perly.y

   1 /*    perly.y
   2  *
   3  *    Copyright (c) 1991-2002, 2003, 2004, 2005, 2006 Larry Wall
   4  *    Copyright (c) 2007, 2008, 2009, 2010, 2011 by Larry Wall and others
   5  *
   6  *    You may distribute under the terms of either the GNU General Public
   7  *    License or the Artistic License, as specified in the README file.
   8  *
   9  */
  10
  11 /*
  12  * 'I see,' laughed Strider.  'I look foul and feel fair.  Is that it?
  13  *  All that is gold does not glitter, not all those who wander are lost.'
  14  *
  15  *     [p.171 of _The Lord of the Rings_, I/x: "Strider"]
  16  */
  17
  18 /*
  19  * This file holds the grammar for the Perl language. If edited, you need
  20  * to run regen_perly.pl, which re-creates the files perly.h, perly.tab
  21  * and perly.act which are derived from this.
  22  *
  23  * The main job of of this grammar is to call the various newFOO()
  24  * functions in op.c to build a syntax tree of OP structs.
  25  * It relies on the lexer in toke.c to do the tokenizing.
  26  *
  27  * Note: due to the way that the cleanup code works WRT to freeing ops on
  28  * the parse stack, it is dangerous to assign to the $n variables within
  29  * an action.
  30  */
  31
  32 /*  Make the parser re-entrant. */
  33
  34 %pure_parser
  35
  36 %start grammar
  37
  38 %union {
  39     I32 ival; /* __DEFAULT__ (marker for regen_perly.pl;
  40                                 must always be 1st union member) */
  41     char *pval;
  42     OP *opval;
  43     GV *gvval;
  44 }
  45
  46 %token <ival> GRAMPROG GRAMEXPR GRAMBLOCK GRAMBARESTMT GRAMFULLSTMT GRAMSTMTSEQ
  47
  48 %token <ival> '{' '}' '[' ']' '-' '+' '$' '@' '%' '*' '&' ';' '=' '.'
  49
  50 %token <opval> WORD METHOD FUNCMETH THING PMFUNC PRIVATEREF QWLIST
  51 %token <opval> FUNC0OP FUNC0SUB UNIOPSUB LSTOPSUB
  52 %token <opval> PLUGEXPR PLUGSTMT
  53 %token <pval> LABEL
  54 %token <ival> FORMAT SUB ANONSUB PACKAGE USE
  55 %token <ival> WHILE UNTIL IF UNLESS ELSE ELSIF CONTINUE FOR
  56 %token <ival> GIVEN WHEN DEFAULT
  57 %token <ival> LOOPEX DOTDOT YADAYADA
  58 %token <ival> FUNC0 FUNC1 FUNC UNIOP LSTOP
  59 %token <ival> RELOP EQOP MULOP ADDOP
  60 %token <ival> DOLSHARP DO HASHBRACK NOAMP
  61 %token <ival> LOCAL MY REQUIRE
  62 %token <ival> COLONATTR FORMLBRACK FORMRBRACK
  63
  64 %type <ival> grammar remember mremember
  65 %type <ival>  startsub startanonsub startformsub
  66
  67 %type <ival> mintro
  68
  69 %type <opval> stmtseq fullstmt labfullstmt barestmt block mblock else
  70 %type <opval> expr term subscripted scalar ary hsh arylen star amper sideff
  71 %type <opval> sliceme kvslice gelem
  72 %type <opval> listexpr nexpr texpr iexpr mexpr mnexpr miexpr
  73 %type <opval> optlistexpr optexpr indirob listop method
  74 %type <opval> formname subname proto optsubbody cont my_scalar my_var
  75 %type <opval> refgen_topic formblock
  76 %type <opval> subattrlist myattrlist myattrterm myterm
  77 %type <opval> realsubbody subsignature termbinop termunop anonymous termdo
  78 %type <opval> formstmtseq formline formarg
  79
  80 %nonassoc <ival> PREC_LOW
  81 %nonassoc LOOPEX
  82
  83 %left <ival> OROP DOROP
  84 %left <ival> ANDOP
  85 %right <ival> NOTOP
  86 %nonassoc LSTOP LSTOPSUB
  87 %left <ival> ','
  88 %right <ival> ASSIGNOP
  89 %right <ival> '?' ':'
  90 %nonassoc DOTDOT YADAYADA
  91 %left <ival> OROR DORDOR
  92 %left <ival> ANDAND
  93 %left <ival> BITOROP
  94 %left <ival> BITANDOP
  95 %nonassoc EQOP
  96 %nonassoc RELOP
  97 %nonassoc UNIOP UNIOPSUB
  98 %nonassoc REQUIRE
  99 %left <ival> SHIFTOP
 100 %left ADDOP
 101 %left MULOP
 102 %left <ival> MATCHOP
 103 %right <ival> '!' '~' UMINUS REFGEN
 104 %right <ival> POWOP
 105 %nonassoc <ival> PREINC PREDEC POSTINC POSTDEC POSTJOIN
 106 %left <ival> ARROW
 107 %nonassoc <ival> ')'
 108 %left <ival> '('
 109 %left '[' '{'
 110
 111 %% /* RULES */
 112
 113 /* Top-level choice of what kind of thing yyparse was called to parse */
 114 grammar :       GRAMPROG
 115                         {
 116                           parser->expect = XSTATE;
 117                         }
 118                 remember stmtseq
 119                         {
 120                           newPROG(block_end($3,$4));
 121                           PL_compiling.cop_seq = 0;
 122                           $$ = 0;
 123                         }
 124         |       GRAMEXPR
 125                         {
 126                           parser->expect = XTERM;
 127                         }
 128                 optexpr
 129                         {
 130                           PL_eval_root = $3;
 131                           $$ = 0;
 132                         }
 133         |       GRAMBLOCK
 134                         {
 135                           parser->expect = XBLOCK;
 136                         }
 137                 block
 138                         {
 139                           PL_pad_reset_pending = TRUE;
 140                           PL_eval_root = $3;
 141                           $$ = 0;
 142                           yyunlex();
 143                           parser->yychar = YYEOF;
 144                         }
 145         |       GRAMBARESTMT
 146                         {
 147                           parser->expect = XSTATE;
 148                         }
 149                 barestmt
 150                         {
 151                           PL_pad_reset_pending = TRUE;
 152                           PL_eval_root = $3;
 153                           $$ = 0;
 154                           yyunlex();
 155                           parser->yychar = YYEOF;
 156                         }
 157         |       GRAMFULLSTMT
 158                         {
 159                           parser->expect = XSTATE;
 160                         }
 161                 fullstmt
 162                         {
 163                           PL_pad_reset_pending = TRUE;
 164                           PL_eval_root = $3;
 165                           $$ = 0;
 166                           yyunlex();
 167                           parser->yychar = YYEOF;
 168                         }
 169         |       GRAMSTMTSEQ
 170                         {
 171                           parser->expect = XSTATE;
 172                         }
 173                 stmtseq
 174                         {
 175                           PL_eval_root = $3;
 176                           $$ = 0;
 177                         }
 178         ;
 179
 180 /* An ordinary block */
 181 block   :       '{' remember stmtseq '}'
 182                         { if (parser->copline > (line_t)$1)
 183                               parser->copline = (line_t)$1;
 184                           $$ = block_end($2, $3);
 185                         }
 186         ;
 187
 188 /* format body */
 189 formblock:      '=' remember ';' FORMRBRACK formstmtseq ';' '.'
