perly.y

   1 /*    perly.y
   2  *
   3  *    Copyright (c) 1991-2002, 2003, 2004, 2005, 2006 Larry Wall
   4  *    Copyright (c) 2007, 2008, 2009, 2010, 2011 by Larry Wall and others
   5  *
   6  *    You may distribute under the terms of either the GNU General Public
   7  *    License or the Artistic License, as specified in the README file.
   8  *
   9  */
  10
  11 /*
  12  * 'I see,' laughed Strider.  'I look foul and feel fair.  Is that it?
  13  *  All that is gold does not glitter, not all those who wander are lost.'
  14  *
  15  *     [p.171 of _The Lord of the Rings_, I/x: "Strider"]
  16  */
  17
  18 /*
  19  * This file holds the grammar for the Perl language. If edited, you need
  20  * to run regen_perly.pl, which re-creates the files perly.h, perly.tab
  21  * and perly.act which are derived from this.
  22  *
  23  * The main job of of this grammar is to call the various newFOO()
  24  * functions in op.c to build a syntax tree of OP structs.
  25  * It relies on the lexer in toke.c to do the tokenizing.
  26  *
  27  * Note: due to the way that the cleanup code works WRT to freeing ops on
  28  * the parse stack, it is dangerous to assign to the $n variables within
  29  * an action.
  30  */
  31
  32 /*  Make the parser re-entrant. */
  33
  34 %pure-parser
  35
  36 %start grammar
  37
  38 %union {
  39     I32 ival; /* __DEFAULT__ (marker for regen_perly.pl;
  40                                 must always be 1st union member) */
  41     char *pval;
  42     OP *opval;
  43     GV *gvval;
  44 }
  45
  46 %token <ival> GRAMPROG GRAMEXPR GRAMBLOCK GRAMBARESTMT GRAMFULLSTMT GRAMSTMTSEQ
  47
  48 %token <ival> '{' '}' '[' ']' '-' '+' '@' '%' '&' '=' '.'
  49
  50 %token <opval> BAREWORD METHOD FUNCMETH THING PMFUNC PRIVATEREF QWLIST
  51 %token <opval> FUNC0OP FUNC0SUB UNIOPSUB LSTOPSUB
  52 %token <opval> PLUGEXPR PLUGSTMT
  53 %token <pval> LABEL
  54 %token <ival> FORMAT SUB 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                         { $$ = $1; }
 252         ;
 253
 254 labfullstmt:    LABEL barestmt
 255                         {
 256                           $$ = newSTATEOP(SVf_UTF8 * $1[strlen($1)+1], $1, $2);
 257                         }
 258         |       LABEL labfullstmt
 259                         {
 260                           $$ = newSTATEOP(SVf_UTF8 * $1[strlen($1)+1], $1, $2);
 261                         }
 262         ;
 263
 264 /* A bare statement, lacking label and other aspects of state op */
 265 barestmt:       PLUGSTMT
 266                         { $$ = $1; }
 267         |       FORMAT startformsub formname formblock
 268                         {
 269                           CV *fmtcv = PL_compcv;
 270                           newFORM($2, $3, $4);
 271                           $$ = NULL;
 272                           if (CvOUTSIDE(fmtcv) && !CvEVAL(CvOUTSIDE(fmtcv))) {
 273                               pad_add_weakref(fmtcv);
 274                           }
 275                           parser->parsed_sub = 1;
 276                         }
 277         |       SUB subname startsub
 278                     /* sub declaration or definition not within scope
 279                        of 'use feature "signatures"'*/
 280                         {
 281                           init_named_cv(PL_compcv, $2);
 282                           parser->in_my = 0;
 283                           parser->in_my_stash = NULL;
 284                         }
 285                     proto subattrlist optsubbody
 286                         {
 287                           SvREFCNT_inc_simple_void(PL_compcv);
 288                           $2->op_type == OP_CONST
 289                               ? newATTRSUB($3, $2, $5, $6, $7)
 290                               : newMYSUB($3, $2, $5, $6, $7)
 291                           ;
 292                           $$ = NULL;
 293                           intro_my();
 294                           parser->parsed_sub = 1;
 295                         }
 296         |       SIGSUB subname startsub
 297                     /* sub declaration or definition under 'use feature
 298                      * "signatures"'. (Note that a signature isn't
 299                      * allowed in a declaration)
 300                      */
 301                         {
 302                           init_named_cv(PL_compcv, $2);
 303                           parser->in_my = 0;
 304                           parser->in_my_stash = NULL;
 305                         }
 306                     subattrlist optsigsubbody
 307                         {
 308                           SvREFCNT_inc_simple_void(PL_compcv);
 309                           $2->op_type == OP_CONST
 310                               ? newATTRSUB($3, $2, NULL, $5, $6)
 311                               : newMYSUB(  $3, $2, NULL, $5, $6)
 312                           ;
 313                           $$ = NULL;
 314                           intro_my();
 315                           parser->parsed_sub = 1;
 316                         }
 317         |       PACKAGE BAREWORD BAREWORD ';'
 318                         {
 319                           package($3);
 320                           if ($2)
 321                               package_version($2);
 322                           $$ = NULL;
 323                         }
 324         |       USE startsub
 325                         { CvSPECIAL_on(PL_compcv); /* It's a BEGIN {} */ }
 326                 BAREWORD BAREWORD optlistexpr ';'
 327                         {
 328                           SvREFCNT_inc_simple_void(PL_compcv);
 329                           utilize($1, $2, $4, $5, $6);
 330                           parser->parsed_sub = 1;
 331                           $$ = NULL;
 332                         }
 333         |       IF '(' remember mexpr ')' mblock else
 334                         {
 335                           $$ = block_end($3,
 336                               newCONDOP(0, $4, op_scope($6), $7));
 337                           parser->copline = (line_t)$1;
 338                         }
 339         |       UNLESS '(' remember mexpr ')' mblock else
 340                         {
 341                           $$ = block_end($3,
 342                               newCONDOP(0, $4, $7, op_scope($6)));
 343                           parser->copline = (line_t)$1;
 344                         }
 345         |       GIVEN '(' remember mexpr ')' mblock
 346                         {
 347                           $$ = block_end($3, newGIVENOP($4, op_scope($6), 0));
 348                           parser->copline = (line_t)$1;
 349                         }
 350         |       WHEN '(' remember mexpr ')' mblock
 351                         { $$ = block_end($3, newWHENOP($4, op_scope($6))); }
 352         |       DEFAULT block
 353                         { $$ = newWHENOP(0, op_scope($2)); }
 354         |       WHILE '(' remember texpr ')' mintro mblock cont
 355                         {
 356                           $$ = block_end($3,
 357                                   newWHILEOP(0, 1, NULL,
 358                                       $4, $7, $8, $6));
 359                           parser->copline = (line_t)$1;
 360                         }
 361         |       UNTIL '(' remember iexpr ')' mintro mblock cont
 362                         {
 363                           $$ = block_end($3,
 364                                   newWHILEOP(0, 1, NULL,
