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> BAREWORD 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
  73 %type <opval> optlistexpr optexpr optrepl 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 termbinop termunop anonymous termdo
  78 %type <ival>  sigslurpsigil
  79 %type <opval> sigvarname sigdefault sigscalarelem sigslurpelem
  80 %type <opval> sigelem siglist siglistornull subsignature
  81 %type <opval> formstmtseq formline formarg
  82
  83 %nonassoc <ival> PREC_LOW
  84 %nonassoc LOOPEX
  85
  86 %left <ival> OROP DOROP
  87 %left <ival> ANDOP
  88 %right <ival> NOTOP
  89 %nonassoc LSTOP LSTOPSUB
  90 %left <ival> ','
  91 %right <ival> ASSIGNOP
  92 %right <ival> '?' ':'
  93 %nonassoc DOTDOT
  94 %left <ival> OROR DORDOR
  95 %left <ival> ANDAND
  96 %left <ival> BITOROP
  97 %left <ival> BITANDOP
  98 %nonassoc EQOP
  99 %nonassoc RELOP
 100 %nonassoc UNIOP UNIOPSUB
 101 %nonassoc REQUIRE
 102 %left <ival> SHIFTOP
 103 %left ADDOP
 104 %left MULOP
 105 %left <ival> MATCHOP
 106 %right <ival> '!' '~' UMINUS REFGEN
 107 %right <ival> POWOP
 108 %nonassoc <ival> PREINC PREDEC POSTINC POSTDEC POSTJOIN
 109 %left <ival> ARROW
 110 %nonassoc <ival> ')'
 111 %left <ival> '('
 112 %left '[' '{'
 113
 114 %% /* RULES */
 115
 116 /* Top-level choice of what kind of thing yyparse was called to parse */
 117 grammar :       GRAMPROG
 118                         {
 119                           parser->expect = XSTATE;
 120                           $<ival>$ = 0;
 121                         }
 122                 remember stmtseq
 123                         {
 124                           newPROG(block_end($3,$4));
 125                           PL_compiling.cop_seq = 0;
 126                           $$ = 0;
 127                         }
 128         |       GRAMEXPR
 129                         {
 130                           parser->expect = XTERM;
 131                           $<ival>$ = 0;
 132                         }
 133                 optexpr
 134                         {
 135                           PL_eval_root = $3;
 136                           $$ = 0;
 137                         }
 138         |       GRAMBLOCK
 139                         {
 140                           parser->expect = XBLOCK;
 141                           $<ival>$ = 0;
 142                         }
 143                 block
 144                         {
 145                           PL_pad_reset_pending = TRUE;
 146                           PL_eval_root = $3;
 147                           $$ = 0;
 148                           yyunlex();
 149                           parser->yychar = yytoken = YYEOF;
 150                         }
 151         |       GRAMBARESTMT
 152                         {
 153                           parser->expect = XSTATE;
 154                           $<ival>$ = 0;
 155                         }
 156                 barestmt
 157                         {
 158                           PL_pad_reset_pending = TRUE;
 159                           PL_eval_root = $3;
 160                           $$ = 0;
 161                           yyunlex();
 162                           parser->yychar = yytoken = YYEOF;
 163                         }
 164         |       GRAMFULLSTMT
 165                         {
 166                           parser->expect = XSTATE;
 167                           $<ival>$ = 0;
 168                         }
 169                 fullstmt
 170                         {
 171                           PL_pad_reset_pending = TRUE;
 172                           PL_eval_root = $3;
 173                           $$ = 0;
 174                           yyunlex();
 175                           parser->yychar = yytoken = YYEOF;
 176                         }
 177         |       GRAMSTMTSEQ
 178                         {
 179                           parser->expect = XSTATE;
 180                           $<ival>$ = 0;
 181                         }
 182                 stmtseq
 183                         {
 184                           PL_eval_root = $3;
 185                           $$ = 0;
 186                         }
 187         ;
 188
 189 /* An ordinary block */
 190 block   :       '{' remember stmtseq '}'
 191                         { if (parser->copline > (line_t)$1)
 192                               parser->copline = (line_t)$1;
 193                           $$ = block_end($2, $3);
 194                         }
 195         ;
 196
 197 /* format body */
 198 formblock:      '=' remember ';' FORMRBRACK formstmtseq ';' '.'
 199                         { if (parser->copline > (line_t)$1)
 200                               parser->copline = (line_t)$1;
 201                           $$ = block_end($2, $5);
 202                         }
 203         ;
 204
 205 remember:       /* NULL */      /* start a full lexical scope */
 206                         { $$ = block_start(TRUE);
 207                           parser->parsed_sub = 0; }
 208         ;
 209
 210 mblock  :       '{' mremember stmtseq '}'
 211                         { if (parser->copline > (line_t)$1)
 212                               parser->copline = (line_t)$1;
 213                           $$ = block_end($2, $3);
 214                         }
 215         ;
 216
 217 mremember:      /* NULL */      /* start a partial lexical scope */
 218                         { $$ = block_start(FALSE);
 219                           parser->parsed_sub = 0; }
 220         ;
 221
 222 /* A sequence of statements in the program */
 223 stmtseq :       /* NULL */
 224                         { $$ = NULL; }
 225         |       stmtseq fullstmt
 226                         {   $$ = op_append_list(OP_LINESEQ, $1, $2);
 227                             PL_pad_reset_pending = TRUE;
 228                             if ($1 && $2)
 229                                 PL_hints |= HINT_BLOCK_SCOPE;
 230                         }
 231         ;
 232
 233 /* A sequence of format lines */
 234 formstmtseq:    /* NULL */
 235                         { $$ = NULL; }
 236         |       formstmtseq formline
 237                         {   $$ = op_append_list(OP_LINESEQ, $1, $2);
 238                             PL_pad_reset_pending = TRUE;
 239                             if ($1 && $2)
 240                                 PL_hints |= HINT_BLOCK_SCOPE;
 241                         }
 242         ;
 243
 244 /* A statement in the program, including optional labels */
 245 fullstmt:       barestmt
 246                         {
 247                           $$ = $1 ? newSTATEOP(0, NULL, $1) : NULL;
 248                         }
 249         |       labfullstmt
 250                         { $$ = $1; }
 251         ;
 252
 253 labfullstmt:    LABEL barestmt
 254                         {
 255                           $$ = newSTATEOP(SVf_UTF8 * $1[strlen($1)+1], $1, $2);
 256                         }
 257         |       LABEL labfullstmt
 258                         {
 259                           $$ = newSTATEOP(SVf_UTF8 * $1[strlen($1)+1], $1, $2);
 260                         }
 261         ;
 262
 263 /* A bare statement, lacking label and other aspects of state op */
