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 %token <ival> SUBLEXSTART SUBLEXEND
  64
  65 %type <ival> grammar remember mremember
  66 %type <ival>  startsub startanonsub startformsub
  67
  68 %type <ival> mintro
  69
  70 %type <opval> stmtseq fullstmt labfullstmt barestmt block mblock else
  71 %type <opval> expr term subscripted scalar ary hsh arylen star amper sideff
  72 %type <opval> sliceme kvslice gelem
  73 %type <opval> listexpr nexpr texpr iexpr mexpr mnexpr
  74 %type <opval> optlistexpr optexpr optrepl indirob listop method
  75 %type <opval> formname subname proto cont my_scalar my_var
  76 %type <opval> refgen_topic formblock
  77 %type <opval> subattrlist myattrlist myattrterm myterm
  78 %type <opval> termbinop termunop anonymous termdo
  79 %type <ival>  sigslurpsigil
  80 %type <opval> sigvarname sigdefault sigscalarelem sigslurpelem
  81 %type <opval> sigelem siglist siglistornull subsignature optsubsignature
  82 %type <opval> subbody optsubbody sigsubbody optsigsubbody
  83 %type <opval> formstmtseq formline formarg
  84
  85 %nonassoc <ival> PREC_LOW
  86 %nonassoc LOOPEX
  87
  88 %left <ival> OROP DOROP
  89 %left <ival> ANDOP
  90 %right <ival> NOTOP
  91 %nonassoc LSTOP LSTOPSUB
  92 %left <ival> ','
  93 %right <ival> ASSIGNOP
  94 %right <ival> '?' ':'
  95 %nonassoc DOTDOT
  96 %left <ival> OROR DORDOR
  97 %left <ival> ANDAND
  98 %left <ival> BITOROP
  99 %left <ival> BITANDOP
 100 %nonassoc EQOP
 101 %nonassoc RELOP
 102 %nonassoc UNIOP UNIOPSUB
 103 %nonassoc REQUIRE
 104 %left <ival> SHIFTOP
 105 %left ADDOP
 106 %left MULOP
 107 %left <ival> MATCHOP
 108 %right <ival> '!' '~' UMINUS REFGEN
 109 %right <ival> POWOP
 110 %nonassoc <ival> PREINC PREDEC POSTINC POSTDEC POSTJOIN
 111 %left <ival> ARROW
 112 %nonassoc <ival> ')'
 113 %left <ival> '('
 114 %left '[' '{'
 115
 116 %% /* RULES */
 117
 118 /* Top-level choice of what kind of thing yyparse was called to parse */
 119 grammar :       GRAMPROG
 120                         {
 121                           parser->expect = XSTATE;
 122                           $<ival>$ = 0;
 123                         }
 124                 remember stmtseq
 125                         {
 126                           newPROG(block_end($3,$4));
 127                           PL_compiling.cop_seq = 0;
 128                           $$ = 0;
 129                         }
 130         |       GRAMEXPR
 131                         {
 132                           parser->expect = XTERM;
 133                           $<ival>$ = 0;
 134                         }
 135                 optexpr
 136                         {
 137                           PL_eval_root = $3;
 138                           $$ = 0;
 139                         }
 140         |       GRAMBLOCK
 141                         {
 142                           parser->expect = XBLOCK;
 143                           $<ival>$ = 0;
 144                         }
 145                 block
 146                         {
 147                           PL_pad_reset_pending = TRUE;
 148                           PL_eval_root = $3;
 149                           $$ = 0;
 150                           yyunlex();
 151                           parser->yychar = yytoken = YYEOF;
 152                         }
 153         |       GRAMBARESTMT
 154                         {
 155                           parser->expect = XSTATE;
 156                           $<ival>$ = 0;
 157                         }
 158                 barestmt
 159                         {
 160                           PL_pad_reset_pending = TRUE;
 161                           PL_eval_root = $3;
 162                           $$ = 0;
 163                           yyunlex();
 164                           parser->yychar = yytoken = YYEOF;
 165                         }
 166         |       GRAMFULLSTMT
 167                         {
 168                           parser->expect = XSTATE;
 169                           $<ival>$ = 0;
 170                         }
 171                 fullstmt
 172                         {
 173                           PL_pad_reset_pending = TRUE;
 174                           PL_eval_root = $3;
 175                           $$ = 0;
 176                           yyunlex();
 177                           parser->yychar = yytoken = YYEOF;
 178                         }
 179         |       GRAMSTMTSEQ
 180                         {
 181                           parser->expect = XSTATE;
 182                           $<ival>$ = 0;
 183                         }
 184                 stmtseq
 185                         {
 186                           PL_eval_root = $3;
 187                           $$ = 0;
 188                         }
 189         ;
 190
 191 /* An ordinary block */
 192 block   :       '{' remember stmtseq '}'
 193                         { if (parser->copline > (line_t)$1)
 194                               parser->copline = (line_t)$1;
 195                           $$ = block_end($2, $3);
 196                         }
 197         ;
 198
 199 /* format body */
 200 formblock:      '=' remember ';' FORMRBRACK formstmtseq ';' '.'