 365                                       $4, $7, $8, $6));
 366                           parser->copline = (line_t)$1;
 367                         }
 368         |       FOR '(' remember mnexpr ';'
 369                         { parser->expect = XTERM; }
 370                 texpr ';'
 371                         { parser->expect = XTERM; }
 372                 mintro mnexpr ')'
 373                 mblock
 374                         {
 375                           OP *initop = $4;
 376                           OP *forop = newWHILEOP(0, 1, NULL,
 377                                       scalar($7), $13, $11, $10);
 378                           if (initop) {
 379                               forop = op_prepend_elem(OP_LINESEQ, initop,
 380                                   op_append_elem(OP_LINESEQ,
 381                                       newOP(OP_UNSTACK, OPf_SPECIAL),
 382                                       forop));
 383                           }
 384                           PL_hints |= HINT_BLOCK_SCOPE;
 385                           $$ = block_end($3, forop);
 386                           parser->copline = (line_t)$1;
 387                         }
 388         |       FOR MY remember my_scalar '(' mexpr ')' mblock cont
 389                         {
 390                           $$ = block_end($3, newFOROP(0, $4, $6, $8, $9));
 391                           parser->copline = (line_t)$1;
 392                         }
 393         |       FOR scalar '(' remember mexpr ')' mblock cont
 394                         {
 395                           $$ = block_end($4, newFOROP(0,
 396                                       op_lvalue($2, OP_ENTERLOOP), $5, $7, $8));
 397                           parser->copline = (line_t)$1;
 398                         }
 399         |       FOR my_refgen remember my_var
 400                         { parser->in_my = 0; $<opval>$ = my($4); }
 401                 '(' mexpr ')' mblock cont
 402                         {
 403                           $$ = block_end(
 404                                 $3,
 405                                 newFOROP(0,
 406                                          op_lvalue(
 407                                             newUNOP(OP_REFGEN, 0,
 408                                                     $<opval>5),
 409                                             OP_ENTERLOOP),
 410                                          $7, $9, $10)
 411                           );
 412                           parser->copline = (line_t)$1;
 413                         }
 414         |       FOR REFGEN refgen_topic '(' remember mexpr ')' mblock cont
 415                         {
 416                           $$ = block_end($5, newFOROP(
 417                                 0, op_lvalue(newUNOP(OP_REFGEN, 0,
 418                                                      $3),
 419                                              OP_ENTERLOOP), $6, $8, $9));
 420                           parser->copline = (line_t)$1;
 421                         }
 422         |       FOR '(' remember mexpr ')' mblock cont
 423                         {
 424                           $$ = block_end($3,
 425                                   newFOROP(0, NULL, $4, $6, $7));
 426                           parser->copline = (line_t)$1;
 427                         }
 428         |       block cont
 429                         {
 430                           /* a block is a loop that happens once */
 431                           $$ = newWHILEOP(0, 1, NULL,
 432                                   NULL, $1, $2, 0);
 433                         }
 434         |       PACKAGE BAREWORD BAREWORD '{' remember
 435                         {
 436                           package($3);
 437                           if ($2) {
 438                               package_version($2);
 439                           }
 440                         }
 441                 stmtseq '}'
 442                         {
 443                           /* a block is a loop that happens once */
 444                           $$ = newWHILEOP(0, 1, NULL,
 445                                   NULL, block_end($5, $7), NULL, 0);
 446                           if (parser->copline > (line_t)$4)
 447                               parser->copline = (line_t)$4;
 448                         }
 449         |       sideff ';'
 450                         {
 451                           $$ = $1;
 452                         }
 453         |       YADAYADA ';'
 454                         {
 455                           $$ = newLISTOP(OP_DIE, 0, newOP(OP_PUSHMARK, 0),
 456                                 newSVOP(OP_CONST, 0, newSVpvs("Unimplemented")));
 457                         }
 458         |       ';'
 459                         {
 460                           $$ = NULL;
 461                           parser->copline = NOLINE;
 462                         }
 463         ;
 464
 465 /* Format line */
 466 formline:       THING formarg
 467                         { OP *list;
 468                           if ($2) {
 469                               OP *term = $2;
 470                               list = op_append_elem(OP_LIST, $1, term);
 471                           }
 472                           else {
 473                               list = $1;
 474                           }
 475                           if (parser->copline == NOLINE)
 476                                parser->copline = CopLINE(PL_curcop)-1;
 477                           else parser->copline--;
 478                           $$ = newSTATEOP(0, NULL,
 479                                           op_convert_list(OP_FORMLINE, 0, list));
 480                         }
 481         ;
 482
 483 formarg :       /* NULL */
 484                         { $$ = NULL; }
 485         |       FORMLBRACK stmtseq FORMRBRACK
 486                         { $$ = op_unscope($2); }
 487         ;
 488
 489 /* An expression which may have a side-effect */
 490 sideff  :       error
 491                         { $$ = NULL; }
 492         |       expr
 493                         { $$ = $1; }
 494         |       expr IF expr
 495                         { $$ = newLOGOP(OP_AND, 0, $3, $1); }
 496         |       expr UNLESS expr
 497                         { $$ = newLOGOP(OP_OR, 0, $3, $1); }
 498         |       expr WHILE expr
 499                         { $$ = newLOOPOP(OPf_PARENS, 1, scalar($3), $1); }
 500         |       expr UNTIL iexpr
 501                         { $$ = newLOOPOP(OPf_PARENS, 1, $3, $1); }
 502         |       expr FOR expr
 503                         { $$ = newFOROP(0, NULL, $3, $1, NULL);
 504                           parser->copline = (line_t)$2; }
 505         |       expr WHEN expr
 506                         { $$ = newWHENOP($3, op_scope($1)); }
 507         ;
 508
 509 /* else and elsif blocks */
 510 else    :       /* NULL */
 511                         { $$ = NULL; }
 512         |       ELSE mblock
 513                         {
 514                           ($2)->op_flags |= OPf_PARENS;
 515                           $$ = op_scope($2);
 516                         }
 517         |       ELSIF '(' mexpr ')' mblock else
 518                         { parser->copline = (line_t)$1;
 519                             $$ = newCONDOP(0,
 520                                 newSTATEOP(OPf_SPECIAL,NULL,$3),
 521                                 op_scope($5), $6);
 522                           PL_hints |= HINT_BLOCK_SCOPE;
