nsz Git - cparser/blob - ast_t.h

   1 /*
   2  * This file is part of cparser.
   3  * Copyright (C) 2012 Matthias Braun <matze@braunis.de>
   4  */
   5 #ifndef AST_T_H
   6 #define AST_T_H
   7
   8 #include <libfirm/firm_types.h>
   9 #include <assert.h>
  10
  11 #include "ast.h"
  12 #include "symbol.h"
  13 #include "token_t.h"
  14 #include "type.h"
  15 #include "entity_t.h"
  16 #include "adt/obst.h"
  17
  18 /** The AST obstack contains all data that must stay in the AST. */
  19 extern struct obstack ast_obstack;
  20
  21 /**
  22  * Operator precedence classes
  23  */
  24 typedef enum precedence_t {
  25         PREC_BOTTOM,
  26         PREC_EXPRESSION,     /* ,                                  left to right */
  27         PREC_ASSIGNMENT,     /* = += -= *= /= %= <<= >>= &= ^= |=  right to left */
  28         PREC_CONDITIONAL,    /* ?:                                 right to left */
  29         PREC_LOGICAL_OR,     /* ||                                 left to right */
  30         PREC_LOGICAL_AND,    /* &&                                 left to right */
  31         PREC_OR,             /* |                                  left to right */
  32         PREC_XOR,            /* ^                                  left to right */
  33         PREC_AND,            /* &                                  left to right */
  34         PREC_EQUALITY,       /* == !=                              left to right */
  35         PREC_RELATIONAL,     /* < <= > >=                          left to right */
  36         PREC_SHIFT,          /* << >>                              left to right */
  37         PREC_ADDITIVE,       /* + -                                left to right */
  38         PREC_MULTIPLICATIVE, /* * / %                              left to right */
  39         PREC_CAST,           /* (type)                             right to left */
  40         PREC_UNARY,          /* ! ~ ++ -- + - * & sizeof           right to left */
  41         PREC_POSTFIX,        /* () [] -> .                         left to right */
  42         PREC_PRIMARY,
  43         PREC_TOP
  44 } precedence_t;
  45
  46 /**
  47  * Expression kinds.
  48  */
  49 typedef enum expression_kind_t {
  50         EXPR_ERROR = 1,
  51         EXPR_REFERENCE,
  52         EXPR_ENUM_CONSTANT,
  53         EXPR_LITERAL_BOOLEAN,
  54         EXPR_LITERAL_INTEGER,
  55         EXPR_LITERAL_FLOATINGPOINT,
  56         EXPR_LITERAL_CHARACTER,
  57         EXPR_LITERAL_MS_NOOP, /**< MS __noop extension */
  58         EXPR_STRING_LITERAL,
  59         EXPR_COMPOUND_LITERAL,
  60         EXPR_CALL,
  61         EXPR_CONDITIONAL,
  62         EXPR_SELECT,
  63         EXPR_ARRAY_ACCESS,
  64         EXPR_SIZEOF,
  65         EXPR_CLASSIFY_TYPE,
  66         EXPR_ALIGNOF,
  67
  68         EXPR_FUNCNAME,
  69         EXPR_BUILTIN_CONSTANT_P,
  70         EXPR_BUILTIN_TYPES_COMPATIBLE_P,
  71         EXPR_OFFSETOF,
  72         EXPR_VA_START,
  73         EXPR_VA_ARG,
  74         EXPR_VA_COPY,
  75         EXPR_STATEMENT,
  76         EXPR_LABEL_ADDRESS, /**< GCC extension &&label operator */
  77
  78         EXPR_UNARY_FIRST,
  79         EXPR_UNARY_NEGATE = EXPR_UNARY_FIRST,