 190                         { if (parser->copline > (line_t)$1)
 191                               parser->copline = (line_t)$1;
 192                           $$ = block_end($2, $5);
 193                         }
 194         ;
 195
 196 remember:       /* NULL */      /* start a full lexical scope */
 197                         { $$ = block_start(TRUE);
 198                           parser->parsed_sub = 0; }
 199         ;
 200
 201 mblock  :       '{' mremember stmtseq '}'
 202                         { if (parser->copline > (line_t)$1)
 203                               parser->copline = (line_t)$1;
 204                           $$ = block_end($2, $3);
 205                         }
 206         ;
 207
 208 mremember:      /* NULL */      /* start a partial lexical scope */
 209                         { $$ = block_start(FALSE);
 210                           parser->parsed_sub = 0; }
 211         ;
 212
 213 /* A sequence of statements in the program */
 214 stmtseq :       /* NULL */
 215                         { $$ = (OP*)NULL; }
 216         |       stmtseq fullstmt
 217                         {   $$ = op_append_list(OP_LINESEQ, $1, $2);
 218                             PL_pad_reset_pending = TRUE;
 219                             if ($1 && $2)
 220                                 PL_hints |= HINT_BLOCK_SCOPE;
 221                         }
 222         ;
 223
 224 /* A sequence of format lines */
 225 formstmtseq:    /* NULL */
 226                         { $$ = (OP*)NULL; }
 227         |       formstmtseq formline
 228                         {   $$ = op_append_list(OP_LINESEQ, $1, $2);
 229                             PL_pad_reset_pending = TRUE;
 230                             if ($1 && $2)
 231                                 PL_hints |= HINT_BLOCK_SCOPE;
 232                         }
 233         ;
 234
 235 /* A statement in the program, including optional labels */
 236 fullstmt:       barestmt
 237                         {
 238                           $$ = $1 ? newSTATEOP(0, NULL, $1) : NULL;
 239                         }
 240         |       labfullstmt
 241                         { $$ = $1; }
 242         ;
 243
 244 labfullstmt:    LABEL barestmt
 245                         {
 246                           $$ = newSTATEOP(SVf_UTF8 * $1[strlen($1)+1], $1, $2);
 247                         }
 248         |       LABEL labfullstmt
 249                         {
 250                           $$ = newSTATEOP(SVf_UTF8 * $1[strlen($1)+1], $1, $2);
 251                         }
 252         ;
 253
 254 /* A bare statement, lacking label and other aspects of state op */
 255 barestmt:       PLUGSTMT
 256                         { $$ = $1; }
 257         |       FORMAT startformsub formname formblock
 258                         {
 259                           CV *fmtcv = PL_compcv;
 260                           newFORM($2, $3, $4);
 261                           $$ = (OP*)NULL;
 262                           if (CvOUTSIDE(fmtcv) && !CvEVAL(CvOUTSIDE(fmtcv))) {
 263                               SvREFCNT_inc_simple_void(fmtcv);
 264                               pad_add_anon(fmtcv, OP_NULL);
 265                           }
 266                           parser->parsed_sub = 1;
 267                         }
 268         |       SUB subname startsub
 269                         {
 270                           if ($2->op_type == OP_CONST) {
 271                             const char *const name =
 272                                 SvPV_nolen_const(((SVOP*)$2)->op_sv);
 273                             if (strEQ(name, "BEGIN") || strEQ(name, "END")
 274                               || strEQ(name, "INIT") || strEQ(name, "CHECK")
 275                               || strEQ(name, "UNITCHECK"))
 276                               CvSPECIAL_on(PL_compcv);
 277                           }
 278                           else
 279                           /* State subs inside anonymous subs need to be
 280                              clonable themselves. */
 281                           if (CvANON(CvOUTSIDE(PL_compcv))
 282                            || CvCLONE(CvOUTSIDE(PL_compcv))
 283                            || !PadnameIsSTATE(PadlistNAMESARRAY(CvPADLIST(
 284                                                 CvOUTSIDE(PL_compcv)
 285                                              ))[$2->op_targ]))
 286                               CvCLONE_on(PL_compcv);
 287                           parser->in_my = 0;
 288                           parser->in_my_stash = NULL;
 289                         }
 290                 proto subattrlist optsubbody
 291                         {
 292                           SvREFCNT_inc_simple_void(PL_compcv);
 293                           $2->op_type == OP_CONST
 294                               ? newATTRSUB($3, $2, $5, $6, $7)
 295                               : newMYSUB($3, $2, $5, $6, $7)
 296                           ;
 297                           $$ = (OP*)NULL;
 298                           intro_my();
 299                           parser->parsed_sub = 1;
 300                         }
 301         |       PACKAGE WORD WORD ';'
 302                         {
 303                           package($3);
 304                           if ($2)
 305                               package_version($2);
 306                           $$ = (OP*)NULL;
 307                         }
 308         |       USE startsub
 309                         { CvSPECIAL_on(PL_compcv); /* It's a BEGIN {} */ }
 310                 WORD WORD optlistexpr ';'
 311                         {
 312                           SvREFCNT_inc_simple_void(PL_compcv);
 313                           utilize($1, $2, $4, $5, $6);
 314                           parser->parsed_sub = 1;
 315                           $$ = (OP*)NULL;
 316                         }
 317         |       IF '(' remember mexpr ')' mblock else
 318                         {
 319                           $$ = block_end($3,
 320                               newCONDOP(0, $4, op_scope($6), $7));
 321                           parser->copline = (line_t)$1;
 322                         }
 323         |       UNLESS '(' remember miexpr ')' mblock else
 324                         {
 325                           $$ = block_end($3,
 326                               newCONDOP(0, $4, op_scope($6), $7));
