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 <opval> LABEL
  54 %token <ival> FORMAT SUB SIGSUB ANONSUB ANON_SIGSUB 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 cont my_scalar my_var
  75 %type <opval> refgen_topic formblock
  76 %type <opval> subattrlist myattrlist myattrterm myterm
  77 %type <opval> termbinop termunop anonymous termdo
  78 %type <ival>  sigslurpsigil
  79 %type <opval> sigvarname sigdefault sigscalarelem sigslurpelem
  80 %type <opval> sigelem siglist siglistornull subsignature optsubsignature
  81 %type <opval> subbody optsubbody sigsubbody optsigsubbody
  82 %type <opval> formstmtseq formline formarg
  83
  84 %nonassoc <ival> PREC_LOW
  85 %nonassoc LOOPEX
  86
  87 %left <ival> OROP DOROP
  88 %left <ival> ANDOP
  89 %right <ival> NOTOP
  90 %nonassoc LSTOP LSTOPSUB
  91 %left <ival> ','
  92 %right <ival> ASSIGNOP
  93 %right <ival> '?' ':'
  94 %nonassoc DOTDOT
  95 %left <ival> OROR DORDOR
  96 %left <ival> ANDAND
  97 %left <ival> BITOROP
  98 %left <ival> BITANDOP
  99 %nonassoc EQOP
 100 %nonassoc RELOP
 101 %nonassoc UNIOP UNIOPSUB
 102 %nonassoc REQUIRE
 103 %left <ival> SHIFTOP
 104 %left ADDOP
 105 %left MULOP
 106 %left <ival> MATCHOP
 107 %right <ival> '!' '~' UMINUS REFGEN
 108 %right <ival> POWOP
 109 %nonassoc <ival> PREINC PREDEC POSTINC POSTDEC POSTJOIN
 110 %left <ival> ARROW
 111 %nonassoc <ival> ')'
 112 %left <ival> '('
 113 %left '[' '{'
 114
 115 %% /* RULES */
 116
 117 /* Top-level choice of what kind of thing yyparse was called to parse */
 118 grammar :       GRAMPROG
 119                         {
 120                           parser->expect = XSTATE;
 121                           $<ival>$ = 0;
 122                         }
 123                 remember stmtseq
 124                         {
 125                           newPROG(block_end($3,$4));
 126                           PL_compiling.cop_seq = 0;
 127                           $$ = 0;
 128                         }
 129         |       GRAMEXPR
 130                         {
 131                           parser->expect = XTERM;
 132                           $<ival>$ = 0;
 133                         }
 134                 optexpr
 135                         {
 136                           PL_eval_root = $3;
 137                           $$ = 0;
 138                         }
 139         |       GRAMBLOCK
 140                         {
 141                           parser->expect = XBLOCK;
 142                           $<ival>$ = 0;
 143                         }
 144                 block
 145                         {
 146                           PL_pad_reset_pending = TRUE;
 147                           PL_eval_root = $3;
 148                           $$ = 0;
 149                           yyunlex();
 150                           parser->yychar = yytoken = YYEOF;
 151                         }
 152         |       GRAMBARESTMT
 153                         {
 154                           parser->expect = XSTATE;
 155                           $<ival>$ = 0;
 156                         }
 157                 barestmt
 158                         {
 159                           PL_pad_reset_pending = TRUE;
 160                           PL_eval_root = $3;
 161                           $$ = 0;
 162                           yyunlex();
 163                           parser->yychar = yytoken = YYEOF;
 164                         }
 165         |       GRAMFULLSTMT
 166                         {
 167                           parser->expect = XSTATE;
 168                           $<ival>$ = 0;
 169                         }
 170                 fullstmt
 171                         {
 172                           PL_pad_reset_pending = TRUE;
 173                           PL_eval_root = $3;
 174                           $$ = 0;
 175                           yyunlex();
 176                           parser->yychar = yytoken = YYEOF;
 177                         }
 178         |       GRAMSTMTSEQ
 179                         {
 180                           parser->expect = XSTATE;
 181                           $<ival>$ = 0;
 182                         }
 183                 stmtseq
 184                         {
 185                           PL_eval_root = $3;
 186                           $$ = 0;
 187                         }
 188         ;
 189
 190 /* An ordinary block */
 191 block   :       '{' remember stmtseq '}'
 192                         { if (parser->copline > (line_t)$1)
 193                               parser->copline = (line_t)$1;
 194                           $$ = block_end($2, $3);
 195                         }
 196         ;
 197
 198 /* format body */
 199 formblock:      '=' remember ';' FORMRBRACK formstmtseq ';' '.'
 200                         { if (parser->copline > (line_t)$1)
 201                               parser->copline = (line_t)$1;
 202                           $$ = block_end($2, $5);
 203                         }
 204         ;
 205
 206 remember:       /* NULL */      /* start a full lexical scope */
 207                         { $$ = block_start(TRUE);
 208                           parser->parsed_sub = 0; }
 209         ;
 210
 211 mblock  :       '{' mremember stmtseq '}'
 212                         { if (parser->copline > (line_t)$1)
 213                               parser->copline = (line_t)$1;
 214                           $$ = block_end($2, $3);
 215                         }
 216         ;
 217
 218 mremember:      /* NULL */      /* start a partial lexical scope */
 219                         { $$ = block_start(FALSE);
 220                           parser->parsed_sub = 0; }
 221         ;
 222
 223 /* A sequence of statements in the program */
 224 stmtseq :       /* NULL */
 225                         { $$ = NULL; }
 226         |       stmtseq fullstmt
 227                         {   $$ = op_append_list(OP_LINESEQ, $1, $2);
 228                             PL_pad_reset_pending = TRUE;
 229                             if ($1 && $2)
 230                                 PL_hints |= HINT_BLOCK_SCOPE;
 231                         }
 232         ;
 233
 234 /* A sequence of format lines */
 235 formstmtseq:    /* NULL */
 236                         { $$ = NULL; }
 237         |       formstmtseq formline
 238                         {   $$ = op_append_list(OP_LINESEQ, $1, $2);
 239                             PL_pad_reset_pending = TRUE;
 240                             if ($1 && $2)
 241                                 PL_hints |= HINT_BLOCK_SCOPE;
 242                         }
 243         ;
 244
 245 /* A statement in the program, including optional labels */
 246 fullstmt:       barestmt
 247                         {
 248                           $$ = $1 ? newSTATEOP(0, NULL, $1) : NULL;
 249                         }
 250         |       labfullstmt
 251                         { $$ = $1; }
 252         ;
 253
 254 labfullstmt:    LABEL barestmt
 255                         {
 256                           SV *label = cSVOPx_sv($1);
 257                           $$ = newSTATEOP(SvFLAGS(label) & SVf_UTF8,
 258                                             savepv(SvPVX_const(label)), $2);
 259                           op_free($1);
 260                         }
 261         |       LABEL labfullstmt
 262                         {
 263                           SV *label = cSVOPx_sv($1);
 264                           $$ = newSTATEOP(SvFLAGS(label) & SVf_UTF8,
 265                                             savepv(SvPVX_const(label)), $2);
 266                           op_free($1);
 267                         }
 268         ;
 269
 270 /* A bare statement, lacking label and other aspects of state op */
 271 barestmt:       PLUGSTMT
 272                         { $$ = $1; }
 273         |       FORMAT startformsub formname formblock
 274                         {
 275                           CV *fmtcv = PL_compcv;
 276                           newFORM($2, $3, $4);
 277                           $$ = NULL;
 278                           if (CvOUTSIDE(fmtcv) && !CvEVAL(CvOUTSIDE(fmtcv))) {