 264 barestmt:       PLUGSTMT
 265                         { $$ = $1; }
 266         |       FORMAT startformsub formname formblock
 267                         {
 268                           CV *fmtcv = PL_compcv;
 269                           newFORM($2, $3, $4);
 270                           $$ = NULL;
 271                           if (CvOUTSIDE(fmtcv) && !CvEVAL(CvOUTSIDE(fmtcv))) {
 272                               pad_add_weakref(fmtcv);
 273                           }
 274                           parser->parsed_sub = 1;
 275                         }
 276         |       SUB subname startsub
 277                         {
 278                           if ($2->op_type == OP_CONST) {
 279                             const char *const name =
 280                                 SvPV_nolen_const(((SVOP*)$2)->op_sv);
 281                             if (strEQ(name, "BEGIN") || strEQ(name, "END")
 282                               || strEQ(name, "INIT") || strEQ(name, "CHECK")
 283                               || strEQ(name, "UNITCHECK"))
 284                               CvSPECIAL_on(PL_compcv);
 285                           }
 286                           else
 287                           /* State subs inside anonymous subs need to be
 288                              clonable themselves. */
 289                           if (CvANON(CvOUTSIDE(PL_compcv))
 290                            || CvCLONE(CvOUTSIDE(PL_compcv))
 291                            || !PadnameIsSTATE(PadlistNAMESARRAY(CvPADLIST(
 292                                                 CvOUTSIDE(PL_compcv)
 293                                              ))[$2->op_targ]))
 294                               CvCLONE_on(PL_compcv);
 295                           parser->in_my = 0;
 296                           parser->in_my_stash = NULL;
 297                         }
 298                 proto subattrlist optsubbody
 299                         {
 300                           SvREFCNT_inc_simple_void(PL_compcv);
 301                           $2->op_type == OP_CONST
 302                               ? newATTRSUB($3, $2, $5, $6, $7)
 303                               : newMYSUB($3, $2, $5, $6, $7)
 304                           ;
 305                           $$ = NULL;
 306                           intro_my();
 307                           parser->parsed_sub = 1;
 308                         }
 309         |       PACKAGE BAREWORD BAREWORD ';'
 310                         {
 311                           package($3);
 312                           if ($2)
 313                               package_version($2);
 314                           $$ = NULL;
 315                         }
 316         |       USE startsub
 317                         { CvSPECIAL_on(PL_compcv); /* It's a BEGIN {} */ }
 318                 BAREWORD BAREWORD optlistexpr ';'
 319                         {
 320                           SvREFCNT_inc_simple_void(PL_compcv);
 321                           utilize($1, $2, $4, $5, $6);
 322                           parser->parsed_sub = 1;
 323                           $$ = NULL;
 324                         }
 325         |       IF '(' remember mexpr ')' mblock else
 326                         {
 327                           $$ = block_end($3,
 328                               newCONDOP(0, $4, op_scope($6), $7));
 329                           parser->copline = (line_t)$1;
 330                         }
 331         |       UNLESS '(' remember mexpr ')' mblock else
 332                         {
 333                           $$ = block_end($3,
 334                               newCONDOP(0, $4, $7, op_scope($6)));
 335                           parser->copline = (line_t)$1;
 336                         }
 337         |       GIVEN '(' remember mexpr ')' mblock
 338                         {
 339                           $$ = block_end($3, newGIVENOP($4, op_scope($6), 0));
 340                           parser->copline = (line_t)$1;
 341                         }
 342         |       WHEN '(' remember mexpr ')' mblock
 343                         { $$ = block_end($3, newWHENOP($4, op_scope($6))); }
 344         |       DEFAULT block
 345                         { $$ = newWHENOP(0, op_scope($2)); }
 346         |       WHILE '(' remember texpr ')' mintro mblock cont
 347                         {
 348                           $$ = block_end($3,
 349                                   newWHILEOP(0, 1, NULL,
 350                                       $4, $7, $8, $6));
 351                           parser->copline = (line_t)$1;
 352                         }
 353         |       UNTIL '(' remember iexpr ')' mintro mblock cont
 354                         {
 355                           $$ = block_end($3,
 356                                   newWHILEOP(0, 1, NULL,
 357                                       $4, $7, $8, $6));
 358                           parser->copline = (line_t)$1;
 359                         }
 360         |       FOR '(' remember mnexpr ';'
 361                         { parser->expect = XTERM; }
 362                 texpr ';'
 363                         { parser->expect = XTERM; }
 364                 mintro mnexpr ')'
 365                 mblock
 366                         {
 367                           OP *initop = $4;
 368                           OP *forop = newWHILEOP(0, 1, NULL,
 369                                       scalar($7), $13, $11, $10);
 370                           if (initop) {
 371                               forop = op_prepend_elem(OP_LINESEQ, initop,
 372                                   op_append_elem(OP_LINESEQ,
 373                                       newOP(OP_UNSTACK, OPf_SPECIAL),
 374                                       forop));
 375                           }
 376                           PL_hints |= HINT_BLOCK_SCOPE;
 377                           $$ = block_end($3, forop);
 378                           parser->copline = (line_t)$1;
 379                         }
 380         |       FOR MY remember my_scalar '(' mexpr ')' mblock cont
 381                         {
 382                           $$ = block_end($3, newFOROP(0, $4, $6, $8, $9));
 383                           parser->copline = (line_t)$1;
 384                         }
 385         |       FOR scalar '(' remember mexpr ')' mblock cont
 386                         {
 387                           $$ = block_end($4, newFOROP(0,
 388                                       op_lvalue($2, OP_ENTERLOOP), $5, $7, $8));
 389                           parser->copline = (line_t)$1;
 390                         }
 391         |       FOR my_refgen remember my_var
 392                         { parser->in_my = 0; $<opval>$ = my($4); }
 393                 '(' mexpr ')' mblock cont
 394                         {
 395                           $$ = block_end(
 396                                 $3,
 397                                 newFOROP(0,
 398                                          op_lvalue(
 399                                             newUNOP(OP_REFGEN, 0,
 400                                                     $<opval>5),
