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