perly.y

   1 /*    perly.y
   2  *
   3  *    Copyright (c) 1991-2002, 2003, 2004 Larry Wall
   4  *
   5  *    You may distribute under the terms of either the GNU General Public
   6  *    License or the Artistic License, as specified in the README file.
   7  *
   8  */
   9
  10 /*
  11  * 'I see,' laughed Strider.  'I look foul and feel fair.  Is that it?
  12  * All that is gold does not glitter, not all those who wander are lost.'
  13  */
  14
  15 /* This file holds the grammar for the Perl language. If edited, you need
  16  * to run regen_perly.pl, which re-creates the files perly.h, perly.tab
  17  * and perly.act which are derived from this.
  18  *
  19  * The main job of of this grammar is to call the various newFOO()
  20  * functions in op.c to build a syntax tree of OP structs.
  21  * It relies on the lexer in toke.c to do the tokenizing.
  22  */
  23
  24 /*  Make the parser re-entrant. */
  25
  26 %pure_parser
  27
  28 %start prog
  29
  30 %union {
  31     I32 ival;
  32     char *pval;
  33     OP *opval;
  34     GV *gvval;
  35 }
  36
  37 %token <ival> '{'
  38
  39 %token <opval> WORD METHOD FUNCMETH THING PMFUNC PRIVATEREF
  40 %token <opval> FUNC0SUB UNIOPSUB LSTOPSUB
  41 %token <pval> LABEL
  42 %token <ival> FORMAT SUB ANONSUB PACKAGE USE
  43 %token <ival> WHILE UNTIL IF UNLESS ELSE ELSIF CONTINUE FOR
  44 %token <ival> LOOPEX DOTDOT
  45 %token <ival> FUNC0 FUNC1 FUNC UNIOP LSTOP
  46 %token <ival> RELOP EQOP MULOP ADDOP
  47 %token <ival> DOLSHARP DO HASHBRACK NOAMP
  48 %token <ival> LOCAL MY MYSUB REQUIRE
  49 %token COLONATTR
  50
  51 %type <ival> prog decl format startsub startanonsub startformsub mintro
  52 %type <ival> progstart remember mremember '&' savescope
  53 %type <opval> block mblock lineseq line loop cond else
  54 %type <opval> expr term subscripted scalar ary hsh arylen star amper sideff
  55 %type <opval> argexpr nexpr texpr iexpr mexpr mnexpr miexpr
  56 %type <opval> listexpr listexprcom indirob listop method
  57 %type <opval> formname subname proto subbody cont my_scalar
  58 %type <opval> subattrlist myattrlist mysubrout myattrterm myterm
  59 %type <opval> termbinop termunop anonymous termdo
  60 %type <pval> label
  61
  62 %nonassoc PREC_LOW
  63 %nonassoc LOOPEX
  64
  65 %left <ival> OROP DOROP
  66 %left ANDOP
  67 %right NOTOP
  68 %nonassoc LSTOP LSTOPSUB
  69 %left ','
  70 %right <ival> ASSIGNOP
  71 %right '?' ':'
  72 %nonassoc DOTDOT
  73 %left OROR DORDOR
  74 %left ANDAND
  75 %left <ival> BITOROP
  76 %left <ival> BITANDOP
  77 %nonassoc EQOP
  78 %nonassoc RELOP
  79 %nonassoc UNIOP UNIOPSUB
  80 %nonassoc REQUIRE
  81 %left <ival> SHIFTOP
  82 %left ADDOP
  83 %left MULOP
  84 %left <ival> MATCHOP
  85 %right '!' '~' UMINUS REFGEN
  86 %right <ival> POWOP
  87 %nonassoc PREINC PREDEC POSTINC POSTDEC
  88 %left ARROW
  89 %nonassoc <ival> ')'
  90 %left '('
  91 %left '[' '{'
  92
  93 %% /* RULES */
  94
  95 /* The whole program */
  96 prog    :       progstart
  97         /*CONTINUED*/   lineseq
  98                         { $$ = $1; newPROG(block_end($1,$2)); }
  99         ;
 100
 101 /* An ordinary block */
 102 block   :       '{' remember lineseq '}'
 103                         { if (PL_copline > (line_t)$1)
 104                               PL_copline = (line_t)$1;
 105                           $$ = block_end($2, $3); }
 106         ;
 107
 108 remember:       /* NULL */      /* start a full lexical scope */
 109                         { $$ = block_start(TRUE); }
 110         ;
 111
 112 progstart:
 113                 {
 114                     PL_expect = XSTATE; $$ = block_start(TRUE);
 115                 }
 116         ;
 117
 118
 119 mblock  :       '{' mremember lineseq '}'
 120                         { if (PL_copline > (line_t)$1)
 121                               PL_copline = (line_t)$1;
 122                           $$ = block_end($2, $3); }
 123         ;
 124
 125 mremember:      /* NULL */      /* start a partial lexical scope */
 126                         { $$ = block_start(FALSE); }
 127         ;
 128
 129 savescope:      /* NULL */      /* remember stack pos in case of error */
 130                 { $$ = PL_savestack_ix; }
 131
 132 /* A collection of "lines" in the program */
 133 lineseq :       /* NULL */
 134                         { $$ = Nullop; }
 135         |       lineseq decl
 136                         { $$ = $1; }
 137         |       lineseq savescope line