 401                                             OP_ENTERLOOP),
 402                                          $7, $9, $10)
 403                           );
 404                           parser->copline = (line_t)$1;
 405                         }
 406         |       FOR REFGEN refgen_topic '(' remember mexpr ')' mblock cont
 407                         {
 408                           $$ = block_end($5, newFOROP(
 409                                 0, op_lvalue(newUNOP(OP_REFGEN, 0,
 410                                                      $3),
 411                                              OP_ENTERLOOP), $6, $8, $9));
 412                           parser->copline = (line_t)$1;
 413                         }
 414         |       FOR '(' remember mexpr ')' mblock cont
 415                         {
 416                           $$ = block_end($3,
 417                                   newFOROP(0, NULL, $4, $6, $7));
 418                           parser->copline = (line_t)$1;
 419                         }
 420         |       block cont
 421                         {
 422                           /* a block is a loop that happens once */
 423                           $$ = newWHILEOP(0, 1, NULL,
 424                                   NULL, $1, $2, 0);
 425                         }
 426         |       PACKAGE BAREWORD BAREWORD '{' remember
 427                         {
 428                           package($3);
 429                           if ($2) {
 430                               package_version($2);
 431                           }
 432                         }
 433                 stmtseq '}'
 434                         {
 435                           /* a block is a loop that happens once */
 436                           $$ = newWHILEOP(0, 1, NULL,
 437                                   NULL, block_end($5, $7), NULL, 0);
 438                           if (parser->copline > (line_t)$4)
 439                               parser->copline = (line_t)$4;
 440                         }
 441         |       sideff ';'
 442                         {
 443                           $$ = $1;
 444                         }
 445         |       YADAYADA ';'
 446                         {
 447                           $$ = newLISTOP(OP_DIE, 0, newOP(OP_PUSHMARK, 0),
 448                                 newSVOP(OP_CONST, 0, newSVpvs("Unimplemented")));
 449                         }
 450         |       ';'
 451                         {
 452                           $$ = NULL;
 453                           parser->copline = NOLINE;
 454                         }
 455         ;
 456
 457 /* Format line */
 458 formline:       THING formarg
 459                         { OP *list;
 460                           if ($2) {
 461                               OP *term = $2;
 462                               list = op_append_elem(OP_LIST, $1, term);
 463                           }
 464                           else {
 465                               list = $1;
 466                           }
 467                           if (parser->copline == NOLINE)
 468                                parser->copline = CopLINE(PL_curcop)-1;
 469                           else parser->copline--;
 470                           $$ = newSTATEOP(0, NULL,
 471                                           op_convert_list(OP_FORMLINE, 0, list));
 472                         }
 473         ;
 474
 475 formarg :       /* NULL */
 476                         { $$ = NULL; }
 477         |       FORMLBRACK stmtseq FORMRBRACK
 478                         { $$ = op_unscope($2); }
 479         ;
 480
 481 /* An expression which may have a side-effect */
 482 sideff  :       error
 483                         { $$ = NULL; }
 484         |       expr
 485                         { $$ = $1; }
 486         |       expr IF expr
 487                         { $$ = newLOGOP(OP_AND, 0, $3, $1); }
 488         |       expr UNLESS expr
 489                         { $$ = newLOGOP(OP_OR, 0, $3, $1); }
 490         |       expr WHILE expr
 491                         { $$ = newLOOPOP(OPf_PARENS, 1, scalar($3), $1); }
 492         |       expr UNTIL iexpr
 493                         { $$ = newLOOPOP(OPf_PARENS, 1, $3, $1); }
 494         |       expr FOR expr
 495                         { $$ = newFOROP(0, NULL, $3, $1, NULL);
 496                           parser->copline = (line_t)$2; }
 497         |       expr WHEN expr
 498                         { $$ = newWHENOP($3, op_scope($1)); }
 499         ;
 500
 501 /* else and elsif blocks */
 502 else    :       /* NULL */
 503                         { $$ = NULL; }
 504         |       ELSE mblock
 505                         {
 506                           ($2)->op_flags |= OPf_PARENS;
 507                           $$ = op_scope($2);
 508                         }
 509         |       ELSIF '(' mexpr ')' mblock else
 510                         { parser->copline = (line_t)$1;
 511                             $$ = newCONDOP(0,
 512                                 newSTATEOP(OPf_SPECIAL,NULL,$3),
 513                                 op_scope($5), $6);
 514                           PL_hints |= HINT_BLOCK_SCOPE;
 515                         }
 516         ;
 517
 518 /* Continue blocks */
 519 cont    :       /* NULL */
 520                         { $$ = NULL; }
 521         |       CONTINUE block
 522                         { $$ = op_scope($2); }
 523         ;
 524
 525 /* determine whether there are any new my declarations */
 526 mintro  :       /* NULL */
 527                         { $$ = (PL_min_intro_pending &&
 528                             PL_max_intro_pending >=  PL_min_intro_pending);
 529                           intro_my(); }
 530
 531 /* Normal expression */
 532 nexpr   :       /* NULL */
 533                         { $$ = NULL; }
 534         |       sideff
 535         ;
 536
 537 /* Boolean expression */
 538 texpr   :       /* NULL means true */
 539                         { YYSTYPE tmplval;
 540                           (void)scan_num("1", &tmplval);
 541                           $$ = tmplval.opval; }
 542         |       expr
 543         ;
 544
 545 /* Inverted boolean expression */
 546 iexpr   :       expr
 547                         { $$ = invert(scalar($1)); }
 548         ;
 549
 550 /* Expression with its own lexical scope */
 551 mexpr   :       expr
 552                         { $$ = $1; intro_my(); }
 553         ;
 554
 555 mnexpr  :       nexpr
 556                         { $$ = $1; intro_my(); }
 557         ;
 558
 559 formname:       BAREWORD        { $$ = $1; }
 560         |       /* NULL */      { $$ = NULL; }
 561         ;
 562
 563 startsub:       /* NULL */      /* start a regular subroutine scope */
 564                         { $$ = start_subparse(FALSE, 0);
 565                             SAVEFREESV(PL_compcv); }
 566
 567         ;
 568
 569 startanonsub:   /* NULL */      /* start an anonymous subroutine scope */
 570                         { $$ = start_subparse(FALSE, CVf_ANON);
 571                             SAVEFREESV(PL_compcv); }
 572         ;
 573
 574 startformsub:   /* NULL */      /* start a format subroutine scope */