 523                         }
 524         ;
 525
 526 /* Continue blocks */
 527 cont    :       /* NULL */
 528                         { $$ = NULL; }
 529         |       CONTINUE block
 530                         { $$ = op_scope($2); }
 531         ;
 532
 533 /* determine whether there are any new my declarations */
 534 mintro  :       /* NULL */
 535                         { $$ = (PL_min_intro_pending &&
 536                             PL_max_intro_pending >=  PL_min_intro_pending);
 537                           intro_my(); }
 538
 539 /* Normal expression */
 540 nexpr   :       /* NULL */
 541                         { $$ = NULL; }
 542         |       sideff
 543         ;
 544
 545 /* Boolean expression */
 546 texpr   :       /* NULL means true */
 547                         { YYSTYPE tmplval;
 548                           (void)scan_num("1", &tmplval);
 549                           $$ = tmplval.opval; }
 550         |       expr
 551         ;
 552
 553 /* Inverted boolean expression */
 554 iexpr   :       expr
 555                         { $$ = invert(scalar($1)); }
 556         ;
 557
 558 /* Expression with its own lexical scope */
 559 mexpr   :       expr
 560                         { $$ = $1; intro_my(); }
 561         ;
 562
 563 mnexpr  :       nexpr
 564                         { $$ = $1; intro_my(); }
 565         ;
 566
 567 formname:       BAREWORD        { $$ = $1; }
 568         |       /* NULL */      { $$ = NULL; }
 569         ;
 570
 571 startsub:       /* NULL */      /* start a regular subroutine scope */
 572                         { $$ = start_subparse(FALSE, 0);
 573                             SAVEFREESV(PL_compcv); }
 574
 575         ;
 576
 577 startanonsub:   /* NULL */      /* start an anonymous subroutine scope */
 578                         { $$ = start_subparse(FALSE, CVf_ANON);
 579                             SAVEFREESV(PL_compcv); }
 580         ;
 581
 582 startformsub:   /* NULL */      /* start a format subroutine scope */
 583                         { $$ = start_subparse(TRUE, 0);
 584                             SAVEFREESV(PL_compcv); }
 585         ;
 586
 587 /* Name of a subroutine - must be a bareword, could be special */
 588 subname :       BAREWORD
 589         |       PRIVATEREF
 590         ;
 591
 592 /* Subroutine prototype */
 593 proto   :       /* NULL */
 594                         { $$ = NULL; }
 595         |       THING
 596         ;
 597
 598 /* Optional list of subroutine attributes */
 599 subattrlist:    /* NULL */
 600                         { $$ = NULL; }
 601         |       COLONATTR THING
 602                         { $$ = $2; }
 603         |       COLONATTR
 604                         { $$ = NULL; }
 605         ;
 606
 607 /* List of attributes for a "my" variable declaration */
 608 myattrlist:     COLONATTR THING
 609                         { $$ = $2; }
 610         |       COLONATTR
 611                         { $$ = NULL; }
 612         ;
 613
 614
 615
 616 /* --------------------------------------
 617  * subroutine signature parsing
 618  */
 619
 620 /* the '' or 'foo' part of a '$' or '@foo' etc signature variable  */
 621 sigvarname:     /* NULL */
 622                         { parser->in_my = 0; $$ = NULL; }
 623         |       PRIVATEREF
 624                         { parser->in_my = 0; $$ = $1; }
 625         ;
 626
 627 sigslurpsigil:
 628                 '@'
 629                         { $$ = '@'; }
 630         |       '%'
 631                         { $$ = '%'; }
 632
 633 /* @, %, @foo, %foo */
 634 sigslurpelem: sigslurpsigil sigvarname sigdefault/* def only to catch errors */
 635                         {
 636                             I32 sigil   = $1;
 637                             OP *var     = $2;
 638                             OP *defexpr = $3;
 639
 640                             if (parser->sig_slurpy)
 641                                 yyerror("Multiple slurpy parameters not allowed");
 642                             parser->sig_slurpy = (char)sigil;
 643
 644                             if (defexpr)
 645                                 yyerror("A slurpy parameter may not have "
 646                                         "a default value");
 647
 648                             $$ = var ? newSTATEOP(0, NULL, var) : NULL;
 649                         }
 650         ;
 651
 652 /* default part of sub signature scalar element: i.e. '= default_expr' */
 653 sigdefault:     /* NULL */
 654                         { $$ = NULL; }
 655         |       ASSIGNOP
 656                         { $$ = newOP(OP_NULL, 0); }
 657         |       ASSIGNOP term
 658                         { $$ = $2; }
 659
 660
 661 /* subroutine signature scalar element: e.g. '$x', '$=', '$x = $default' */
 662 sigscalarelem:
 663                 '$' sigvarname sigdefault
 664                         {
 665                             OP *var     = $2;
 666                             OP *defexpr = $3;
 667
 668                             if (parser->sig_slurpy)
 669                                 yyerror("Slurpy parameter not last");
 670
 671                             parser->sig_elems++;
 672
 673                             if (defexpr) {
 674                                 parser->sig_optelems++;
 675
 676                                 if (   defexpr->op_type == OP_NULL
 677                                     && !(defexpr->op_flags & OPf_KIDS))
 678                                 {
 679                                     /* handle '$=' special case */
 680                                     if (var)
 681                                         yyerror("Optional parameter "
 682                                                     "lacks default expression");
 683                                     op_free(defexpr);
 684                                 }
 685                                 else {
 686                                     /* a normal '=default' expression */
 687                                     OP *defop = (OP*)alloc_LOGOP(OP_ARGDEFELEM,
 688                                                         defexpr,
 689                                                         LINKLIST(defexpr));
 690                                     /* re-purpose op_targ to hold @_ index */
 691                                     defop->op_targ =
 692                                         (PADOFFSET)(parser->sig_elems - 1);
 693
 694                                     if (var) {
 695                                         var->op_flags |= OPf_STACKED;
 696                                         (void)op_sibling_splice(var,
 697                                                         NULL, 0, defop);
 698                                         scalar(defop);
 699                                     }
 700                                     else
 701                                         var = newUNOP(OP_NULL, 0, defop);
 702
 703                                     LINKLIST(var);
 704                                     /* NB: normally the first child of a
 705                                      * logop is executed before the logop,
 706                                      * and it pushes a boolean result
 707                                      * ready for the logop. For ARGDEFELEM,
 708                                      * the op itself does the boolean
 709                                      * calculation, so set the first op to
 710                                      * it instead.