 138                         {   LEAVE_SCOPE($2);
 139                             $$ = append_list(OP_LINESEQ,
 140                                 (LISTOP*)$1, (LISTOP*)$3);
 141                             PL_pad_reset_pending = TRUE;
 142                             if ($1 && $3) PL_hints |= HINT_BLOCK_SCOPE; }
 143         ;
 144
 145 /* A "line" in the program */
 146 line    :       label cond
 147                         { $$ = newSTATEOP(0, $1, $2); }
 148         |       loop    /* loops add their own labels */
 149         |       label ';'
 150                         { if ($1 != Nullch) {
 151                               $$ = newSTATEOP(0, $1, newOP(OP_NULL, 0));
 152                             }
 153                             else {
 154                               $$ = Nullop;
 155                               PL_copline = NOLINE;
 156                             }
 157                             PL_expect = XSTATE; }
 158         |       label sideff ';'
 159                         { $$ = newSTATEOP(0, $1, $2);
 160                           PL_expect = XSTATE; }
 161         ;
 162
 163 /* An expression which may have a side-effect */
 164 sideff  :       error
 165                         { $$ = Nullop; }
 166         |       expr
 167                         { $$ = $1; }
 168         |       expr IF expr
 169                         { $$ = newLOGOP(OP_AND, 0, $3, $1); }
 170         |       expr UNLESS expr
 171                         { $$ = newLOGOP(OP_OR, 0, $3, $1); }
 172         |       expr WHILE expr
 173                         { $$ = newLOOPOP(OPf_PARENS, 1, scalar($3), $1); }
 174         |       expr UNTIL iexpr
 175                         { $$ = newLOOPOP(OPf_PARENS, 1, $3, $1);}
 176         |       expr FOR expr
 177                         { $$ = newFOROP(0, Nullch, (line_t)$2,
 178                                         Nullop, $3, $1, Nullop); }
 179         ;
 180
 181 /* else and elsif blocks */
 182 else    :       /* NULL */
 183                         { $$ = Nullop; }
 184         |       ELSE mblock
 185                         { ($2)->op_flags |= OPf_PARENS; $$ = scope($2); }
 186         |       ELSIF '(' mexpr ')' mblock else
 187                         { PL_copline = (line_t)$1;
 188                             $$ = newCONDOP(0, $3, scope($5), $6);
 189                             PL_hints |= HINT_BLOCK_SCOPE; }
 190         ;
 191
 192 /* Real conditional expressions */
 193 cond    :       IF '(' remember mexpr ')' mblock else
 194                         { PL_copline = (line_t)$1;
 195                             $$ = block_end($3,
 196                                    newCONDOP(0, $4, scope($6), $7)); }
 197         |       UNLESS '(' remember miexpr ')' mblock else
 198                         { PL_copline = (line_t)$1;
 199                             $$ = block_end($3,
 200                                    newCONDOP(0, $4, scope($6), $7)); }
 201         ;
 202
 203 /* Continue blocks */
 204 cont    :       /* NULL */
 205                         { $$ = Nullop; }
 206         |       CONTINUE block
 207                         { $$ = scope($2); }
 208         ;
 209
 210 /* Loops: while, until, for, and a bare block */
 211 loop    :       label WHILE '(' remember texpr ')' mintro mblock cont
 212                         { PL_copline = (line_t)$2;
 213                             $$ = block_end($4,
 214                                    newSTATEOP(0, $1,
 215                                      newWHILEOP(0, 1, (LOOP*)Nullop,
 216                                                 $2, $5, $8, $9, $7))); }
 217         |       label UNTIL '(' remember iexpr ')' mintro mblock cont
 218                         { PL_copline = (line_t)$2;
 219                             $$ = block_end($4,
 220                                    newSTATEOP(0, $1,
 221                                      newWHILEOP(0, 1, (LOOP*)Nullop,
 222                                                 $2, $5, $8, $9, $7))); }
 223         |       label FOR MY remember my_scalar '(' mexpr ')' mblock cont
 224                         { $$ = block_end($4,
 225                                  newFOROP(0, $1, (line_t)$2, $5, $7, $9, $10)); }
 226         |       label FOR scalar '(' remember mexpr ')' mblock cont
 227                         { $$ = block_end($5,
 228                                  newFOROP(0, $1, (line_t)$2, mod($3, OP_ENTERLOOP),