 201                         { if (parser->copline > (line_t)$1)
 202                               parser->copline = (line_t)$1;
 203                           $$ = block_end($2, $5);
 204                         }
 205         ;
 206
 207 remember:       /* NULL */      /* start a full lexical scope */
 208                         { $$ = block_start(TRUE);
 209                           parser->parsed_sub = 0; }
 210         ;
 211
 212 mblock  :       '{' mremember stmtseq '}'
 213                         { if (parser->copline > (line_t)$1)
 214                               parser->copline = (line_t)$1;
 215                           $$ = block_end($2, $3);
 216                         }
 217         ;
 218
 219 mremember:      /* NULL */      /* start a partial lexical scope */
 220                         { $$ = block_start(FALSE);
 221                           parser->parsed_sub = 0; }
 222         ;
 223
 224 /* A sequence of statements in the program */
 225 stmtseq :       /* NULL */
 226                         { $$ = NULL; }
 227         |       stmtseq fullstmt
 228                         {   $$ = op_append_list(OP_LINESEQ, $1, $2);
 229                             PL_pad_reset_pending = TRUE;
 230                             if ($1 && $2)
 231                                 PL_hints |= HINT_BLOCK_SCOPE;
 232                         }
 233         ;
 234
 235 /* A sequence of format lines */
 236 formstmtseq:    /* NULL */
 237                         { $$ = NULL; }
 238         |       formstmtseq formline
 239                         {   $$ = op_append_list(OP_LINESEQ, $1, $2);
 240                             PL_pad_reset_pending = TRUE;
 241                             if ($1 && $2)
 242                                 PL_hints |= HINT_BLOCK_SCOPE;
 243                         }
 244         ;
 245
 246 /* A statement in the program, including optional labels */
 247 fullstmt:       barestmt
 248                         {
 249                           $$ = $1 ? newSTATEOP(0, NULL, $1) : NULL;
 250                         }
 251         |       labfullstmt
 252                         { $$ = $1; }
 253         ;
 254
 255 labfullstmt:    LABEL barestmt
 256                         {
 257                           SV *label = cSVOPx_sv($1);
 258                           $$ = newSTATEOP(SvFLAGS(label) & SVf_UTF8,
 259                                             savepv(SvPVX_const(label)), $2);
 260                           op_free($1);
 261                         }
 262         |       LABEL labfullstmt
 263                         {
 264                           SV *label = cSVOPx_sv($1);
 265                           $$ = newSTATEOP(SvFLAGS(label) & SVf_UTF8,
 266                                             savepv(SvPVX_const(label)), $2);
 267                           op_free($1);
 268                         }
 269         ;
 270
 271 /* A bare statement, lacking label and other aspects of state op */
 272 barestmt:       PLUGSTMT
 273                         { $$ = $1; }
 274         |       FORMAT startformsub formname formblock
 275                         {
 276                           CV *fmtcv = PL_compcv;
 277                           newFORM($2, $3, $4);
 278                           $$ = NULL;
 279                           if (CvOUTSIDE(fmtcv) && !CvEVAL(CvOUTSIDE(fmtcv))) {
 280                               pad_add_weakref(fmtcv);
 281                           }
 282                           parser->parsed_sub = 1;
 283                         }
 284         |       SUB subname startsub
 285                     /* sub declaration or definition not within scope
 286                        of 'use feature "signatures"'*/
 287                         {
 288                           init_named_cv(PL_compcv, $2);
 289                           parser->in_my = 0;
 290                           parser->in_my_stash = NULL;
 291                         }
 292                     proto subattrlist optsubbody
 293                         {
 294                           SvREFCNT_inc_simple_void(PL_compcv);
 295                           $2->op_type == OP_CONST
 296                               ? newATTRSUB($3, $2, $5, $6, $7)
 297                               : newMYSUB($3, $2, $5, $6, $7)
 298                           ;
 299                           $$ = NULL;
 300                           intro_my();
 301                           parser->parsed_sub = 1;
 302                         }
 303         |       SIGSUB subname startsub
 304                     /* sub declaration or definition under 'use feature
 305                      * "signatures"'. (Note that a signature isn't
 306                      * allowed in a declaration)
 307                      */
 308                         {
 309                           init_named_cv(PL_compcv, $2);
 310                           parser->in_my = 0;
 311                           parser->in_my_stash = NULL;
 312                         }
 313                     subattrlist optsigsubbody
 314                         {
 315                           SvREFCNT_inc_simple_void(PL_compcv);
 316                           $2->op_type == OP_CONST
 317                               ? newATTRSUB($3, $2, NULL, $5, $6)
 318                               : newMYSUB(  $3, $2, NULL, $5, $6)
 319                           ;
 320                           $$ = NULL;
 321                           intro_my();
 322                           parser->parsed_sub = 1;
 323                         }
 324         |       PACKAGE BAREWORD BAREWORD ';'
 325                         {
 326                           package($3);
 327                           if ($2)
 328                               package_version($2);
 329                           $$ = NULL;
 330                         }
 331         |       USE startsub
 332                         { CvSPECIAL_on(PL_compcv); /* It's a BEGIN {} */ }
 333                 BAREWORD BAREWORD optlistexpr ';'
 334                         {
 335                           SvREFCNT_inc_simple_void(PL_compcv);
 336                           utilize($1, $2, $4, $5, $6);
 337                           parser->parsed_sub = 1;
 338                           $$ = NULL;
 339                         }
 340         |       IF '(' remember mexpr ')' mblock else
 341                         {
 342                           $$ = block_end($3,
 343                               newCONDOP(0, $4, op_scope($6), $7));
 344                           parser->copline = (line_t)$1;
 345                         }
 346         |       UNLESS '(' remember mexpr ')' mblock else
 347                         {
 348                           $$ = block_end($3,
 349                               newCONDOP(0, $4, $7, op_scope($6)));
 350                           parser->copline = (line_t)$1;
 351                         }
 352         |       GIVEN '(' remember mexpr ')' mblock
 353                         {
 354                           $$ = block_end($3, newGIVENOP($4, op_scope($6), 0));
 355                           parser->copline = (line_t)$1;
 356                         }
 357         |       WHEN '(' remember mexpr ')' mblock
 358                         { $$ = block_end($3, newWHENOP($4, op_scope($6))); }
 359         |       DEFAULT block
 360                         { $$ = newWHENOP(0, op_scope($2)); }
 361         |       WHILE '(' remember texpr ')' mintro mblock cont
 362                         {
 363                           $$ = block_end($3,
 364                                   newWHILEOP(0, 1, NULL,
 365                                       $4, $7, $8, $6));
 366                           parser->copline = (line_t)$1;
 367                         }
 368         |       UNTIL '(' remember iexpr ')' mintro mblock cont
 369                         {
 370                           $$ = block_end($3,
 371                                   newWHILEOP(0, 1, NULL,
 372                                       $4, $7, $8, $6));
 373                           parser->copline = (line_t)$1;
 374                         }
 375         |       FOR '(' remember mnexpr ';'
 376                         { parser->expect = XTERM; }
 377                 texpr ';'
 378                         { parser->expect = XTERM; }
 379                 mintro mnexpr ')'
 380                 mblock
 381                         {
 382                           OP *initop = $4;
 383                           OP *forop = newWHILEOP(0, 1, NULL,
 384                                       scalar($7), $13, $11, $10);
 385                           if (initop) {
 386                               forop = op_prepend_elem(OP_LINESEQ, initop,
 387                                   op_append_elem(OP_LINESEQ,
 388                                       newOP(OP_UNSTACK, OPf_SPECIAL),
 389                                       forop));
 390                           }
 391                           PL_hints |= HINT_BLOCK_SCOPE;
 392                           $$ = block_end($3, forop);
 393                           parser->copline = (line_t)$1;
 394                         }
 395         |       FOR MY remember my_scalar '(' mexpr ')' mblock cont
 396                         {