 575                         { $$ = start_subparse(TRUE, 0);
 576                             SAVEFREESV(PL_compcv); }
 577         ;
 578
 579 /* Name of a subroutine - must be a bareword, could be special */
 580 subname :       BAREWORD
 581         |       PRIVATEREF
 582         ;
 583
 584 /* Subroutine prototype */
 585 proto   :       /* NULL */
 586                         { $$ = NULL; }
 587         |       THING
 588         ;
 589
 590 /* Optional list of subroutine attributes */
 591 subattrlist:    /* NULL */
 592                         { $$ = NULL; }
 593         |       COLONATTR THING
 594                         { $$ = $2; }
 595         |       COLONATTR
 596                         { $$ = NULL; }
 597         ;
 598
 599 /* List of attributes for a "my" variable declaration */
 600 myattrlist:     COLONATTR THING
 601                         { $$ = $2; }
 602         |       COLONATTR
 603                         { $$ = NULL; }
 604         ;
 605
 606
 607
 608 /* --------------------------------------
 609  * subroutine signature parsing
 610  */
 611
 612 /* the '' or 'foo' part of a '$' or '@foo' etc signature variable  */
 613 sigvarname:     /* NULL */
 614                         { parser->in_my = 0; $$ = NULL; }
 615         |       PRIVATEREF
 616                         { parser->in_my = 0; $$ = $1; }
 617         ;
 618
 619 sigslurpsigil:
 620                 '@'
 621                         { $$ = '@'; }
 622         |       '%'
 623                         { $$ = '%'; }
 624
 625 /* @, %, @foo, %foo */
 626 sigslurpelem: sigslurpsigil sigvarname sigdefault/* def only to catch errors */
 627                         {
 628                             I32 sigil   = $1;
 629                             OP *var     = $2;
 630                             OP *defexpr = $3;
 631
 632                             if (parser->sig_slurpy)
 633                                 yyerror("Multiple slurpy parameters not allowed");
 634                             parser->sig_slurpy = (char)sigil;
 635
 636                             if (defexpr)
 637                                 yyerror("A slurpy parameter may not have "
 638                                         "a default value");
 639
 640                             $$ = var ? newSTATEOP(0, NULL, var) : NULL;
 641                         }
 642         ;
 643
 644 /* default part of sub signature scalar element: i.e. '= default_expr' */
 645 sigdefault:     /* NULL */
 646                         { $$ = NULL; }
 647         |       ASSIGNOP
 648                         { $$ = newOP(OP_NULL, 0); }
 649         |       ASSIGNOP term
 650                         { $$ = $2; }
 651
 652
 653 /* subroutine signature scalar element: e.g. '$x', '$=', '$x = $default' */
 654 sigscalarelem:
 655                 '$' sigvarname sigdefault
 656                         {
 657                             OP *var     = $2;
 658                             OP *defexpr = $3;
 659
 660                             if (parser->sig_slurpy)
 661                                 yyerror("Slurpy parameter not last");
 662
 663                             parser->sig_elems++;
 664
 665                             if (defexpr) {
 666                                 parser->sig_optelems++;
 667
 668                                 if (   defexpr->op_type == OP_NULL
 669                                     && !(defexpr->op_flags & OPf_KIDS))
 670                                 {
 671                                     /* handle '$=' special case */
 672                                     if (var)
 673                                         yyerror("Optional parameter "
 674                                                     "lacks default expression");
 675                                     op_free(defexpr);
 676                                 }
 677                                 else {
 678                                     /* a normal '=default' expression */
 679                                     OP *defop = (OP*)alloc_LOGOP(OP_ARGDEFELEM,
 680                                                         defexpr,
 681                                                         LINKLIST(defexpr));
 682                                     /* re-purpose op_targ to hold @_ index */
 683                                     defop->op_targ =
 684                                         (PADOFFSET)(parser->sig_elems - 1);
 685
 686                                     if (var) {
 687                                         var->op_flags |= OPf_STACKED;
 688                                         (void)op_sibling_splice(var,
 689                                                         NULL, 0, defop);
 690                                         scalar(defop);
 691                                     }
 692                                     else
 693                                         var = newUNOP(OP_NULL, 0, defop);
 694
 695                                     LINKLIST(var);
 696                                     /* NB: normally the first child of a
 697                                      * logop is executed before the logop,
 698                                      * and it pushes a boolean result
 699                                      * ready for the logop. For ARGDEFELEM,
 700                                      * the op itself does the boolean
 701                                      * calculation, so set the first op to
 702                                      * it instead.
 703                                      */
 704                                     var->op_next = defop;
 705                                     defexpr->op_next = var;
 706                                 }
 707                             }
 708                             else {
 709                                 if (parser->sig_optelems)
 710                                     yyerror("Mandatory parameter "
 711                                             "follows optional parameter");
 712                             }
 713
 714                             $$ = var ? newSTATEOP(0, NULL, var) : NULL;
 715                         }
 716         ;
 717
 718
 719 /* subroutine signature element: e.g. '$x = $default' or '%h' */
 720 sigelem:        sigscalarelem
 721                         { parser->in_my = KEY_sigvar; $$ = $1; }
 722         |       sigslurpelem
 723                         { parser->in_my = KEY_sigvar; $$ = $1; }
 724         ;
 725
 726 /* list of subroutine signature elements */
 727 siglist:
 728                 siglist ','
 729                         { $$ = $1; }
 730         |       siglist ',' sigelem
 731                         {
 732                           $$ = op_append_list(OP_LINESEQ, $1, $3);
 733                         }
 734         |       sigelem  %prec PREC_LOW
 735                         { $$ = $1; }
 736         ;
 737
 738 /* () or (....) */
 739 siglistornull:          /* NULL */
 740                         { $$ = NULL; }
 741         |       siglist
 742                         { $$ = $1; }
 743
 744 /* Subroutine signature */
 745 subsignature:   /* NULL */ { $$ = (OP*)NULL; }