 711                                      */
 712                                     var->op_next = defop;
 713                                     defexpr->op_next = var;
 714                                 }
 715                             }
 716                             else {
 717                                 if (parser->sig_optelems)
 718                                     yyerror("Mandatory parameter "
 719                                             "follows optional parameter");
 720                             }
 721
 722                             $$ = var ? newSTATEOP(0, NULL, var) : NULL;
 723                         }
 724         ;
 725
 726
 727 /* subroutine signature element: e.g. '$x = $default' or '%h' */
 728 sigelem:        sigscalarelem
 729                         { parser->in_my = KEY_sigvar; $$ = $1; }
 730         |       sigslurpelem
 731                         { parser->in_my = KEY_sigvar; $$ = $1; }
 732         ;
 733
 734 /* list of subroutine signature elements */
 735 siglist:
 736                 siglist ','
 737                         { $$ = $1; }
 738         |       siglist ',' sigelem
 739                         {
 740                           $$ = op_append_list(OP_LINESEQ, $1, $3);
 741                         }
 742         |       sigelem  %prec PREC_LOW
 743                         { $$ = $1; }
 744         ;
 745
 746 /* () or (....) */
 747 siglistornull:          /* NULL */
 748                         { $$ = NULL; }
 749         |       siglist
 750                         { $$ = $1; }
 751
 752 /* optional subroutine signature */
 753 optsubsignature:        /* NULL */
 754                         { $$ = NULL; }
 755         |       subsignature
 756                         { $$ = $1; }
 757
 758 /* Subroutine signature */
 759 subsignature:   '('
 760                         {
 761                             ENTER;
 762                             SAVEIV(parser->sig_elems);
 763                             SAVEIV(parser->sig_optelems);
 764                             SAVEI8(parser->sig_slurpy);
 765                             parser->sig_elems    = 0;
 766                             parser->sig_optelems = 0;
 767                             parser->sig_slurpy   = 0;
 768                             parser->in_my        = KEY_sigvar;
 769                         }
 770                 siglistornull
 771                 ')'
 772                         {
 773                             OP            *sigops = $3;
 774                             UNOP_AUX_item *aux;
 775                             OP            *check;
 776
 777                             if (!FEATURE_SIGNATURES_IS_ENABLED)
 778                                 Perl_croak(aTHX_ "Experimental "
 779                                     "subroutine signatures not enabled");
 780
 781                             /* We shouldn't get here otherwise */
 782                             Perl_ck_warner_d(aTHX_
 783                                 packWARN(WARN_EXPERIMENTAL__SIGNATURES),
 784                                 "The signatures feature is experimental");
 785
 786                             aux = (UNOP_AUX_item*)PerlMemShared_malloc(
 787                                 sizeof(UNOP_AUX_item) * 3);
 788                             aux[0].iv = parser->sig_elems;
 789                             aux[1].iv = parser->sig_optelems;
 790                             aux[2].iv = parser->sig_slurpy;
 791                             check = newUNOP_AUX(OP_ARGCHECK, 0, NULL, aux);
 792                             sigops = op_prepend_elem(OP_LINESEQ, check, sigops);
 793                             sigops = op_prepend_elem(OP_LINESEQ,
 794                                                 newSTATEOP(0, NULL, NULL),
 795                                                 sigops);
 796                             /* a nextstate at the end handles context
 797                              * correctly for an empty sub body */
 798                             $$ = op_append_elem(OP_LINESEQ,
 799                                                 sigops,
 800                                                 newSTATEOP(0, NULL, NULL));
 801
 802                             parser->in_my = 0;
 803                             /* tell the toker that attrributes can follow
 804                              * this sig, but only so that the toker
 805                              * can skip through any (illegal) trailing
 806                              * attribute text then give a useful error
 807                              * message about "attributes before sig",
 808                              * rather than falling over ina mess at
 809                              * unrecognised syntax.