 397                           $$ = block_end($3, newFOROP(0, $4, $6, $8, $9));
 398                           parser->copline = (line_t)$1;
 399                         }
 400         |       FOR scalar '(' remember mexpr ')' mblock cont
 401                         {
 402                           $$ = block_end($4, newFOROP(0,
 403                                       op_lvalue($2, OP_ENTERLOOP), $5, $7, $8));
 404                           parser->copline = (line_t)$1;
 405                         }
 406         |       FOR my_refgen remember my_var
 407                         { parser->in_my = 0; $<opval>$ = my($4); }
 408                 '(' mexpr ')' mblock cont
 409                         {
 410                           $$ = block_end(
 411                                 $3,
 412                                 newFOROP(0,
 413                                          op_lvalue(
 414                                             newUNOP(OP_REFGEN, 0,
 415                                                     $<opval>5),
 416                                             OP_ENTERLOOP),
 417                                          $7, $9, $10)
 418                           );
 419                           parser->copline = (line_t)$1;
 420                         }
 421         |       FOR REFGEN refgen_topic '(' remember mexpr ')' mblock cont
 422                         {
 423                           $$ = block_end($5, newFOROP(
 424                                 0, op_lvalue(newUNOP(OP_REFGEN, 0,
 425                                                      $3),
 426                                              OP_ENTERLOOP), $6, $8, $9));
 427                           parser->copline = (line_t)$1;
 428                         }
 429         |       FOR '(' remember mexpr ')' mblock cont
 430                         {
 431                           $$ = block_end($3,
 432                                   newFOROP(0, NULL, $4, $6, $7));
 433                           parser->copline = (line_t)$1;
 434                         }
 435         |       block cont
 436                         {
 437                           /* a block is a loop that happens once */
 438                           $$ = newWHILEOP(0, 1, NULL,
 439                                   NULL, $1, $2, 0);
 440                         }
 441         |       PACKAGE BAREWORD BAREWORD '{' remember
 442                         {
 443                           package($3);
 444                           if ($2) {
 445                               package_version($2);
 446                           }
 447                         }
 448                 stmtseq '}'
 449                         {
 450                           /* a block is a loop that happens once */
 451                           $$ = newWHILEOP(0, 1, NULL,
 452                                   NULL, block_end($5, $7), NULL, 0);
 453                           if (parser->copline > (line_t)$4)
 454                               parser->copline = (line_t)$4;
 455                         }
 456         |       sideff ';'
 457                         {
 458                           $$ = $1;
 459                         }
 460         |       YADAYADA ';'
 461                         {
 462                           $$ = newLISTOP(OP_DIE, 0, newOP(OP_PUSHMARK, 0),
 463                                 newSVOP(OP_CONST, 0, newSVpvs("Unimplemented")));
 464                         }
 465         |       ';'
 466                         {
 467                           $$ = NULL;
 468                           parser->copline = NOLINE;
 469                         }
 470         ;
 471
 472 /* Format line */
 473 formline:       THING formarg
 474                         { OP *list;
 475                           if ($2) {
 476                               OP *term = $2;
 477                               list = op_append_elem(OP_LIST, $1, term);
 478                           }
 479                           else {
 480                               list = $1;
 481                           }
 482                           if (parser->copline == NOLINE)
 483                                parser->copline = CopLINE(PL_curcop)-1;
 484                           else parser->copline--;
 485                           $$ = newSTATEOP(0, NULL,
 486                                           op_convert_list(OP_FORMLINE, 0, list));
 487                         }
 488         ;
 489
 490 formarg :       /* NULL */
 491                         { $$ = NULL; }
 492         |       FORMLBRACK stmtseq FORMRBRACK
 493                         { $$ = op_unscope($2); }
 494         ;
 495
 496 /* An expression which may have a side-effect */
 497 sideff  :       error
 498                         { $$ = NULL; }
 499         |       expr
 500                         { $$ = $1; }
 501         |       expr IF expr
 502                         { $$ = newLOGOP(OP_AND, 0, $3, $1); }
 503         |       expr UNLESS expr
 504                         { $$ = newLOGOP(OP_OR, 0, $3, $1); }
 505         |       expr WHILE expr
 506                         { $$ = newLOOPOP(OPf_PARENS, 1, scalar($3), $1); }
 507         |       expr UNTIL iexpr
 508                         { $$ = newLOOPOP(OPf_PARENS, 1, $3, $1); }
 509         |       expr FOR expr
 510                         { $$ = newFOROP(0, NULL, $3, $1, NULL);
 511                           parser->copline = (line_t)$2; }
 512         |       expr WHEN expr
 513                         { $$ = newWHENOP($3, op_scope($1)); }
 514         ;
 515
 516 /* else and elsif blocks */
 517 else    :       /* NULL */
 518                         { $$ = NULL; }
 519         |       ELSE mblock
 520                         {
 521                           ($2)->op_flags |= OPf_PARENS;
 522                           $$ = op_scope($2);
 523                         }
 524         |       ELSIF '(' mexpr ')' mblock else
 525                         { parser->copline = (line_t)$1;
 526                             $$ = newCONDOP(0,
 527                                 newSTATEOP(OPf_SPECIAL,NULL,$3),
 528                                 op_scope($5), $6);
 529                           PL_hints |= HINT_BLOCK_SCOPE;
 530                         }
 531         ;
 532
 533 /* Continue blocks */
 534 cont    :       /* NULL */
 535                         { $$ = NULL; }
 536         |       CONTINUE block
 537                         { $$ = op_scope($2); }
 538         ;
 539
 540 /* determine whether there are any new my declarations */
 541 mintro  :       /* NULL */
 542                         { $$ = (PL_min_intro_pending &&
 543                             PL_max_intro_pending >=  PL_min_intro_pending);
 544                           intro_my(); }
 545
 546 /* Normal expression */
 547 nexpr   :       /* NULL */
 548                         { $$ = NULL; }
 549         |       sideff
 550         ;
 551
 552 /* Boolean expression */
 553 texpr   :       /* NULL means true */
 554                         { YYSTYPE tmplval;
 555                           (void)scan_num("1", &tmplval);
 556                           $$ = tmplval.opval; }
 557         |       expr
 558         ;
 559
 560 /* Inverted boolean expression */
 561 iexpr   :       expr
 562                         { $$ = invert(scalar($1)); }
 563         ;
 564
 565 /* Expression with its own lexical scope */
 566 mexpr   :       expr
 567                         { $$ = $1; intro_my(); }
 568         ;
 569
 570 mnexpr  :       nexpr
 571                         { $$ = $1; intro_my(); }
 572         ;
 573
 574 formname:       BAREWORD        { $$ = $1; }
 575         |       /* NULL */      { $$ = NULL; }
 576         ;
 577
 578 startsub:       /* NULL */      /* start a regular subroutine scope */
 579                         { $$ = start_subparse(FALSE, 0);
 580                             SAVEFREESV(PL_compcv); }
 581
 582         ;
 583
 584 startanonsub:   /* NULL */      /* start an anonymous subroutine scope */
 585                         { $$ = start_subparse(FALSE, CVf_ANON);
 586                             SAVEFREESV(PL_compcv); }
 587         ;
 588
 589 startformsub:   /* NULL */      /* start a format subroutine scope */
 590                         { $$ = start_subparse(TRUE, 0);
 591                             SAVEFREESV(PL_compcv); }
 592         ;
 593
 594 /* Name of a subroutine - must be a bareword, could be special */
 595 subname :       BAREWORD
 596         |       PRIVATEREF
 597         ;
 598
 599 /* Subroutine prototype */
 600 proto   :       /* NULL */
 601                         { $$ = NULL; }
 602         |       THING
 603         ;
 604
 605 /* Optional list of subroutine attributes */
 606 subattrlist:    /* NULL */
 607                         { $$ = NULL; }
 608         |       COLONATTR THING
 609                         { $$ = $2; }
 610         |       COLONATTR
 611                         { $$ = NULL; }
 612         ;
 613
 614 /* List of attributes for a "my" variable declaration */
 615 myattrlist:     COLONATTR THING
 616                         { $$ = $2; }
 617         |       COLONATTR
 618                         { $$ = NULL; }
 619         ;
 620
 621
 622
 623 /* --------------------------------------