  80         EXPR_UNARY_PLUS,
  81         EXPR_UNARY_COMPLEMENT,
  82         EXPR_UNARY_NOT,
  83         EXPR_UNARY_DEREFERENCE,
  84         EXPR_UNARY_TAKE_ADDRESS,
  85         EXPR_UNARY_POSTFIX_INCREMENT,
  86         EXPR_UNARY_POSTFIX_DECREMENT,
  87         EXPR_UNARY_PREFIX_INCREMENT,
  88         EXPR_UNARY_PREFIX_DECREMENT,
  89         EXPR_UNARY_CAST,
  90         EXPR_UNARY_ASSUME,        /**< MS __assume() */
  91         EXPR_UNARY_DELETE,
  92         EXPR_UNARY_DELETE_ARRAY,
  93         EXPR_UNARY_THROW,
  94         EXPR_UNARY_REAL,
  95         EXPR_UNARY_IMAG,
  96         EXPR_UNARY_LAST = EXPR_UNARY_IMAG,
  97
  98         EXPR_BINARY_FIRST,
  99         EXPR_BINARY_ADD = EXPR_BINARY_FIRST,
 100         EXPR_BINARY_SUB,
 101         EXPR_BINARY_MUL,
 102         EXPR_BINARY_DIV,
 103         EXPR_BINARY_MOD,
 104         EXPR_BINARY_EQUAL,
 105         EXPR_BINARY_NOTEQUAL,
 106         EXPR_BINARY_LESS,
 107         EXPR_BINARY_LESSEQUAL,
 108         EXPR_BINARY_GREATER,
 109         EXPR_BINARY_GREATEREQUAL,
 110         EXPR_BINARY_BITWISE_AND,
 111         EXPR_BINARY_BITWISE_OR,
 112         EXPR_BINARY_BITWISE_XOR,
 113         EXPR_BINARY_LOGICAL_AND,
 114         EXPR_BINARY_LOGICAL_OR,
 115         EXPR_BINARY_SHIFTLEFT,
 116         EXPR_BINARY_SHIFTRIGHT,
 117         EXPR_BINARY_ASSIGN,
 118         EXPR_BINARY_MUL_ASSIGN,
 119         EXPR_BINARY_DIV_ASSIGN,
 120         EXPR_BINARY_MOD_ASSIGN,
 121         EXPR_BINARY_ADD_ASSIGN,
 122         EXPR_BINARY_SUB_ASSIGN,
 123         EXPR_BINARY_SHIFTLEFT_ASSIGN,
 124         EXPR_BINARY_SHIFTRIGHT_ASSIGN,
 125         EXPR_BINARY_BITWISE_AND_ASSIGN,
 126         EXPR_BINARY_BITWISE_XOR_ASSIGN,
 127         EXPR_BINARY_BITWISE_OR_ASSIGN,
 128         EXPR_BINARY_COMMA,
 129
 130         EXPR_BINARY_ISGREATER,
 131         EXPR_BINARY_ISGREATEREQUAL,
 132         EXPR_BINARY_ISLESS,
 133         EXPR_BINARY_ISLESSEQUAL,
 134         EXPR_BINARY_ISLESSGREATER,
 135         EXPR_BINARY_ISUNORDERED,
 136         EXPR_BINARY_LAST = EXPR_BINARY_ISUNORDERED,
 137 } expression_kind_t;
 138
 139 typedef enum funcname_kind_t {
 140         FUNCNAME_FUNCTION,           /**< C99 __func__, older __FUNCTION__ */
 141         FUNCNAME_PRETTY_FUNCTION,    /**< GNUC __PRETTY_FUNCTION__ */
 142         FUNCNAME_FUNCSIG,            /**< MS __FUNCSIG__ */
 143         FUNCNAME_FUNCDNAME           /**< MS __FUNCDNAME__ */
 144 } funcname_kind_t;
 145
 146 /* convenience macros */
 147 #define EXPR_BINARY_CASES              \
 148              EXPR_BINARY_ADD:                \
 149         case EXPR_BINARY_SUB:                \
 150         case EXPR_BINARY_MUL:                \
 151         case EXPR_BINARY_DIV:                \
 152         case EXPR_BINARY_MOD:                \
 153         case EXPR_BINARY_EQUAL:              \
 154         case EXPR_BINARY_NOTEQUAL:           \
 155         case EXPR_BINARY_LESS:               \
 156         case EXPR_BINARY_LESSEQUAL:          \
 157         case EXPR_BINARY_GREATER:            \
 158         case EXPR_BINARY_GREATEREQUAL:       \
 159         case EXPR_BINARY_BITWISE_AND:        \
 160         case EXPR_BINARY_BITWISE_OR:         \
