perly.y

   1 /*    perly.y
   2  *
   3  *    Copyright (c) 1991-2002, 2003, 2004, 2005, 2006 Larry Wall
   4  *    Copyright (c) 2007, 2008, 2009, 2010, 2011 by Larry Wall and others
   5  *
   6  *    You may distribute under the terms of either the GNU General Public
   7  *    License or the Artistic License, as specified in the README file.
   8  *
   9  */
  10
  11 /*
  12  * 'I see,' laughed Strider.  'I look foul and feel fair.  Is that it?
  13  *  All that is gold does not glitter, not all those who wander are lost.'
  14  *
  15  *     [p.171 of _The Lord of the Rings_, I/x: "Strider"]
  16  */
  17
  18 /*
  19  * This file holds the grammar for the Perl language. If edited, you need
  20  * to run regen_perly.pl, which re-creates the files perly.h, perly.tab
  21  * and perly.act which are derived from this.
  22  *
  23  * The main job of of this grammar is to call the various newFOO()
  24  * functions in op.c to build a syntax tree of OP structs.
  25  * It relies on the lexer in toke.c to do the tokenizing.
  26  *
  27  * Note: due to the way that the cleanup code works WRT to freeing ops on
  28  * the parse stack, it is dangerous to assign to the $n variables within
  29  * an action.
  30  */
  31
  32 /*  Make the parser re-entrant. */
  33
  34 %pure-parser
  35
  36 %start grammar
  37
  38 %union {
  39     I32 ival; /* __DEFAULT__ (marker for regen_perly.pl;
  40                                 must always be 1st union member) */
  41     char *pval;
  42     OP *opval;
  43     GV *gvval;
  44 }
  45
  46 %token <ival> GRAMPROG GRAMEXPR GRAMBLOCK GRAMBARESTMT GRAMFULLSTMT GRAMSTMTSEQ
  47
  48 %token <ival> '{' '}' '[' ']' '-' '+' '@' '%' '&' '=' '.'
  49
  50 %token <opval> BAREWORD METHOD FUNCMETH THING PMFUNC PRIVATEREF QWLIST
  51 %token <opval> FUNC0OP FUNC0SUB UNIOPSUB LSTOPSUB
  52 %token <opval> PLUGEXPR PLUGSTMT
  53 %token <pval> LABEL
  54 %token <ival> FORMAT SUB 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
  73 %type <opval> optlistexpr optexpr optrepl 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> termbinop termunop anonymous termdo
  78 %type <ival>  sigslurpsigil
  79 %type <opval> sigvarname sigdefault sigscalarelem sigslurpelem
  80 %type <opval> sigelem siglist siglistornull subsignature
  81 %type <opval> formstmtseq formline formarg
  82
  83 %nonassoc <ival> PREC_LOW
  84 %nonassoc LOOPEX
  85
  86 %left <ival> OROP DOROP
  87 %left <ival> ANDOP
  88 %right <ival> NOTOP
  89 %nonassoc LSTOP LSTOPSUB
  90 %left <ival> ','
  91 %right <ival> ASSIGNOP
  92 %right <ival> '?' ':'
  93 %nonassoc DOTDOT
  94 %left <ival> OROR DORDOR
  95 %left <ival> ANDAND
  96 %left <ival> BITOROP
  97 %left <ival> BITANDOP
  98 %nonassoc EQOP
  99 %nonassoc RELOP
 100 %nonassoc UNIOP UNIOPSUB
 101 %nonassoc REQUIRE
 102 %left <ival> SHIFTOP
 103 %left ADDOP
 104 %left MULOP
 105 %left <ival> MATCHOP
 106 %right <ival> '!' '~' UMINUS REFGEN
 107 %right <ival> POWOP
 108 %nonassoc <ival> PREINC PREDEC POSTINC POSTDEC POSTJOIN
 109 %left <ival> ARROW
 110 %nonassoc <ival> ')'
 111 %left <ival> '('
 112 %left '[' '{'
 113
 114 %% /* RULES */
 115
 116 /* Top-level choice of what kind of thing yyparse was called to parse */
 117 grammar :       GRAMPROG
 118                         {
 119                           parser->expect = XSTATE;
 120                           $<ival>$ = 0;
 121                         }
 122                 remember stmtseq
 123                         {
 124                           newPROG(block_end($3,$4));
 125                           PL_compiling.cop_seq = 0;
 126                           $$ = 0;
 127                         }
 128         |       GRAMEXPR
 129                         {
 130                           parser->expect = XTERM;
 131                           $<ival>$ = 0;
 132                         }
 133                 optexpr
 134                         {
 135                           PL_eval_root = $3;
 136                           $$ = 0;
 137                         }
 138         |       GRAMBLOCK
 139                         {
 140                           parser->expect = XBLOCK;
 141                           $<ival>$ = 0;
 142                         }
 143                 block
 144                         {
 145                           PL_pad_reset_pending = TRUE;
 146                           PL_eval_root = $3;
 147                           $$ = 0;
 148                           yyunlex();
 149                           parser->yychar = yytoken = YYEOF;
 150                         }
 151         |       GRAMBARESTMT
 152                         {
 153                           parser->expect = XSTATE;
 154                           $<ival>$ = 0;
 155                         }
 156                 barestmt
 157                         {
 158                           PL_pad_reset_pending = TRUE;
 159                           PL_eval_root = $3;
 160                           $$ = 0;
 161                           yyunlex();
 162                           parser->yychar = yytoken = YYEOF;
 163                         }
 164         |       GRAMFULLSTMT
 165                         {
 166                           parser->expect = XSTATE;
 167                           $<ival>$ = 0;
 168                         }
 169                 fullstmt
 170                         {
 171                           PL_pad_reset_pending = TRUE;
 172                           PL_eval_root = $3;
 173                           $$ = 0;
 174                           yyunlex();
 175                           parser->yychar = yytoken = YYEOF;
 176                         }
 177         |       GRAMSTMTSEQ
 178                         {
 179                           parser->expect = XSTATE;
 180                           $<ival>$ = 0;
 181                         }
 182                 stmtseq
 183                         {
 184                           PL_eval_root = $3;
 185                           $$ = 0;
 186                         }
 187         ;
 188
 189 /* An ordinary block */
 190 block   :       '{' remember stmtseq '}'
 191                         { if (parser->copline > (line_t)$1)
 192                               parser->copline = (line_t)$1;
 193                           $$ = block_end($2, $3);
 194                         }
 195         ;
 196
 197 /* format body */
 198 formblock:      '=' remember ';' FORMRBRACK formstmtseq ';' '.'