 624  * subroutine signature parsing
 625  */
 626
 627 /* the '' or 'foo' part of a '$' or '@foo' etc signature variable  */
 628 sigvarname:     /* NULL */
 629                         { parser->in_my = 0; $$ = NULL; }
 630         |       PRIVATEREF
 631                         { parser->in_my = 0; $$ = $1; }
 632         ;
 633
 634 sigslurpsigil:
 635                 '@'
 636                         { $$ = '@'; }
 637         |       '%'
 638                         { $$ = '%'; }
 639
 640 /* @, %, @foo, %foo */
 641 sigslurpelem: sigslurpsigil sigvarname sigdefault/* def only to catch errors */
 642                         {
 643                             I32 sigil   = $1;
 644                             OP *var     = $2;
 645                             OP *defexpr = $3;
 646
 647                             if (parser->sig_slurpy)
 648                                 yyerror("Multiple slurpy parameters not allowed");
 649                             parser->sig_slurpy = (char)sigil;
 650
 651                             if (defexpr)
 652                                 yyerror("A slurpy parameter may not have "
 653                                         "a default value");
 654
 655                             $$ = var ? newSTATEOP(0, NULL, var) : NULL;
 656                         }
 657         ;
 658
 659 /* default part of sub signature scalar element: i.e. '= default_expr' */
 660 sigdefault:     /* NULL */
 661                         { $$ = NULL; }
 662         |       ASSIGNOP
 663                         { $$ = newOP(OP_NULL, 0); }
 664         |       ASSIGNOP term
 665                         { $$ = $2; }
 666
 667
 668 /* subroutine signature scalar element: e.g. '$x', '$=', '$x = $default' */
 669 sigscalarelem:
 670                 '$' sigvarname sigdefault
 671                         {
 672                             OP *var     = $2;
 673                             OP *defexpr = $3;
 674
 675                             if (parser->sig_slurpy)
 676                                 yyerror("Slurpy parameter not last");
 677
 678                             parser->sig_elems++;
 679
 680                             if (defexpr) {
 681                                 parser->sig_optelems++;
 682
 683                                 if (   defexpr->op_type == OP_NULL
 684                                     && !(defexpr->op_flags & OPf_KIDS))
 685                                 {
 686                                     /* handle '$=' special case */
 687                                     if (var)
 688                                         yyerror("Optional parameter "
 689                                                     "lacks default expression");
 690                                     op_free(defexpr);
 691                                 }
 692                                 else {
 693                                     /* a normal '=default' expression */
 694                                     OP *defop = (OP*)alloc_LOGOP(OP_ARGDEFELEM,
 695                                                         defexpr,
 696                                                         LINKLIST(defexpr));
 697                                     /* re-purpose op_targ to hold @_ index */
 698                                     defop->op_targ =
 699                                         (PADOFFSET)(parser->sig_elems - 1);
 700
 701                                     if (var) {
 702                                         var->op_flags |= OPf_STACKED;
 703                                         (void)op_sibling_splice(var,
 704                                                         NULL, 0, defop);
 705                                         scalar(defop);
 706                                     }
 707                                     else
 708                                         var = newUNOP(OP_NULL, 0, defop);
 709
 710                                     LINKLIST(var);
 711                                     /* NB: normally the first child of a
 712                                      * logop is executed before the logop,
 713                                      * and it pushes a boolean result
 714                                      * ready for the logop. For ARGDEFELEM,
 715                                      * the op itself does the boolean
 716                                      * calculation, so set the first op to
 717                                      * it instead.
 718                                      */
 719                                     var->op_next = defop;
 720                                     defexpr->op_next = var;
 721                                 }
 722                             }
 723                             else {
 724                                 if (parser->sig_optelems)
 725                                     yyerror("Mandatory parameter "
 726                                             "follows optional parameter");
 727                             }
 728
 729                             $$ = var ? newSTATEOP(0, NULL, var) : NULL;
 730                         }
 731         ;
 732
 733
 734 /* subroutine signature element: e.g. '$x = $default' or '%h' */
 735 sigelem:        sigscalarelem
 736                         { parser->in_my = KEY_sigvar; $$ = $1; }
 737         |       sigslurpelem
 738                         { parser->in_my = KEY_sigvar; $$ = $1; }
 739         ;
 740
 741 /* list of subroutine signature elements */
 742 siglist:
 743                 siglist ','
 744                         { $$ = $1; }
 745         |       siglist ',' sigelem
 746                         {
 747                           $$ = op_append_list(OP_LINESEQ, $1, $3);
 748                         }
 749         |       sigelem  %prec PREC_LOW
 750                         { $$ = $1; }
 751         ;
 752
 753 /* () or (....) */
 754 siglistornull:          /* NULL */
 755                         { $$ = NULL; }
 756         |       siglist
 757                         { $$ = $1; }
 758
 759 /* optional subroutine signature */
 760 optsubsignature:        /* NULL */
 761                         { $$ = NULL; }
 762         |       subsignature
 763                         { $$ = $1; }
 764
 765 /* Subroutine signature */
 766 subsignature:   '('
 767                         {
 768                             ENTER;
 769                             SAVEIV(parser->sig_elems);
 770                             SAVEIV(parser->sig_optelems);
 771                             SAVEI8(parser->sig_slurpy);
 772                             parser->sig_elems    = 0;
 773                             parser->sig_optelems = 0;
 774                             parser->sig_slurpy   = 0;
 775                             parser->in_my        = KEY_sigvar;
 776                         }
 777                 siglistornull
 778                 ')'
 779                         {
 780                             OP            *sigops = $3;
 781                             UNOP_AUX_item *aux;
 782                             OP            *check;
 783
 784                             if (!FEATURE_SIGNATURES_IS_ENABLED)
 785                                 Perl_croak(aTHX_ "Experimental "
 786                                     "subroutine signatures not enabled");
 787
 788                             /* We shouldn't get here otherwise */
 789                             Perl_ck_warner_d(aTHX_
 790                                 packWARN(WARN_EXPERIMENTAL__SIGNATURES),
 791                                 "The signatures feature is experimental");
 792
 793                             aux = (UNOP_AUX_item*)PerlMemShared_malloc(
 794                                 sizeof(UNOP_AUX_item) * 3);
 795                             aux[0].iv = parser->sig_elems;
 796                             aux[1].iv = parser->sig_optelems;
 797                             aux[2].iv = parser->sig_slurpy;
 798                             check = newUNOP_AUX(OP_ARGCHECK, 0, NULL, aux);
 799                             sigops = op_prepend_elem(OP_LINESEQ, check, sigops);
 800                             sigops = op_prepend_elem(OP_LINESEQ,
 801                                                 newSTATEOP(0, NULL, NULL),
 802                                                 sigops);
 803                             /* a nextstate at the end handles context
 804                              * correctly for an empty sub body */
 805                             $$ = op_append_elem(OP_LINESEQ,
 806                                                 sigops,
 807                                                 newSTATEOP(0, NULL, NULL));
 808
 809                             parser->in_my = 0;
 810                             /* tell the toker that attrributes can follow
 811                              * this sig, but only so that the toker
 812                              * can skip through any (illegal) trailing
 813                              * attribute text then give a useful error
 814                              * message about "attributes before sig",
 815                              * rather than falling over ina mess at
 816                              * unrecognised syntax.