 229                                           $6, $8, $9)); }
 230         |       label FOR '(' remember mexpr ')' mblock cont
 231                         { $$ = block_end($4,
 232                                  newFOROP(0, $1, (line_t)$2, Nullop, $5, $7, $8)); }
 233         |       label FOR '(' remember mnexpr ';' texpr ';' mintro mnexpr ')'
 234                     mblock
 235                         /* basically fake up an initialize-while lineseq */
 236                         { OP *forop;
 237                           PL_copline = (line_t)$2;
 238                           forop = newSTATEOP(0, $1,
 239                                             newWHILEOP(0, 1, (LOOP*)Nullop,
 240                                                 $2, scalar($7),
 241                                                 $12, $10, $9));
 242                           if ($5) {
 243                                 forop = append_elem(OP_LINESEQ,
 244                                         newSTATEOP(0, ($1?savepv($1):Nullch),
 245                                                    $5),
 246                                         forop);
 247                           }
 248
 249                           $$ = block_end($4, forop); }
 250         |       label block cont  /* a block is a loop that happens once */
 251                         { $$ = newSTATEOP(0, $1,
 252                                  newWHILEOP(0, 1, (LOOP*)Nullop,
 253                                             NOLINE, Nullop, $2, $3, 0)); }
 254         ;
 255
 256 /* determine whether there are any new my declarations */
 257 mintro  :       /* NULL */
 258                         { $$ = (PL_min_intro_pending &&
 259                             PL_max_intro_pending >=  PL_min_intro_pending);
 260                           intro_my(); }
 261
 262 /* Normal expression */
 263 nexpr   :       /* NULL */
 264                         { $$ = Nullop; }
 265         |       sideff
 266         ;
 267
 268 /* Boolean expression */
 269 texpr   :       /* NULL means true */
 270                         { (void)scan_num("1", &yylval); $$ = yylval.opval; }
 271         |       expr
 272         ;
 273
 274 /* Inverted boolean expression */
 275 iexpr   :       expr
 276                         { $$ = invert(scalar($1)); }
 277         ;
 278
 279 /* Expression with its own lexical scope */
 280 mexpr   :       expr
 281                         { $$ = $1; intro_my(); }
 282         ;
 283
 284 mnexpr  :       nexpr
 285                         { $$ = $1; intro_my(); }
 286         ;
 287
 288 miexpr  :       iexpr
 289                         { $$ = $1; intro_my(); }
 290         ;
 291
 292 /* Optional "MAIN:"-style loop labels */
 293 label   :       /* empty */
 294                         { $$ = Nullch; }
 295         |       LABEL
 296         ;
 297
 298 /* Some kind of declaration - does not take part in the parse tree */
 299 decl    :       format
 300                         { $$ = 0; }
 301         |       subrout
 302                         { $$ = 0; }
 303         |       mysubrout
 304                         { $$ = 0; }
 305         |       package
 306                         { $$ = 0; }
 307         |       use
 308                         { $$ = 0; }
 309         ;
 310
 311 format  :       FORMAT startformsub formname block
 312                         { newFORM($2, $3, $4); }
 313         ;
 314
 315 formname:       WORD            { $$ = $1; }
 316         |       /* NULL */      { $$ = Nullop; }
 317         ;
 318
 319 /* Unimplemented "my sub foo { }" */
 320 mysubrout:      MYSUB startsub subname proto subattrlist subbody
 321                         { newMYSUB($2, $3, $4, $5, $6); }
 322         ;
 323
 324 /* Subroutine definition */
 325 subrout :       SUB startsub subname proto subattrlist subbody
 326                         { newATTRSUB($2, $3, $4, $5, $6); }
 327         ;
 328
 329 startsub:       /* NULL */      /* start a regular subroutine scope */
 330                         { $$ = start_subparse(FALSE, 0); }
 331         ;
 332
 333 startanonsub:   /* NULL */      /* start an anonymous subroutine scope */
 334                         { $$ = start_subparse(FALSE, CVf_ANON); }
 335         ;
 336
 337 startformsub:   /* NULL */      /* start a format subroutine scope */
 338                         { $$ = start_subparse(TRUE, 0); }
 339         ;
 340
 341 /* Name of a subroutine - must be a bareword, could be special */