 199                         { if (parser->copline > (line_t)$1)
 200                               parser->copline = (line_t)$1;
 201                           $$ = block_end($2, $5);
 202                         }
 203         ;
 204
 205 remember:       /* NULL */      /* start a full lexical scope */
 206                         { $$ = block_start(TRUE);
 207                           parser->parsed_sub = 0; }
 208         ;
 209
 210 mblock  :       '{' mremember stmtseq '}'
 211                         { if (parser->copline > (line_t)$1)
 212                               parser->copline = (line_t)$1;
 213                           $$ = block_end($2, $3);
 214                         }
 215         ;
 216
 217 mremember:      /* NULL */      /* start a partial lexical scope */
 218                         { $$ = block_start(FALSE);
 219                           parser->parsed_sub = 0; }
 220         ;
 221
 222 /* A sequence of statements in the program */
 223 stmtseq :       /* NULL */
 224                         { $$ = NULL; }
 225         |       stmtseq fullstmt
 226                         {   $$ = op_append_list(OP_LINESEQ, $1, $2);
 227                             PL_pad_reset_pending = TRUE;
 228                             if ($1 && $2)
 229                                 PL_hints |= HINT_BLOCK_SCOPE;
 230                         }
 231         ;
 232
 233 /* A sequence of format lines */
 234 formstmtseq:    /* NULL */
 235                         { $$ = NULL; }
 236         |       formstmtseq formline
 237                         {   $$ = op_append_list(OP_LINESEQ, $1, $2);
 238                             PL_pad_reset_pending = TRUE;
 239                             if ($1 && $2)
 240                                 PL_hints |= HINT_BLOCK_SCOPE;
 241                         }
 242         ;
 243
 244 /* A statement in the program, including optional labels */
 245 fullstmt:       barestmt
 246                         {
 247                           $$ = $1 ? newSTATEOP(0, NULL, $1) : NULL;
 248                         }
 249         |       labfullstmt
 250                         { $$ = $1; }
 251         ;
 252
 253 labfullstmt:    LABEL barestmt
 254                         {
 255                           $$ = newSTATEOP(SVf_UTF8 * $1[strlen($1)+1], $1, $2);
 256                         }
 257         |       LABEL labfullstmt
 258                         {
 259                           $$ = newSTATEOP(SVf_UTF8 * $1[strlen($1)+1], $1, $2);
 260                         }
 261         ;
 262
 263 /* A bare statement, lacking label and other aspects of state op */
 264 barestmt:       PLUGSTMT
 265                         { $$ = $1; }
 266         |       FORMAT startformsub formname formblock
 267                         {
 268                           CV *fmtcv = PL_compcv;
 269                           newFORM($2, $3, $4);
 270                           $$ = NULL;
 271                           if (CvOUTSIDE(fmtcv) && !CvEVAL(CvOUTSIDE(fmtcv))) {
 272                               pad_add_weakref(fmtcv);
 273                           }
 274                           parser->parsed_sub = 1;
 275                         }
 276         |       SUB subname startsub
 277                         {
 278                           if ($2->op_type == OP_CONST) {
 279                             const char *const name =
 280                                 SvPV_nolen_const(((SVOP*)$2)->op_sv);
 281                             if (strEQ(name, "BEGIN") || strEQ(name, "END")
 282                               || strEQ(name, "INIT") || strEQ(name, "CHECK")
 283                               || strEQ(name, "UNITCHECK"))
 284                               CvSPECIAL_on(PL_compcv);
 285                           }
 286                           else
 287                           /* State subs inside anonymous subs need to be
 288                              clonable themselves. */
 289                           if (CvANON(CvOUTSIDE(PL_compcv))
 290                            || CvCLONE(CvOUTSIDE(PL_compcv))
 291                            || !PadnameIsSTATE(PadlistNAMESARRAY(CvPADLIST(
 292                                                 CvOUTSIDE(PL_compcv)
 293                                              ))[$2->op_targ]))
 294                               CvCLONE_on(PL_compcv);
 295                           parser->in_my = 0;
 296                           parser->in_my_stash = NULL;
 297                         }
 298                 proto subattrlist optsubbody
 299                         {
 300                           SvREFCNT_inc_simple_void(PL_compcv);
 301                           $2->op_type == OP_CONST
 302                               ? newATTRSUB($3, $2, $5, $6, $7)
 303                               : newMYSUB($3, $2, $5, $6, $7)
 304                           ;
 305                           $$ = NULL;
 306                           intro_my();
 307                           parser->parsed_sub = 1;
 308                         }
 309         |       SUB subname startsub
 310                         {
 311                           if ($2->op_type == OP_CONST) {
 312                             const char *const name =
 313                                 SvPV_nolen_const(((SVOP*)$2)->op_sv);
 314                             if (strEQ(name, "BEGIN") || strEQ(name, "END")
 315                               || strEQ(name, "INIT") || strEQ(name, "CHECK")
 316                               || strEQ(name, "UNITCHECK"))
 317                               CvSPECIAL_on(PL_compcv);
 318                           }
 319                           else
 320                           /* State subs inside anonymous subs need to be
 321                              clonable themselves. */
 322                           if (CvANON(CvOUTSIDE(PL_compcv))
 323                            || CvCLONE(CvOUTSIDE(PL_compcv))
 324                            || !PadnameIsSTATE(PadlistNAMESARRAY(CvPADLIST(
 325                                                 CvOUTSIDE(PL_compcv)
 326                                              ))[$2->op_targ]))
 327                               CvCLONE_on(PL_compcv);
 328                           parser->in_my = 0;
 329                           parser->in_my_stash = NULL;
 330                         }
 331                 remember subsignature subattrlist '{' stmtseq '}'
 332                         {
 333                           OP *body;
 334                           if (parser->copline > (line_t)$8)
 335                               parser->copline = (line_t)$8;
 336                           body = block_end($5,
 337                                 op_append_list(OP_LINESEQ, $6, $9));
 338
 339                           SvREFCNT_inc_simple_void(PL_compcv);
 340                           $2->op_type == OP_CONST
 341                               ? newATTRSUB($3, $2, NULL, $7, body)
 342                               : newMYSUB($3, $2, NULL, $7, body)
 343                           ;
 344                           $$ = NULL;
 345                           intro_my();
 346                           parser->parsed_sub = 1;
 347                         }
 348         |       PACKAGE BAREWORD BAREWORD ';'
 349                         {
 350                           package($3);
 351                           if ($2)
 352                               package_version($2);
 353                           $$ = NULL;
 354                         }
 355         |       USE startsub
 356                         { CvSPECIAL_on(PL_compcv); /* It's a BEGIN {} */ }
 357                 BAREWORD BAREWORD optlistexpr ';'
 358                         {
 359                           SvREFCNT_inc_simple_void(PL_compcv);
 360                           utilize($1, $2, $4, $5, $6);
 361                           parser->parsed_sub = 1;
 362                           $$ = NULL;
 363                         }
 364         |       IF '(' remember mexpr ')' mblock else
 365                         {
 366                           $$ = block_end($3,
 367                               newCONDOP(0, $4, op_scope($6), $7));
 368                           parser->copline = (line_t)$1;