 817                              */
 818                             parser->expect = XATTRBLOCK;
 819                             parser->sig_seen = TRUE;
 820                             LEAVE;
 821                         }
 822         ;
 823
 824 /* Optional subroutine body (for named subroutine declaration) */
 825 optsubbody:     subbody { $$ = $1; }
 826         |       ';'     { $$ = NULL; }
 827         ;
 828
 829
 830 /* Subroutine body (without signature) */
 831 subbody:        remember  '{' stmtseq '}'
 832                         {
 833                           if (parser->copline > (line_t)$2)
 834                               parser->copline = (line_t)$2;
 835                           $$ = block_end($1, $3);
 836                         }
 837         ;
 838
 839
 840 /* optional [ Subroutine body with optional signature ] (for named
 841  * subroutine declaration) */
 842 optsigsubbody:  sigsubbody { $$ = $1; }
 843         |       ';'        { $$ = NULL; }
 844
 845 /* Subroutine body with optional signature */
 846 sigsubbody:     remember optsubsignature '{' stmtseq '}'
 847                         {
 848                           if (parser->copline > (line_t)$3)
 849                               parser->copline = (line_t)$3;
 850                           $$ = block_end($1,
 851                                 op_append_list(OP_LINESEQ, $2, $4));
 852                         }
 853         ;
 854
 855
 856 /* Ordinary expressions; logical combinations */
 857 expr    :       expr ANDOP expr
 858                         { $$ = newLOGOP(OP_AND, 0, $1, $3); }
 859         |       expr OROP expr
 860                         { $$ = newLOGOP($2, 0, $1, $3); }
 861         |       expr DOROP expr
 862                         { $$ = newLOGOP(OP_DOR, 0, $1, $3); }
 863         |       listexpr %prec PREC_LOW
 864         ;
 865
 866 /* Expressions are a list of terms joined by commas */
 867 listexpr:       listexpr ','
 868                         { $$ = $1; }
 869         |       listexpr ',' term
 870                         {
 871                           OP* term = $3;
 872                           $$ = op_append_elem(OP_LIST, $1, term);
 873                         }
 874         |       term %prec PREC_LOW
 875         ;
 876
 877 /* List operators */
 878 listop  :       LSTOP indirob listexpr /* map {...} @args or print $fh @args */
 879                         { $$ = op_convert_list($1, OPf_STACKED,
 880                                 op_prepend_elem(OP_LIST, newGVREF($1,$2), $3) );
 881                         }
 882         |       FUNC '(' indirob expr ')'      /* print ($fh @args */
 883                         { $$ = op_convert_list($1, OPf_STACKED,
 884                                 op_prepend_elem(OP_LIST, newGVREF($1,$3), $4) );
 885                         }
 886         |       term ARROW method '(' optexpr ')' /* $foo->bar(list) */
 887                         { $$ = op_convert_list(OP_ENTERSUB, OPf_STACKED,
 888                                 op_append_elem(OP_LIST,
 889                                     op_prepend_elem(OP_LIST, scalar($1), $5),
 890                                     newMETHOP(OP_METHOD, 0, $3)));
 891                         }
 892         |       term ARROW method                     /* $foo->bar */
 893                         { $$ = op_convert_list(OP_ENTERSUB, OPf_STACKED,
 894                                 op_append_elem(OP_LIST, scalar($1),
 895                                     newMETHOP(OP_METHOD, 0, $3)));
 896                         }
 897         |       METHOD indirob optlistexpr           /* new Class @args */
 898                         { $$ = op_convert_list(OP_ENTERSUB, OPf_STACKED,
 899                                 op_append_elem(OP_LIST,
 900                                     op_prepend_elem(OP_LIST, $2, $3),
 901                                     newMETHOP(OP_METHOD, 0, $1)));
 902                         }
 903         |       FUNCMETH indirob '(' optexpr ')'    /* method $object (@args) */
 904                         { $$ = op_convert_list(OP_ENTERSUB, OPf_STACKED,
 905                                 op_append_elem(OP_LIST,
 906                                     op_prepend_elem(OP_LIST, $2, $4),
 907                                     newMETHOP(OP_METHOD, 0, $1)));
 908                         }
 909         |       LSTOP optlistexpr                    /* print @args */
 910                         { $$ = op_convert_list($1, 0, $2); }
 911         |       FUNC '(' optexpr ')'                 /* print (@args) */
 912                         { $$ = op_convert_list($1, 0, $3); }
 913         |       FUNC SUBLEXSTART optexpr SUBLEXEND          /* uc($arg) from "\U..." */
 914                         { $$ = op_convert_list($1, 0, $3); }
 915         |       LSTOPSUB startanonsub block /* sub f(&@);   f { foo } ... */
 916                         { SvREFCNT_inc_simple_void(PL_compcv);
 917                           $<opval>$ = newANONATTRSUB($2, 0, NULL, $3); }
 918                     optlistexpr         %prec LSTOP  /* ... @bar */
 919                         { $$ = newUNOP(OP_ENTERSUB, OPf_STACKED,
 920                                  op_append_elem(OP_LIST,
 921                                    op_prepend_elem(OP_LIST, $<opval>4, $5), $1));
 922                         }
 923         ;
 924
 925 /* Names of methods. May use $object->$methodname */
 926 method  :       METHOD
 927         |       scalar
 928         ;
 929
 930 /* Some kind of subscripted expression */
 931 subscripted:    gelem '{' expr ';' '}'        /* *main::{something} */
 932                         /* In this and all the hash accessors, ';' is
 933                          * provided by the tokeniser */
 934                         { $$ = newBINOP(OP_GELEM, 0, $1, scalar($3)); }
 935         |       scalar '[' expr ']'          /* $array[$element] */
 936                         { $$ = newBINOP(OP_AELEM, 0, oopsAV($1), scalar($3));
 937                         }
 938         |       term ARROW '[' expr ']'      /* somearef->[$element] */
 939                         { $$ = newBINOP(OP_AELEM, 0,
 940                                         ref(newAVREF($1),OP_RV2AV),
 941                                         scalar($4));
 942                         }
 943         |       subscripted '[' expr ']'    /* $foo->[$bar]->[$baz] */
 944                         { $$ = newBINOP(OP_AELEM, 0,
 945                                         ref(newAVREF($1),OP_RV2AV),
 946                                         scalar($3));
 947                         }
 948         |       scalar '{' expr ';' '}'    /* $foo{bar();} */
 949                         { $$ = newBINOP(OP_HELEM, 0, oopsHV($1), jmaybe($3));
 950                         }