 746         |       '('
 747                         {
 748                             ENTER;
 749                             SAVEIV(parser->sig_elems);
 750                             SAVEIV(parser->sig_optelems);
 751                             SAVEI8(parser->sig_slurpy);
 752                             parser->sig_elems    = 0;
 753                             parser->sig_optelems = 0;
 754                             parser->sig_slurpy   = 0;
 755                             parser->in_my        = KEY_sigvar;
 756                         }
 757                 siglistornull
 758                 ')'
 759                         {
 760                             OP            *sigops = $3;
 761                             UNOP_AUX_item *aux;
 762                             OP            *check;
 763
 764                             if (!FEATURE_SIGNATURES_IS_ENABLED)
 765                                 Perl_croak(aTHX_ "Experimental "
 766                                     "subroutine signatures not enabled");
 767
 768                             /* We shouldn't get here otherwise */
 769                             Perl_ck_warner_d(aTHX_
 770                                 packWARN(WARN_EXPERIMENTAL__SIGNATURES),
 771                                 "The signatures feature is experimental");
 772
 773                             aux = (UNOP_AUX_item*)PerlMemShared_malloc(
 774                                 sizeof(UNOP_AUX_item) * 3);
 775                             aux[0].iv = parser->sig_elems;
 776                             aux[1].iv = parser->sig_optelems;
 777                             aux[2].iv = parser->sig_slurpy;
 778                             check = newUNOP_AUX(OP_ARGCHECK, 0, NULL, aux);
 779                             sigops = op_prepend_elem(OP_LINESEQ, check, sigops);
 780                             sigops = op_prepend_elem(OP_LINESEQ,
 781                                                 newSTATEOP(0, NULL, NULL),
 782                                                 sigops);
 783                             /* a nextstate at the end handles context
 784                              * correctly for an empty sub body */
 785                             $$ = op_append_elem(OP_LINESEQ,
 786                                                 sigops,
 787                                                 newSTATEOP(0, NULL, NULL));
 788
 789                             parser->in_my = 0;
 790                             parser->expect = XBLOCK;
 791                             LEAVE;
 792                         }
 793         ;
 794
 795
 796 /* Subroutine body - block with optional signature */
 797 realsubbody:    remember subsignature '{' stmtseq '}'
 798                         {
 799                           if (parser->copline > (line_t)$3)
 800                               parser->copline = (line_t)$3;
 801                           $$ = block_end($1,
 802                                 op_append_list(OP_LINESEQ, $2, $4));
 803                         }
 804         ;
 805
 806
 807 /* Optional subroutine body, for named subroutine declaration */
 808 optsubbody:     realsubbody { $$ = $1; }
 809         |       ';'     { $$ = NULL; }
 810         ;
 811
 812 /* Ordinary expressions; logical combinations */
 813 expr    :       expr ANDOP expr
 814                         { $$ = newLOGOP(OP_AND, 0, $1, $3); }
 815         |       expr OROP expr
 816                         { $$ = newLOGOP($2, 0, $1, $3); }
 817         |       expr DOROP expr
 818                         { $$ = newLOGOP(OP_DOR, 0, $1, $3); }
 819         |       listexpr %prec PREC_LOW
 820         ;
 821
 822 /* Expressions are a list of terms joined by commas */
 823 listexpr:       listexpr ','
 824                         { $$ = $1; }
 825         |       listexpr ',' term
 826                         {
 827                           OP* term = $3;
 828                           $$ = op_append_elem(OP_LIST, $1, term);
 829                         }
 830         |       term %prec PREC_LOW
 831         ;
 832
 833 /* List operators */
 834 listop  :       LSTOP indirob listexpr /* map {...} @args or print $fh @args */
 835                         { $$ = op_convert_list($1, OPf_STACKED,
 836                                 op_prepend_elem(OP_LIST, newGVREF($1,$2), $3) );
 837                         }
 838         |       FUNC '(' indirob expr ')'      /* print ($fh @args */
 839                         { $$ = op_convert_list($1, OPf_STACKED,
 840                                 op_prepend_elem(OP_LIST, newGVREF($1,$3), $4) );
 841                         }
 842         |       term ARROW method '(' optexpr ')' /* $foo->bar(list) */
 843                         { $$ = op_convert_list(OP_ENTERSUB, OPf_STACKED,
 844                                 op_append_elem(OP_LIST,
 845                                     op_prepend_elem(OP_LIST, scalar($1), $5),
 846                                     newMETHOP(OP_METHOD, 0, $3)));
 847                         }
 848         |       term ARROW method                     /* $foo->bar */
 849                         { $$ = op_convert_list(OP_ENTERSUB, OPf_STACKED,
 850                                 op_append_elem(OP_LIST, scalar($1),
 851                                     newMETHOP(OP_METHOD, 0, $3)));
 852                         }
 853         |       METHOD indirob optlistexpr           /* new Class @args */
 854                         { $$ = op_convert_list(OP_ENTERSUB, OPf_STACKED,
 855                                 op_append_elem(OP_LIST,
 856                                     op_prepend_elem(OP_LIST, $2, $3),
 857                                     newMETHOP(OP_METHOD, 0, $1)));
 858                         }
 859         |       FUNCMETH indirob '(' optexpr ')'    /* method $object (@args) */
 860                         { $$ = op_convert_list(OP_ENTERSUB, OPf_STACKED,
 861                                 op_append_elem(OP_LIST,
 862                                     op_prepend_elem(OP_LIST, $2, $4),
 863                                     newMETHOP(OP_METHOD, 0, $1)));
 864                         }
 865         |       LSTOP optlistexpr                    /* print @args */
 866                         { $$ = op_convert_list($1, 0, $2); }
 867         |       FUNC '(' optexpr ')'                 /* print (@args) */
 868                         { $$ = op_convert_list($1, 0, $3); }
 869         |       LSTOPSUB startanonsub block /* sub f(&@);   f { foo } ... */
 870                         { SvREFCNT_inc_simple_void(PL_compcv);
 871                           $<opval>$ = newANONATTRSUB($2, 0, NULL, $3); }
 872                     optlistexpr         %prec LSTOP  /* ... @bar */
 873                         { $$ = newUNOP(OP_ENTERSUB, OPf_STACKED,
 874                                  op_append_elem(OP_LIST,
 875                                    op_prepend_elem(OP_LIST, $<opval>4, $5), $1));
 876                         }
 877         ;
 878
 879 /* Names of methods. May use $object->$methodname */
 880 method  :       METHOD
 881         |       scalar
 882         ;
 883
 884 /* Some kind of subscripted expression */