 279                               pad_add_weakref(fmtcv);
 280                           }
 281                           parser->parsed_sub = 1;
 282                         }
 283         |       SUB subname startsub
 284                     /* sub declaration or definition not within scope
 285                        of 'use feature "signatures"'*/
 286                         {
 287                           init_named_cv(PL_compcv, $2);
 288                           parser->in_my = 0;
 289                           parser->in_my_stash = NULL;
 290                         }
 291                     proto subattrlist optsubbody
 292                         {
 293                           SvREFCNT_inc_simple_void(PL_compcv);
 294                           $2->op_type == OP_CONST
 295                               ? newATTRSUB($3, $2, $5, $6, $7)
 296                               : newMYSUB($3, $2, $5, $6, $7)
 297                           ;
 298                           $$ = NULL;
 299                           intro_my();
 300                           parser->parsed_sub = 1;
 301                         }
 302         |       SIGSUB subname startsub
 303                     /* sub declaration or definition under 'use feature
 304                      * "signatures"'. (Note that a signature isn't
 305                      * allowed in a declaration)
 306                      */
 307                         {
 308                           init_named_cv(PL_compcv, $2);
 309                           parser->in_my = 0;
 310                           parser->in_my_stash = NULL;
 311                         }
 312                     subattrlist optsigsubbody
 313                         {
 314                           SvREFCNT_inc_simple_void(PL_compcv);
 315                           $2->op_type == OP_CONST
 316                               ? newATTRSUB($3, $2, NULL, $5, $6)
 317                               : newMYSUB(  $3, $2, NULL, $5, $6)
 318                           ;
 319                           $$ = NULL;
 320                           intro_my();
 321                           parser->parsed_sub = 1;
 322                         }
 323         |       PACKAGE BAREWORD BAREWORD ';'
 324                         {
 325                           package($3);
 326                           if ($2)
 327                               package_version($2);
 328                           $$ = NULL;
 329                         }
 330         |       USE startsub
 331                         { CvSPECIAL_on(PL_compcv); /* It's a BEGIN {} */ }
 332                 BAREWORD BAREWORD optlistexpr ';'
 333                         {
 334                           SvREFCNT_inc_simple_void(PL_compcv);
 335                           utilize($1, $2, $4, $5, $6);
 336                           parser->parsed_sub = 1;
 337                           $$ = NULL;
 338                         }
 339         |       IF '(' remember mexpr ')' mblock else
 340                         {
 341                           $$ = block_end($3,
 342                               newCONDOP(0, $4, op_scope($6), $7));
 343                           parser->copline = (line_t)$1;
 344                         }
 345         |       UNLESS '(' remember mexpr ')' mblock else
 346                         {
 347                           $$ = block_end($3,
 348                               newCONDOP(0, $4, $7, op_scope($6)));
 349                           parser->copline = (line_t)$1;
 350                         }
 351         |       GIVEN '(' remember mexpr ')' mblock
 352                         {
 353                           $$ = block_end($3, newGIVENOP($4, op_scope($6), 0));
 354                           parser->copline = (line_t)$1;
 355                         }
 356         |       WHEN '(' remember mexpr ')' mblock
 357                         { $$ = block_end($3, newWHENOP($4, op_scope($6))); }
 358         |       DEFAULT block
 359                         { $$ = newWHENOP(0, op_scope($2)); }
 360         |       WHILE '(' remember texpr ')' mintro mblock cont
 361                         {
 362                           $$ = block_end($3,
 363                                   newWHILEOP(0, 1, NULL,
 364                                       $4, $7, $8, $6));
 365                           parser->copline = (line_t)$1;
 366                         }
 367         |       UNTIL '(' remember iexpr ')' mintro mblock cont
 368                         {
 369                           $$ = block_end($3,
 370                                   newWHILEOP(0, 1, NULL,
 371                                       $4, $7, $8, $6));
 372                           parser->copline = (line_t)$1;
 373                         }
 374         |       FOR '(' remember mnexpr ';'
 375                         { parser->expect = XTERM; }
 376                 texpr ';'
 377                         { parser->expect = XTERM; }
 378                 mintro mnexpr ')'
 379                 mblock
 380                         {
 381                           OP *initop = $4;
 382                           OP *forop = newWHILEOP(0, 1, NULL,
 383                                       scalar($7), $13, $11, $10);
 384                           if (initop) {
 385                               forop = op_prepend_elem(OP_LINESEQ, initop,
 386                                   op_append_elem(OP_LINESEQ,
 387                                       newOP(OP_UNSTACK, OPf_SPECIAL),
 388                                       forop));
 389                           }
 390                           PL_hints |= HINT_BLOCK_SCOPE;
 391                           $$ = block_end($3, forop);
 392                           parser->copline = (line_t)$1;
 393                         }
 394         |       FOR MY remember my_scalar '(' mexpr ')' mblock cont
 395                         {
 396                           $$ = block_end($3, newFOROP(0, $4, $6, $8, $9));
 397                           parser->copline = (line_t)$1;
 398                         }
 399         |       FOR scalar '(' remember mexpr ')' mblock cont
 400                         {
 401                           $$ = block_end($4, newFOROP(0,
 402                                       op_lvalue($2, OP_ENTERLOOP), $5, $7, $8));
 403                           parser->copline = (line_t)$1;
 404                         }
 405         |       FOR my_refgen remember my_var
 406                         { parser->in_my = 0; $<opval>$ = my($4); }
 407                 '(' mexpr ')' mblock cont
 408                         {
 409                           $$ = block_end(
 410                                 $3,
 411                                 newFOROP(0,
 412                                          op_lvalue(
 413                                             newUNOP(OP_REFGEN, 0,
 414                                                     $<opval>5),
 415                                             OP_ENTERLOOP),
 416                                          $7, $9, $10)
 417                           );
 418                           parser->copline = (line_t)$1;
 419                         }
 420         |       FOR REFGEN refgen_topic '(' remember mexpr ')' mblock cont
 421                         {
 422                           $$ = block_end($5, newFOROP(
 423                                 0, op_lvalue(newUNOP(OP_REFGEN, 0,
 424                                                      $3),
 425                                              OP_ENTERLOOP), $6, $8, $9));
 426                           parser->copline = (line_t)$1;
 427                         }
 428         |       FOR '(' remember mexpr ')' mblock cont
 429                         {
 430                           $$ = block_end($3,
 431                                   newFOROP(0, NULL, $4, $6, $7));
 432                           parser->copline = (line_t)$1;
 433                         }
 434         |       block cont
 435                         {
 436                           /* a block is a loop that happens once */
 437                           $$ = newWHILEOP(0, 1, NULL,