 327                           parser->copline = (line_t)$1;
 328                         }
 329         |       GIVEN '(' remember mexpr ')' mblock
 330                         {
 331                           const PADOFFSET offset = pad_findmy_pvs("$_", 0);
 332                           $$ = block_end($3,
 333                                   newGIVENOP($4, op_scope($6),
 334                                     offset == NOT_IN_PAD
 335                                     || PAD_COMPNAME_FLAGS_isOUR(offset)
 336                                       ? 0
 337                                       : offset));
 338                           parser->copline = (line_t)$1;
 339                         }
 340         |       WHEN '(' remember mexpr ')' mblock
 341                         { $$ = block_end($3, newWHENOP($4, op_scope($6))); }
 342         |       DEFAULT block
 343                         { $$ = newWHENOP(0, op_scope($2)); }
 344         |       WHILE '(' remember texpr ')' mintro mblock cont
 345                         {
 346                           $$ = block_end($3,
 347                                   newWHILEOP(0, 1, (LOOP*)(OP*)NULL,
 348                                       $4, $7, $8, $6));
 349                           parser->copline = (line_t)$1;
 350                         }
 351         |       UNTIL '(' remember iexpr ')' mintro mblock cont
 352                         {
 353                           $$ = block_end($3,
 354                                   newWHILEOP(0, 1, (LOOP*)(OP*)NULL,
 355                                       $4, $7, $8, $6));
 356                           parser->copline = (line_t)$1;
 357                         }
 358         |       FOR '(' remember mnexpr ';'
 359                         { parser->expect = XTERM; }
 360                 texpr ';'
 361                         { parser->expect = XTERM; }
 362                 mintro mnexpr ')'
 363                 mblock
 364                         {
 365                           OP *initop = $4;
 366                           OP *forop = newWHILEOP(0, 1, (LOOP*)(OP*)NULL,
 367                                       scalar($7), $13, $11, $10);
 368                           if (initop) {
 369                               forop = op_prepend_elem(OP_LINESEQ, initop,
 370                                   op_append_elem(OP_LINESEQ,
 371                                       newOP(OP_UNSTACK, OPf_SPECIAL),
 372                                       forop));
 373                           }
 374                           PL_hints |= HINT_BLOCK_SCOPE;
 375                           $$ = block_end($3, forop);
 376                           parser->copline = (line_t)$1;
 377                         }
 378         |       FOR MY remember my_scalar '(' mexpr ')' mblock cont
 379                         {
 380                           $$ = block_end($3, newFOROP(0, $4, $6, $8, $9));
 381                           parser->copline = (line_t)$1;
 382                         }
 383         |       FOR scalar '(' remember mexpr ')' mblock cont
 384                         {
 385                           $$ = block_end($4, newFOROP(0,
 386                                       op_lvalue($2, OP_ENTERLOOP), $5, $7, $8));
 387                           parser->copline = (line_t)$1;
 388                         }
 389         |       FOR REFGEN MY remember my_var
 390                         { parser->in_my = 0; $<opval>$ = my($5); }
 391                 '(' mexpr ')' mblock cont
 392                         {
 393                           $$ = block_end(
 394                                 $4,
 395                                 newFOROP(0,
 396                                          op_lvalue(
 397                                             newUNOP(OP_REFGEN, 0,
 398                                                     $<opval>6),
 399                                             OP_ENTERLOOP),
 400                                          $8, $10, $11)
 401                           );
 402                           parser->copline = (line_t)$1;
 403                         }
 404         |       FOR REFGEN refgen_topic '(' remember mexpr ')' mblock cont
 405                         {
 406                           $$ = block_end($5, newFOROP(
 407                                 0, op_lvalue(newUNOP(OP_REFGEN, 0,
 408                                                      $3),
 409                                              OP_ENTERLOOP), $6, $8, $9));
 410                           parser->copline = (line_t)$1;
 411                         }
 412         |       FOR '(' remember mexpr ')' mblock cont
 413                         {
 414                           $$ = block_end($3,
 415                                   newFOROP(0, (OP*)NULL, $4, $6, $7));
 416                           parser->copline = (line_t)$1;
 417                         }
 418         |       block cont
 419                         {
 420                           /* a block is a loop that happens once */
 421                           $$ = newWHILEOP(0, 1, (LOOP*)(OP*)NULL,
 422                                   (OP*)NULL, $1, $2, 0);
 423                         }
 424         |       PACKAGE WORD WORD '{' remember
 425                         {
 426                           package($3);
 427                           if ($2) {
 428                               package_version($2);
 429                           }
 430                         }
 431                 stmtseq '}'
 432                         {
 433                           /* a block is a loop that happens once */
 434                           $$ = newWHILEOP(0, 1, (LOOP*)(OP*)NULL,
 435                                   (OP*)NULL, block_end($5, $7), (OP*)NULL, 0);
 436                           if (parser->copline > (line_t)$4)
 437                               parser->copline = (line_t)$4;
 438                         }
 439         |       sideff ';'
 440                         {
 441                           $$ = $1;
 442                         }
 443         |       ';'
 444                         {
 445                           $$ = (OP*)NULL;
 446                           parser->copline = NOLINE;
 447                         }
 448         ;
 449
 450 /* Format line */
 451 formline:       THING formarg
 452                         { OP *list;