 951         |       term ARROW '{' expr ';' '}' /* somehref->{bar();} */
 952                         { $$ = newBINOP(OP_HELEM, 0,
 953                                         ref(newHVREF($1),OP_RV2HV),
 954                                         jmaybe($4)); }
 955         |       subscripted '{' expr ';' '}' /* $foo->[bar]->{baz;} */
 956                         { $$ = newBINOP(OP_HELEM, 0,
 957                                         ref(newHVREF($1),OP_RV2HV),
 958                                         jmaybe($3)); }
 959         |       term ARROW '(' ')'          /* $subref->() */
 960                         { $$ = newUNOP(OP_ENTERSUB, OPf_STACKED,
 961                                    newCVREF(0, scalar($1)));
 962                           if (parser->expect == XBLOCK)
 963                               parser->expect = XOPERATOR;
 964                         }
 965         |       term ARROW '(' expr ')'     /* $subref->(@args) */
 966                         { $$ = newUNOP(OP_ENTERSUB, OPf_STACKED,
 967                                    op_append_elem(OP_LIST, $4,
 968                                        newCVREF(0, scalar($1))));
 969                           if (parser->expect == XBLOCK)
 970                               parser->expect = XOPERATOR;
 971                         }
 972
 973         |       subscripted '(' expr ')'   /* $foo->{bar}->(@args) */
 974                         { $$ = newUNOP(OP_ENTERSUB, OPf_STACKED,
 975                                    op_append_elem(OP_LIST, $3,
 976                                                newCVREF(0, scalar($1))));
 977                           if (parser->expect == XBLOCK)
 978                               parser->expect = XOPERATOR;
 979                         }
 980         |       subscripted '(' ')'        /* $foo->{bar}->() */
 981                         { $$ = newUNOP(OP_ENTERSUB, OPf_STACKED,
 982                                    newCVREF(0, scalar($1)));
 983                           if (parser->expect == XBLOCK)
 984                               parser->expect = XOPERATOR;
 985                         }
 986         |       '(' expr ')' '[' expr ']'            /* list slice */
 987                         { $$ = newSLICEOP(0, $5, $2); }
 988         |       QWLIST '[' expr ']'            /* list literal slice */
 989                         { $$ = newSLICEOP(0, $3, $1); }
 990         |       '(' ')' '[' expr ']'                 /* empty list slice! */
 991                         { $$ = newSLICEOP(0, $4, NULL); }
 992     ;
 993
 994 /* Binary operators between terms */
 995 termbinop:      term ASSIGNOP term                     /* $x = $y, $x += $y */
 996                         { $$ = newASSIGNOP(OPf_STACKED, $1, $2, $3); }
 997         |       term POWOP term                        /* $x ** $y */
 998                         { $$ = newBINOP($2, 0, scalar($1), scalar($3)); }
 999         |       term MULOP term                        /* $x * $y, $x x $y */
1000                         {   if ($2 != OP_REPEAT)
1001                                 scalar($1);
1002                             $$ = newBINOP($2, 0, $1, scalar($3));
1003                         }
1004         |       term ADDOP term                        /* $x + $y */
1005                         { $$ = newBINOP($2, 0, scalar($1), scalar($3)); }
1006         |       term SHIFTOP term                      /* $x >> $y, $x << $y */
1007                         { $$ = newBINOP($2, 0, scalar($1), scalar($3)); }
1008         |       term RELOP term                        /* $x > $y, etc. */
1009                         { $$ = newBINOP($2, 0, scalar($1), scalar($3)); }
1010         |       term EQOP term                         /* $x == $y, $x eq $y */
1011                         { $$ = newBINOP($2, 0, scalar($1), scalar($3)); }
1012         |       term BITANDOP term                     /* $x & $y */
1013                         { $$ = newBINOP($2, 0, scalar($1), scalar($3)); }
1014         |       term BITOROP term                      /* $x | $y */
1015                         { $$ = newBINOP($2, 0, scalar($1), scalar($3)); }
1016         |       term DOTDOT term                       /* $x..$y, $x...$y */
1017                         { $$ = newRANGE($2, scalar($1), scalar($3)); }
1018         |       term ANDAND term                       /* $x && $y */
1019                         { $$ = newLOGOP(OP_AND, 0, $1, $3); }
1020         |       term OROR term                         /* $x || $y */
1021                         { $$ = newLOGOP(OP_OR, 0, $1, $3); }
1022         |       term DORDOR term                       /* $x // $y */
1023                         { $$ = newLOGOP(OP_DOR, 0, $1, $3); }
1024         |       term MATCHOP term                      /* $x =~ /$y/ */
1025                         { $$ = bind_match($2, $1, $3); }
1026     ;
1027
1028 /* Unary operators and terms */
1029 termunop : '-' term %prec UMINUS                       /* -$x */
1030                         { $$ = newUNOP(OP_NEGATE, 0, scalar($2)); }
1031         |       '+' term %prec UMINUS                  /* +$x */
1032                         { $$ = $2; }
1033
1034         |       '!' term                               /* !$x */
1035                         { $$ = newUNOP(OP_NOT, 0, scalar($2)); }
1036         |       '~' term                               /* ~$x */
1037                         { $$ = newUNOP($1, 0, scalar($2)); }
1038         |       term POSTINC                           /* $x++ */
1039                         { $$ = newUNOP(OP_POSTINC, 0,
1040                                         op_lvalue(scalar($1), OP_POSTINC)); }
1041         |       term POSTDEC                           /* $x-- */
1042                         { $$ = newUNOP(OP_POSTDEC, 0,
1043                                         op_lvalue(scalar($1), OP_POSTDEC));}
1044         |       term POSTJOIN    /* implicit join after interpolated ->@ */
1045                         { $$ = op_convert_list(OP_JOIN, 0,
1046                                        op_append_elem(
1047                                         OP_LIST,
1048                                         newSVREF(scalar(
1049                                             newSVOP(OP_CONST,0,
1050                                                     newSVpvs("\""))
1051                                         )),
1052                                         $1
1053                                        ));
1054                         }
1055         |       PREINC term                            /* ++$x */
1056                         { $$ = newUNOP(OP_PREINC, 0,
1057                                         op_lvalue(scalar($2), OP_PREINC)); }
1058         |       PREDEC term                            /* --$x */
1059                         { $$ = newUNOP(OP_PREDEC, 0,