 342 subname :       WORD    { const char *const name = SvPV_nolen_const(((SVOP*)$1)->op_sv);
 343                           if (strEQ(name, "BEGIN") || strEQ(name, "END")
 344                               || strEQ(name, "INIT") || strEQ(name, "CHECK"))
 345                               CvSPECIAL_on(PL_compcv);
 346                           $$ = $1; }
 347         ;
 348
 349 /* Subroutine prototype */
 350 proto   :       /* NULL */
 351                         { $$ = Nullop; }
 352         |       THING
 353         ;
 354
 355 /* Optional list of subroutine attributes */
 356 subattrlist:    /* NULL */
 357                         { $$ = Nullop; }
 358         |       COLONATTR THING
 359                         { $$ = $2; }
 360         |       COLONATTR
 361                         { $$ = Nullop; }
 362         ;
 363
 364 /* List of attributes for a "my" variable declaration */
 365 myattrlist:     COLONATTR THING
 366                         { $$ = $2; }
 367         |       COLONATTR
 368                         { $$ = Nullop; }
 369         ;
 370
 371 /* Subroutine body - either null or a block */
 372 subbody :       block   { $$ = $1; }
 373         |       ';'     { $$ = Nullop; PL_expect = XSTATE; }
 374         ;
 375
 376 package :       PACKAGE WORD ';'
 377                         { package($2); }
 378         ;
 379
 380 use     :       USE startsub
 381                         { CvSPECIAL_on(PL_compcv); /* It's a BEGIN {} */ }
 382                     WORD WORD listexpr ';'
 383                         { utilize($1, $2, $4, $5, $6); }
 384         ;
 385
 386 /* Ordinary expressions; logical combinations */
 387 expr    :       expr ANDOP expr
 388                         { $$ = newLOGOP(OP_AND, 0, $1, $3); }
 389         |       expr OROP expr
 390                         { $$ = newLOGOP($2, 0, $1, $3); }
 391         |       expr DOROP expr
 392                         { $$ = newLOGOP(OP_DOR, 0, $1, $3); }
 393         |       argexpr %prec PREC_LOW
 394         ;
 395
 396 /* Expressions are a list of terms joined by commas */
 397 argexpr :       argexpr ','
 398                         { $$ = $1; }
 399         |       argexpr ',' term
 400                         { $$ = append_elem(OP_LIST, $1, $3); }
 401         |       term %prec PREC_LOW
 402         ;
 403
 404 /* List operators */
 405 listop  :       LSTOP indirob argexpr /* map {...} @args or print $fh @args */
 406                         { $$ = convert($1, OPf_STACKED,
 407                                 prepend_elem(OP_LIST, newGVREF($1,$2), $3) ); }
 408         |       FUNC '(' indirob expr ')'      /* print ($fh @args */
 409                         { $$ = convert($1, OPf_STACKED,
 410                                 prepend_elem(OP_LIST, newGVREF($1,$3), $4) ); }
 411         |       term ARROW method '(' listexprcom ')' /* $foo->bar(list) */
 412                         { $$ = convert(OP_ENTERSUB, OPf_STACKED,
 413                                 append_elem(OP_LIST,
 414                                     prepend_elem(OP_LIST, scalar($1), $5),
 415                                     newUNOP(OP_METHOD, 0, $3))); }
 416         |       term ARROW method                     /* $foo->bar */
 417                         { $$ = convert(OP_ENTERSUB, OPf_STACKED,
 418                                 append_elem(OP_LIST, scalar($1),
 419                                     newUNOP(OP_METHOD, 0, $3))); }
 420         |       METHOD indirob listexpr              /* new Class @args */
 421                         { $$ = convert(OP_ENTERSUB, OPf_STACKED,
 422                                 append_elem(OP_LIST,
 423                                     prepend_elem(OP_LIST, $2, $3),
 424                                     newUNOP(OP_METHOD, 0, $1))); }
 425         |       FUNCMETH indirob '(' listexprcom ')' /* method $object (@args) */
 426                         { $$ = convert(OP_ENTERSUB, OPf_STACKED,
 427                                 append_elem(OP_LIST,
 428                                     prepend_elem(OP_LIST, $2, $4),
 429                                     newUNOP(OP_METHOD, 0, $1))); }
 430         |       LSTOP listexpr                       /* print @args */
 431                         { $$ = convert($1, 0, $2); }
 432         |       FUNC '(' listexprcom ')'             /* print (@args) */
 433                         { $$ = convert($1, 0, $3); }
 434         |       LSTOPSUB startanonsub block /* sub f(&@);   f { foo } ... */