 438                                   NULL, $1, $2, 0);
 439                         }
 440         |       PACKAGE BAREWORD BAREWORD '{' remember
 441                         {
 442                           package($3);
 443                           if ($2) {
 444                               package_version($2);
 445                           }
 446                         }
 447                 stmtseq '}'
 448                         {
 449                           /* a block is a loop that happens once */
 450                           $$ = newWHILEOP(0, 1, NULL,
 451                                   NULL, block_end($5, $7), NULL, 0);
 452                           if (parser->copline > (line_t)$4)
 453                               parser->copline = (line_t)$4;
 454                         }
 455         |       sideff ';'
 456                         {
 457                           $$ = $1;
 458                         }
 459         |       YADAYADA ';'
 460                         {
 461                           $$ = newLISTOP(OP_DIE, 0, newOP(OP_PUSHMARK, 0),
 462                                 newSVOP(OP_CONST, 0, newSVpvs("Unimplemented")));
 463                         }
 464         |       ';'
 465                         {
 466                           $$ = NULL;
 467                           parser->copline = NOLINE;
 468                         }
 469         ;
 470
 471 /* Format line */
 472 formline:       THING formarg
 473                         { OP *list;
 474                           if ($2) {
 475                               OP *term = $2;
 476                               list = op_append_elem(OP_LIST, $1, term);
 477                           }
 478                           else {
 479                               list = $1;
 480                           }
 481                           if (parser->copline == NOLINE)
 482                                parser->copline = CopLINE(PL_curcop)-1;
 483                           else parser->copline--;
 484                           $$ = newSTATEOP(0, NULL,
 485                                           op_convert_list(OP_FORMLINE, 0, list));
 486                         }
 487         ;
 488
 489 formarg :       /* NULL */
 490                         { $$ = NULL; }
 491         |       FORMLBRACK stmtseq FORMRBRACK
 492                         { $$ = op_unscope($2); }
 493         ;
 494
 495 /* An expression which may have a side-effect */
 496 sideff  :       error
 497                         { $$ = NULL; }
 498         |       expr
 499                         { $$ = $1; }
 500         |       expr IF expr
 501                         { $$ = newLOGOP(OP_AND, 0, $3, $1); }
 502         |       expr UNLESS expr
 503                         { $$ = newLOGOP(OP_OR, 0, $3, $1); }
 504         |       expr WHILE expr
 505                         { $$ = newLOOPOP(OPf_PARENS, 1, scalar($3), $1); }
 506         |       expr UNTIL iexpr
 507                         { $$ = newLOOPOP(OPf_PARENS, 1, $3, $1); }
 508         |       expr FOR expr
 509                         { $$ = newFOROP(0, NULL, $3, $1, NULL);
 510                           parser->copline = (line_t)$2; }
 511         |       expr WHEN expr
 512                         { $$ = newWHENOP($3, op_scope($1)); }
 513         ;
 514
 515 /* else and elsif blocks */
 516 else    :       /* NULL */
 517                         { $$ = NULL; }
 518         |       ELSE mblock
 519                         {
 520                           ($2)->op_flags |= OPf_PARENS;
 521                           $$ = op_scope($2);
 522                         }
 523         |       ELSIF '(' mexpr ')' mblock else
 524                         { parser->copline = (line_t)$1;
 525                             $$ = newCONDOP(0,
 526                                 newSTATEOP(OPf_SPECIAL,NULL,$3),
 527                                 op_scope($5), $6);
 528                           PL_hints |= HINT_BLOCK_SCOPE;
 529                         }
 530         ;
 531
 532 /* Continue blocks */
 533 cont    :       /* NULL */
 534                         { $$ = NULL; }
 535         |       CONTINUE block
 536                         { $$ = op_scope($2); }
 537         ;
 538
 539 /* determine whether there are any new my declarations */
 540 mintro  :       /* NULL */
 541                         { $$ = (PL_min_intro_pending &&
 542                             PL_max_intro_pending >=  PL_min_intro_pending);
 543                           intro_my(); }
 544
 545 /* Normal expression */
 546 nexpr   :       /* NULL */
 547                         { $$ = NULL; }
 548         |       sideff
 549         ;
 550
 551 /* Boolean expression */
 552 texpr   :       /* NULL means true */
 553                         { YYSTYPE tmplval;
 554                           (void)scan_num("1", &tmplval);
 555                           $$ = tmplval.opval; }
 556         |       expr
 557         ;
 558
 559 /* Inverted boolean expression */
 560 iexpr   :       expr
 561                         { $$ = invert(scalar($1)); }
 562         ;
 563
 564 /* Expression with its own lexical scope */
 565 mexpr   :       expr
 566                         { $$ = $1; intro_my(); }
 567         ;
 568
 569 mnexpr  :       nexpr
 570                         { $$ = $1; intro_my(); }
 571         ;
 572
 573 formname:       BAREWORD        { $$ = $1; }
 574         |       /* NULL */      { $$ = NULL; }
 575         ;
 576
 577 startsub:       /* NULL */      /* start a regular subroutine scope */
 578                         { $$ = start_subparse(FALSE, 0);
 579                             SAVEFREESV(PL_compcv); }
 580
 581         ;
 582
 583 startanonsub:   /* NULL */      /* start an anonymous subroutine scope */
 584                         { $$ = start_subparse(FALSE, CVf_ANON);
 585                             SAVEFREESV(PL_compcv); }
 586         ;
 587
 588 startformsub:   /* NULL */      /* start a format subroutine scope */
 589                         { $$ = start_subparse(TRUE, 0);
 590                             SAVEFREESV(PL_compcv); }
 591         ;
 592
 593 /* Name of a subroutine - must be a bareword, could be special */
 594 subname :       BAREWORD
 595         |       PRIVATEREF
 596         ;
 597
 598 /* Subroutine prototype */
 599 proto   :       /* NULL */
 600                         { $$ = NULL; }
 601         |       THING
 602         ;
 603
 604 /* Optional list of subroutine attributes */
 605 subattrlist:    /* NULL */
 606                         { $$ = NULL; }
 607         |       COLONATTR THING
 608                         { $$ = $2; }
 609         |       COLONATTR
 610                         { $$ = NULL; }
 611         ;
 612
 613 /* List of attributes for a "my" variable declaration */
 614 myattrlist:     COLONATTR THING
 615                         { $$ = $2; }
 616         |       COLONATTR
 617                         { $$ = NULL; }
 618         ;
 619
 620
 621
 622 /* --------------------------------------
 623  * subroutine signature parsing
 624  */
 625
 626 /* the '' or 'foo' part of a '$' or '@foo' etc signature variable  */
 627 sigvarname:     /* NULL */
 628                         { parser->in_my = 0; $$ = NULL; }
 629         |       PRIVATEREF
 630                         { parser->in_my = 0; $$ = $1; }
 631         ;
 632
 633 sigslurpsigil:
 634                 '@'
 635                         { $$ = '@'; }
 636         |       '%'
 637                         { $$ = '%'; }
 638
 639 /* @, %, @foo, %foo */
 640 sigslurpelem: sigslurpsigil sigvarname sigdefault/* def only to catch errors */
 641                         {
 642                             I32 sigil   = $1;
 643                             OP *var     = $2;
 644                             OP *defexpr = $3;
 645
 646                             if (parser->sig_slurpy)
 647                                 yyerror("Multiple slurpy parameters not allowed");
 648                             parser->sig_slurpy = (char)sigil;
 649
 650                             if (defexpr)
 651                                 yyerror("A slurpy parameter may not have "