 369                         }
 370         |       UNLESS '(' remember mexpr ')' mblock else
 371                         {
 372                           $$ = block_end($3,
 373                               newCONDOP(0, $4, $7, op_scope($6)));
 374                           parser->copline = (line_t)$1;
 375                         }
 376         |       GIVEN '(' remember mexpr ')' mblock
 377                         {
 378                           $$ = block_end($3, newGIVENOP($4, op_scope($6), 0));
 379                           parser->copline = (line_t)$1;
 380                         }
 381         |       WHEN '(' remember mexpr ')' mblock
 382                         { $$ = block_end($3, newWHENOP($4, op_scope($6))); }
 383         |       DEFAULT block
 384                         { $$ = newWHENOP(0, op_scope($2)); }
 385         |       WHILE '(' remember texpr ')' mintro mblock cont
 386                         {
 387                           $$ = block_end($3,
 388                                   newWHILEOP(0, 1, NULL,
 389                                       $4, $7, $8, $6));
 390                           parser->copline = (line_t)$1;
 391                         }
 392         |       UNTIL '(' remember iexpr ')' mintro mblock cont
 393                         {
 394                           $$ = block_end($3,
 395                                   newWHILEOP(0, 1, NULL,
 396                                       $4, $7, $8, $6));
 397                           parser->copline = (line_t)$1;
 398                         }
 399         |       FOR '(' remember mnexpr ';'
 400                         { parser->expect = XTERM; }
 401                 texpr ';'
 402                         { parser->expect = XTERM; }
 403                 mintro mnexpr ')'
 404                 mblock
 405                         {
 406                           OP *initop = $4;
 407                           OP *forop = newWHILEOP(0, 1, NULL,
 408                                       scalar($7), $13, $11, $10);
 409                           if (initop) {
 410                               forop = op_prepend_elem(OP_LINESEQ, initop,
 411                                   op_append_elem(OP_LINESEQ,
 412                                       newOP(OP_UNSTACK, OPf_SPECIAL),
 413                                       forop));
 414                           }
 415                           PL_hints |= HINT_BLOCK_SCOPE;
 416                           $$ = block_end($3, forop);
 417                           parser->copline = (line_t)$1;
 418                         }
 419         |       FOR MY remember my_scalar '(' mexpr ')' mblock cont
 420                         {
 421                           $$ = block_end($3, newFOROP(0, $4, $6, $8, $9));
 422                           parser->copline = (line_t)$1;
 423                         }
 424         |       FOR scalar '(' remember mexpr ')' mblock cont
 425                         {
 426                           $$ = block_end($4, newFOROP(0,
 427                                       op_lvalue($2, OP_ENTERLOOP), $5, $7, $8));
 428                           parser->copline = (line_t)$1;
 429                         }
 430         |       FOR my_refgen remember my_var
 431                         { parser->in_my = 0; $<opval>$ = my($4); }
 432                 '(' mexpr ')' mblock cont
 433                         {
 434                           $$ = block_end(
 435                                 $3,
 436                                 newFOROP(0,
 437                                          op_lvalue(
 438                                             newUNOP(OP_REFGEN, 0,
 439                                                     $<opval>5),
 440                                             OP_ENTERLOOP),
 441                                          $7, $9, $10)
 442                           );
 443                           parser->copline = (line_t)$1;
 444                         }
 445         |       FOR REFGEN refgen_topic '(' remember mexpr ')' mblock cont
 446                         {
 447                           $$ = block_end($5, newFOROP(
 448                                 0, op_lvalue(newUNOP(OP_REFGEN, 0,
 449                                                      $3),
 450                                              OP_ENTERLOOP), $6, $8, $9));
 451                           parser->copline = (line_t)$1;
 452                         }
 453         |       FOR '(' remember mexpr ')' mblock cont
 454                         {
 455                           $$ = block_end($3,
 456                                   newFOROP(0, NULL, $4, $6, $7));
 457                           parser->copline = (line_t)$1;
 458                         }
 459         |       block cont
 460                         {
 461                           /* a block is a loop that happens once */
 462                           $$ = newWHILEOP(0, 1, NULL,
 463                                   NULL, $1, $2, 0);
 464                         }
 465         |       PACKAGE BAREWORD BAREWORD '{' remember
 466                         {
 467                           package($3);
 468                           if ($2) {
 469                               package_version($2);
 470                           }
 471                         }
 472                 stmtseq '}'
 473                         {
 474                           /* a block is a loop that happens once */
 475                           $$ = newWHILEOP(0, 1, NULL,
 476                                   NULL, block_end($5, $7), NULL, 0);
 477                           if (parser->copline > (line_t)$4)
 478                               parser->copline = (line_t)$4;
 479                         }
 480         |       sideff ';'
 481                         {
 482                           $$ = $1;
 483                         }
 484         |       YADAYADA ';'
 485                         {
 486                           $$ = newLISTOP(OP_DIE, 0, newOP(OP_PUSHMARK, 0),
 487                                 newSVOP(OP_CONST, 0, newSVpvs("Unimplemented")));
 488                         }
 489         |       ';'
 490                         {
 491                           $$ = NULL;
 492                           parser->copline = NOLINE;
 493                         }
 494         ;
 495
 496 /* Format line */
 497 formline:       THING formarg
 498                         { OP *list;
 499                           if ($2) {
 500                               OP *term = $2;
 501                               list = op_append_elem(OP_LIST, $1, term);
 502                           }
 503                           else {
 504                               list = $1;
 505                           }
 506                           if (parser->copline == NOLINE)
 507                                parser->copline = CopLINE(PL_curcop)-1;
 508                           else parser->copline--;
 509                           $$ = newSTATEOP(0, NULL,
 510                                           op_convert_list(OP_FORMLINE, 0, list));
 511                         }
 512         ;
 513
 514 formarg :       /* NULL */
 515                         { $$ = NULL; }
 516         |       FORMLBRACK stmtseq FORMRBRACK
 517                         { $$ = op_unscope($2); }
 518         ;
 519
 520 /* An expression which may have a side-effect */
 521 sideff  :       error
 522                         { $$ = NULL; }
 523         |       expr
 524                         { $$ = $1; }
 525         |       expr IF expr
 526                         { $$ = newLOGOP(OP_AND, 0, $3, $1); }
 527         |       expr UNLESS expr
 528                         { $$ = newLOGOP(OP_OR, 0, $3, $1); }
 529         |       expr WHILE expr
 530                         { $$ = newLOOPOP(OPf_PARENS, 1, scalar($3), $1); }
 531         |       expr UNTIL iexpr
 532                         { $$ = newLOOPOP(OPf_PARENS, 1, $3, $1); }
 533         |       expr FOR expr
 534                         { $$ = newFOROP(0, NULL, $3, $1, NULL);
 535                           parser->copline = (line_t)$2; }
 536         |       expr WHEN expr
 537                         { $$ = newWHENOP($3, op_scope($1)); }