 435                         { $3 = newANONATTRSUB($2, 0, Nullop, $3); }
 436                     listexpr            %prec LSTOP  /* ... @bar */
 437                         { $$ = newUNOP(OP_ENTERSUB, OPf_STACKED,
 438                                  append_elem(OP_LIST,
 439                                    prepend_elem(OP_LIST, $3, $5), $1)); }
 440         ;
 441
 442 /* Names of methods. May use $object->$methodname */
 443 method  :       METHOD
 444         |       scalar
 445         ;
 446
 447 /* Some kind of subscripted expression */
 448 subscripted:    star '{' expr ';' '}'        /* *main::{something} */
 449                         /* In this and all the hash accessors, ';' is
 450                          * provided by the tokeniser */
 451                         { $$ = newBINOP(OP_GELEM, 0, $1, scalar($3));
 452                             PL_expect = XOPERATOR; }
 453         |       scalar '[' expr ']'          /* $array[$element] */
 454                         { $$ = newBINOP(OP_AELEM, 0, oopsAV($1), scalar($3)); }
 455         |       term ARROW '[' expr ']'      /* somearef->[$element] */
 456                         { $$ = newBINOP(OP_AELEM, 0,
 457                                         ref(newAVREF($1),OP_RV2AV),
 458                                         scalar($4));}
 459         |       subscripted '[' expr ']'    /* $foo->[$bar]->[$baz] */
 460                         { $$ = newBINOP(OP_AELEM, 0,
 461                                         ref(newAVREF($1),OP_RV2AV),
 462                                         scalar($3));}
 463         |       scalar '{' expr ';' '}'    /* $foo->{bar();} */
 464                         { $$ = newBINOP(OP_HELEM, 0, oopsHV($1), jmaybe($3));
 465                             PL_expect = XOPERATOR; }
 466         |       term ARROW '{' expr ';' '}' /* somehref->{bar();} */
 467                         { $$ = newBINOP(OP_HELEM, 0,
 468                                         ref(newHVREF($1),OP_RV2HV),
 469                                         jmaybe($4));
 470                             PL_expect = XOPERATOR; }
 471         |       subscripted '{' expr ';' '}' /* $foo->[bar]->{baz;} */
 472                         { $$ = newBINOP(OP_HELEM, 0,
 473                                         ref(newHVREF($1),OP_RV2HV),
 474                                         jmaybe($3));
 475                             PL_expect = XOPERATOR; }
 476         |       term ARROW '(' ')'          /* $subref->() */
 477                         { $$ = newUNOP(OP_ENTERSUB, OPf_STACKED,
 478                                    newCVREF(0, scalar($1))); }
 479         |       term ARROW '(' expr ')'     /* $subref->(@args) */
 480                         { $$ = newUNOP(OP_ENTERSUB, OPf_STACKED,
 481                                    append_elem(OP_LIST, $4,
 482                                        newCVREF(0, scalar($1)))); }
 483
 484         |       subscripted '(' expr ')'   /* $foo->{bar}->(@args) */
 485                         { $$ = newUNOP(OP_ENTERSUB, OPf_STACKED,
 486                                    append_elem(OP_LIST, $3,
 487                                                newCVREF(0, scalar($1)))); }
 488         |       subscripted '(' ')'        /* $foo->{bar}->() */
 489                         { $$ = newUNOP(OP_ENTERSUB, OPf_STACKED,
 490                                    newCVREF(0, scalar($1))); }
 491         |       '(' expr ')' '[' expr ']'            /* list slice */
 492                         { $$ = newSLICEOP(0, $5, $2); }
 493         |       '(' ')' '[' expr ']'                 /* empty list slice! */
 494                         { $$ = newSLICEOP(0, $4, Nullop); }
 495     ;
 496
 497 /* Binary operators between terms */
 498 termbinop       :       term ASSIGNOP term             /* $x = $y */
 499                         { $$ = newASSIGNOP(OPf_STACKED, $1, $2, $3); }
 500         |       term POWOP term                        /* $x ** $y */
 501                         { $$ = newBINOP($2, 0, scalar($1), scalar($3)); }
 502         |       term MULOP term                        /* $x * $y, $x x $y */
 503                         {   if ($2 != OP_REPEAT)
 504                                 scalar($1);
 505                             $$ = newBINOP($2, 0, $1, scalar($3)); }
 506         |       term ADDOP term                        /* $x + $y */
 507                         { $$ = newBINOP($2, 0, scalar($1), scalar($3)); }