 810                              */
 811                             parser->expect = XATTRBLOCK;
 812                             parser->sig_seen = TRUE;
 813                             LEAVE;
 814                         }
 815         ;
 816
 817 /* Optional subroutine body (for named subroutine declaration) */
 818 optsubbody:     subbody { $$ = $1; }
 819         |       ';'     { $$ = NULL; }
 820         ;
 821
 822
 823 /* Subroutine body (without signature) */
 824 subbody:        remember  '{' stmtseq '}'
 825                         {
 826                           if (parser->copline > (line_t)$2)
 827                               parser->copline = (line_t)$2;
 828                           $$ = block_end($1, $3);
 829                         }
 830         ;
 831
 832
 833 /* optional [ Subroutine body with optional signature ] (for named
 834  * subroutine declaration) */
 835 optsigsubbody:  sigsubbody { $$ = $1; }
 836         |       ';'        { $$ = NULL; }
 837
 838 /* Subroutine body with optional signature */
 839 sigsubbody:     remember optsubsignature '{' stmtseq '}'
 840                         {
 841                           if (parser->copline > (line_t)$3)
 842                               parser->copline = (line_t)$3;
 843                           $$ = block_end($1,
 844                                 op_append_list(OP_LINESEQ, $2, $4));
 845                         }
 846         ;
 847
 848
 849 /* Ordinary expressions; logical combinations */
 850 expr    :       expr ANDOP expr
 851                         { $$ = newLOGOP(OP_AND, 0, $1, $3); }
 852         |       expr OROP expr
 853                         { $$ = newLOGOP($2, 0, $1, $3); }
 854         |       expr DOROP expr
 855                         { $$ = newLOGOP(OP_DOR, 0, $1, $3); }
 856         |       listexpr %prec PREC_LOW
 857         ;
 858
 859 /* Expressions are a list of terms joined by commas */
 860 listexpr:       listexpr ','
 861                         { $$ = $1; }
 862         |       listexpr ',' term
 863                         {
 864                           OP* term = $3;
 865                           $$ = op_append_elem(OP_LIST, $1, term);
 866                         }
 867         |       term %prec PREC_LOW
 868         ;
 869
 870 /* List operators */
 871 listop  :       LSTOP indirob listexpr /* map {...} @args or print $fh @args */
 872                         { $$ = op_convert_list($1, OPf_STACKED,
 873                                 op_prepend_elem(OP_LIST, newGVREF($1,$2), $3) );
 874                         }
 875         |       FUNC '(' indirob expr ')'      /* print ($fh @args */
 876                         { $$ = op_convert_list($1, OPf_STACKED,
 877                                 op_prepend_elem(OP_LIST, newGVREF($1,$3), $4) );
 878                         }
 879         |       term ARROW method '(' optexpr ')' /* $foo->bar(list) */
 880                         { $$ = op_convert_list(OP_ENTERSUB, OPf_STACKED,
 881                                 op_append_elem(OP_LIST,
 882                                     op_prepend_elem(OP_LIST, scalar($1), $5),
 883                                     newMETHOP(OP_METHOD, 0, $3)));
 884                         }
 885         |       term ARROW method                     /* $foo->bar */
 886                         { $$ = op_convert_list(OP_ENTERSUB, OPf_STACKED,
 887                                 op_append_elem(OP_LIST, scalar($1),
 888                                     newMETHOP(OP_METHOD, 0, $3)));
 889                         }
 890         |       METHOD indirob optlistexpr           /* new Class @args */
 891                         { $$ = op_convert_list(OP_ENTERSUB, OPf_STACKED,
 892                                 op_append_elem(OP_LIST,
 893                                     op_prepend_elem(OP_LIST, $2, $3),
 894                                     newMETHOP(OP_METHOD, 0, $1)));
 895                         }
 896         |       FUNCMETH indirob '(' optexpr ')'    /* method $object (@args) */
 897                         { $$ = op_convert_list(OP_ENTERSUB, OPf_STACKED,
 898                                 op_append_elem(OP_LIST,
 899                                     op_prepend_elem(OP_LIST, $2, $4),
 900                                     newMETHOP(OP_METHOD, 0, $1)));
 901                         }
 902         |       LSTOP optlistexpr                    /* print @args */
 903                         { $$ = op_convert_list($1, 0, $2); }
 904         |       FUNC '(' optexpr ')'                 /* print (@args) */
 905                         { $$ = op_convert_list($1, 0, $3); }
 906         |       LSTOPSUB startanonsub block /* sub f(&@);   f { foo } ... */
 907                         { SvREFCNT_inc_simple_void(PL_compcv);
 908                           $<opval>$ = newANONATTRSUB($2, 0, NULL, $3); }
 909                     optlistexpr         %prec LSTOP  /* ... @bar */
 910                         { $$ = newUNOP(OP_ENTERSUB, OPf_STACKED,
 911                                  op_append_elem(OP_LIST,
 912                                    op_prepend_elem(OP_LIST, $<opval>4, $5), $1));
 913                         }
 914         ;
 915
 916 /* Names of methods. May use $object->$methodname */
 917 method  :       METHOD
 918         |       scalar
 919         ;
 920
 921 /* Some kind of subscripted expression */
 922 subscripted:    gelem '{' expr ';' '}'        /* *main::{something} */
 923                         /* In this and all the hash accessors, ';' is
 924                          * provided by the tokeniser */
 925                         { $$ = newBINOP(OP_GELEM, 0, $1, scalar($3)); }
 926         |       scalar '[' expr ']'          /* $array[$element] */
 927                         { $$ = newBINOP(OP_AELEM, 0, oopsAV($1), scalar($3));
 928                         }
 929         |       term ARROW '[' expr ']'      /* somearef->[$element] */
 930                         { $$ = newBINOP(OP_AELEM, 0,
 931                                         ref(newAVREF($1),OP_RV2AV),
 932                                         scalar($4));
 933                         }
 934         |       subscripted '[' expr ']'    /* $foo->[$bar]->[$baz] */
 935                         { $$ = newBINOP(OP_AELEM, 0,
 936                                         ref(newAVREF($1),OP_RV2AV),
 937                                         scalar($3));
 938                         }
 939         |       scalar '{' expr ';' '}'    /* $foo{bar();} */
 940                         { $$ = newBINOP(OP_HELEM, 0, oopsHV($1), jmaybe($3));
 941                         }
 942         |       term ARROW '{' expr ';' '}' /* somehref->{bar();} */
 943                         { $$ = newBINOP(OP_HELEM, 0,