 538         ;
 539
 540 /* else and elsif blocks */
 541 else    :       /* NULL */
 542                         { $$ = NULL; }
 543         |       ELSE mblock
 544                         {
 545                           ($2)->op_flags |= OPf_PARENS;
 546                           $$ = op_scope($2);
 547                         }
 548         |       ELSIF '(' mexpr ')' mblock else
 549                         { parser->copline = (line_t)$1;
 550                             $$ = newCONDOP(0,
 551                                 newSTATEOP(OPf_SPECIAL,NULL,$3),
 552                                 op_scope($5), $6);
 553                           PL_hints |= HINT_BLOCK_SCOPE;
 554                         }
 555         ;
 556
 557 /* Continue blocks */
 558 cont    :       /* NULL */
 559                         { $$ = NULL; }
 560         |       CONTINUE block
 561                         { $$ = op_scope($2); }
 562         ;
 563
 564 /* determine whether there are any new my declarations */
 565 mintro  :       /* NULL */
 566                         { $$ = (PL_min_intro_pending &&
 567                             PL_max_intro_pending >=  PL_min_intro_pending);
 568                           intro_my(); }
 569
 570 /* Normal expression */
 571 nexpr   :       /* NULL */
 572                         { $$ = NULL; }
 573         |       sideff
 574         ;
 575
 576 /* Boolean expression */
 577 texpr   :       /* NULL means true */
 578                         { YYSTYPE tmplval;
 579                           (void)scan_num("1", &tmplval);
 580                           $$ = tmplval.opval; }
 581         |       expr
 582         ;
 583
 584 /* Inverted boolean expression */
 585 iexpr   :       expr
 586                         { $$ = invert(scalar($1)); }
 587         ;
 588
 589 /* Expression with its own lexical scope */
 590 mexpr   :       expr
 591                         { $$ = $1; intro_my(); }
 592         ;
 593
 594 mnexpr  :       nexpr
 595                         { $$ = $1; intro_my(); }
 596         ;
 597
 598 formname:       BAREWORD        { $$ = $1; }
 599         |       /* NULL */      { $$ = NULL; }
 600         ;
 601
 602 startsub:       /* NULL */      /* start a regular subroutine scope */
 603                         { $$ = start_subparse(FALSE, 0);
 604                             SAVEFREESV(PL_compcv); }
 605
 606         ;
 607
 608 startanonsub:   /* NULL */      /* start an anonymous subroutine scope */
 609                         { $$ = start_subparse(FALSE, CVf_ANON);
 610                             SAVEFREESV(PL_compcv); }
 611         ;
 612
 613 startformsub:   /* NULL */      /* start a format subroutine scope */
 614                         { $$ = start_subparse(TRUE, 0);
 615                             SAVEFREESV(PL_compcv); }
 616         ;
 617
 618 /* Name of a subroutine - must be a bareword, could be special */
 619 subname :       BAREWORD
 620         |       PRIVATEREF
 621         ;
 622
 623 /* Subroutine prototype */
 624 proto   :       /* NULL */
 625                         { $$ = NULL; }
 626         |       THING
 627         ;
 628
 629 /* Optional list of subroutine attributes */
 630 subattrlist:    /* NULL */
 631                         { $$ = NULL; }
 632         |       COLONATTR THING
 633                         { $$ = $2; }
 634         |       COLONATTR
 635                         { $$ = NULL; }
 636         ;
 637
 638 /* List of attributes for a "my" variable declaration */
 639 myattrlist:     COLONATTR THING
 640                         { $$ = $2; }
 641         |       COLONATTR
 642                         { $$ = NULL; }
 643         ;
 644
 645
 646
 647 /* --------------------------------------
 648  * subroutine signature parsing
 649  */
 650
 651 /* the '' or 'foo' part of a '$' or '@foo' etc signature variable  */
 652 sigvarname:     /* NULL */
 653                         { parser->in_my = 0; $$ = NULL; }
 654         |       PRIVATEREF
 655                         { parser->in_my = 0; $$ = $1; }
 656         ;
 657
 658 sigslurpsigil:
 659                 '@'
 660                         { $$ = '@'; }
 661         |       '%'
 662                         { $$ = '%'; }
 663
 664 /* @, %, @foo, %foo */
 665 sigslurpelem: sigslurpsigil sigvarname sigdefault/* def only to catch errors */
 666                         {
 667                             I32 sigil   = $1;
 668                             OP *var     = $2;
 669                             OP *defexpr = $3;
 670
 671                             if (parser->sig_slurpy)
 672                                 yyerror("Multiple slurpy parameters not allowed");
 673                             parser->sig_slurpy = (char)sigil;
 674
 675                             if (defexpr)
 676                                 yyerror("A slurpy parameter may not have "
 677                                         "a default value");
 678
 679                             $$ = var ? newSTATEOP(0, NULL, var) : NULL;
 680                         }
 681         ;
 682
 683 /* default part of sub signature scalar element: i.e. '= default_expr' */
 684 sigdefault:     /* NULL */
 685                         { $$ = NULL; }
 686         |       ASSIGNOP
 687                         { $$ = newOP(OP_NULL, 0); }
 688         |       ASSIGNOP term
 689                         { $$ = $2; }
 690
 691
 692 /* subroutine signature scalar element: e.g. '$x', '$=', '$x = $default' */
 693 sigscalarelem:
 694                 '$' sigvarname sigdefault
 695                         {
 696                             OP *var     = $2;
 697                             OP *defexpr = $3;
 698
 699                             if (parser->sig_slurpy)
 700                                 yyerror("Slurpy parameter not last");
 701
 702                             parser->sig_elems++;
 703
 704                             if (defexpr) {
 705                                 parser->sig_optelems++;
 706
 707                                 if (   defexpr->op_type == OP_NULL
 708                                     && !(defexpr->op_flags & OPf_KIDS))
 709                                 {
 710                                     /* handle '$=' special case */
 711                                     if (var)
 712                                         yyerror("Optional parameter "
 713                                                     "lacks default expression");
 714                                     op_free(defexpr);
 715                                 }
 716                                 else {
 717                                     /* a normal '=default' expression */
 718                                     OP *defop = (OP*)alloc_LOGOP(OP_ARGDEFELEM,
 719                                                         defexpr,
 720                                                         LINKLIST(defexpr));
 721                                     /* re-purpose op_targ to hold @_ index */
 722                                     defop->op_targ =
 723                                         (PADOFFSET)(parser->sig_elems - 1);
 724
 725                                     if (var) {
 726                                         var->op_flags |= OPf_STACKED;
 727                                         (void)op_sibling_splice(var,
 728                                                         NULL, 0, defop);
 729                                         scalar(defop);
 730                                     }
 731                                     else
 732                                         var = newUNOP(OP_NULL, 0, defop);
 733
 734                                     LINKLIST(var);
 735                                     /* NB: normally the first child of a
 736                                      * logop is executed before the logop,
 737                                      * and it pushes a boolean result
 738                                      * ready for the logop. For ARGDEFELEM,
 739                                      * the op itself does the boolean
 740                                      * calculation, so set the first op to
 741                                      * it instead.