 885 subscripted:    gelem '{' expr ';' '}'        /* *main::{something} */
 886                         /* In this and all the hash accessors, ';' is
 887                          * provided by the tokeniser */
 888                         { $$ = newBINOP(OP_GELEM, 0, $1, scalar($3)); }
 889         |       scalar '[' expr ']'          /* $array[$element] */
 890                         { $$ = newBINOP(OP_AELEM, 0, oopsAV($1), scalar($3));
 891                         }
 892         |       term ARROW '[' expr ']'      /* somearef->[$element] */
 893                         { $$ = newBINOP(OP_AELEM, 0,
 894                                         ref(newAVREF($1),OP_RV2AV),
 895                                         scalar($4));
 896                         }
 897         |       subscripted '[' expr ']'    /* $foo->[$bar]->[$baz] */
 898                         { $$ = newBINOP(OP_AELEM, 0,
 899                                         ref(newAVREF($1),OP_RV2AV),
 900                                         scalar($3));
 901                         }
 902         |       scalar '{' expr ';' '}'    /* $foo{bar();} */
 903                         { $$ = newBINOP(OP_HELEM, 0, oopsHV($1), jmaybe($3));
 904                         }
 905         |       term ARROW '{' expr ';' '}' /* somehref->{bar();} */
 906                         { $$ = newBINOP(OP_HELEM, 0,
 907                                         ref(newHVREF($1),OP_RV2HV),
 908                                         jmaybe($4)); }
 909         |       subscripted '{' expr ';' '}' /* $foo->[bar]->{baz;} */
 910                         { $$ = newBINOP(OP_HELEM, 0,
 911                                         ref(newHVREF($1),OP_RV2HV),
 912                                         jmaybe($3)); }
 913         |       term ARROW '(' ')'          /* $subref->() */
 914                         { $$ = newUNOP(OP_ENTERSUB, OPf_STACKED,
 915                                    newCVREF(0, scalar($1)));
 916                           if (parser->expect == XBLOCK)
 917                               parser->expect = XOPERATOR;
 918                         }
 919         |       term ARROW '(' expr ')'     /* $subref->(@args) */
 920                         { $$ = newUNOP(OP_ENTERSUB, OPf_STACKED,
 921                                    op_append_elem(OP_LIST, $4,
 922                                        newCVREF(0, scalar($1))));
 923                           if (parser->expect == XBLOCK)
 924                               parser->expect = XOPERATOR;
 925                         }
 926
 927         |       subscripted '(' expr ')'   /* $foo->{bar}->(@args) */
 928                         { $$ = newUNOP(OP_ENTERSUB, OPf_STACKED,
 929                                    op_append_elem(OP_LIST, $3,
 930                                                newCVREF(0, scalar($1))));
 931                           if (parser->expect == XBLOCK)
 932                               parser->expect = XOPERATOR;
 933                         }
 934         |       subscripted '(' ')'        /* $foo->{bar}->() */
 935                         { $$ = newUNOP(OP_ENTERSUB, OPf_STACKED,
 936                                    newCVREF(0, scalar($1)));
 937                           if (parser->expect == XBLOCK)
 938                               parser->expect = XOPERATOR;
 939                         }
 940         |       '(' expr ')' '[' expr ']'            /* list slice */
 941                         { $$ = newSLICEOP(0, $5, $2); }
 942         |       QWLIST '[' expr ']'            /* list literal slice */
 943                         { $$ = newSLICEOP(0, $3, $1); }
 944         |       '(' ')' '[' expr ']'                 /* empty list slice! */
 945                         { $$ = newSLICEOP(0, $4, NULL); }
 946     ;
 947
 948 /* Binary operators between terms */
 949 termbinop:      term ASSIGNOP term                     /* $x = $y, $x += $y */
 950                         { $$ = newASSIGNOP(OPf_STACKED, $1, $2, $3); }
 951         |       term POWOP term                        /* $x ** $y */
 952                         { $$ = newBINOP($2, 0, scalar($1), scalar($3)); }
 953         |       term MULOP term                        /* $x * $y, $x x $y */
 954                         {   if ($2 != OP_REPEAT)
 955                                 scalar($1);
 956                             $$ = newBINOP($2, 0, $1, scalar($3));
 957                         }
 958         |       term ADDOP term                        /* $x + $y */
 959                         { $$ = newBINOP($2, 0, scalar($1), scalar($3)); }
 960         |       term SHIFTOP term                      /* $x >> $y, $x << $y */
 961                         { $$ = newBINOP($2, 0, scalar($1), scalar($3)); }
 962         |       term RELOP term                        /* $x > $y, etc. */
 963                         { $$ = newBINOP($2, 0, scalar($1), scalar($3)); }
 964         |       term EQOP term                         /* $x == $y, $x eq $y */
 965                         { $$ = newBINOP($2, 0, scalar($1), scalar($3)); }
 966         |       term BITANDOP term                     /* $x & $y */
 967                         { $$ = newBINOP($2, 0, scalar($1), scalar($3)); }
 968         |       term BITOROP term                      /* $x | $y */
 969                         { $$ = newBINOP($2, 0, scalar($1), scalar($3)); }
 970         |       term DOTDOT term                       /* $x..$y, $x...$y */
 971                         { $$ = newRANGE($2, scalar($1), scalar($3)); }
 972         |       term ANDAND term                       /* $x && $y */
 973                         { $$ = newLOGOP(OP_AND, 0, $1, $3); }
 974         |       term OROR term                         /* $x || $y */
 975                         { $$ = newLOGOP(OP_OR, 0, $1, $3); }
 976         |       term DORDOR term                       /* $x // $y */
 977                         { $$ = newLOGOP(OP_DOR, 0, $1, $3); }
 978         |       term MATCHOP term                      /* $x =~ /$y/ */
 979                         { $$ = bind_match($2, $1, $3); }
 980     ;
 981
 982 /* Unary operators and terms */
 983 termunop : '-' term %prec UMINUS                       /* -$x */
 984                         { $$ = newUNOP(OP_NEGATE, 0, scalar($2)); }
 985         |       '+' term %prec UMINUS                  /* +$x */
 986                         { $$ = $2; }
 987
 988         |       '!' term                               /* !$x */
 989                         { $$ = newUNOP(OP_NOT, 0, scalar($2)); }
 990         |       '~' term                               /* ~$x */
 991                         { $$ = newUNOP($1, 0, scalar($2)); }
 992         |       term POSTINC                           /* $x++ */
 993                         { $$ = newUNOP(OP_POSTINC, 0,
 994                                         op_lvalue(scalar($1), OP_POSTINC)); }
 995         |       term POSTDEC                           /* $x-- */
 996                         { $$ = newUNOP(OP_POSTDEC, 0,
 997                                         op_lvalue(scalar($1), OP_POSTDEC));}
 998         |       term POSTJOIN    /* implicit join after interpolated ->@ */