 944                                         ref(newHVREF($1),OP_RV2HV),
 945                                         jmaybe($4)); }
 946         |       subscripted '{' expr ';' '}' /* $foo->[bar]->{baz;} */
 947                         { $$ = newBINOP(OP_HELEM, 0,
 948                                         ref(newHVREF($1),OP_RV2HV),
 949                                         jmaybe($3)); }
 950         |       term ARROW '(' ')'          /* $subref->() */
 951                         { $$ = newUNOP(OP_ENTERSUB, OPf_STACKED,
 952                                    newCVREF(0, scalar($1)));
 953                           if (parser->expect == XBLOCK)
 954                               parser->expect = XOPERATOR;
 955                         }
 956         |       term ARROW '(' expr ')'     /* $subref->(@args) */
 957                         { $$ = newUNOP(OP_ENTERSUB, OPf_STACKED,
 958                                    op_append_elem(OP_LIST, $4,
 959                                        newCVREF(0, scalar($1))));
 960                           if (parser->expect == XBLOCK)
 961                               parser->expect = XOPERATOR;
 962                         }
 963
 964         |       subscripted '(' expr ')'   /* $foo->{bar}->(@args) */
 965                         { $$ = newUNOP(OP_ENTERSUB, OPf_STACKED,
 966                                    op_append_elem(OP_LIST, $3,
 967                                                newCVREF(0, scalar($1))));
 968                           if (parser->expect == XBLOCK)
 969                               parser->expect = XOPERATOR;
 970                         }
 971         |       subscripted '(' ')'        /* $foo->{bar}->() */
 972                         { $$ = newUNOP(OP_ENTERSUB, OPf_STACKED,
 973                                    newCVREF(0, scalar($1)));
 974                           if (parser->expect == XBLOCK)
 975                               parser->expect = XOPERATOR;
 976                         }
 977         |       '(' expr ')' '[' expr ']'            /* list slice */
 978                         { $$ = newSLICEOP(0, $5, $2); }
 979         |       QWLIST '[' expr ']'            /* list literal slice */
 980                         { $$ = newSLICEOP(0, $3, $1); }
 981         |       '(' ')' '[' expr ']'                 /* empty list slice! */
 982                         { $$ = newSLICEOP(0, $4, NULL); }
 983     ;
 984
 985 /* Binary operators between terms */
 986 termbinop:      term ASSIGNOP term                     /* $x = $y, $x += $y */
 987                         { $$ = newASSIGNOP(OPf_STACKED, $1, $2, $3); }
 988         |       term POWOP term                        /* $x ** $y */
 989                         { $$ = newBINOP($2, 0, scalar($1), scalar($3)); }
 990         |       term MULOP term                        /* $x * $y, $x x $y */
 991                         {   if ($2 != OP_REPEAT)
 992                                 scalar($1);
 993                             $$ = newBINOP($2, 0, $1, scalar($3));
 994                         }
 995         |       term ADDOP term                        /* $x + $y */
 996                         { $$ = newBINOP($2, 0, scalar($1), scalar($3)); }
 997         |       term SHIFTOP term                      /* $x >> $y, $x << $y */
 998                         { $$ = newBINOP($2, 0, scalar($1), scalar($3)); }
 999         |       term RELOP term                        /* $x > $y, etc. */
1000                         { $$ = newBINOP($2, 0, scalar($1), scalar($3)); }
1001         |       term EQOP term                         /* $x == $y, $x eq $y */
1002                         { $$ = newBINOP($2, 0, scalar($1), scalar($3)); }
1003         |       term BITANDOP term                     /* $x & $y */
1004                         { $$ = newBINOP($2, 0, scalar($1), scalar($3)); }
1005         |       term BITOROP term                      /* $x | $y */
1006                         { $$ = newBINOP($2, 0, scalar($1), scalar($3)); }
1007         |       term DOTDOT term                       /* $x..$y, $x...$y */
1008                         { $$ = newRANGE($2, scalar($1), scalar($3)); }
1009         |       term ANDAND term                       /* $x && $y */
1010                         { $$ = newLOGOP(OP_AND, 0, $1, $3); }
1011         |       term OROR term                         /* $x || $y */
1012                         { $$ = newLOGOP(OP_OR, 0, $1, $3); }
1013         |       term DORDOR term                       /* $x // $y */
1014                         { $$ = newLOGOP(OP_DOR, 0, $1, $3); }
1015         |       term MATCHOP term                      /* $x =~ /$y/ */
1016                         { $$ = bind_match($2, $1, $3); }
1017     ;
1018
1019 /* Unary operators and terms */
1020 termunop : '-' term %prec UMINUS                       /* -$x */
1021                         { $$ = newUNOP(OP_NEGATE, 0, scalar($2)); }
1022         |       '+' term %prec UMINUS                  /* +$x */
1023                         { $$ = $2; }
1024
1025         |       '!' term                               /* !$x */
1026                         { $$ = newUNOP(OP_NOT, 0, scalar($2)); }
1027         |       '~' term                               /* ~$x */
1028                         { $$ = newUNOP($1, 0, scalar($2)); }
1029         |       term POSTINC                           /* $x++ */
1030                         { $$ = newUNOP(OP_POSTINC, 0,
1031                                         op_lvalue(scalar($1), OP_POSTINC)); }
1032         |       term POSTDEC                           /* $x-- */
1033                         { $$ = newUNOP(OP_POSTDEC, 0,
1034                                         op_lvalue(scalar($1), OP_POSTDEC));}
1035         |       term POSTJOIN    /* implicit join after interpolated ->@ */
1036                         { $$ = op_convert_list(OP_JOIN, 0,
1037                                        op_append_elem(
1038                                         OP_LIST,
1039                                         newSVREF(scalar(
1040                                             newSVOP(OP_CONST,0,
1041                                                     newSVpvs("\""))
1042                                         )),
1043                                         $1
1044                                        ));
1045                         }
1046         |       PREINC term                            /* ++$x */
1047                         { $$ = newUNOP(OP_PREINC, 0,
1048                                         op_lvalue(scalar($2), OP_PREINC)); }
1049         |       PREDEC term                            /* --$x */
1050                         { $$ = newUNOP(OP_PREDEC, 0,
1051                                         op_lvalue(scalar($2), OP_PREDEC)); }
1052
