perly.y

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