 742                                      */
 743                                     var->op_next = defop;
 744                                     defexpr->op_next = var;
 745                                 }
 746                             }
 747                             else {
 748                                 if (parser->sig_optelems)
 749                                     yyerror("Mandatory parameter "
 750                                             "follows optional parameter");
 751                             }
 752
 753                             $$ = var ? newSTATEOP(0, NULL, var) : NULL;
 754                         }
 755         ;
 756
 757
 758 /* subroutine signature element: e.g. '$x = $default' or '%h' */
 759 sigelem:        sigscalarelem
 760                         { parser->in_my = KEY_sigvar; $$ = $1; }
 761         |       sigslurpelem
 762                         { parser->in_my = KEY_sigvar; $$ = $1; }
 763         ;
 764
 765 /* list of subroutine signature elements */
 766 siglist:
 767                 siglist ','
 768                         { $$ = $1; }
 769         |       siglist ',' sigelem
 770                         {
 771                           $$ = op_append_list(OP_LINESEQ, $1, $3);
 772                         }
 773         |       sigelem  %prec PREC_LOW
 774                         { $$ = $1; }
 775         ;
 776
 777 /* () or (....) */
 778 siglistornull:          /* NULL */
 779                         { $$ = NULL; }
 780         |       siglist
 781                         { $$ = $1; }
 782
 783 /* Subroutine signature */
 784 subsignature:   '('
 785                         {
 786                             ENTER;
 787                             SAVEIV(parser->sig_elems);
 788                             SAVEIV(parser->sig_optelems);
 789                             SAVEI8(parser->sig_slurpy);
 790                             parser->sig_elems    = 0;
 791                             parser->sig_optelems = 0;
 792                             parser->sig_slurpy   = 0;
 793                             parser->in_my        = KEY_sigvar;
 794                         }
 795                 siglistornull
 796                 ')'
 797                         {
 798                             OP            *sigops = $3;
 799                             UNOP_AUX_item *aux;
 800                             OP            *check;
 801
 802                             if (!parser->error_count) {
 803                                 assert(FEATURE_SIGNATURES_IS_ENABLED);
 804                             }
 805
 806                             /* We shouldn't get here otherwise */
 807                             Perl_ck_warner_d(aTHX_
 808                                 packWARN(WARN_EXPERIMENTAL__SIGNATURES),
 809                                 "The signatures feature is experimental");
 810
 811                             aux = (UNOP_AUX_item*)PerlMemShared_malloc(
 812                                 sizeof(UNOP_AUX_item) * 3);
 813                             aux[0].iv = parser->sig_elems;
 814                             aux[1].iv = parser->sig_optelems;
 815                             aux[2].iv = parser->sig_slurpy;
 816                             check = newUNOP_AUX(OP_ARGCHECK, 0, NULL, aux);
 817                             sigops = op_prepend_elem(OP_LINESEQ, check, sigops);
 818                             sigops = op_prepend_elem(OP_LINESEQ,
 819                                                 newSTATEOP(0, NULL, NULL),
 820                                                 sigops);
 821                             /* a nextstate at the end handles context
 822                              * correctly for an empty sub body */
 823                             $$ = op_append_elem(OP_LINESEQ,
 824                                                 sigops,
 825                                                 newSTATEOP(0, NULL, NULL));
 826
 827                             parser->in_my = 0;
 828                             parser->expect = XATTRBLOCK;
 829                             LEAVE;
 830                         }
 831         ;
 832
 833
 834
 835 /* Optional subroutine body, for named subroutine declaration */
 836 optsubbody:     block
 837         |       ';'     { $$ = NULL; }
 838         ;
 839
 840 /* Ordinary expressions; logical combinations */
 841 expr    :       expr ANDOP expr
 842                         { $$ = newLOGOP(OP_AND, 0, $1, $3); }
 843         |       expr OROP expr
 844                         { $$ = newLOGOP($2, 0, $1, $3); }
 845         |       expr DOROP expr
 846                         { $$ = newLOGOP(OP_DOR, 0, $1, $3); }
 847         |       listexpr %prec PREC_LOW
 848         ;
 849
 850 /* Expressions are a list of terms joined by commas */
 851 listexpr:       listexpr ','
 852                         { $$ = $1; }
 853         |       listexpr ',' term
 854                         {
 855                           OP* term = $3;
 856                           $$ = op_append_elem(OP_LIST, $1, term);
 857                         }
 858         |       term %prec PREC_LOW
 859         ;
 860
 861 /* List operators */
 862 listop  :       LSTOP indirob listexpr /* map {...} @args or print $fh @args */
 863                         { $$ = op_convert_list($1, OPf_STACKED,
 864                                 op_prepend_elem(OP_LIST, newGVREF($1,$2), $3) );
 865                         }
 866         |       FUNC '(' indirob expr ')'      /* print ($fh @args */
 867                         { $$ = op_convert_list($1, OPf_STACKED,
 868                                 op_prepend_elem(OP_LIST, newGVREF($1,$3), $4) );
 869                         }
 870         |       term ARROW method '(' optexpr ')' /* $foo->bar(list) */
 871                         { $$ = op_convert_list(OP_ENTERSUB, OPf_STACKED,
 872                                 op_append_elem(OP_LIST,
 873                                     op_prepend_elem(OP_LIST, scalar($1), $5),
 874                                     newMETHOP(OP_METHOD, 0, $3)));
 875                         }
 876         |       term ARROW method                     /* $foo->bar */
 877                         { $$ = op_convert_list(OP_ENTERSUB, OPf_STACKED,
 878                                 op_append_elem(OP_LIST, scalar($1),
 879                                     newMETHOP(OP_METHOD, 0, $3)));
 880                         }
 881         |       METHOD indirob optlistexpr           /* new Class @args */
 882                         { $$ = op_convert_list(OP_ENTERSUB, OPf_STACKED,
 883                                 op_append_elem(OP_LIST,
 884                                     op_prepend_elem(OP_LIST, $2, $3),
 885                                     newMETHOP(OP_METHOD, 0, $1)));
 886                         }
 887         |       FUNCMETH indirob '(' optexpr ')'    /* method $object (@args) */
 888                         { $$ = op_convert_list(OP_ENTERSUB, OPf_STACKED,
 889                                 op_append_elem(OP_LIST,
 890                                     op_prepend_elem(OP_LIST, $2, $4),
 891                                     newMETHOP(OP_METHOD, 0, $1)));
 892                         }
 893         |       LSTOP optlistexpr                    /* print @args */
 894                         { $$ = op_convert_list($1, 0, $2); }
 895         |       FUNC '(' optexpr ')'                 /* print (@args) */