 652                                         "a default value");
 653
 654                             $$ = var ? newSTATEOP(0, NULL, var) : NULL;
 655                         }
 656         ;
 657
 658 /* default part of sub signature scalar element: i.e. '= default_expr' */
 659 sigdefault:     /* NULL */
 660                         { $$ = NULL; }
 661         |       ASSIGNOP
 662                         { $$ = newOP(OP_NULL, 0); }
 663         |       ASSIGNOP term
 664                         { $$ = $2; }
 665
 666
 667 /* subroutine signature scalar element: e.g. '$x', '$=', '$x = $default' */
 668 sigscalarelem:
 669                 '$' sigvarname sigdefault
 670                         {
 671                             OP *var     = $2;
 672                             OP *defexpr = $3;
 673
 674                             if (parser->sig_slurpy)
 675                                 yyerror("Slurpy parameter not last");
 676
 677                             parser->sig_elems++;
 678
 679                             if (defexpr) {
 680                                 parser->sig_optelems++;
 681
 682                                 if (   defexpr->op_type == OP_NULL
 683                                     && !(defexpr->op_flags & OPf_KIDS))
 684                                 {
 685                                     /* handle '$=' special case */
 686                                     if (var)
 687                                         yyerror("Optional parameter "
 688                                                     "lacks default expression");
 689                                     op_free(defexpr);
 690                                 }
 691                                 else {
 692                                     /* a normal '=default' expression */
 693                                     OP *defop = (OP*)alloc_LOGOP(OP_ARGDEFELEM,
 694                                                         defexpr,
 695                                                         LINKLIST(defexpr));
 696                                     /* re-purpose op_targ to hold @_ index */
 697                                     defop->op_targ =
 698                                         (PADOFFSET)(parser->sig_elems - 1);
 699
 700                                     if (var) {
 701                                         var->op_flags |= OPf_STACKED;
 702                                         (void)op_sibling_splice(var,
 703                                                         NULL, 0, defop);
 704                                         scalar(defop);
 705                                     }
 706                                     else
 707                                         var = newUNOP(OP_NULL, 0, defop);
 708
 709                                     LINKLIST(var);
 710                                     /* NB: normally the first child of a
 711                                      * logop is executed before the logop,
 712                                      * and it pushes a boolean result
 713                                      * ready for the logop. For ARGDEFELEM,
 714                                      * the op itself does the boolean
 715                                      * calculation, so set the first op to
 716                                      * it instead.
 717                                      */
 718                                     var->op_next = defop;
 719                                     defexpr->op_next = var;
 720                                 }
 721                             }
 722                             else {
 723                                 if (parser->sig_optelems)
 724                                     yyerror("Mandatory parameter "
 725                                             "follows optional parameter");
 726                             }
 727
 728                             $$ = var ? newSTATEOP(0, NULL, var) : NULL;
 729                         }
 730         ;
 731
 732
 733 /* subroutine signature element: e.g. '$x = $default' or '%h' */
 734 sigelem:        sigscalarelem
 735                         { parser->in_my = KEY_sigvar; $$ = $1; }
 736         |       sigslurpelem
 737                         { parser->in_my = KEY_sigvar; $$ = $1; }
 738         ;
 739
 740 /* list of subroutine signature elements */
 741 siglist:
 742                 siglist ','
 743                         { $$ = $1; }
 744         |       siglist ',' sigelem
 745                         {
 746                           $$ = op_append_list(OP_LINESEQ, $1, $3);
 747                         }
 748         |       sigelem  %prec PREC_LOW
 749                         { $$ = $1; }
 750         ;
 751
 752 /* () or (....) */
 753 siglistornull:          /* NULL */
 754                         { $$ = NULL; }
 755         |       siglist
 756                         { $$ = $1; }
 757
 758 /* optional subroutine signature */
 759 optsubsignature:        /* NULL */
 760                         { $$ = NULL; }
 761         |       subsignature
 762                         { $$ = $1; }
 763
 764 /* Subroutine signature */
 765 subsignature:   '('
 766                         {
 767                             ENTER;
 768                             SAVEIV(parser->sig_elems);
 769                             SAVEIV(parser->sig_optelems);
 770                             SAVEI8(parser->sig_slurpy);
 771                             parser->sig_elems    = 0;
 772                             parser->sig_optelems = 0;
 773                             parser->sig_slurpy   = 0;
 774                             parser->in_my        = KEY_sigvar;
 775                         }
 776                 siglistornull
 777                 ')'
 778                         {
 779                             OP            *sigops = $3;
 780                             UNOP_AUX_item *aux;
 781                             OP            *check;
 782
 783                             if (!FEATURE_SIGNATURES_IS_ENABLED)
 784                                 Perl_croak(aTHX_ "Experimental "
 785                                     "subroutine signatures not enabled");
 786
 787                             /* We shouldn't get here otherwise */
 788                             Perl_ck_warner_d(aTHX_
 789                                 packWARN(WARN_EXPERIMENTAL__SIGNATURES),
 790                                 "The signatures feature is experimental");
 791
 792                             aux = (UNOP_AUX_item*)PerlMemShared_malloc(
 793                                 sizeof(UNOP_AUX_item) * 3);
 794                             aux[0].iv = parser->sig_elems;
 795                             aux[1].iv = parser->sig_optelems;
 796                             aux[2].iv = parser->sig_slurpy;
 797                             check = newUNOP_AUX(OP_ARGCHECK, 0, NULL, aux);
 798                             sigops = op_prepend_elem(OP_LINESEQ, check, sigops);
 799                             sigops = op_prepend_elem(OP_LINESEQ,
 800                                                 newSTATEOP(0, NULL, NULL),
 801                                                 sigops);
 802                             /* a nextstate at the end handles context
 803                              * correctly for an empty sub body */
 804                             $$ = op_append_elem(OP_LINESEQ,
 805                                                 sigops,
 806                                                 newSTATEOP(0, NULL, NULL));
 807
 808                             parser->in_my = 0;
 809                             /* tell the toker that attrributes can follow
 810                              * this sig, but only so that the toker
 811                              * can skip through any (illegal) trailing
 812                              * attribute text then give a useful error
 813                              * message about "attributes before sig",
 814                              * rather than falling over ina mess at
 815                              * unrecognised syntax.