1060                                         op_lvalue(scalar($2), OP_PREDEC)); }
1061
1062     ;
1063
1064 /* Constructors for anonymous data */
1065 anonymous:      '[' expr ']'
1066                         { $$ = newANONLIST($2); }
1067         |       '[' ']'
1068                         { $$ = newANONLIST(NULL);}
1069         |       HASHBRACK expr ';' '}'  %prec '(' /* { foo => "Bar" } */
1070                         { $$ = newANONHASH($2); }
1071         |       HASHBRACK ';' '}'       %prec '(' /* { } (';' by tokener) */
1072                         { $$ = newANONHASH(NULL); }
1073         |       ANONSUB     startanonsub proto subattrlist subbody    %prec '('
1074                         { SvREFCNT_inc_simple_void(PL_compcv);
1075                           $$ = newANONATTRSUB($2, $3, $4, $5); }
1076         |       ANON_SIGSUB startanonsub subattrlist sigsubbody %prec '('
1077                         { SvREFCNT_inc_simple_void(PL_compcv);
1078                           $$ = newANONATTRSUB($2, NULL, $3, $4); }
1079     ;
1080
1081 /* Things called with "do" */
1082 termdo  :       DO term %prec UNIOP                     /* do $filename */
1083                         { $$ = dofile($2, $1);}
1084         |       DO block        %prec '('               /* do { code */
1085                         { $$ = newUNOP(OP_NULL, OPf_SPECIAL, op_scope($2));}
1086         ;
1087
1088 term    :       termbinop
1089         |       termunop
1090         |       anonymous
1091         |       termdo
1092         |       term '?' term ':' term
1093                         { $$ = newCONDOP(0, $1, $3, $5); }
1094         |       REFGEN term                          /* \$x, \@y, \%z */
1095                         { $$ = newUNOP(OP_REFGEN, 0, $2); }
1096         |       MY REFGEN term
1097                         { $$ = newUNOP(OP_REFGEN, 0, localize($3,1)); }
1098         |       myattrterm      %prec UNIOP
1099                         { $$ = $1; }
1100         |       LOCAL term      %prec UNIOP
1101                         { $$ = localize($2,0); }
1102         |       '(' expr ')'
1103                         { $$ = sawparens($2); }
1104         |       QWLIST
1105                         { $$ = $1; }
1106         |       '(' ')'
1107                         { $$ = sawparens(newNULLLIST()); }
1108         |       scalar  %prec '('
1109                         { $$ = $1; }
1110         |       star    %prec '('
1111                         { $$ = $1; }
1112         |       hsh     %prec '('
1113                         { $$ = $1; }
1114         |       ary     %prec '('
1115                         { $$ = $1; }
1116         |       arylen  %prec '('                    /* $#x, $#{ something } */
1117                         { $$ = newUNOP(OP_AV2ARYLEN, 0, ref($1, OP_AV2ARYLEN));}
1118         |       subscripted
1119                         { $$ = $1; }
1120         |       sliceme '[' expr ']'                     /* array slice */
1121                         { $$ = op_prepend_elem(OP_ASLICE,
1122                                 newOP(OP_PUSHMARK, 0),
1123                                     newLISTOP(OP_ASLICE, 0,
1124                                         list($3),
1125                                         ref($1, OP_ASLICE)));
1126                           if ($$ && $1)
1127                               $$->op_private |=
1128                                   $1->op_private & OPpSLICEWARNING;
1129                         }
1130         |       kvslice '[' expr ']'                 /* array key/value slice */
1131                         { $$ = op_prepend_elem(OP_KVASLICE,
1132                                 newOP(OP_PUSHMARK, 0),
1133                                     newLISTOP(OP_KVASLICE, 0,
1134                                         list($3),
1135                                         ref(oopsAV($1), OP_KVASLICE)));
1136                           if ($$ && $1)
1137                               $$->op_private |=
1138                                   $1->op_private & OPpSLICEWARNING;
1139                         }
1140         |       sliceme '{' expr ';' '}'                 /* @hash{@keys} */
1141                         { $$ = op_prepend_elem(OP_HSLICE,
1142                                 newOP(OP_PUSHMARK, 0),
1143                                     newLISTOP(OP_HSLICE, 0,
1144                                         list($3),
1145                                         ref(oopsHV($1), OP_HSLICE)));
1146                           if ($$ && $1)
1147                               $$->op_private |=
1148                                   $1->op_private & OPpSLICEWARNING;
1149                         }
1150         |       kvslice '{' expr ';' '}'                 /* %hash{@keys} */
1151                         { $$ = op_prepend_elem(OP_KVHSLICE,
1152                                 newOP(OP_PUSHMARK, 0),
1153                                     newLISTOP(OP_KVHSLICE, 0,
1154                                         list($3),
1155                                         ref($1, OP_KVHSLICE)));
1156                           if ($$ && $1)
1157                               $$->op_private |=
1158                                   $1->op_private & OPpSLICEWARNING;
1159                         }
1160         |       THING   %prec '('
1161                         { $$ = $1; }
1162         |       amper                                /* &foo; */
1163                         { $$ = newUNOP(OP_ENTERSUB, 0, scalar($1)); }
1164         |       amper '(' ')'                 /* &foo() or foo() */
1165                         { $$ = newUNOP(OP_ENTERSUB, OPf_STACKED, scalar($1));
1166                         }
1167         |       amper '(' expr ')'          /* &foo(@args) or foo(@args) */
1168                         {
1169                           $$ = newUNOP(OP_ENTERSUB, OPf_STACKED,
1170                                 op_append_elem(OP_LIST, $3, scalar($1)));
1171                         }
1172         |       NOAMP subname optlistexpr       /* foo @args (no parens) */
1173                         { $$ = newUNOP(OP_ENTERSUB, OPf_STACKED,
1174                             op_append_elem(OP_LIST, $3, scalar($2)));
1175                         }
1176         |       term ARROW '$' '*'
1177                         { $$ = newSVREF($1); }
1178         |       term ARROW '@' '*'
1179                         { $$ = newAVREF($1); }
1180         |       term ARROW '%' '*'
1181                         { $$ = newHVREF($1); }
1182         |       term ARROW '&' '*'
1183                         { $$ = newUNOP(OP_ENTERSUB, 0,
1184                                        scalar(newCVREF($3,$1))); }
1185         |       term ARROW '*' '*'      %prec '('
1186                         { $$ = newGVREF(0,$1); }
1187         |       LOOPEX  /* loop exiting command (goto, last, dump, etc) */