1053     ;
1054
1055 /* Constructors for anonymous data */
1056 anonymous:      '[' expr ']'
1057                         { $$ = newANONLIST($2); }
1058         |       '[' ']'
1059                         { $$ = newANONLIST(NULL);}
1060         |       HASHBRACK expr ';' '}'  %prec '(' /* { foo => "Bar" } */
1061                         { $$ = newANONHASH($2); }
1062         |       HASHBRACK ';' '}'       %prec '(' /* { } (';' by tokener) */
1063                         { $$ = newANONHASH(NULL); }
1064         |       ANONSUB     startanonsub proto subattrlist subbody    %prec '('
1065                         { SvREFCNT_inc_simple_void(PL_compcv);
1066                           $$ = newANONATTRSUB($2, $3, $4, $5); }
1067         |       ANON_SIGSUB startanonsub subattrlist sigsubbody %prec '('
1068                         { SvREFCNT_inc_simple_void(PL_compcv);
1069                           $$ = newANONATTRSUB($2, NULL, $3, $4); }
1070     ;
1071
1072 /* Things called with "do" */
1073 termdo  :       DO term %prec UNIOP                     /* do $filename */
1074                         { $$ = dofile($2, $1);}
1075         |       DO block        %prec '('               /* do { code */
1076                         { $$ = newUNOP(OP_NULL, OPf_SPECIAL, op_scope($2));}
1077         ;
1078
1079 term    :       termbinop
1080         |       termunop
1081         |       anonymous
1082         |       termdo
1083         |       term '?' term ':' term
1084                         { $$ = newCONDOP(0, $1, $3, $5); }
1085         |       REFGEN term                          /* \$x, \@y, \%z */
1086                         { $$ = newUNOP(OP_REFGEN, 0, $2); }
1087         |       MY REFGEN term
1088                         { $$ = newUNOP(OP_REFGEN, 0, localize($3,1)); }
1089         |       myattrterm      %prec UNIOP
1090                         { $$ = $1; }
1091         |       LOCAL term      %prec UNIOP
1092                         { $$ = localize($2,0); }
1093         |       '(' expr ')'
1094                         { $$ = sawparens($2); }
1095         |       QWLIST
1096                         { $$ = $1; }
1097         |       '(' ')'
1098                         { $$ = sawparens(newNULLLIST()); }
1099         |       scalar  %prec '('
1100                         { $$ = $1; }
1101         |       star    %prec '('
1102                         { $$ = $1; }
1103         |       hsh     %prec '('
1104                         { $$ = $1; }
1105         |       ary     %prec '('
1106                         { $$ = $1; }
1107         |       arylen  %prec '('                    /* $#x, $#{ something } */
1108                         { $$ = newUNOP(OP_AV2ARYLEN, 0, ref($1, OP_AV2ARYLEN));}
1109         |       subscripted
1110                         { $$ = $1; }
1111         |       sliceme '[' expr ']'                     /* array slice */
1112                         { $$ = op_prepend_elem(OP_ASLICE,
1113                                 newOP(OP_PUSHMARK, 0),
1114                                     newLISTOP(OP_ASLICE, 0,
1115                                         list($3),
1116                                         ref($1, OP_ASLICE)));
1117                           if ($$ && $1)
1118                               $$->op_private |=
1119                                   $1->op_private & OPpSLICEWARNING;
1120                         }
1121         |       kvslice '[' expr ']'                 /* array key/value slice */
1122                         { $$ = op_prepend_elem(OP_KVASLICE,
1123                                 newOP(OP_PUSHMARK, 0),
1124                                     newLISTOP(OP_KVASLICE, 0,
1125                                         list($3),
1126                                         ref(oopsAV($1), OP_KVASLICE)));
1127                           if ($$ && $1)
1128                               $$->op_private |=
1129                                   $1->op_private & OPpSLICEWARNING;
1130                         }
1131         |       sliceme '{' expr ';' '}'                 /* @hash{@keys} */
1132                         { $$ = op_prepend_elem(OP_HSLICE,
1133                                 newOP(OP_PUSHMARK, 0),
1134                                     newLISTOP(OP_HSLICE, 0,
1135                                         list($3),
1136                                         ref(oopsHV($1), OP_HSLICE)));
1137                           if ($$ && $1)
1138                               $$->op_private |=
1139                                   $1->op_private & OPpSLICEWARNING;
1140                         }
1141         |       kvslice '{' expr ';' '}'                 /* %hash{@keys} */
1142                         { $$ = op_prepend_elem(OP_KVHSLICE,
1143                                 newOP(OP_PUSHMARK, 0),
1144                                     newLISTOP(OP_KVHSLICE, 0,
1145                                         list($3),
1146                                         ref($1, OP_KVHSLICE)));
1147                           if ($$ && $1)
1148                               $$->op_private |=
1149                                   $1->op_private & OPpSLICEWARNING;
1150                         }
1151         |       THING   %prec '('
1152                         { $$ = $1; }
1153         |       amper                                /* &foo; */
1154                         { $$ = newUNOP(OP_ENTERSUB, 0, scalar($1)); }
1155         |       amper '(' ')'                 /* &foo() or foo() */
1156                         { $$ = newUNOP(OP_ENTERSUB, OPf_STACKED, scalar($1));
1157                         }
1158         |       amper '(' expr ')'          /* &foo(@args) or foo(@args) */
1159                         {
1160                           $$ = newUNOP(OP_ENTERSUB, OPf_STACKED,
1161                                 op_append_elem(OP_LIST, $3, scalar($1)));
1162                         }
1163         |       NOAMP subname optlistexpr       /* foo @args (no parens) */
1164                         { $$ = newUNOP(OP_ENTERSUB, OPf_STACKED,
1165                             op_append_elem(OP_LIST, $3, scalar($2)));
1166                         }
1167         |       term ARROW '$' '*'
1168                         { $$ = newSVREF($1); }
1169         |       term ARROW '@' '*'
1170                         { $$ = newAVREF($1); }
1171         |       term ARROW '%' '*'
1172                         { $$ = newHVREF($1); }
1173         |       term ARROW '&' '*'
1174                         { $$ = newUNOP(OP_ENTERSUB, 0,
1175                                        scalar(newCVREF($3,$1))); }
1176         |       term ARROW '*' '*'      %prec '('
1177                         { $$ = newGVREF(0,$1); }
1178         |       LOOPEX  /* loop exiting command (goto, last, dump, etc) */