 508         |       term SHIFTOP term                      /* $x >> $y, $x << $y */
 509                         { $$ = newBINOP($2, 0, scalar($1), scalar($3)); }
 510         |       term RELOP term                        /* $x > $y, etc. */
 511                         { $$ = newBINOP($2, 0, scalar($1), scalar($3)); }
 512         |       term EQOP term                         /* $x == $y, $x eq $y */
 513                         { $$ = newBINOP($2, 0, scalar($1), scalar($3)); }
 514         |       term BITANDOP term                     /* $x & $y */
 515                         { $$ = newBINOP($2, 0, scalar($1), scalar($3)); }
 516         |       term BITOROP term                      /* $x | $y */
 517                         { $$ = newBINOP($2, 0, scalar($1), scalar($3)); }
 518         |       term DOTDOT term                       /* $x..$y, $x...$y */
 519                         { $$ = newRANGE($2, scalar($1), scalar($3));}
 520         |       term ANDAND term                       /* $x && $y */
 521                         { $$ = newLOGOP(OP_AND, 0, $1, $3); }
 522         |       term OROR term                         /* $x || $y */
 523                         { $$ = newLOGOP(OP_OR, 0, $1, $3); }
 524         |       term DORDOR term                       /* $x // $y */
 525                         { $$ = newLOGOP(OP_DOR, 0, $1, $3); }
 526         |       term MATCHOP term                      /* $x =~ /$y/ */
 527                         { $$ = bind_match($2, $1, $3); }
 528     ;
 529
 530 /* Unary operators and terms */
 531 termunop : '-' term %prec UMINUS                       /* -$x */
 532                         { $$ = newUNOP(OP_NEGATE, 0, scalar($2)); }
 533         |       '+' term %prec UMINUS                  /* +$x */
 534                         { $$ = $2; }
 535         |       '!' term                               /* !$x */
 536                         { $$ = newUNOP(OP_NOT, 0, scalar($2)); }
 537         |       '~' term                               /* ~$x */
 538                         { $$ = newUNOP(OP_COMPLEMENT, 0, scalar($2));}
 539         |       term POSTINC                           /* $x++ */
 540                         { $$ = newUNOP(OP_POSTINC, 0,
 541                                         mod(scalar($1), OP_POSTINC)); }
 542         |       term POSTDEC                           /* $x-- */
 543                         { $$ = newUNOP(OP_POSTDEC, 0,
 544                                         mod(scalar($1), OP_POSTDEC)); }
 545         |       PREINC term                            /* ++$x */
 546                         { $$ = newUNOP(OP_PREINC, 0,
 547                                         mod(scalar($2), OP_PREINC)); }
 548         |       PREDEC term                            /* --$x */
 549                         { $$ = newUNOP(OP_PREDEC, 0,
 550                                         mod(scalar($2), OP_PREDEC)); }
 551
 552     ;
 553
 554 /* Constructors for anonymous data */
 555 anonymous:      '[' expr ']'
 556                         { $$ = newANONLIST($2); }
 557         |       '[' ']'
 558                         { $$ = newANONLIST(Nullop); }
 559         |       HASHBRACK expr ';' '}'  %prec '(' /* { foo => "Bar" } */
 560                         { $$ = newANONHASH($2); }
 561         |       HASHBRACK ';' '}'       %prec '(' /* { } (';' by tokener) */
 562                         { $$ = newANONHASH(Nullop); }
 563         |       ANONSUB startanonsub proto subattrlist block    %prec '('
 564                         { $$ = newANONATTRSUB($2, $3, $4, $5); }
 565
 566     ;
 567
 568 /* Things called with "do" */
 569 termdo  :       DO term %prec UNIOP                     /* do $filename */
 570                         { $$ = dofile($2, $1); }
 571         |       DO block        %prec '('               /* do { code */
 572                         { $$ = newUNOP(OP_NULL, OPf_SPECIAL, scope($2)); }
 573         |       DO WORD '(' ')'                         /* do somesub() */
 574                         { $$ = newUNOP(OP_ENTERSUB,
 575                             OPf_SPECIAL|OPf_STACKED,
 576                             prepend_elem(OP_LIST,
 577                                 scalar(newCVREF(
 578                                     (OPpENTERSUB_AMPER<<8),
 579                                     scalar($2)
 580                                 )),Nullop)); dep();}