 816                              */
 817                             parser->expect = XATTRBLOCK;
 818                             parser->sig_seen = TRUE;
 819                             LEAVE;
 820                         }
 821         ;
 822
 823 /* Optional subroutine body (for named subroutine declaration) */
 824 optsubbody:     subbody { $$ = $1; }
 825         |       ';'     { $$ = NULL; }
 826         ;
 827
 828
 829 /* Subroutine body (without signature) */
 830 subbody:        remember  '{' stmtseq '}'
 831                         {
 832                           if (parser->copline > (line_t)$2)
 833                               parser->copline = (line_t)$2;
 834                           $$ = block_end($1, $3);
 835                         }
 836         ;
 837
 838
 839 /* optional [ Subroutine body with optional signature ] (for named
 840  * subroutine declaration) */
 841 optsigsubbody:  sigsubbody { $$ = $1; }
 842         |       ';'        { $$ = NULL; }
 843
 844 /* Subroutine body with optional signature */
 845 sigsubbody:     remember optsubsignature '{' stmtseq '}'
 846                         {
 847                           if (parser->copline > (line_t)$3)
 848                               parser->copline = (line_t)$3;
 849                           $$ = block_end($1,
 850                                 op_append_list(OP_LINESEQ, $2, $4));
 851                         }
 852         ;
 853
 854
 855 /* Ordinary expressions; logical combinations */
 856 expr    :       expr ANDOP expr
 857                         { $$ = newLOGOP(OP_AND, 0, $1, $3); }
 858         |       expr OROP expr
 859                         { $$ = newLOGOP($2, 0, $1, $3); }
 860         |       expr DOROP expr
 861                         { $$ = newLOGOP(OP_DOR, 0, $1, $3); }
 862         |       listexpr %prec PREC_LOW
 863         ;
 864
 865 /* Expressions are a list of terms joined by commas */
 866 listexpr:       listexpr ','
 867                         { $$ = $1; }
 868         |       listexpr ',' term
 869                         {
 870                           OP* term = $3;
 871                           $$ = op_append_elem(OP_LIST, $1, term);
 872                         }
 873         |       term %prec PREC_LOW
 874         ;
 875
 876 /* List operators */
 877 listop  :       LSTOP indirob listexpr /* map {...} @args or print $fh @args */
 878                         { $$ = op_convert_list($1, OPf_STACKED,
 879                                 op_prepend_elem(OP_LIST, newGVREF($1,$2), $3) );
 880                         }
 881         |       FUNC '(' indirob expr ')'      /* print ($fh @args */
 882                         { $$ = op_convert_list($1, OPf_STACKED,
 883                                 op_prepend_elem(OP_LIST, newGVREF($1,$3), $4) );
 884                         }
 885         |       term ARROW method '(' optexpr ')' /* $foo->bar(list) */
 886                         { $$ = op_convert_list(OP_ENTERSUB, OPf_STACKED,
 887                                 op_append_elem(OP_LIST,
 888                                     op_prepend_elem(OP_LIST, scalar($1), $5),
 889                                     newMETHOP(OP_METHOD, 0, $3)));
 890                         }
 891         |       term ARROW method                     /* $foo->bar */
 892                         { $$ = op_convert_list(OP_ENTERSUB, OPf_STACKED,
 893                                 op_append_elem(OP_LIST, scalar($1),
 894                                     newMETHOP(OP_METHOD, 0, $3)));
 895                         }
 896         |       METHOD indirob optlistexpr           /* new Class @args */
 897                         { $$ = op_convert_list(OP_ENTERSUB, OPf_STACKED,
 898                                 op_append_elem(OP_LIST,
 899                                     op_prepend_elem(OP_LIST, $2, $3),
 900                                     newMETHOP(OP_METHOD, 0, $1)));
 901                         }
 902         |       FUNCMETH indirob '(' optexpr ')'    /* method $object (@args) */
 903                         { $$ = op_convert_list(OP_ENTERSUB, OPf_STACKED,
 904                                 op_append_elem(OP_LIST,
 905                                     op_prepend_elem(OP_LIST, $2, $4),
 906                                     newMETHOP(OP_METHOD, 0, $1)));
 907                         }
 908         |       LSTOP optlistexpr                    /* print @args */
 909                         { $$ = op_convert_list($1, 0, $2); }
 910         |       FUNC '(' optexpr ')'                 /* print (@args) */
 911                         { $$ = op_convert_list($1, 0, $3); }
 912         |       LSTOPSUB startanonsub block /* sub f(&@);   f { foo } ... */
 913                         { SvREFCNT_inc_simple_void(PL_compcv);
 914                           $<opval>$ = newANONATTRSUB($2, 0, NULL, $3); }
 915                     optlistexpr         %prec LSTOP  /* ... @bar */
 916                         { $$ = newUNOP(OP_ENTERSUB, OPf_STACKED,
 917                                  op_append_elem(OP_LIST,
 918                                    op_prepend_elem(OP_LIST, $<opval>4, $5), $1));
 919                         }
 920         ;
 921
 922 /* Names of methods. May use $object->$methodname */
 923 method  :       METHOD
 924         |       scalar
 925         ;
 926
 927 /* Some kind of subscripted expression */
 928 subscripted:    gelem '{' expr ';' '}'        /* *main::{something} */
 929                         /* In this and all the hash accessors, ';' is
 930                          * provided by the tokeniser */
 931                         { $$ = newBINOP(OP_GELEM, 0, $1, scalar($3)); }
 932         |       scalar '[' expr ']'          /* $array[$element] */
 933                         { $$ = newBINOP(OP_AELEM, 0, oopsAV($1), scalar($3));
 934                         }
 935         |       term ARROW '[' expr ']'      /* somearef->[$element] */
 936                         { $$ = newBINOP(OP_AELEM, 0,
 937                                         ref(newAVREF($1),OP_RV2AV),
 938                                         scalar($4));
 939                         }
 940         |       subscripted '[' expr ']'    /* $foo->[$bar]->[$baz] */
 941                         { $$ = newBINOP(OP_AELEM, 0,
 942                                         ref(newAVREF($1),OP_RV2AV),
 943                                         scalar($3));
 944                         }
 945         |       scalar '{' expr ';' '}'    /* $foo{bar();} */
 946                         { $$ = newBINOP(OP_HELEM, 0, oopsHV($1), jmaybe($3));
 947                         }
 948         |       term ARROW '{' expr ';' '}' /* somehref->{bar();} */
 949                         { $$ = newBINOP(OP_HELEM, 0,
