 381 382 -- This procedure is called to scan out an optional sequence of pragmas. 383 -- Any pragmas found are appended to the list provided as an argument. 384 385 -- Error recovery: Cannot raise Error_Resync 386 387 procedure P_Pragmas_Opt (List : List_Id) is 388 P : Node_Id; 389 390 begin 391 while Token = Tok_Pragma loop 392 P := P_Pragma; 393 394 if Chars (P) = Name_Assert or else Chars (P) = Name_Debug then 395 Error_Msg_Name_1 := Chars (P); 396 Error_Msg_N 397 ("pragma% must be in declaration/statement context", P); 398 else 399 Append (P, List); 400 end if; 401 end loop; 402 end P_Pragmas_Opt; 403 404 -------------------------------------- 405 -- 2.8 Pragma_Argument Association -- 406 -------------------------------------- 407 408 -- PRAGMA_ARGUMENT_ASSOCIATION ::= 409 -- [pragma_argument_IDENTIFIER =>] NAME 410 -- | [pragma_argument_IDENTIFIER =>] EXPRESSION 411 412 -- Error recovery: cannot raise Error_Resync 413 414 function P_Pragma_Argument_Association return Node_Id is 415 Scan_State : Saved_Scan_State; 416 Pragma_Arg_Node : Node_Id; 417 Identifier_Node : Node_Id; 418 419 begin 420 Pragma_Arg_Node := New_Node (N_Pragma_Argument_Association, Token_Ptr); 421 Set_Chars (Pragma_Arg_Node, No_Name); 422 423 if Token = Tok_Identifier then 424 Identifier_Node := Token_Node; 425 Save_Scan_State (Scan_State); -- at Identifier 426 Scan; -- past Identifier 427 428 if Token = Tok_Arrow then 429 Scan; -- past arrow 430 Set_Chars (Pragma_Arg_Node, Chars (Identifier_Node)); 431 Delete_Node (Identifier_Node); 432 else 433 Restore_Scan_State (Scan_State); -- to Identifier 434 end if; 435 end if; 436 437 Set_Expression (Pragma_Arg_Node, P_Expression); 438 return Pragma_Arg_Node; 439 440 end P_Pragma_Argument_Association; 441 442end Ch2; 443