 999                         { $$ = op_convert_list(OP_JOIN, 0,
1000                                        op_append_elem(
1001                                         OP_LIST,
1002                                         newSVREF(scalar(
1003                                             newSVOP(OP_CONST,0,
1004                                                     newSVpvs("\""))
1005                                         )),
1006                                         $1
1007                                        ));
1008                         }
1009         |       PREINC term                            /* ++$x */
1010                         { $$ = newUNOP(OP_PREINC, 0,
1011                                         op_lvalue(scalar($2), OP_PREINC)); }
1012         |       PREDEC term                            /* --$x */
1013                         { $$ = newUNOP(OP_PREDEC, 0,
1014                                         op_lvalue(scalar($2), OP_PREDEC)); }
1015
1016     ;
1017
1018 /* Constructors for anonymous data */
1019 anonymous:      '[' expr ']'
1020                         { $$ = newANONLIST($2); }
1021         |       '[' ']'
1022                         { $$ = newANONLIST(NULL);}
1023         |       HASHBRACK expr ';' '}'  %prec '(' /* { foo => "Bar" } */
1024                         { $$ = newANONHASH($2); }
1025         |       HASHBRACK ';' '}'       %prec '(' /* { } (';' by tokener) */
1026                         { $$ = newANONHASH(NULL); }
1027         |       ANONSUB startanonsub proto subattrlist realsubbody      %prec '('
1028                         { SvREFCNT_inc_simple_void(PL_compcv);
1029                           $$ = newANONATTRSUB($2, $3, $4, $5); }
1030     ;
1031
1032 /* Things called with "do" */
1033 termdo  :       DO term %prec UNIOP                     /* do $filename */
1034                         { $$ = dofile($2, $1);}
1035         |       DO block        %prec '('               /* do { code */
1036                         { $$ = newUNOP(OP_NULL, OPf_SPECIAL, op_scope($2));}
1037         ;
1038
1039 term    :       termbinop
1040         |       termunop
1041         |       anonymous
1042         |       termdo
1043         |       term '?' term ':' term
1044                         { $$ = newCONDOP(0, $1, $3, $5); }
1045         |       REFGEN term                          /* \$x, \@y, \%z */
1046                         { $$ = newUNOP(OP_REFGEN, 0, $2); }
1047         |       MY REFGEN term
1048                         { $$ = newUNOP(OP_REFGEN, 0, localize($3,1)); }
1049         |       myattrterm      %prec UNIOP
1050                         { $$ = $1; }
1051         |       LOCAL term      %prec UNIOP
1052                         { $$ = localize($2,0); }
1053         |       '(' expr ')'
1054                         { $$ = sawparens($2); }
1055         |       QWLIST
1056                         { $$ = $1; }
1057         |       '(' ')'
1058                         { $$ = sawparens(newNULLLIST()); }
1059         |       scalar  %prec '('
1060                         { $$ = $1; }
1061         |       star    %prec '('
1062                         { $$ = $1; }
1063         |       hsh     %prec '('
1064                         { $$ = $1; }
1065         |       ary     %prec '('
1066                         { $$ = $1; }
1067         |       arylen  %prec '('                    /* $#x, $#{ something } */
1068                         { $$ = newUNOP(OP_AV2ARYLEN, 0, ref($1, OP_AV2ARYLEN));}
1069         |       subscripted
1070                         { $$ = $1; }
1071         |       sliceme '[' expr ']'                     /* array slice */
1072                         { $$ = op_prepend_elem(OP_ASLICE,
1073                                 newOP(OP_PUSHMARK, 0),
1074                                     newLISTOP(OP_ASLICE, 0,
1075                                         list($3),
1076                                         ref($1, OP_ASLICE)));
1077                           if ($$ && $1)
1078                               $$->op_private |=
1079                                   $1->op_private & OPpSLICEWARNING;
1080                         }
1081         |       kvslice '[' expr ']'                 /* array key/value slice */
1082                         { $$ = op_prepend_elem(OP_KVASLICE,
1083                                 newOP(OP_PUSHMARK, 0),
1084                                     newLISTOP(OP_KVASLICE, 0,
1085                                         list($3),
1086                                         ref(oopsAV($1), OP_KVASLICE)));
1087                           if ($$ && $1)
1088                               $$->op_private |=
1089                                   $1->op_private & OPpSLICEWARNING;
1090                         }
1091         |       sliceme '{' expr ';' '}'                 /* @hash{@keys} */
1092                         { $$ = op_prepend_elem(OP_HSLICE,
1093                                 newOP(OP_PUSHMARK, 0),
1094                                     newLISTOP(OP_HSLICE, 0,
1095                                         list($3),
1096                                         ref(oopsHV($1), OP_HSLICE)));
1097                           if ($$ && $1)
1098                               $$->op_private |=
1099                                   $1->op_private & OPpSLICEWARNING;
1100                         }
1101         |       kvslice '{' expr ';' '}'                 /* %hash{@keys} */
1102                         { $$ = op_prepend_elem(OP_KVHSLICE,
1103                                 newOP(OP_PUSHMARK, 0),
1104                                     newLISTOP(OP_KVHSLICE, 0,
1105                                         list($3),
1106                                         ref($1, OP_KVHSLICE)));
1107                           if ($$ && $1)
1108                               $$->op_private |=
1109                                   $1->op_private & OPpSLICEWARNING;
1110                         }
1111         |       THING   %prec '('
1112                         { $$ = $1; }
1113         |       amper                                /* &foo; */
1114                         { $$ = newUNOP(OP_ENTERSUB, 0, scalar($1)); }
1115         |       amper '(' ')'                 /* &foo() or foo() */
1116                         { $$ = newUNOP(OP_ENTERSUB, OPf_STACKED, scalar($1));
1117                         }
1118         |       amper '(' expr ')'          /* &foo(@args) or foo(@args) */
1119                         {
1120                           $$ = newUNOP(OP_ENTERSUB, OPf_STACKED,
1121                                 op_append_elem(OP_LIST, $3, scalar($1)));
1122                         }
1123         |       NOAMP subname optlistexpr       /* foo @args (no parens) */
1124                         { $$ = newUNOP(OP_ENTERSUB, OPf_STACKED,
1125                             op_append_elem(OP_LIST, $3, scalar($2)));
1126                         }
1127         |       term ARROW '$' '*'
1128                         { $$ = newSVREF($1); }
1129         |       term ARROW '@' '*'
1130                         { $$ = newAVREF($1); }
1131         |       term ARROW '%' '*'