1179                         { $$ = newOP($1, OPf_SPECIAL);
1180                             PL_hints |= HINT_BLOCK_SCOPE; }
1181         |       LOOPEX term
1182                         { $$ = newLOOPEX($1,$2); }
1183         |       NOTOP listexpr                       /* not $foo */
1184                         { $$ = newUNOP(OP_NOT, 0, scalar($2)); }
1185         |       UNIOP                                /* Unary op, $_ implied */
1186                         { $$ = newOP($1, 0); }
1187         |       UNIOP block                          /* eval { foo }* */
1188                         { $$ = newUNOP($1, 0, $2); }
1189         |       UNIOP term                           /* Unary op */
1190                         { $$ = newUNOP($1, 0, $2); }
1191         |       REQUIRE                              /* require, $_ implied */
1192                         { $$ = newOP(OP_REQUIRE, $1 ? OPf_SPECIAL : 0); }
1193         |       REQUIRE term                         /* require Foo */
1194                         { $$ = newUNOP(OP_REQUIRE, $1 ? OPf_SPECIAL : 0, $2); }
1195         |       UNIOPSUB
1196                         { $$ = newUNOP(OP_ENTERSUB, OPf_STACKED, scalar($1)); }
1197         |       UNIOPSUB term                        /* Sub treated as unop */
1198                         { $$ = newUNOP(OP_ENTERSUB, OPf_STACKED,
1199                             op_append_elem(OP_LIST, $2, scalar($1))); }
1200         |       FUNC0                                /* Nullary operator */
1201                         { $$ = newOP($1, 0); }
1202         |       FUNC0 '(' ')'
1203                         { $$ = newOP($1, 0);}
1204         |       FUNC0OP       /* Same as above, but op created in toke.c */
1205                         { $$ = $1; }
1206         |       FUNC0OP '(' ')'
1207                         { $$ = $1; }
1208         |       FUNC0SUB                             /* Sub treated as nullop */
1209                         { $$ = newUNOP(OP_ENTERSUB, OPf_STACKED, scalar($1)); }
1210         |       FUNC1 '(' ')'                        /* not () */
1211                         { $$ = ($1 == OP_NOT)
1212                           ? newUNOP($1, 0, newSVOP(OP_CONST, 0, newSViv(0)))
1213                           : newOP($1, OPf_SPECIAL); }
1214         |       FUNC1 '(' expr ')'                   /* not($foo) */
1215                         { $$ = newUNOP($1, 0, $3); }
1216         |       PMFUNC /* m//, s///, qr//, tr/// */
1217                         {
1218                             if (   $1->op_type != OP_TRANS
1219                                 && $1->op_type != OP_TRANSR
1220                                 && (((PMOP*)$1)->op_pmflags & PMf_HAS_CV))
1221                             {
1222                                 $<ival>$ = start_subparse(FALSE, CVf_ANON);
1223                                 SAVEFREESV(PL_compcv);
1224                             } else
1225                                 $<ival>$ = 0;
1226                         }
1227                     '(' listexpr optrepl ')'
1228                         { $$ = pmruntime($1, $4, $5, 1, $<ival>2); }
1229         |       BAREWORD
1230         |       listop
1231         |       PLUGEXPR
1232         ;
1233
1234 /* "my" declarations, with optional attributes */
1235 myattrterm:     MY myterm myattrlist
1236                         { $$ = my_attrs($2,$3); }
1237         |       MY myterm
1238                         { $$ = localize($2,1); }
1239         |       MY REFGEN myterm myattrlist
1240                         { $$ = newUNOP(OP_REFGEN, 0, my_attrs($3,$4)); }
1241         ;
1242
1243 /* Things that can be "my"'d */
1244 myterm  :       '(' expr ')'
1245                         { $$ = sawparens($2); }
1246         |       '(' ')'
1247                         { $$ = sawparens(newNULLLIST()); }
1248
1249         |       scalar  %prec '('
1250                         { $$ = $1; }
1251         |       hsh     %prec '('
1252                         { $$ = $1; }
1253         |       ary     %prec '('
1254                         { $$ = $1; }
1255         ;
1256
1257 /* Basic list expressions */
1258 optlistexpr:    /* NULL */ %prec PREC_LOW
1259                         { $$ = NULL; }
1260         |       listexpr    %prec PREC_LOW
1261                         { $$ = $1; }
1262         ;
1263
1264 optexpr:        /* NULL */
1265                         { $$ = NULL; }
1266         |       expr
1267                         { $$ = $1; }
1268         ;
1269
1270 optrepl:        /* NULL */
1271                         { $$ = NULL; }
1272         |       '/' expr
1273                         { $$ = $2; }
1274         ;
1275
1276 /* A little bit of trickery to make "for my $foo (@bar)" actually be
1277    lexical */
1278 my_scalar:      scalar
1279                         { parser->in_my = 0; $$ = my($1); }
1280         ;
1281
1282 my_var  :       scalar
1283         |       ary
1284         |       hsh
1285         ;
1286
1287 refgen_topic:   my_var
1288         |       amper
1289         ;
1290
1291 my_refgen:      MY REFGEN
1292         |       REFGEN MY
1293         ;
1294
1295 amper   :       '&' indirob
1296                         { $$ = newCVREF($1,$2); }
1297         ;
1298
1299 scalar  :       '$' indirob
1300                         { $$ = newSVREF($2); }
1301         ;
1302
1303 ary     :       '@' indirob
1304                         { $$ = newAVREF($2);
1305                           if ($$) $$->op_private |= $1;
1306                         }
1307         ;
1308
1309 hsh     :       '%' indirob
1310                         { $$ = newHVREF($2);
1311                           if ($$) $$->op_private |= $1;
1312                         }
1313         ;
1314
1315 arylen  :       DOLSHARP indirob
1316                         { $$ = newAVREF($2); }
1317         |       term ARROW DOLSHARP '*'
1318                         { $$ = newAVREF($1); }
1319         ;
1320
1321 star    :       '*' indirob
1322                         { $$ = newGVREF(0,$2); }
1323         ;
1324
1325 sliceme :       ary
1326         |       term ARROW '@'
1327                         { $$ = newAVREF($1); }
1328         ;
1329
1330 kvslice :       hsh
1331         |       term ARROW '%'
1332                         { $$ = newHVREF($1); }
1333         ;
1334
1335 gelem   :       star
1336         |       term ARROW '*'
1337                         { $$ = newGVREF(0,$1); }
1338         ;
1339
1340 /* Indirect objects */
1341 indirob :       BAREWORD
1342                         { $$ = scalar($1); }
1343         |       scalar %prec PREC_LOW
1344                         { $$ = scalar($1); }
1345         |       block
1346                         { $$ = op_scope($1); }
1347
1348         |       PRIVATEREF
1349                         { $$ = $1; }
1350         ;