 581         |       DO WORD '(' expr ')'                    /* do somesub(@args) */
 582                         { $$ = newUNOP(OP_ENTERSUB,
 583                             OPf_SPECIAL|OPf_STACKED,
 584                             append_elem(OP_LIST,
 585                                 $4,
 586                                 scalar(newCVREF(
 587                                     (OPpENTERSUB_AMPER<<8),
 588                                     scalar($2)
 589                                 )))); dep();}
 590         |       DO scalar '(' ')'                      /* do $subref () */
 591                         { $$ = newUNOP(OP_ENTERSUB, OPf_SPECIAL|OPf_STACKED,
 592                             prepend_elem(OP_LIST,
 593                                 scalar(newCVREF(0,scalar($2))), Nullop)); dep();}
 594         |       DO scalar '(' expr ')'                 /* do $subref (@args) */
 595                         { $$ = newUNOP(OP_ENTERSUB, OPf_SPECIAL|OPf_STACKED,
 596                             prepend_elem(OP_LIST,
 597                                 $4,
 598                                 scalar(newCVREF(0,scalar($2))))); dep();}
 599
 600         ;
 601
 602 term    :       termbinop
 603         |       termunop
 604         |       anonymous
 605         |       termdo
 606         |       term '?' term ':' term
 607                         { $$ = newCONDOP(0, $1, $3, $5); }
 608         |       REFGEN term                          /* \$x, \@y, \%z */
 609                         { $$ = newUNOP(OP_REFGEN, 0, mod($2,OP_REFGEN)); }
 610         |       myattrterm      %prec UNIOP
 611                         { $$ = $1; }
 612         |       LOCAL term      %prec UNIOP
 613                         { $$ = localize($2,$1); }
 614         |       '(' expr ')'
 615                         { $$ = sawparens($2); }
 616         |       '(' ')'
 617                         { $$ = sawparens(newNULLLIST()); }
 618         |       scalar  %prec '('
 619                         { $$ = $1; }
 620         |       star    %prec '('
 621                         { $$ = $1; }
 622         |       hsh     %prec '('
 623                         { $$ = $1; }
 624         |       ary     %prec '('
 625                         { $$ = $1; }
 626         |       arylen  %prec '('                    /* $#x, $#{ something } */
 627                         { $$ = newUNOP(OP_AV2ARYLEN, 0, ref($1, OP_AV2ARYLEN));}
 628         |       subscripted
 629                         { $$ = $1; }
 630         |       ary '[' expr ']'                     /* array slice */
 631                         { $$ = prepend_elem(OP_ASLICE,
 632                                 newOP(OP_PUSHMARK, 0),
 633                                     newLISTOP(OP_ASLICE, 0,
 634                                         list($3),
 635                                         ref($1, OP_ASLICE))); }
 636         |       ary '{' expr ';' '}'                 /* @hash{@keys} */
 637                         { $$ = prepend_elem(OP_HSLICE,
 638                                 newOP(OP_PUSHMARK, 0),
 639                                     newLISTOP(OP_HSLICE, 0,
 640                                         list($3),
 641                                         ref(oopsHV($1), OP_HSLICE)));
 642                             PL_expect = XOPERATOR; }
 643         |       THING   %prec '('
 644                         { $$ = $1; }
 645         |       amper                                /* &foo; */
 646                         { $$ = newUNOP(OP_ENTERSUB, 0, scalar($1)); }
 647         |       amper '(' ')'                        /* &foo() */
 648                         { $$ = newUNOP(OP_ENTERSUB, OPf_STACKED, scalar($1)); }
 649         |       amper '(' expr ')'                   /* &foo(@args) */
 650                         { $$ = newUNOP(OP_ENTERSUB, OPf_STACKED,
 651                             append_elem(OP_LIST, $3, scalar($1))); }
 652         |       NOAMP WORD listexpr                  /* foo(@args) */
 653                         { $$ = newUNOP(OP_ENTERSUB, OPf_STACKED,
 654                             append_elem(OP_LIST, $3, scalar($2))); }
 655         |       LOOPEX  /* loop exiting command (goto, last, dump, etc) */
 656                         { $$ = newOP($1, OPf_SPECIAL);
 657                             PL_hints |= HINT_BLOCK_SCOPE; }
 658         |       LOOPEX term
 659                         { $$ = newLOOPEX($1,$2); }
 660         |       NOTOP argexpr                        /* not $foo */