 950                                         ref(newHVREF($1),OP_RV2HV),
 951                                         jmaybe($4)); }
 952         |       subscripted '{' expr ';' '}' /* $foo->[bar]->{baz;} */
 953                         { $$ = newBINOP(OP_HELEM, 0,
 954                                         ref(newHVREF($1),OP_RV2HV),
 955                                         jmaybe($3)); }
 956         |       term ARROW '(' ')'          /* $subref->() */
 957                         { $$ = newUNOP(OP_ENTERSUB, OPf_STACKED,
 958                                    newCVREF(0, scalar($1)));
 959                           if (parser->expect == XBLOCK)
 960                               parser->expect = XOPERATOR;
 961                         }
 962         |       term ARROW '(' expr ')'     /* $subref->(@args) */
 963                         { $$ = newUNOP(OP_ENTERSUB, OPf_STACKED,
 964                                    op_append_elem(OP_LIST, $4,
 965                                        newCVREF(0, scalar($1))));
 966                           if (parser->expect == XBLOCK)
 967                               parser->expect = XOPERATOR;
 968                         }
 969
 970         |       subscripted '(' expr ')'   /* $foo->{bar}->(@args) */
 971                         { $$ = newUNOP(OP_ENTERSUB, OPf_STACKED,
 972                                    op_append_elem(OP_LIST, $3,
 973                                                newCVREF(0, scalar($1))));
 974                           if (parser->expect == XBLOCK)
 975                               parser->expect = XOPERATOR;
 976                         }
 977         |       subscripted '(' ')'        /* $foo->{bar}->() */
 978                         { $$ = newUNOP(OP_ENTERSUB, OPf_STACKED,
 979                                    newCVREF(0, scalar($1)));
 980                           if (parser->expect == XBLOCK)
 981                               parser->expect = XOPERATOR;
 982                         }
 983         |       '(' expr ')' '[' expr ']'            /* list slice */
 984                         { $$ = newSLICEOP(0, $5, $2); }
 985         |       QWLIST '[' expr ']'            /* list literal slice */
 986                         { $$ = newSLICEOP(0, $3, $1); }
 987         |       '(' ')' '[' expr ']'                 /* empty list slice! */
 988                         { $$ = newSLICEOP(0, $4, NULL); }
 989     ;
 990
 991 /* Binary operators between terms */
 992 termbinop:      term ASSIGNOP term                     /* $x = $y, $x += $y */
 993                         { $$ = newASSIGNOP(OPf_STACKED, $1, $2, $3); }
 994         |       term POWOP term                        /* $x ** $y */
 995                         { $$ = newBINOP($2, 0, scalar($1), scalar($3)); }
 996         |       term MULOP term                        /* $x * $y, $x x $y */
 997                         {   if ($2 != OP_REPEAT)
 998                                 scalar($1);
 999                             $$ = newBINOP($2, 0, $1, scalar($3));
1000                         }
1001         |       term ADDOP term                        /* $x + $y */
1002                         { $$ = newBINOP($2, 0, scalar($1), scalar($3)); }
1003         |       term SHIFTOP term                      /* $x >> $y, $x << $y */
1004                         { $$ = newBINOP($2, 0, scalar($1), scalar($3)); }
1005         |       term RELOP term                        /* $x > $y, etc. */
1006                         { $$ = newBINOP($2, 0, scalar($1), scalar($3)); }
1007         |       term EQOP term                         /* $x == $y, $x eq $y */
1008                         { $$ = newBINOP($2, 0, scalar($1), scalar($3)); }
1009         |       term BITANDOP term                     /* $x & $y */
1010                         { $$ = newBINOP($2, 0, scalar($1), scalar($3)); }
1011         |       term BITOROP term                      /* $x | $y */
1012                         { $$ = newBINOP($2, 0, scalar($1), scalar($3)); }
1013         |       term DOTDOT term                       /* $x..$y, $x...$y */
1014                         { $$ = newRANGE($2, scalar($1), scalar($3)); }
1015         |       term ANDAND term                       /* $x && $y */
1016                         { $$ = newLOGOP(OP_AND, 0, $1, $3); }
1017         |       term OROR term                         /* $x || $y */
1018                         { $$ = newLOGOP(OP_OR, 0, $1, $3); }
1019         |       term DORDOR term                       /* $x // $y */
1020                         { $$ = newLOGOP(OP_DOR, 0, $1, $3); }
1021         |       term MATCHOP term                      /* $x =~ /$y/ */
1022                         { $$ = bind_match($2, $1, $3); }
1023     ;
1024
1025 /* Unary operators and terms */
1026 termunop : '-' term %prec UMINUS                       /* -$x */
1027                         { $$ = newUNOP(OP_NEGATE, 0, scalar($2)); }
1028         |       '+' term %prec UMINUS                  /* +$x */
1029                         { $$ = $2; }
1030
1031         |       '!' term                               /* !$x */
1032                         { $$ = newUNOP(OP_NOT, 0, scalar($2)); }
1033         |       '~' term                               /* ~$x */
1034                         { $$ = newUNOP($1, 0, scalar($2)); }
1035         |       term POSTINC                           /* $x++ */
1036                         { $$ = newUNOP(OP_POSTINC, 0,
1037                                         op_lvalue(scalar($1), OP_POSTINC)); }
1038         |       term POSTDEC                           /* $x-- */
1039                         { $$ = newUNOP(OP_POSTDEC, 0,
1040                                         op_lvalue(scalar($1), OP_POSTDEC));}
1041         |       term POSTJOIN    /* implicit join after interpolated ->@ */
1042                         { $$ = op_convert_list(OP_JOIN, 0,
1043                                        op_append_elem(
1044                                         OP_LIST,
1045                                         newSVREF(scalar(
1046                                             newSVOP(OP_CONST,0,
1047                                                     newSVpvs("\""))
1048                                         )),
1049                                         $1
1050                                        ));
1051                         }
1052         |       PREINC term                            /* ++$x */
1053                         { $$ = newUNOP(OP_PREINC, 0,
1054                                         op_lvalue(scalar($2), OP_PREINC)); }
1055         |       PREDEC term                            /* --$x */
1056                         { $$ = newUNOP(OP_PREDEC, 0,
1057                                         op_lvalue(scalar($2), OP_PREDEC)); }
1058