 896                         { $$ = op_convert_list($1, 0, $3); }
 897         |       LSTOPSUB startanonsub block /* sub f(&@);   f { foo } ... */
 898                         { SvREFCNT_inc_simple_void(PL_compcv);
 899                           $<opval>$ = newANONATTRSUB($2, 0, NULL, $3); }
 900                     optlistexpr         %prec LSTOP  /* ... @bar */
 901                         { $$ = newUNOP(OP_ENTERSUB, OPf_STACKED,
 902                                  op_append_elem(OP_LIST,
 903                                    op_prepend_elem(OP_LIST, $<opval>4, $5), $1));
 904                         }
 905         ;
 906
 907 /* Names of methods. May use $object->$methodname */
 908 method  :       METHOD
 909         |       scalar
 910         ;
 911
 912 /* Some kind of subscripted expression */
 913 subscripted:    gelem '{' expr ';' '}'        /* *main::{something} */
 914                         /* In this and all the hash accessors, ';' is
 915                          * provided by the tokeniser */
 916                         { $$ = newBINOP(OP_GELEM, 0, $1, scalar($3)); }
 917         |       scalar '[' expr ']'          /* $array[$element] */
 918                         { $$ = newBINOP(OP_AELEM, 0, oopsAV($1), scalar($3));
 919                         }
 920         |       term ARROW '[' expr ']'      /* somearef->[$element] */
 921                         { $$ = newBINOP(OP_AELEM, 0,
 922                                         ref(newAVREF($1),OP_RV2AV),
 923                                         scalar($4));
 924                         }
 925         |       subscripted '[' expr ']'    /* $foo->[$bar]->[$baz] */
 926                         { $$ = newBINOP(OP_AELEM, 0,
 927                                         ref(newAVREF($1),OP_RV2AV),
 928                                         scalar($3));
 929                         }
 930         |       scalar '{' expr ';' '}'    /* $foo{bar();} */
 931                         { $$ = newBINOP(OP_HELEM, 0, oopsHV($1), jmaybe($3));
 932                         }
 933         |       term ARROW '{' expr ';' '}' /* somehref->{bar();} */
 934                         { $$ = newBINOP(OP_HELEM, 0,
 935                                         ref(newHVREF($1),OP_RV2HV),
 936                                         jmaybe($4)); }
 937         |       subscripted '{' expr ';' '}' /* $foo->[bar]->{baz;} */
 938                         { $$ = newBINOP(OP_HELEM, 0,
 939                                         ref(newHVREF($1),OP_RV2HV),
 940                                         jmaybe($3)); }
 941         |       term ARROW '(' ')'          /* $subref->() */
 942                         { $$ = newUNOP(OP_ENTERSUB, OPf_STACKED,
 943                                    newCVREF(0, scalar($1))); }
 944         |       term ARROW '(' expr ')'     /* $subref->(@args) */
 945                         { $$ = newUNOP(OP_ENTERSUB, OPf_STACKED,
 946                                    op_append_elem(OP_LIST, $4,
 947                                        newCVREF(0, scalar($1)))); }
 948
 949         |       subscripted '(' expr ')'   /* $foo->{bar}->(@args) */
 950                         { $$ = newUNOP(OP_ENTERSUB, OPf_STACKED,
 951                                    op_append_elem(OP_LIST, $3,
 952                                                newCVREF(0, scalar($1)))); }
 953         |       subscripted '(' ')'        /* $foo->{bar}->() */
 954                         { $$ = newUNOP(OP_ENTERSUB, OPf_STACKED,
 955                                    newCVREF(0, scalar($1))); }
 956         |       '(' expr ')' '[' expr ']'            /* list slice */
 957                         { $$ = newSLICEOP(0, $5, $2); }
 958         |       QWLIST '[' expr ']'            /* list literal slice */
 959                         { $$ = newSLICEOP(0, $3, $1); }
 960         |       '(' ')' '[' expr ']'                 /* empty list slice! */
 961                         { $$ = newSLICEOP(0, $4, NULL); }
 962     ;
 963
 964 /* Binary operators between terms */
 965 termbinop:      term ASSIGNOP term                     /* $x = $y */
 966                         { $$ = newASSIGNOP(OPf_STACKED, $1, $2, $3); }
 967         |       term POWOP term                        /* $x ** $y */
 968                         { $$ = newBINOP($2, 0, scalar($1), scalar($3)); }
 969         |       term MULOP term                        /* $x * $y, $x x $y */
 970                         {   if ($2 != OP_REPEAT)
 971                                 scalar($1);
 972                             $$ = newBINOP($2, 0, $1, scalar($3));
 973                         }
 974         |       term ADDOP term                        /* $x + $y */
 975                         { $$ = newBINOP($2, 0, scalar($1), scalar($3)); }
 976         |       term SHIFTOP term                      /* $x >> $y, $x << $y */
 977                         { $$ = newBINOP($2, 0, scalar($1), scalar($3)); }
 978         |       term RELOP term                        /* $x > $y, etc. */
 979                         { $$ = newBINOP($2, 0, scalar($1), scalar($3)); }
 980         |       term EQOP term                         /* $x == $y, $x eq $y */
 981                         { $$ = newBINOP($2, 0, scalar($1), scalar($3)); }
 982         |       term BITANDOP term                     /* $x & $y */
 983                         { $$ = newBINOP($2, 0, scalar($1), scalar($3)); }
 984         |       term BITOROP term                      /* $x | $y */
 985                         { $$ = newBINOP($2, 0, scalar($1), scalar($3)); }
 986         |       term DOTDOT term                       /* $x..$y, $x...$y */
 987                         { $$ = newRANGE($2, scalar($1), scalar($3)); }
 988         |       term ANDAND term                       /* $x && $y */
 989                         { $$ = newLOGOP(OP_AND, 0, $1, $3); }
 990         |       term OROR term                         /* $x || $y */
 991                         { $$ = newLOGOP(OP_OR, 0, $1, $3); }
 992         |       term DORDOR term                       /* $x // $y */
 993                         { $$ = newLOGOP(OP_DOR, 0, $1, $3); }
 994         |       term MATCHOP term                      /* $x =~ /$y/ */
 995                         { $$ = bind_match($2, $1, $3); }
 996     ;
 997
 998 /* Unary operators and terms */
 999 termunop : '-' term %prec UMINUS                       /* -$x */
1000                         { $$ = newUNOP(OP_NEGATE, 0, scalar($2)); }
1001         |       '+' term %prec UMINUS                  /* +$x */
1002                         { $$ = $2; }
1003
1004         |       '!' term                               /* !$x */
1005                         { $$ = newUNOP(OP_NOT, 0, scalar($2)); }
1006         |       '~' term                               /* ~$x */
1007                         { $$ = newUNOP($1, 0, scalar($2)); }
1008         |       term POSTINC                           /* $x++ */
1009                         { $$ = newUNOP(OP_POSTINC, 0,
1010                                         op_lvalue(scalar($1), OP_POSTINC)); }
1011         |       term POSTDEC                           /* $x-- */
1012                         { $$ = newUNOP(OP_POSTDEC, 0,
1013                                         op_lvalue(scalar($1), OP_POSTDEC));}
1014         |       term POSTJOIN    /* implicit join after interpolated ->@ */
1015                         { $$ = op_convert_list(OP_JOIN, 0,
