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