1059     ;
1060
1061 /* Constructors for anonymous data */
1062 anonymous:      '[' expr ']'
1063                         { $$ = newANONLIST($2); }
1064         |       '[' ']'
1065                         { $$ = newANONLIST(NULL);}
1066         |       HASHBRACK expr ';' '}'  %prec '(' /* { foo => "Bar" } */
1067                         { $$ = newANONHASH($2); }
1068         |       HASHBRACK ';' '}'       %prec '(' /* { } (';' by tokener) */
1069                         { $$ = newANONHASH(NULL); }
1070         |       ANONSUB     startanonsub proto subattrlist subbody    %prec '('
1071                         { SvREFCNT_inc_simple_void(PL_compcv);
1072                           $$ = newANONATTRSUB($2, $3, $4, $5); }
1073         |       ANON_SIGSUB startanonsub subattrlist sigsubbody %prec '('
1074                         { SvREFCNT_inc_simple_void(PL_compcv);
1075                           $$ = newANONATTRSUB($2, NULL, $3, $4); }
1076     ;
1077
1078 /* Things called with "do" */
1079 termdo  :       DO term %prec UNIOP                     /* do $filename */
1080                         { $$ = dofile($2, $1);}
1081         |       DO block        %prec '('               /* do { code */
1082                         { $$ = newUNOP(OP_NULL, OPf_SPECIAL, op_scope($2));}
1083         ;
1084
1085 term    :       termbinop
1086         |       termunop
1087         |       anonymous
1088         |       termdo
1089         |       term '?' term ':' term
1090                         { $$ = newCONDOP(0, $1, $3, $5); }
1091         |       REFGEN term                          /* \$x, \@y, \%z */
1092                         { $$ = newUNOP(OP_REFGEN, 0, $2); }
1093         |       MY REFGEN term
1094                         { $$ = newUNOP(OP_REFGEN, 0, localize($3,1)); }
1095         |       myattrterm      %prec UNIOP
1096                         { $$ = $1; }
1097         |       LOCAL term      %prec UNIOP
1098                         { $$ = localize($2,0); }
1099         |       '(' expr ')'
1100                         { $$ = sawparens($2); }
1101         |       QWLIST
1102                         { $$ = $1; }
1103         |       '(' ')'
1104                         { $$ = sawparens(newNULLLIST()); }
1105         |       scalar  %prec '('
1106                         { $$ = $1; }
1107         |       star    %prec '('
1108                         { $$ = $1; }
1109         |       hsh     %prec '('
1110                         { $$ = $1; }
1111         |       ary     %prec '('
1112                         { $$ = $1; }
1113         |       arylen  %prec '('                    /* $#x, $#{ something } */
1114                         { $$ = newUNOP(OP_AV2ARYLEN, 0, ref($1, OP_AV2ARYLEN));}
1115         |       subscripted
1116                         { $$ = $1; }
1117         |       sliceme '[' expr ']'                     /* array slice */
1118                         { $$ = op_prepend_elem(OP_ASLICE,
1119                                 newOP(OP_PUSHMARK, 0),
1120                                     newLISTOP(OP_ASLICE, 0,
1121                                         list($3),
1122                                         ref($1, OP_ASLICE)));
1123                           if ($$ && $1)
1124                               $$->op_private |=
1125                                   $1->op_private & OPpSLICEWARNING;
1126                         }
1127         |       kvslice '[' expr ']'                 /* array key/value slice */
1128                         { $$ = op_prepend_elem(OP_KVASLICE,
1129                                 newOP(OP_PUSHMARK, 0),
1130                                     newLISTOP(OP_KVASLICE, 0,
1131                                         list($3),
1132                                         ref(oopsAV($1), OP_KVASLICE)));
1133                           if ($$ && $1)
1134                               $$->op_private |=
1135                                   $1->op_private & OPpSLICEWARNING;
1136                         }
1137         |       sliceme '{' expr ';' '}'                 /* @hash{@keys} */
1138                         { $$ = op_prepend_elem(OP_HSLICE,
1139                                 newOP(OP_PUSHMARK, 0),
1140                                     newLISTOP(OP_HSLICE, 0,
1141                                         list($3),
1142                                         ref(oopsHV($1), OP_HSLICE)));
1143                           if ($$ && $1)
1144                               $$->op_private |=
1145                                   $1->op_private & OPpSLICEWARNING;
1146                         }
1147         |       kvslice '{' expr ';' '}'                 /* %hash{@keys} */
1148                         { $$ = op_prepend_elem(OP_KVHSLICE,
1149                                 newOP(OP_PUSHMARK, 0),
1150                                     newLISTOP(OP_KVHSLICE, 0,
1151                                         list($3),
1152                                         ref($1, OP_KVHSLICE)));
1153                           if ($$ && $1)
1154                               $$->op_private |=
1155                                   $1->op_private & OPpSLICEWARNING;
1156                         }
1157         |       THING   %prec '('
1158                         { $$ = $1; }
1159         |       amper                                /* &foo; */
1160                         { $$ = newUNOP(OP_ENTERSUB, 0, scalar($1)); }
1161         |       amper '(' ')'                 /* &foo() or foo() */
1162                         { $$ = newUNOP(OP_ENTERSUB, OPf_STACKED, scalar($1));
1163                         }
1164         |       amper '(' expr ')'          /* &foo(@args) or foo(@args) */
1165                         {
1166                           $$ = newUNOP(OP_ENTERSUB, OPf_STACKED,
1167                                 op_append_elem(OP_LIST, $3, scalar($1)));
1168                         }
1169         |       NOAMP subname optlistexpr       /* foo @args (no parens) */
1170                         { $$ = newUNOP(OP_ENTERSUB, OPf_STACKED,
1171                             op_append_elem(OP_LIST, $3, scalar($2)));
1172                         }
1173         |       term ARROW '$' '*'
1174                         { $$ = newSVREF($1); }
1175         |       term ARROW '@' '*'
1176                         { $$ = newAVREF($1); }
1177         |       term ARROW '%' '*'
1178                         { $$ = newHVREF($1); }
1179         |       term ARROW '&' '*'
1180                         { $$ = newUNOP(OP_ENTERSUB, 0,
1181                                        scalar(newCVREF($3,$1))); }
1182         |       term ARROW '*' '*'      %prec '('
1183                         { $$ = newGVREF(0,$1); }
1184         |       LOOPEX  /* loop exiting command (goto, last, dump, etc) */