 453                           if ($2) {
 454                               OP *term = $2;
 455                               list = op_append_elem(OP_LIST, $1, term);
 456                           }
 457                           else {
 458                               list = $1;
 459                           }
 460                           if (parser->copline == NOLINE)
 461                                parser->copline = CopLINE(PL_curcop)-1;
 462                           else parser->copline--;
 463                           $$ = newSTATEOP(0, NULL,
 464                                           op_convert_list(OP_FORMLINE, 0, list));
 465                         }
 466         ;
 467
 468 formarg :       /* NULL */
 469                         { $$ = NULL; }
 470         |       FORMLBRACK stmtseq FORMRBRACK
 471                         { $$ = op_unscope($2); }
 472         ;
 473
 474 /* An expression which may have a side-effect */
 475 sideff  :       error
 476                         { $$ = (OP*)NULL; }
 477         |       expr
 478                         { $$ = $1; }
 479         |       expr IF expr
 480                         { $$ = newLOGOP(OP_AND, 0, $3, $1); }
 481         |       expr UNLESS expr
 482                         { $$ = newLOGOP(OP_OR, 0, $3, $1); }
 483         |       expr WHILE expr
 484                         { $$ = newLOOPOP(OPf_PARENS, 1, scalar($3), $1); }
 485         |       expr UNTIL iexpr
 486                         { $$ = newLOOPOP(OPf_PARENS, 1, $3, $1); }
 487         |       expr FOR expr
 488                         { $$ = newFOROP(0, (OP*)NULL, $3, $1, (OP*)NULL);
 489                           parser->copline = (line_t)$2; }
 490         |       expr WHEN expr
 491                         { $$ = newWHENOP($3, op_scope($1)); }
 492         ;
 493
 494 /* else and elsif blocks */
 495 else    :       /* NULL */
 496                         { $$ = (OP*)NULL; }
 497         |       ELSE mblock
 498                         {
 499                           ($2)->op_flags |= OPf_PARENS;
 500                           $$ = op_scope($2);
 501                         }
 502         |       ELSIF '(' mexpr ')' mblock else
 503                         { parser->copline = (line_t)$1;
 504                             $$ = newCONDOP(0,
 505                                 newSTATEOP(OPf_SPECIAL,NULL,$3),
 506                                 op_scope($5), $6);
 507                           PL_hints |= HINT_BLOCK_SCOPE;
 508                         }
 509         ;
 510
 511 /* Continue blocks */
 512 cont    :       /* NULL */
 513                         { $$ = (OP*)NULL; }
 514         |       CONTINUE block
 515                         { $$ = op_scope($2); }
 516         ;
 517
 518 /* determine whether there are any new my declarations */
 519 mintro  :       /* NULL */
 520                         { $$ = (PL_min_intro_pending &&
 521                             PL_max_intro_pending >=  PL_min_intro_pending);
 522                           intro_my(); }
 523
 524 /* Normal expression */
 525 nexpr   :       /* NULL */
 526                         { $$ = (OP*)NULL; }
 527         |       sideff
 528         ;
 529
 530 /* Boolean expression */
 531 texpr   :       /* NULL means true */
 532                         { YYSTYPE tmplval;
 533                           (void)scan_num("1", &tmplval);
 534                           $$ = tmplval.opval; }
 535         |       expr
 536         ;
 537
 538 /* Inverted boolean expression */
 539 iexpr   :       expr
 540                         { $$ = invert(scalar($1)); }
 541         ;
 542
 543 /* Expression with its own lexical scope */
 544 mexpr   :       expr
 545                         { $$ = $1; intro_my(); }
 546         ;
 547
 548 mnexpr  :       nexpr
 549                         { $$ = $1; intro_my(); }
 550         ;
 551
 552 miexpr  :       iexpr
 553                         { $$ = $1; intro_my(); }
 554         ;
 555
 556 formname:       WORD            { $$ = $1; }
 557         |       /* NULL */      { $$ = (OP*)NULL; }
 558         ;
 559
 560 startsub:       /* NULL */      /* start a regular subroutine scope */
 561                         { $$ = start_subparse(FALSE, 0);
 562                             SAVEFREESV(PL_compcv); }
 563
 564         ;
 565
 566 startanonsub:   /* NULL */      /* start an anonymous subroutine scope */
 567                         { $$ = start_subparse(FALSE, CVf_ANON);
 568                             SAVEFREESV(PL_compcv); }
 569         ;
 570
 571 startformsub:   /* NULL */      /* start a format subroutine scope */
 572                         { $$ = start_subparse(TRUE, 0);
 573                             SAVEFREESV(PL_compcv); }
 574         ;
 575
 576 /* Name of a subroutine - must be a bareword, could be special */
 577 subname :       WORD
 578         |       PRIVATEREF
 579         ;
 580
 581 /* Subroutine prototype */
 582 proto   :       /* NULL */
 583                         { $$ = (OP*)NULL; }
 584         |       THING
 585         ;
 586
 587 /* Optional list of subroutine attributes */
 588 subattrlist:    /* NULL */
 589                         { $$ = (OP*)NULL; }
 590         |       COLONATTR THING
 591                         { $$ = $2; }
 592         |       COLONATTR
 593                         { $$ = (OP*)NULL; }
 594         ;
 595
 596 /* List of attributes for a "my" variable declaration */
 597 myattrlist:     COLONATTR THING
 598                         { $$ = $2; }
 599         |       COLONATTR
 600                         { $$ = (OP*)NULL; }
 601         ;
 602
 603 /* Optional subroutine signature */
 604 subsignature:   /* NULL */ { $$ = (OP*)NULL; }
 605         |       '('
 606                         {
 607                           if (!FEATURE_SIGNATURES_IS_ENABLED)
 608                             Perl_croak(aTHX_ "Experimental "
 609                                 "subroutine signatures not enabled");
 610                           Perl_ck_warner_d(aTHX_
 611                                 packWARN(WARN_EXPERIMENTAL__SIGNATURES),
 612                                 "The signatures feature is experimental");
 613                           $<opval>$ = parse_subsignature();
 614                         }
 615                 ')'
 616                         {
 617                           $$ = op_append_list(OP_LINESEQ, $<opval>2,