1016                                        op_append_elem(
1017                                         OP_LIST,
1018                                         newSVREF(scalar(
1019                                             newSVOP(OP_CONST,0,
1020                                                     newSVpvs("\""))
1021                                         )),
1022                                         $1
1023                                        ));
1024                         }
1025         |       PREINC term                            /* ++$x */
1026                         { $$ = newUNOP(OP_PREINC, 0,
1027                                         op_lvalue(scalar($2), OP_PREINC)); }
1028         |       PREDEC term                            /* --$x */
1029                         { $$ = newUNOP(OP_PREDEC, 0,
1030                                         op_lvalue(scalar($2), OP_PREDEC)); }
1031
1032     ;
1033
1034 /* Constructors for anonymous data */
1035 anonymous:      '[' expr ']'
1036                         { $$ = newANONLIST($2); }
1037         |       '[' ']'
1038                         { $$ = newANONLIST(NULL);}
1039         |       HASHBRACK expr ';' '}'  %prec '(' /* { foo => "Bar" } */
1040                         { $$ = newANONHASH($2); }
1041         |       HASHBRACK ';' '}'       %prec '(' /* { } (';' by tokener) */
1042                         { $$ = newANONHASH(NULL); }
1043         |       ANONSUB startanonsub proto subattrlist block            %prec '('
1044                         { SvREFCNT_inc_simple_void(PL_compcv);
1045                           $$ = newANONATTRSUB($2, $3, $4, $5); }
1046         |       ANONSUB startanonsub remember subsignature subattrlist '{' stmtseq '}'  %prec '('
1047                         {
1048                           OP *body;
1049                           if (parser->copline > (line_t)$6)
1050                               parser->copline = (line_t)$6;
1051                           body = block_end($3,
1052                                 op_append_list(OP_LINESEQ, $4, $7));
1053                           SvREFCNT_inc_simple_void(PL_compcv);
1054                           $$ = newANONATTRSUB($2, NULL, $5, body);
1055                         }
1056
1057     ;
1058
1059 /* Things called with "do" */
1060 termdo  :       DO term %prec UNIOP                     /* do $filename */
1061                         { $$ = dofile($2, $1);}
1062         |       DO block        %prec '('               /* do { code */
1063                         { $$ = newUNOP(OP_NULL, OPf_SPECIAL, op_scope($2));}
1064         ;
1065
1066 term    :       termbinop
1067         |       termunop
1068         |       anonymous
1069         |       termdo
1070         |       term '?' term ':' term
1071                         { $$ = newCONDOP(0, $1, $3, $5); }
1072         |       REFGEN term                          /* \$x, \@y, \%z */
1073                         { $$ = newUNOP(OP_REFGEN, 0, $2); }
1074         |       MY REFGEN term
1075                         { $$ = newUNOP(OP_REFGEN, 0, localize($3,1)); }
1076         |       myattrterm      %prec UNIOP
1077                         { $$ = $1; }
1078         |       LOCAL term      %prec UNIOP
1079                         { $$ = localize($2,0); }
1080         |       '(' expr ')'
1081                         { $$ = sawparens($2); }
1082         |       QWLIST
1083                         { $$ = $1; }
1084         |       '(' ')'
1085                         { $$ = sawparens(newNULLLIST()); }
1086         |       scalar  %prec '('
1087                         { $$ = $1; }
1088         |       star    %prec '('
1089                         { $$ = $1; }
1090         |       hsh     %prec '('
1091                         { $$ = $1; }
1092         |       ary     %prec '('
1093                         { $$ = $1; }
1094         |       arylen  %prec '('                    /* $#x, $#{ something } */
1095                         { $$ = newUNOP(OP_AV2ARYLEN, 0, ref($1, OP_AV2ARYLEN));}
1096         |       subscripted
1097                         { $$ = $1; }
1098         |       sliceme '[' expr ']'                     /* array slice */
1099                         { $$ = op_prepend_elem(OP_ASLICE,
1100                                 newOP(OP_PUSHMARK, 0),
1101                                     newLISTOP(OP_ASLICE, 0,
1102                                         list($3),
1103                                         ref($1, OP_ASLICE)));
1104                           if ($$ && $1)
1105                               $$->op_private |=
1106                                   $1->op_private & OPpSLICEWARNING;
1107                         }
1108         |       kvslice '[' expr ']'                 /* array key/value slice */
1109                         { $$ = op_prepend_elem(OP_KVASLICE,
1110                                 newOP(OP_PUSHMARK, 0),
1111                                     newLISTOP(OP_KVASLICE, 0,
1112                                         list($3),
1113                                         ref(oopsAV($1), OP_KVASLICE)));
1114                           if ($$ && $1)
1115                               $$->op_private |=
1116                                   $1->op_private & OPpSLICEWARNING;
1117                         }
1118         |       sliceme '{' expr ';' '}'                 /* @hash{@keys} */
1119                         { $$ = op_prepend_elem(OP_HSLICE,
1120                                 newOP(OP_PUSHMARK, 0),
1121                                     newLISTOP(OP_HSLICE, 0,
1122                                         list($3),
1123                                         ref(oopsHV($1), OP_HSLICE)));
1124                           if ($$ && $1)
1125                               $$->op_private |=
1126                                   $1->op_private & OPpSLICEWARNING;
1127                         }
1128         |       kvslice '{' expr ';' '}'                 /* %hash{@keys} */
1129                         { $$ = op_prepend_elem(OP_KVHSLICE,
1130                                 newOP(OP_PUSHMARK, 0),
1131                                     newLISTOP(OP_KVHSLICE, 0,
1132                                         list($3),
1133                                         ref($1, OP_KVHSLICE)));
1134                           if ($$ && $1)
1135                               $$->op_private |=
1136                                   $1->op_private & OPpSLICEWARNING;
1137                         }
1138         |       THING   %prec '('
1139                         { $$ = $1; }
1140         |       amper                                /* &foo; */
1141                         { $$ = newUNOP(OP_ENTERSUB, 0, scalar($1)); }
1142         |       amper '(' ')'                 /* &foo() or foo() */
1143                         { $$ = newUNOP(OP_ENTERSUB, OPf_STACKED, scalar($1));
1144                         }
1145         |       amper '(' expr ')'          /* &foo(@args) or foo(@args) */
1146                         {
1147                           $$ = newUNOP(OP_ENTERSUB, OPf_STACKED,
1148                                 op_append_elem(OP_LIST, $3, scalar($1)));
1149                         }
1150         |       NOAMP subname optlistexpr       /* foo @args (no parens) */
1151                         { $$ = newUNOP(OP_ENTERSUB, OPf_STACKED,
1152                             op_append_elem(OP_LIST, $3, scalar($2)));