1185                         { $$ = newOP($1, OPf_SPECIAL);
1186                             PL_hints |= HINT_BLOCK_SCOPE; }
1187         |       LOOPEX term
1188                         { $$ = newLOOPEX($1,$2); }
1189         |       NOTOP listexpr                       /* not $foo */
1190                         { $$ = newUNOP(OP_NOT, 0, scalar($2)); }
1191         |       UNIOP                                /* Unary op, $_ implied */
1192                         { $$ = newOP($1, 0); }
1193         |       UNIOP block                          /* eval { foo }* */
1194                         { $$ = newUNOP($1, 0, $2); }
1195         |       UNIOP term                           /* Unary op */
1196                         { $$ = newUNOP($1, 0, $2); }
1197         |       REQUIRE                              /* require, $_ implied */
1198                         { $$ = newOP(OP_REQUIRE, $1 ? OPf_SPECIAL : 0); }
1199         |       REQUIRE term                         /* require Foo */
1200                         { $$ = newUNOP(OP_REQUIRE, $1 ? OPf_SPECIAL : 0, $2); }
1201         |       UNIOPSUB
1202                         { $$ = newUNOP(OP_ENTERSUB, OPf_STACKED, scalar($1)); }
1203         |       UNIOPSUB term                        /* Sub treated as unop */
1204                         { $$ = newUNOP(OP_ENTERSUB, OPf_STACKED,
1205                             op_append_elem(OP_LIST, $2, scalar($1))); }
1206         |       FUNC0                                /* Nullary operator */
1207                         { $$ = newOP($1, 0); }
1208         |       FUNC0 '(' ')'
1209                         { $$ = newOP($1, 0);}
1210         |       FUNC0OP       /* Same as above, but op created in toke.c */
1211                         { $$ = $1; }
1212         |       FUNC0OP '(' ')'
1213                         { $$ = $1; }
1214         |       FUNC0SUB                             /* Sub treated as nullop */
1215                         { $$ = newUNOP(OP_ENTERSUB, OPf_STACKED, scalar($1)); }
1216         |       FUNC1 '(' ')'                        /* not () */
1217                         { $$ = ($1 == OP_NOT)
1218                           ? newUNOP($1, 0, newSVOP(OP_CONST, 0, newSViv(0)))
1219                           : newOP($1, OPf_SPECIAL); }
1220         |       FUNC1 '(' expr ')'                   /* not($foo) */
1221                         { $$ = newUNOP($1, 0, $3); }
1222         |       PMFUNC /* m//, s///, qr//, tr/// */
1223                         {
1224                             if (   $1->op_type != OP_TRANS
1225                                 && $1->op_type != OP_TRANSR
1226                                 && (((PMOP*)$1)->op_pmflags & PMf_HAS_CV))
1227                             {
1228                                 $<ival>$ = start_subparse(FALSE, CVf_ANON);
1229                                 SAVEFREESV(PL_compcv);
1230                             } else
1231                                 $<ival>$ = 0;
1232                         }
1233                     '(' listexpr optrepl ')'
1234                         { $$ = pmruntime($1, $4, $5, 1, $<ival>2); }
1235         |       BAREWORD
1236         |       listop
1237         |       PLUGEXPR
1238         ;
1239
1240 /* "my" declarations, with optional attributes */
1241 myattrterm:     MY myterm myattrlist
1242                         { $$ = my_attrs($2,$3); }
1243         |       MY myterm
1244                         { $$ = localize($2,1); }
1245         |       MY REFGEN myterm myattrlist
1246                         { $$ = newUNOP(OP_REFGEN, 0, my_attrs($3,$4)); }
1247         ;
1248
1249 /* Things that can be "my"'d */
1250 myterm  :       '(' expr ')'
1251                         { $$ = sawparens($2); }
1252         |       '(' ')'
1253                         { $$ = sawparens(newNULLLIST()); }
1254
1255         |       scalar  %prec '('
1256                         { $$ = $1; }
1257         |       hsh     %prec '('
1258                         { $$ = $1; }
1259         |       ary     %prec '('
1260                         { $$ = $1; }
1261         ;
1262
1263 /* Basic list expressions */
1264 optlistexpr:    /* NULL */ %prec PREC_LOW
1265                         { $$ = NULL; }
1266         |       listexpr    %prec PREC_LOW
1267                         { $$ = $1; }
1268         ;
1269
1270 optexpr:        /* NULL */
1271                         { $$ = NULL; }
1272         |       expr
1273                         { $$ = $1; }
1274         ;
1275
1276 optrepl:        /* NULL */
1277                         { $$ = NULL; }
1278         |       '/' expr
1279                         { $$ = $2; }
1280         ;
1281
1282 /* A little bit of trickery to make "for my $foo (@bar)" actually be
1283    lexical */
1284 my_scalar:      scalar
1285                         { parser->in_my = 0; $$ = my($1); }
1286         ;
1287
1288 my_var  :       scalar
1289         |       ary
1290         |       hsh
1291         ;
1292
1293 refgen_topic:   my_var
1294         |       amper
1295         ;
1296
1297 my_refgen:      MY REFGEN
1298         |       REFGEN MY
1299         ;
1300
1301 amper   :       '&' indirob
1302                         { $$ = newCVREF($1,$2); }
1303         ;
1304
1305 scalar  :       '$' indirob
1306                         { $$ = newSVREF($2); }
1307         ;
1308
1309 ary     :       '@' indirob
1310                         { $$ = newAVREF($2);
1311                           if ($$) $$->op_private |= $1;
1312                         }
1313         ;
1314
1315 hsh     :       '%' indirob
1316                         { $$ = newHVREF($2);
1317                           if ($$) $$->op_private |= $1;
1318                         }
1319         ;
1320
1321 arylen  :       DOLSHARP indirob
1322                         { $$ = newAVREF($2); }
1323         |       term ARROW DOLSHARP '*'
1324                         { $$ = newAVREF($1); }
1325         ;
1326
1327 star    :       '*' indirob
1328                         { $$ = newGVREF(0,$2); }
1329         ;
1330
1331 sliceme :       ary
1332         |       term ARROW '@'
1333                         { $$ = newAVREF($1); }
1334         ;
1335
1336 kvslice :       hsh
1337         |       term ARROW '%'
1338                         { $$ = newHVREF($1); }
1339         ;
1340
1341 gelem   :       star
1342         |       term ARROW '*'
1343                         { $$ = newGVREF(0,$1); }
1344         ;
1345
1346 /* Indirect objects */
1347 indirob :       BAREWORD
1348                         { $$ = scalar($1); }
1349         |       scalar %prec PREC_LOW
1350                         { $$ = scalar($1); }
1351         |       block
1352                         { $$ = op_scope($1); }
1353
1354         |       PRIVATEREF
1355                         { $$ = $1; }
1356         ;