 618                                 newSTATEOP(0, NULL, sawparens(newNULLLIST())));
 619                           parser->expect = XBLOCK;
 620                         }
 621         ;
 622
 623 /* Subroutine body - block with optional signature */
 624 realsubbody:    remember subsignature '{' stmtseq '}'
 625                         {
 626                           if (parser->copline > (line_t)$3)
 627                               parser->copline = (line_t)$3;
 628                           $$ = block_end($1,
 629                                 op_append_list(OP_LINESEQ, $2, $4));
 630                         }
 631         ;
 632
 633 /* Optional subroutine body, for named subroutine declaration */
 634 optsubbody:     realsubbody { $$ = $1; }
 635         |       ';'     { $$ = (OP*)NULL; }
 636         ;
 637
 638 /* Ordinary expressions; logical combinations */
 639 expr    :       expr ANDOP expr
 640                         { $$ = newLOGOP(OP_AND, 0, $1, $3); }
 641         |       expr OROP expr
 642                         { $$ = newLOGOP($2, 0, $1, $3); }
 643         |       expr DOROP expr
 644                         { $$ = newLOGOP(OP_DOR, 0, $1, $3); }
 645         |       listexpr %prec PREC_LOW
 646         ;
 647
 648 /* Expressions are a list of terms joined by commas */
 649 listexpr:       listexpr ','
 650                         { $$ = $1; }
 651         |       listexpr ',' term
 652                         {
 653                           OP* term = $3;
 654                           $$ = op_append_elem(OP_LIST, $1, term);
 655                         }
 656         |       term %prec PREC_LOW
 657         ;
 658
 659 /* List operators */
 660 listop  :       LSTOP indirob listexpr /* map {...} @args or print $fh @args */
 661                         { $$ = op_convert_list($1, OPf_STACKED,
 662                                 op_prepend_elem(OP_LIST, newGVREF($1,$2), $3) );
 663                         }
 664         |       FUNC '(' indirob expr ')'      /* print ($fh @args */
 665                         { $$ = op_convert_list($1, OPf_STACKED,
 666                                 op_prepend_elem(OP_LIST, newGVREF($1,$3), $4) );
 667                         }
 668         |       term ARROW method '(' optexpr ')' /* $foo->bar(list) */
 669                         { $$ = op_convert_list(OP_ENTERSUB, OPf_STACKED,
 670                                 op_append_elem(OP_LIST,
 671                                     op_prepend_elem(OP_LIST, scalar($1), $5),
 672                                     newMETHOP(OP_METHOD, 0, $3)));
 673                         }
 674         |       term ARROW method                     /* $foo->bar */
 675                         { $$ = op_convert_list(OP_ENTERSUB, OPf_STACKED,
 676                                 op_append_elem(OP_LIST, scalar($1),
 677                                     newMETHOP(OP_METHOD, 0, $3)));
 678                         }
 679         |       METHOD indirob optlistexpr           /* new Class @args */
 680                         { $$ = op_convert_list(OP_ENTERSUB, OPf_STACKED,
 681                                 op_append_elem(OP_LIST,
 682                                     op_prepend_elem(OP_LIST, $2, $3),
 683                                     newMETHOP(OP_METHOD, 0, $1)));
 684                         }
 685         |       FUNCMETH indirob '(' optexpr ')'    /* method $object (@args) */
 686                         { $$ = op_convert_list(OP_ENTERSUB, OPf_STACKED,
 687                                 op_append_elem(OP_LIST,
 688                                     op_prepend_elem(OP_LIST, $2, $4),
 689                                     newMETHOP(OP_METHOD, 0, $1)));
 690                         }
 691         |       LSTOP optlistexpr                    /* print @args */
 692                         { $$ = op_convert_list($1, 0, $2); }
 693         |       FUNC '(' optexpr ')'                 /* print (@args) */
 694                         { $$ = op_convert_list($1, 0, $3); }
 695         |       LSTOPSUB startanonsub block /* sub f(&@);   f { foo } ... */
 696                         { SvREFCNT_inc_simple_void(PL_compcv);
 697                           $<opval>$ = newANONATTRSUB($2, 0, (OP*)NULL, $3); }
 698                     optlistexpr         %prec LSTOP  /* ... @bar */
 699                         { $$ = newUNOP(OP_ENTERSUB, OPf_STACKED,
 700                                  op_append_elem(OP_LIST,
 701                                    op_prepend_elem(OP_LIST, $<opval>4, $5), $1));
 702                         }
 703         ;
 704
 705 /* Names of methods. May use $object->$methodname */
 706 method  :       METHOD
 707         |       scalar
 708         ;
 709
 710 /* Some kind of subscripted expression */
 711 subscripted:    gelem '{' expr ';' '}'        /* *main::{something} */
 712                         /* In this and all the hash accessors, ';' is
 713                          * provided by the tokeniser */
 714                         { $$ = newBINOP(OP_GELEM, 0, $1, scalar($3)); }
 715         |       scalar '[' expr ']'          /* $array[$element] */
 716                         { $$ = newBINOP(OP_AELEM, 0, oopsAV($1), scalar($3));
 717                         }
 718         |       term ARROW '[' expr ']'      /* somearef->[$element] */
 719                         { $$ = newBINOP(OP_AELEM, 0,
 720                                         ref(newAVREF($1),OP_RV2AV),
 721                                         scalar($4));
 722                         }
 723         |       subscripted '[' expr ']'    /* $foo->[$bar]->[$baz] */
 724                         { $$ = newBINOP(OP_AELEM, 0,
 725                                         ref(newAVREF($1),OP_RV2AV),
 726                                         scalar($3));
 727                         }
 728         |       scalar '{' expr ';' '}'    /* $foo{bar();} */
 729                         { $$ = newBINOP(OP_HELEM, 0, oopsHV($1), jmaybe($3));
 730                         }
 731         |       term ARROW '{' expr ';' '}' /* somehref->{bar();} */
 732                         { $$ = newBINOP(OP_HELEM, 0,
 733                                         ref(newHVREF($1),OP_RV2HV),
 734                                         jmaybe($4)); }
 735         |       subscripted '{' expr ';' '}' /* $foo->[bar]->{baz;} */