1153                         }
1154         |       term ARROW '$' '*'
1155                         { $$ = newSVREF($1); }
1156         |       term ARROW '@' '*'
1157                         { $$ = newAVREF($1); }
1158         |       term ARROW '%' '*'
1159                         { $$ = newHVREF($1); }
1160         |       term ARROW '&' '*'
1161                         { $$ = newUNOP(OP_ENTERSUB, 0,
1162                                        scalar(newCVREF($3,$1))); }
1163         |       term ARROW '*' '*'      %prec '('
1164                         { $$ = newGVREF(0,$1); }
1165         |       LOOPEX  /* loop exiting command (goto, last, dump, etc) */
1166                         { $$ = newOP($1, OPf_SPECIAL);
1167                             PL_hints |= HINT_BLOCK_SCOPE; }
1168         |       LOOPEX term
1169                         { $$ = newLOOPEX($1,$2); }
1170         |       NOTOP listexpr                       /* not $foo */
1171                         { $$ = newUNOP(OP_NOT, 0, scalar($2)); }
1172         |       UNIOP                                /* Unary op, $_ implied */
1173                         { $$ = newOP($1, 0); }
1174         |       UNIOP block                          /* eval { foo }* */
1175                         { $$ = newUNOP($1, 0, $2); }
1176         |       UNIOP term                           /* Unary op */
1177                         { $$ = newUNOP($1, 0, $2); }
1178         |       REQUIRE                              /* require, $_ implied */
1179                         { $$ = newOP(OP_REQUIRE, $1 ? OPf_SPECIAL : 0); }
1180         |       REQUIRE term                         /* require Foo */
1181                         { $$ = newUNOP(OP_REQUIRE, $1 ? OPf_SPECIAL : 0, $2); }
1182         |       UNIOPSUB
1183                         { $$ = newUNOP(OP_ENTERSUB, OPf_STACKED, scalar($1)); }
1184         |       UNIOPSUB term                        /* Sub treated as unop */
1185                         { $$ = newUNOP(OP_ENTERSUB, OPf_STACKED,
1186                             op_append_elem(OP_LIST, $2, scalar($1))); }
1187         |       FUNC0                                /* Nullary operator */
1188                         { $$ = newOP($1, 0); }
1189         |       FUNC0 '(' ')'
1190                         { $$ = newOP($1, 0);}
1191         |       FUNC0OP       /* Same as above, but op created in toke.c */
1192                         { $$ = $1; }
1193         |       FUNC0OP '(' ')'
1194                         { $$ = $1; }
1195         |       FUNC0SUB                             /* Sub treated as nullop */
1196                         { $$ = newUNOP(OP_ENTERSUB, OPf_STACKED, scalar($1)); }
1197         |       FUNC1 '(' ')'                        /* not () */
1198                         { $$ = ($1 == OP_NOT)
1199                           ? newUNOP($1, 0, newSVOP(OP_CONST, 0, newSViv(0)))
1200                           : newOP($1, OPf_SPECIAL); }
1201         |       FUNC1 '(' expr ')'                   /* not($foo) */
1202                         { $$ = newUNOP($1, 0, $3); }
1203         |       PMFUNC /* m//, s///, qr//, tr/// */
1204                         {
1205                             if (   $1->op_type != OP_TRANS
1206                                 && $1->op_type != OP_TRANSR
1207                                 && (((PMOP*)$1)->op_pmflags & PMf_HAS_CV))
1208                             {
1209                                 $<ival>$ = start_subparse(FALSE, CVf_ANON);
1210                                 SAVEFREESV(PL_compcv);
1211                             } else
1212                                 $<ival>$ = 0;
1213                         }
1214                     '(' listexpr optrepl ')'
1215                         { $$ = pmruntime($1, $4, $5, 1, $<ival>2); }
1216         |       BAREWORD
1217         |       listop
1218         |       PLUGEXPR
1219         ;
1220
1221 /* "my" declarations, with optional attributes */
1222 myattrterm:     MY myterm myattrlist
1223                         { $$ = my_attrs($2,$3); }
1224         |       MY myterm
1225                         { $$ = localize($2,1); }
1226         |       MY REFGEN myterm myattrlist
1227                         { $$ = newUNOP(OP_REFGEN, 0, my_attrs($3,$4)); }
1228         ;
1229
1230 /* Things that can be "my"'d */
1231 myterm  :       '(' expr ')'
1232                         { $$ = sawparens($2); }
1233         |       '(' ')'
1234                         { $$ = sawparens(newNULLLIST()); }
1235
1236         |       scalar  %prec '('
1237                         { $$ = $1; }
1238         |       hsh     %prec '('
1239                         { $$ = $1; }
1240         |       ary     %prec '('
1241                         { $$ = $1; }
1242         ;
1243
1244 /* Basic list expressions */
1245 optlistexpr:    /* NULL */ %prec PREC_LOW
1246                         { $$ = NULL; }
1247         |       listexpr    %prec PREC_LOW
1248                         { $$ = $1; }
1249         ;
1250
1251 optexpr:        /* NULL */
1252                         { $$ = NULL; }
1253         |       expr
1254                         { $$ = $1; }
1255         ;
1256
1257 optrepl:        /* NULL */
1258                         { $$ = NULL; }
1259         |       '/' expr
1260                         { $$ = $2; }
1261         ;
1262
1263 /* A little bit of trickery to make "for my $foo (@bar)" actually be
1264    lexical */
1265 my_scalar:      scalar
1266                         { parser->in_my = 0; $$ = my($1); }
1267         ;
1268
1269 my_var  :       scalar
1270         |       ary
1271         |       hsh
1272         ;
1273
1274 refgen_topic:   my_var
1275         |       amper
1276         ;
1277
1278 my_refgen:      MY REFGEN
1279         |       REFGEN MY
1280         ;
1281
1282 amper   :       '&' indirob
1283                         { $$ = newCVREF($1,$2); }
1284         ;
1285
1286 scalar  :       '$' indirob
1287                         { $$ = newSVREF($2); }
1288         ;
1289
1290 ary     :       '@' indirob
1291                         { $$ = newAVREF($2);
1292                           if ($$) $$->op_private |= $1;
1293                         }
1294         ;
1295
1296 hsh     :       '%' indirob
1297                         { $$ = newHVREF($2);
1298                           if ($$) $$->op_private |= $1;
1299                         }
1300         ;
1301
1302 arylen  :       DOLSHARP indirob
1303                         { $$ = newAVREF($2); }
1304         |       term ARROW DOLSHARP '*'
1305                         { $$ = newAVREF($1); }
1306         ;
1307
1308 star    :       '*' indirob
1309                         { $$ = newGVREF(0,$2); }
1310         ;
1311
1312 sliceme :       ary
1313         |       term ARROW '@'
1314                         { $$ = newAVREF($1); }
1315         ;
1316
1317 kvslice :       hsh
1318         |       term ARROW '%'
1319                         { $$ = newHVREF($1); }
1320         ;
1321
1322 gelem   :       star
1323         |       term ARROW '*'
1324                         { $$ = newGVREF(0,$1); }
1325         ;
1326
1327 /* Indirect objects */
1328 indirob :       BAREWORD
1329                         { $$ = scalar($1); }
1330         |       scalar %prec PREC_LOW
1331                         { $$ = scalar($1); }
1332         |       block
1333                         { $$ = op_scope($1); }
1334
1335         |       PRIVATEREF
1336                         { $$ = $1; }
1337         ;