1132                         { $$ = newHVREF($1); }
1133         |       term ARROW '&' '*'
1134                         { $$ = newUNOP(OP_ENTERSUB, 0,
1135                                        scalar(newCVREF($3,$1))); }
1136         |       term ARROW '*' '*'      %prec '('
1137                         { $$ = newGVREF(0,$1); }
1138         |       LOOPEX  /* loop exiting command (goto, last, dump, etc) */
1139                         { $$ = newOP($1, OPf_SPECIAL);
1140                             PL_hints |= HINT_BLOCK_SCOPE; }
1141         |       LOOPEX term
1142                         { $$ = newLOOPEX($1,$2); }
1143         |       NOTOP listexpr                       /* not $foo */
1144                         { $$ = newUNOP(OP_NOT, 0, scalar($2)); }
1145         |       UNIOP                                /* Unary op, $_ implied */
1146                         { $$ = newOP($1, 0); }
1147         |       UNIOP block                          /* eval { foo }* */
1148                         { $$ = newUNOP($1, 0, $2); }
1149         |       UNIOP term                           /* Unary op */
1150                         { $$ = newUNOP($1, 0, $2); }
1151         |       REQUIRE                              /* require, $_ implied */
1152                         { $$ = newOP(OP_REQUIRE, $1 ? OPf_SPECIAL : 0); }
1153         |       REQUIRE term                         /* require Foo */
1154                         { $$ = newUNOP(OP_REQUIRE, $1 ? OPf_SPECIAL : 0, $2); }
1155         |       UNIOPSUB
1156                         { $$ = newUNOP(OP_ENTERSUB, OPf_STACKED, scalar($1)); }
1157         |       UNIOPSUB term                        /* Sub treated as unop */
1158                         { $$ = newUNOP(OP_ENTERSUB, OPf_STACKED,
1159                             op_append_elem(OP_LIST, $2, scalar($1))); }
1160         |       FUNC0                                /* Nullary operator */
1161                         { $$ = newOP($1, 0); }
1162         |       FUNC0 '(' ')'
1163                         { $$ = newOP($1, 0);}
1164         |       FUNC0OP       /* Same as above, but op created in toke.c */
1165                         { $$ = $1; }
1166         |       FUNC0OP '(' ')'
1167                         { $$ = $1; }
1168         |       FUNC0SUB                             /* Sub treated as nullop */
1169                         { $$ = newUNOP(OP_ENTERSUB, OPf_STACKED, scalar($1)); }
1170         |       FUNC1 '(' ')'                        /* not () */
1171                         { $$ = ($1 == OP_NOT)
1172                           ? newUNOP($1, 0, newSVOP(OP_CONST, 0, newSViv(0)))
1173                           : newOP($1, OPf_SPECIAL); }
1174         |       FUNC1 '(' expr ')'                   /* not($foo) */
1175                         { $$ = newUNOP($1, 0, $3); }
1176         |       PMFUNC /* m//, s///, qr//, tr/// */
1177                         {
1178                             if (   $1->op_type != OP_TRANS
1179                                 && $1->op_type != OP_TRANSR
1180                                 && (((PMOP*)$1)->op_pmflags & PMf_HAS_CV))
1181                             {
1182                                 $<ival>$ = start_subparse(FALSE, CVf_ANON);
1183                                 SAVEFREESV(PL_compcv);
1184                             } else
1185                                 $<ival>$ = 0;
1186                         }
1187                     '(' listexpr optrepl ')'
1188                         { $$ = pmruntime($1, $4, $5, 1, $<ival>2); }
1189         |       BAREWORD
1190         |       listop
1191         |       PLUGEXPR
1192         ;
1193
1194 /* "my" declarations, with optional attributes */
1195 myattrterm:     MY myterm myattrlist
1196                         { $$ = my_attrs($2,$3); }
1197         |       MY myterm
1198                         { $$ = localize($2,1); }
1199         |       MY REFGEN myterm myattrlist
1200                         { $$ = newUNOP(OP_REFGEN, 0, my_attrs($3,$4)); }
1201         ;
1202
1203 /* Things that can be "my"'d */
1204 myterm  :       '(' expr ')'
1205                         { $$ = sawparens($2); }
1206         |       '(' ')'
1207                         { $$ = sawparens(newNULLLIST()); }
1208
1209         |       scalar  %prec '('
1210                         { $$ = $1; }
1211         |       hsh     %prec '('
1212                         { $$ = $1; }
1213         |       ary     %prec '('
1214                         { $$ = $1; }
1215         ;
1216
1217 /* Basic list expressions */
1218 optlistexpr:    /* NULL */ %prec PREC_LOW
1219                         { $$ = NULL; }
1220         |       listexpr    %prec PREC_LOW
1221                         { $$ = $1; }
1222         ;
1223
1224 optexpr:        /* NULL */
1225                         { $$ = NULL; }
1226         |       expr
1227                         { $$ = $1; }
1228         ;
1229
1230 optrepl:        /* NULL */
1231                         { $$ = NULL; }
1232         |       '/' expr
1233                         { $$ = $2; }
1234         ;
1235
1236 /* A little bit of trickery to make "for my $foo (@bar)" actually be
1237    lexical */
1238 my_scalar:      scalar
1239                         { parser->in_my = 0; $$ = my($1); }
1240         ;
1241
1242 my_var  :       scalar
1243         |       ary
1244         |       hsh
1245         ;
1246
1247 refgen_topic:   my_var
1248         |       amper
1249         ;
1250
1251 my_refgen:      MY REFGEN
1252         |       REFGEN MY
1253         ;
1254
1255 amper   :       '&' indirob
1256                         { $$ = newCVREF($1,$2); }
1257         ;
1258
1259 scalar  :       '$' indirob
1260                         { $$ = newSVREF($2); }
1261         ;
1262
1263 ary     :       '@' indirob
1264                         { $$ = newAVREF($2);
1265                           if ($$) $$->op_private |= $1;
1266                         }
1267         ;
1268
1269 hsh     :       '%' indirob
1270                         { $$ = newHVREF($2);
1271                           if ($$) $$->op_private |= $1;
1272                         }
1273         ;
1274
1275 arylen  :       DOLSHARP indirob
1276                         { $$ = newAVREF($2); }
1277         |       term ARROW DOLSHARP '*'
1278                         { $$ = newAVREF($1); }
1279         ;
1280
1281 star    :       '*' indirob
1282                         { $$ = newGVREF(0,$2); }
1283         ;
1284
1285 sliceme :       ary
1286         |       term ARROW '@'
1287                         { $$ = newAVREF($1); }
1288         ;
1289
1290 kvslice :       hsh
1291         |       term ARROW '%'
1292                         { $$ = newHVREF($1); }
1293         ;
1294
1295 gelem   :       star
1296         |       term ARROW '*'
1297                         { $$ = newGVREF(0,$1); }
1298         ;
1299
1300 /* Indirect objects */
1301 indirob :       BAREWORD
1302                         { $$ = scalar($1); }
1303         |       scalar %prec PREC_LOW
1304                         { $$ = scalar($1); }
1305         |       block
1306                         { $$ = op_scope($1); }
1307
1308         |       PRIVATEREF
1309                         { $$ = $1; }
1310         ;