 161         case EXPR_BINARY_BITWISE_XOR:        \
 162         case EXPR_BINARY_LOGICAL_AND:        \
 163         case EXPR_BINARY_LOGICAL_OR:         \
 164         case EXPR_BINARY_SHIFTLEFT:          \
 165         case EXPR_BINARY_SHIFTRIGHT:         \
 166         case EXPR_BINARY_ASSIGN:             \
 167         case EXPR_BINARY_MUL_ASSIGN:         \
 168         case EXPR_BINARY_DIV_ASSIGN:         \
 169         case EXPR_BINARY_MOD_ASSIGN:         \
 170         case EXPR_BINARY_ADD_ASSIGN:         \
 171         case EXPR_BINARY_SUB_ASSIGN:         \
 172         case EXPR_BINARY_SHIFTLEFT_ASSIGN:   \
 173         case EXPR_BINARY_SHIFTRIGHT_ASSIGN:  \
 174         case EXPR_BINARY_BITWISE_AND_ASSIGN: \
 175         case EXPR_BINARY_BITWISE_XOR_ASSIGN: \
 176         case EXPR_BINARY_BITWISE_OR_ASSIGN:  \
 177         case EXPR_BINARY_COMMA:              \
 178         case EXPR_BINARY_ISGREATER:          \
 179         case EXPR_BINARY_ISGREATEREQUAL:     \
 180         case EXPR_BINARY_ISLESS:             \
 181         case EXPR_BINARY_ISLESSEQUAL:        \
 182         case EXPR_BINARY_ISLESSGREATER:      \
 183         case EXPR_BINARY_ISUNORDERED
 184
 185 /**
 186  * unary expression with mandatory operand
 187  */
 188 #define EXPR_UNARY_CASES_MANDATORY   \
 189              EXPR_UNARY_NEGATE:            \
 190         case EXPR_UNARY_PLUS:              \
 191         case EXPR_UNARY_COMPLEMENT:        \
 192         case EXPR_UNARY_NOT:               \
 193         case EXPR_UNARY_DEREFERENCE:       \
 194         case EXPR_UNARY_TAKE_ADDRESS:      \
 195         case EXPR_UNARY_POSTFIX_INCREMENT: \
 196         case EXPR_UNARY_POSTFIX_DECREMENT: \
 197         case EXPR_UNARY_PREFIX_INCREMENT:  \
 198         case EXPR_UNARY_PREFIX_DECREMENT:  \
 199         case EXPR_UNARY_CAST:              \
 200         case EXPR_UNARY_ASSUME:            \
 201         case EXPR_UNARY_DELETE:            \
 202         case EXPR_UNARY_DELETE_ARRAY:      \
 203         case EXPR_UNARY_IMAG:              \
 204         case EXPR_UNARY_REAL
 205
 206 /**
 207  * unary expression with optional operand
 208  */
 209 #define EXPR_UNARY_CASES_OPTIONAL \
 210         EXPR_UNARY_THROW
 211
 212 #define EXPR_UNARY_CASES           \
 213              EXPR_UNARY_CASES_MANDATORY: \
 214         case EXPR_UNARY_CASES_OPTIONAL
 215
 216 #define EXPR_LITERAL_CASES                     \
 217              EXPR_LITERAL_BOOLEAN:                   \
 218         case EXPR_LITERAL_INTEGER:                   \
 219         case EXPR_LITERAL_FLOATINGPOINT:             \
 220         case EXPR_LITERAL_MS_NOOP
 221
 222 /**
 223  * The base class of every expression.
 224  */
 225 struct expression_base_t {
 226         expression_kind_t kind;     /**< The expression kind. */
 227         type_t           *type;     /**< The type of the expression. */
 228         position_t        pos;      /**< The source position of this expression. */
 229         bool              parenthesized : 1;
 230 #ifndef NDEBUG
 231         bool              transformed : 1; /**< Set if this expression was transformed. */
 232 #endif
 233         bool              implicit : 1;  /**< compiler generated expression.