 736                         { $$ = newBINOP(OP_HELEM, 0,
 737                                         ref(newHVREF($1),OP_RV2HV),
 738                                         jmaybe($3)); }
 739         |       term ARROW '(' ')'          /* $subref->() */
 740                         { $$ = newUNOP(OP_ENTERSUB, OPf_STACKED,
 741                                    newCVREF(0, scalar($1))); }
 742         |       term ARROW '(' expr ')'     /* $subref->(@args) */
 743                         { $$ = newUNOP(OP_ENTERSUB, OPf_STACKED,
 744                                    op_append_elem(OP_LIST, $4,
 745                                        newCVREF(0, scalar($1)))); }
 746
 747         |       subscripted '(' expr ')'   /* $foo->{bar}->(@args) */
 748                         { $$ = newUNOP(OP_ENTERSUB, OPf_STACKED,
 749                                    op_append_elem(OP_LIST, $3,
 750                                                newCVREF(0, scalar($1)))); }
 751         |       subscripted '(' ')'        /* $foo->{bar}->() */
 752                         { $$ = newUNOP(OP_ENTERSUB, OPf_STACKED,
 753                                    newCVREF(0, scalar($1))); }
 754         |       '(' expr ')' '[' expr ']'            /* list slice */
 755                         { $$ = newSLICEOP(0, $5, $2); }
 756         |       QWLIST '[' expr ']'            /* list literal slice */
 757                         { $$ = newSLICEOP(0, $3, $1); }
 758         |       '(' ')' '[' expr ']'                 /* empty list slice! */
 759                         { $$ = newSLICEOP(0, $4, (OP*)NULL); }
 760     ;
 761
 762 /* Binary operators between terms */
 763 termbinop:      term ASSIGNOP term                     /* $x = $y */
 764                         { $$ = newASSIGNOP(OPf_STACKED, $1, $2, $3); }
 765         |       term POWOP term                        /* $x ** $y */
 766                         { $$ = newBINOP($2, 0, scalar($1), scalar($3)); }
 767         |       term MULOP term                        /* $x * $y, $x x $y */
 768                         {   if ($2 != OP_REPEAT)
 769                                 scalar($1);
 770                             $$ = newBINOP($2, 0, $1, scalar($3));
 771                         }
 772         |       term ADDOP term                        /* $x + $y */
 773                         { $$ = newBINOP($2, 0, scalar($1), scalar($3)); }
 774         |       term SHIFTOP term                      /* $x >> $y, $x << $y */
 775                         { $$ = newBINOP($2, 0, scalar($1), scalar($3)); }
 776         |       term RELOP term                        /* $x > $y, etc. */
 777                         { $$ = newBINOP($2, 0, scalar($1), scalar($3)); }
 778         |       term EQOP term                         /* $x == $y, $x eq $y */
 779                         { $$ = newBINOP($2, 0, scalar($1), scalar($3)); }
 780         |       term BITANDOP term                     /* $x & $y */
 781                         { $$ = newBINOP($2, 0, scalar($1), scalar($3)); }
 782         |       term BITOROP term                      /* $x | $y */
 783                         { $$ = newBINOP($2, 0, scalar($1), scalar($3)); }
 784         |       term DOTDOT term                       /* $x..$y, $x...$y */
 785                         { $$ = newRANGE($2, scalar($1), scalar($3)); }
 786         |       term ANDAND term                       /* $x && $y */
 787                         { $$ = newLOGOP(OP_AND, 0, $1, $3); }
 788         |       term OROR term                         /* $x || $y */
 789                         { $$ = newLOGOP(OP_OR, 0, $1, $3); }
 790         |       term DORDOR term                       /* $x // $y */
 791                         { $$ = newLOGOP(OP_DOR, 0, $1, $3); }
 792         |       term MATCHOP term                      /* $x =~ /$y/ */
 793                         { $$ = bind_match($2, $1, $3); }
 794     ;
 795
 796 /* Unary operators and terms */
 797 termunop : '-' term %prec UMINUS                       /* -$x */
 798                         { $$ = newUNOP(OP_NEGATE, 0, scalar($2)); }
 799         |       '+' term %prec UMINUS                  /* +$x */
 800                         { $$ = $2; }
 801
 802         |       '!' term                               /* !$x */
 803                         { $$ = newUNOP(OP_NOT, 0, scalar($2)); }
 804         |       '~' term                               /* ~$x */
 805                         { $$ = newUNOP(OP_COMPLEMENT, 0, scalar($2)); }
 806         |       term POSTINC                           /* $x++ */
 807                         { $$ = newUNOP(OP_POSTINC, 0,
 808                                         op_lvalue(scalar($1), OP_POSTINC)); }
 809         |       term POSTDEC                           /* $x-- */
 810                         { $$ = newUNOP(OP_POSTDEC, 0,
 811                                         op_lvalue(scalar($1), OP_POSTDEC));}
 812         |       term POSTJOIN    /* implicit join after interpolated ->@ */
 813                         { $$ = op_convert_list(OP_JOIN, 0,
 814                                        op_append_elem(
 815                                         OP_LIST,
 816                                         newSVREF(scalar(
 817                                             newSVOP(OP_CONST,0,
 818                                                     newSVpvs("\""))
 819                                         )),
 820                                         $1
 821                                        ));
 822                         }
 823         |       PREINC term                            /* ++$x */
 824                         { $$ = newUNOP(OP_PREINC, 0,
 825                                         op_lvalue(scalar($2), OP_PREINC)); }
 826         |       PREDEC term                            /* --$x */
 827                         { $$ = newUNOP(OP_PREDEC, 0,
 828                                         op_lvalue(scalar($2), OP_PREDEC)); }
 829
 830     ;
 831
 832 /* Constructors for anonymous data */
 833 anonymous:      '[' expr ']'
 834                         { $$ = newANONLIST($2); }
 835         |       '[' ']'
 836                         { $$ = newANONLIST((OP*)NULL);}
 837         |       HASHBRACK expr ';' '}'  %prec '(' /* { foo => "Bar" } */
 838                         { $$ = newANONHASH($2); }