1188                         { $$ = newOP($1, OPf_SPECIAL);
1189                             PL_hints |= HINT_BLOCK_SCOPE; }
1190         |       LOOPEX term
1191                         { $$ = newLOOPEX($1,$2); }
1192         |       NOTOP listexpr                       /* not $foo */
1193                         { $$ = newUNOP(OP_NOT, 0, scalar($2)); }
1194         |       UNIOP                                /* Unary op, $_ implied */
1195                         { $$ = newOP($1, 0); }
1196         |       UNIOP block                          /* eval { foo }* */
1197                         { $$ = newUNOP($1, 0, $2); }
1198         |       UNIOP term                           /* Unary op */
1199                         { $$ = newUNOP($1, 0, $2); }
1200         |       REQUIRE                              /* require, $_ implied */
1201                         { $$ = newOP(OP_REQUIRE, $1 ? OPf_SPECIAL : 0); }
1202         |       REQUIRE term                         /* require Foo */
1203                         { $$ = newUNOP(OP_REQUIRE, $1 ? OPf_SPECIAL : 0, $2); }
1204         |       UNIOPSUB
1205                         { $$ = newUNOP(OP_ENTERSUB, OPf_STACKED, scalar($1)); }
1206         |       UNIOPSUB term                        /* Sub treated as unop */
1207                         { $$ = newUNOP(OP_ENTERSUB, OPf_STACKED,
1208                             op_append_elem(OP_LIST, $2, scalar($1))); }
1209         |       FUNC0                                /* Nullary operator */
1210                         { $$ = newOP($1, 0); }
1211         |       FUNC0 '(' ')'
1212                         { $$ = newOP($1, 0);}
1213         |       FUNC0OP       /* Same as above, but op created in toke.c */
1214                         { $$ = $1; }
1215         |       FUNC0OP '(' ')'
1216                         { $$ = $1; }
1217         |       FUNC0SUB                             /* Sub treated as nullop */
1218                         { $$ = newUNOP(OP_ENTERSUB, OPf_STACKED, scalar($1)); }
1219         |       FUNC1 '(' ')'                        /* not () */
1220                         { $$ = ($1 == OP_NOT)
1221                           ? newUNOP($1, 0, newSVOP(OP_CONST, 0, newSViv(0)))
1222                           : newOP($1, OPf_SPECIAL); }
1223         |       FUNC1 '(' expr ')'                   /* not($foo) */
1224                         { $$ = newUNOP($1, 0, $3); }
1225         |       PMFUNC /* m//, s///, qr//, tr/// */
1226                         {
1227                             if (   $1->op_type != OP_TRANS
1228                                 && $1->op_type != OP_TRANSR
1229                                 && (((PMOP*)$1)->op_pmflags & PMf_HAS_CV))
1230                             {
1231                                 $<ival>$ = start_subparse(FALSE, CVf_ANON);
1232                                 SAVEFREESV(PL_compcv);
1233                             } else
1234                                 $<ival>$ = 0;
1235                         }
1236                     SUBLEXSTART listexpr optrepl SUBLEXEND
1237                         { $$ = pmruntime($1, $4, $5, 1, $<ival>2); }
1238         |       BAREWORD
1239         |       listop
1240         |       PLUGEXPR
1241         ;
1242
1243 /* "my" declarations, with optional attributes */
1244 myattrterm:     MY myterm myattrlist
1245                         { $$ = my_attrs($2,$3); }
1246         |       MY myterm
1247                         { $$ = localize($2,1); }
1248         |       MY REFGEN myterm myattrlist
1249                         { $$ = newUNOP(OP_REFGEN, 0, my_attrs($3,$4)); }
1250         ;
1251
1252 /* Things that can be "my"'d */
1253 myterm  :       '(' expr ')'
1254                         { $$ = sawparens($2); }
1255         |       '(' ')'
1256                         { $$ = sawparens(newNULLLIST()); }
1257
1258         |       scalar  %prec '('
1259                         { $$ = $1; }
1260         |       hsh     %prec '('
1261                         { $$ = $1; }
1262         |       ary     %prec '('
1263                         { $$ = $1; }
1264         ;
1265
1266 /* Basic list expressions */
1267 optlistexpr:    /* NULL */ %prec PREC_LOW
1268                         { $$ = NULL; }
1269         |       listexpr    %prec PREC_LOW
1270                         { $$ = $1; }
1271         ;
1272
1273 optexpr:        /* NULL */
1274                         { $$ = NULL; }
1275         |       expr
1276                         { $$ = $1; }
1277         ;
1278
1279 optrepl:        /* NULL */
1280                         { $$ = NULL; }
1281         |       '/' expr
1282                         { $$ = $2; }
1283         ;
1284
1285 /* A little bit of trickery to make "for my $foo (@bar)" actually be
1286    lexical */
1287 my_scalar:      scalar
1288                         { parser->in_my = 0; $$ = my($1); }
1289         ;
1290
1291 my_var  :       scalar
1292         |       ary
1293         |       hsh
1294         ;
1295
1296 refgen_topic:   my_var
1297         |       amper
1298         ;
1299
1300 my_refgen:      MY REFGEN
1301         |       REFGEN MY
1302         ;
1303
1304 amper   :       '&' indirob
1305                         { $$ = newCVREF($1,$2); }
1306         ;
1307
1308 scalar  :       '$' indirob
1309                         { $$ = newSVREF($2); }
1310         ;
1311
1312 ary     :       '@' indirob
1313                         { $$ = newAVREF($2);
1314                           if ($$) $$->op_private |= $1;
1315                         }
1316         ;
1317
1318 hsh     :       '%' indirob
1319                         { $$ = newHVREF($2);
1320                           if ($$) $$->op_private |= $1;
1321                         }
1322         ;
1323
1324 arylen  :       DOLSHARP indirob
1325                         { $$ = newAVREF($2); }
1326         |       term ARROW DOLSHARP '*'
1327                         { $$ = newAVREF($1); }
1328         ;
1329
1330 star    :       '*' indirob
1331                         { $$ = newGVREF(0,$2); }
1332         ;
1333
1334 sliceme :       ary
1335         |       term ARROW '@'
1336                         { $$ = newAVREF($1); }
1337         ;
1338
1339 kvslice :       hsh
1340         |       term ARROW '%'
1341                         { $$ = newHVREF($1); }
1342         ;
1343
1344 gelem   :       star
1345         |       term ARROW '*'
1346                         { $$ = newGVREF(0,$1); }
1347         ;
1348
1349 /* Indirect objects */
1350 indirob :       BAREWORD
1351                         { $$ = scalar($1); }
1352         |       scalar %prec PREC_LOW
1353                         { $$ = scalar($1); }
1354         |       block
1355                         { $$ = op_scope($1); }
1356
1357         |       PRIVATEREF
1358                         { $$ = $1; }
1359         ;