 234                                             Examples: select into anonymous structs,
 235                                             implicit casts */
 236 };
 237
 238 /**
 239  * integer, float and boolean constants
 240  */
 241 struct literal_expression_t {
 242         expression_base_t base;
 243         string_t          value;
 244         char const       *suffix; /**< Start of the suffix in value. */
 245
 246         /* ast2firm data */
 247         ir_tarval        *target_value;
 248 };
 249
 250 /**
 251  * string and character literals
 252  */
 253 struct string_literal_expression_t {
 254         expression_base_t base;
 255         string_t          value;
 256 };
 257
 258 struct funcname_expression_t {
 259         expression_base_t  base;
 260         funcname_kind_t    kind;
 261 };
 262
 263 struct compound_literal_expression_t {
 264         expression_base_t  base;
 265         type_t            *type;
 266         initializer_t     *initializer;
 267         bool               global_scope;
 268 };
 269
 270 struct builtin_constant_expression_t {
 271         expression_base_t  base;
 272         expression_t      *value;
 273 };
 274
 275 struct builtin_types_compatible_expression_t {
 276         expression_base_t  base;
 277         type_t            *left;
 278         type_t            *right;
 279 };
 280
 281 struct reference_expression_t {
 282         expression_base_t  base;
 283         entity_t          *entity;
 284 };
 285
 286 /**
 287  * An argument of a call.
 288  */
 289 struct call_argument_t {
 290         expression_t    *expression;  /**< The expression which value is transmitted. */
 291         call_argument_t *next;        /**< Links to the next argument of this call. */
 292 };
 293
 294
 295 struct call_expression_t {
 296         expression_base_t  base;
 297         expression_t      *function;  /**< The address of the function to call. */
 298         call_argument_t   *arguments; /**< List of arguments of this call. */
 299 };
 300
 301
 302 struct unary_expression_t {
 303         expression_base_t  base;
 304         expression_t      *value;     /**< The unary operand. */
 305 };
 306
 307 struct binary_expression_t {
 308         expression_base_t  base;
 309         expression_t      *left;
 310         expression_t      *right;
 311 };
 312
 313 struct select_expression_t {
 314         expression_base_t  base;
 315         expression_t      *compound;
 316         entity_t          *compound_entry;
 317 };
 318
 319 struct array_access_expression_t {
 320         expression_base_t  base;
 321         expression_t      *array_ref; /**< the referenced array */
 322         expression_t      *index;     /**< the index used */
 323         bool               flipped;   /**< True if index/ref was written in a 5[a] way */
 324 };
 325
 326 struct typeprop_expression_t {
 327         expression_base_t  base;
 328         type_t            *type;
 329         expression_t      *tp_expression;
 330 };
 331
 332 struct designator_t {
 333         position_t    pos;
 334         symbol_t     *symbol;      /**< the symbol if any */
 335         expression_t *array_index; /**< the array index if any */
 336         expression_t *range_last;  /**< last index of a range initializer, if any */
 337         designator_t *next;
 338 };
 339
 340 struct offsetof_expression_t {
 341         expression_base_t  base;
 342         type_t            *type;
 343         designator_t      *designator;
 344 };
 345
 346 struct va_start_expression_t {
 347         expression_base_t  base;
 348         expression_t      *ap;
 349         expression_t      *parameter;
 350 };
 351
 352 struct va_arg_expression_t {
 353         expression_base_t  base;
 354         expression_t      *ap;
 355 };
 356
 357 struct va_copy_expression_t {
 358         expression_base_t  base;
 359         expression_t      *dst;    /**< destination argument */
 360         expression_t      *src;    /**< source argument */
 361 };
 362
 363 struct conditional_expression_t {
 364         expression_base_t  base;
 365         expression_t      *condition;
 366         expression_t      *true_expression;
 367         expression_t      *false_expression;
 368 };
 369
 370 struct statement_expression_t {
 371         expression_base_t  base;
 372         statement_t       *statement;
 373 };
 374
 375 struct classify_type_expression_t {
 376         expression_base_t  base;
 377         expression_t      *type_expression;
 378 };
 379
 380 struct label_address_expression_t {
 381         expression_base_t  base;