 839         |       HASHBRACK ';' '}'       %prec '(' /* { } (';' by tokener) */
 840                         { $$ = newANONHASH((OP*)NULL); }
 841         |       ANONSUB startanonsub proto subattrlist realsubbody      %prec '('
 842                         { SvREFCNT_inc_simple_void(PL_compcv);
 843                           $$ = newANONATTRSUB($2, $3, $4, $5); }
 844
 845     ;
 846
 847 /* Things called with "do" */
 848 termdo  :       DO term %prec UNIOP                     /* do $filename */
 849                         { $$ = dofile($2, $1);}
 850         |       DO block        %prec '('               /* do { code */
 851                         { $$ = newUNOP(OP_NULL, OPf_SPECIAL, op_scope($2));}
 852         ;
 853
 854 term    :       termbinop
 855         |       termunop
 856         |       anonymous
 857         |       termdo
 858         |       term '?' term ':' term
 859                         { $$ = newCONDOP(0, $1, $3, $5); }
 860         |       REFGEN term                          /* \$x, \@y, \%z */
 861                         { $$ = newUNOP(OP_REFGEN, 0, op_lvalue($2,OP_REFGEN)); }
 862         |       myattrterm      %prec UNIOP
 863                         { $$ = $1; }
 864         |       LOCAL term      %prec UNIOP
 865                         { $$ = localize($2,$1); }
 866         |       '(' expr ')'
 867                         { $$ = sawparens($2); }
 868         |       QWLIST
 869                         { $$ = $1; }
 870         |       '(' ')'
 871                         { $$ = sawparens(newNULLLIST()); }
 872         |       scalar  %prec '('
 873                         { $$ = $1; }
 874         |       star    %prec '('
 875                         { $$ = $1; }
 876         |       hsh     %prec '('
 877                         { $$ = $1; }
 878         |       ary     %prec '('
 879                         { $$ = $1; }
 880         |       arylen  %prec '('                    /* $#x, $#{ something } */
 881                         { $$ = newUNOP(OP_AV2ARYLEN, 0, ref($1, OP_AV2ARYLEN));}
 882         |       subscripted
 883                         { $$ = $1; }
 884         |       sliceme '[' expr ']'                     /* array slice */
 885                         { $$ = op_prepend_elem(OP_ASLICE,
 886                                 newOP(OP_PUSHMARK, 0),
 887                                     newLISTOP(OP_ASLICE, 0,
 888                                         list($3),
 889                                         ref($1, OP_ASLICE)));
 890                           if ($$ && $1)
 891                               $$->op_private |=
 892                                   $1->op_private & OPpSLICEWARNING;
 893                         }
 894         |       kvslice '[' expr ']'                 /* array key/value slice */
 895                         { $$ = op_prepend_elem(OP_KVASLICE,
 896                                 newOP(OP_PUSHMARK, 0),
 897                                     newLISTOP(OP_KVASLICE, 0,
 898                                         list($3),
 899                                         ref(oopsAV($1), OP_KVASLICE)));
 900                           if ($$ && $1)
 901                               $$->op_private |=
 902                                   $1->op_private & OPpSLICEWARNING;
 903                         }
 904         |       sliceme '{' expr ';' '}'                 /* @hash{@keys} */
 905                         { $$ = op_prepend_elem(OP_HSLICE,
 906                                 newOP(OP_PUSHMARK, 0),
 907                                     newLISTOP(OP_HSLICE, 0,
 908                                         list($3),
 909                                         ref(oopsHV($1), OP_HSLICE)));
 910                           if ($$ && $1)
 911                               $$->op_private |=
 912                                   $1->op_private & OPpSLICEWARNING;
 913                         }
 914         |       kvslice '{' expr ';' '}'                 /* %hash{@keys} */
 915                         { $$ = op_prepend_elem(OP_KVHSLICE,
 916                                 newOP(OP_PUSHMARK, 0),
 917                                     newLISTOP(OP_KVHSLICE, 0,
 918                                         list($3),
 919                                         ref($1, OP_KVHSLICE)));
 920                           if ($$ && $1)
 921                               $$->op_private |=
 922                                   $1->op_private & OPpSLICEWARNING;
 923                         }
 924         |       THING   %prec '('
 925                         { $$ = $1; }
 926         |       amper                                /* &foo; */
 927                         { $$ = newUNOP(OP_ENTERSUB, 0, scalar($1)); }
 928         |       amper '(' ')'                 /* &foo() or foo() */
 929                         { $$ = newUNOP(OP_ENTERSUB, OPf_STACKED, scalar($1));
 930                         }
 931         |       amper '(' expr ')'          /* &foo(@args) or foo(@args) */
 932                         {
 933                           $$ = newUNOP(OP_ENTERSUB, OPf_STACKED,
 934                                 op_append_elem(OP_LIST, $3, scalar($1)));
 935                         }
 936         |       NOAMP subname optlistexpr       /* foo @args (no parens) */
 937                         { $$ = newUNOP(OP_ENTERSUB, OPf_STACKED,
 938                             op_append_elem(OP_LIST, $3, scalar($2)));
 939                         }
 940         |       term ARROW '$' '*'
 941                         { $$ = newSVREF($1); }
 942         |       term ARROW '@' '*'
 943                         { $$ = newAVREF($1); }
 944         |       term ARROW '%' '*'
 945                         { $$ = newHVREF($1); }
 946         |       term ARROW '&' '*'
 947                         { $$ = newUNOP(OP_ENTERSUB, 0,
 948                                        scalar(newCVREF($3,$1))); }
 949         |       term ARROW '*' '*'      %prec '('
 950                         { $$ = newGVREF(0,$1); }
 951         |       LOOPEX  /* loop exiting command (goto, last, dump, etc) */
 952                         { $$ = newOP($1, OPf_SPECIAL);
 953                             PL_hints |= HINT_BLOCK_SCOPE; }
 954         |       LOOPEX term
 955                         { $$ = newLOOPEX($1,$2); }
 956         |       NOTOP listexpr                       /* not $foo */