 661                         { $$ = newUNOP(OP_NOT, 0, scalar($2)); }
 662         |       UNIOP                                /* Unary op, $_ implied */
 663                         { $$ = newOP($1, 0); }
 664         |       UNIOP block                          /* eval { foo } */
 665                         { $$ = newUNOP($1, 0, $2); }
 666         |       UNIOP term                           /* Unary op */
 667                         { $$ = newUNOP($1, 0, $2); }
 668         |       REQUIRE                              /* require, $_ implied */
 669                         { $$ = newOP(OP_REQUIRE, $1 ? OPf_SPECIAL : 0); }
 670         |       REQUIRE term                         /* require Foo */
 671                         { $$ = newUNOP(OP_REQUIRE, $1 ? OPf_SPECIAL : 0, $2); }
 672         |       UNIOPSUB term                        /* Sub treated as unop */
 673                         { $$ = newUNOP(OP_ENTERSUB, OPf_STACKED,
 674                             append_elem(OP_LIST, $2, scalar($1))); }
 675         |       FUNC0                                /* Nullary operator */
 676                         { $$ = newOP($1, 0); }
 677         |       FUNC0 '(' ')'
 678                         { $$ = newOP($1, 0); }
 679         |       FUNC0SUB                             /* Sub treated as nullop */
 680                         { $$ = newUNOP(OP_ENTERSUB, OPf_STACKED,
 681                                 scalar($1)); }
 682         |       FUNC1 '(' ')'                        /* not () */
 683                         { $$ = $1 == OP_NOT ? newUNOP($1, 0, newSVOP(OP_CONST, 0, newSViv(0)))
 684                                             : newOP($1, OPf_SPECIAL); }
 685         |       FUNC1 '(' expr ')'                   /* not($foo) */
 686                         { $$ = newUNOP($1, 0, $3); }
 687         |       PMFUNC '(' argexpr ')'           /* m//, s///, tr/// */
 688                         { $$ = pmruntime($1, $3, 1); }
 689         |       WORD
 690         |       listop
 691         ;
 692
 693 /* "my" declarations, with optional attributes */
 694 myattrterm:     MY myterm myattrlist
 695                         { $$ = my_attrs($2,$3); }
 696         |       MY myterm
 697                         { $$ = localize($2,$1); }
 698         ;
 699
 700 /* Things that can be "my"'d */
 701 myterm  :       '(' expr ')'
 702                         { $$ = sawparens($2); }
 703         |       '(' ')'
 704                         { $$ = sawparens(newNULLLIST()); }
 705         |       scalar  %prec '('
 706                         { $$ = $1; }
 707         |       hsh     %prec '('
 708                         { $$ = $1; }
 709         |       ary     %prec '('
 710                         { $$ = $1; }
 711         ;
 712
 713 /* Basic list expressions */
 714 listexpr:       /* NULL */ %prec PREC_LOW
 715                         { $$ = Nullop; }
 716         |       argexpr    %prec PREC_LOW
 717                         { $$ = $1; }
 718         ;
 719
 720 listexprcom:    /* NULL */
 721                         { $$ = Nullop; }
 722         |       expr
 723                         { $$ = $1; }
 724         |       expr ','
 725                         { $$ = $1; }
 726         ;
 727
 728 /* A little bit of trickery to make "for my $foo (@bar)" actually be
 729    lexical */
 730 my_scalar:      scalar
 731                         { PL_in_my = 0; $$ = my($1); }
 732         ;
 733
 734 amper   :       '&' indirob
 735                         { $$ = newCVREF($1,$2); }
 736         ;
 737
 738 scalar  :       '$' indirob
 739                         { $$ = newSVREF($2); }
 740         ;
 741
 742 ary     :       '@' indirob
 743                         { $$ = newAVREF($2); }
 744         ;
 745
 746 hsh     :       '%' indirob
 747                         { $$ = newHVREF($2); }
 748         ;
 749
 750 arylen  :       DOLSHARP indirob
 751                         { $$ = newAVREF($2); }
 752         ;
 753
 754 star    :       '*' indirob
 755                         { $$ = newGVREF(0,$2); }
 756         ;
 757
 758 /* Indirect objects */
 759 indirob :       WORD
 760                         { $$ = scalar($1); }
 761         |       scalar %prec PREC_LOW
 762                         { $$ = scalar($1);  }
 763         |       block
 764                         { $$ = scope($1); }
 765
 766         |       PRIVATEREF
 767                         { $$ = $1; }
 768         ;