 957                         { $$ = newUNOP(OP_NOT, 0, scalar($2)); }
 958         |       UNIOP                                /* Unary op, $_ implied */
 959                         { $$ = newOP($1, 0); }
 960         |       UNIOP block                          /* eval { foo }* */
 961                         { $$ = newUNOP($1, 0, $2); }
 962         |       UNIOP term                           /* Unary op */
 963                         { $$ = newUNOP($1, 0, $2); }
 964         |       REQUIRE                              /* require, $_ implied */
 965                         { $$ = newOP(OP_REQUIRE, $1 ? OPf_SPECIAL : 0); }
 966         |       REQUIRE term                         /* require Foo */
 967                         { $$ = newUNOP(OP_REQUIRE, $1 ? OPf_SPECIAL : 0, $2); }
 968         |       UNIOPSUB
 969                         { $$ = newUNOP(OP_ENTERSUB, OPf_STACKED, scalar($1)); }
 970         |       UNIOPSUB term                        /* Sub treated as unop */
 971                         { $$ = newUNOP(OP_ENTERSUB, OPf_STACKED,
 972                             op_append_elem(OP_LIST, $2, scalar($1))); }
 973         |       FUNC0                                /* Nullary operator */
 974                         { $$ = newOP($1, 0); }
 975         |       FUNC0 '(' ')'
 976                         { $$ = newOP($1, 0);}
 977         |       FUNC0OP       /* Same as above, but op created in toke.c */
 978                         { $$ = $1; }
 979         |       FUNC0OP '(' ')'
 980                         { $$ = $1; }
 981         |       FUNC0SUB                             /* Sub treated as nullop */
 982                         { $$ = newUNOP(OP_ENTERSUB, OPf_STACKED, scalar($1)); }
 983         |       FUNC1 '(' ')'                        /* not () */
 984                         { $$ = ($1 == OP_NOT)
 985                           ? newUNOP($1, 0, newSVOP(OP_CONST, 0, newSViv(0)))
 986                           : newOP($1, OPf_SPECIAL); }
 987         |       FUNC1 '(' expr ')'                   /* not($foo) */
 988                         { $$ = newUNOP($1, 0, $3); }
 989         |       PMFUNC /* m//, s///, qr//, tr/// */
 990                         {
 991                             if (   $1->op_type != OP_TRANS
 992                                 && $1->op_type != OP_TRANSR
 993                                 && (((PMOP*)$1)->op_pmflags & PMf_HAS_CV))
 994                             {
 995                                 $<ival>$ = start_subparse(FALSE, CVf_ANON);
 996                                 SAVEFREESV(PL_compcv);
 997                             } else
 998                                 $<ival>$ = 0;
 999                         }
1000                     '(' listexpr ')'
1001                         { $$ = pmruntime($1, $4, 1, $<ival>2); }
1002         |       WORD
1003         |       listop
1004         |       YADAYADA
1005                         {
1006                           $$ = newLISTOP(OP_DIE, 0, newOP(OP_PUSHMARK, 0),
1007                                 newSVOP(OP_CONST, 0, newSVpvs("Unimplemented")));
1008                         }
1009         |       PLUGEXPR
1010         ;
1011
1012 /* "my" declarations, with optional attributes */
1013 myattrterm:     MY myterm myattrlist
1014                         { $$ = my_attrs($2,$3); }
1015         |       MY myterm
1016                         { $$ = localize($2,$1); }
1017         ;
1018
1019 /* Things that can be "my"'d */
1020 myterm  :       '(' expr ')'
1021                         { $$ = sawparens($2); }
1022         |       '(' ')'
1023                         { $$ = sawparens(newNULLLIST()); }
1024
1025         |       scalar  %prec '('
1026                         { $$ = $1; }
1027         |       hsh     %prec '('
1028                         { $$ = $1; }
1029         |       ary     %prec '('
1030                         { $$ = $1; }
1031         ;
1032
1033 /* Basic list expressions */
1034 optlistexpr:    /* NULL */ %prec PREC_LOW
1035                         { $$ = (OP*)NULL; }
1036         |       listexpr    %prec PREC_LOW
1037                         { $$ = $1; }
1038         ;
1039
1040 optexpr:        /* NULL */
1041                         { $$ = (OP*)NULL; }
1042         |       expr
1043                         { $$ = $1; }
1044         ;
1045
1046 /* A little bit of trickery to make "for my $foo (@bar)" actually be
1047    lexical */
1048 my_scalar:      scalar
1049                         { parser->in_my = 0; $$ = my($1); }
1050         ;
1051
1052 my_var  :       scalar
1053         |       ary
1054         |       hsh
1055         ;
1056
1057 refgen_topic:   my_var
1058         |       amper
1059         ;
1060
1061 amper   :       '&' indirob
1062                         { $$ = newCVREF($1,$2); }
1063         ;
1064
1065 scalar  :       '$' indirob
1066                         { $$ = newSVREF($2); }
1067         ;
1068
1069 ary     :       '@' indirob
1070                         { $$ = newAVREF($2);
1071                           if ($$) $$->op_private |= $1;
1072                         }
1073         ;
1074
1075 hsh     :       '%' indirob
1076                         { $$ = newHVREF($2);
1077                           if ($$) $$->op_private |= $1;
1078                         }
1079         ;
1080
1081 arylen  :       DOLSHARP indirob
1082                         { $$ = newAVREF($2); }
1083         |       term ARROW DOLSHARP '*'
1084                         { $$ = newAVREF($1); }
1085         ;
1086
1087 star    :       '*' indirob
1088                         { $$ = newGVREF(0,$2); }
1089         ;
1090
1091 sliceme :       ary
1092         |       term ARROW '@'
1093                         { $$ = newAVREF($1); }
1094         ;
1095
1096 kvslice :       hsh
1097         |       term ARROW '%'
1098                         { $$ = newHVREF($1); }
1099         ;
1100
1101 gelem   :       star
1102         |       term ARROW '*'
1103                         { $$ = newGVREF(0,$1); }
1104         ;
1105
1106 /* Indirect objects */
1107 indirob :       WORD
1108                         { $$ = scalar($1); }
1109         |       scalar %prec PREC_LOW
1110                         { $$ = scalar($1); }
1111         |       block
1112                         { $$ = op_scope($1); }
1113
1114         |       PRIVATEREF
1115                         { $$ = $1; }
1116         ;