 382         label_t           *label;
 383 };
 384
 385 union expression_t {
 386         expression_kind_t                     kind;
 387         expression_base_t                     base;
 388         literal_expression_t                  literal;
 389         string_literal_expression_t           string_literal;
 390         funcname_expression_t                 funcname;
 391         compound_literal_expression_t         compound_literal;
 392         builtin_constant_expression_t         builtin_constant;
 393         builtin_types_compatible_expression_t builtin_types_compatible;
 394         reference_expression_t                reference;
 395         call_expression_t                     call;
 396         unary_expression_t                    unary;
 397         binary_expression_t                   binary;
 398         select_expression_t                   select;
 399         array_access_expression_t             array_access;
 400         typeprop_expression_t                 typeprop;
 401         offsetof_expression_t                 offsetofe;
 402         va_start_expression_t                 va_starte;
 403         va_arg_expression_t                   va_arge;
 404         va_copy_expression_t                  va_copye;
 405         conditional_expression_t              conditional;
 406         statement_expression_t                statement;
 407         classify_type_expression_t            classify_type;
 408         label_address_expression_t            label_address;
 409 };
 410
 411 typedef enum initializer_kind_t {
 412         INITIALIZER_VALUE,
 413         INITIALIZER_LIST,
 414         INITIALIZER_STRING,
 415         INITIALIZER_DESIGNATOR
 416 } initializer_kind_t;
 417
 418 struct initializer_base_t {
 419         initializer_kind_t kind;
 420 };
 421
 422 struct initializer_value_t {
 423         initializer_base_t  base;
 424         expression_t       *value;
 425 };
 426
 427 struct initializer_list_t {
 428         initializer_base_t  base;
 429         size_t              len;
 430         initializer_t      *initializers[];
 431 };
 432
 433 struct initializer_designator_t {
 434         initializer_base_t  base;
 435         designator_t       *designator;
 436 };
 437
 438 union initializer_t {
 439         initializer_kind_t        kind;
 440         initializer_base_t        base;
 441         initializer_value_t       value;
 442         initializer_list_t        list;
 443         initializer_designator_t  designator;
 444 };
 445
 446 static inline string_literal_expression_t const *get_init_string(initializer_t const *const init)
 447 {
 448         assert(init->kind == INITIALIZER_STRING);
 449         assert(init->value.value->kind == EXPR_STRING_LITERAL);
 450         return &init->value.value->string_literal;
 451 }
 452
 453 /**
 454  * The statement kinds.
 455  */
 456 typedef enum statement_kind_t {
 457         STATEMENT_ERROR = 1,
 458         STATEMENT_EMPTY,
 459         STATEMENT_COMPOUND,
 460         STATEMENT_RETURN,
 461         STATEMENT_DECLARATION,
 462         STATEMENT_IF,
 463         STATEMENT_SWITCH,
 464         STATEMENT_EXPRESSION,
 465         STATEMENT_CONTINUE,
 466         STATEMENT_BREAK,
 467         STATEMENT_COMPUTED_GOTO,
 468         STATEMENT_GOTO,
 469         STATEMENT_LABEL,
 470         STATEMENT_CASE_LABEL,
 471         STATEMENT_DO_WHILE,
 472         STATEMENT_FOR,
 473         STATEMENT_ASM,
 474         STATEMENT_MS_TRY,          /**< MS __try/__finally or __try/__except */
 475         STATEMENT_LEAVE            /**< MS __leave */
 476 } statement_kind_t;
 477
 478 /**
 479  * The base class of every statement.
 480  */
 481 struct statement_base_t {
 482         statement_kind_t kind;
 483         statement_t     *next;      /**< Point to the next statement in a compound statement. */
 484         position_t       pos;
 485         statement_t     *parent;    /**< The Parent statement that controls the execution. */
 486         bool             reachable; /**< True, if this statement is reachable. */
 487 #ifndef NDEBUG
 488         bool             transformed;
 489 #endif
 490 };
 491
 492 struct return_statement_t {
 493         statement_base_t  base;
 494         expression_t     *value;    /**< The return value if any. */
 495 };
 496
 497 struct compound_statement_t {
 498         statement_base_t  base;
 499         statement_t      *statements;
 500         scope_t           scope;
 501         bool              stmt_expr; /**< True if this compound statement is a statement expression. */
 502 };
 503
 504 struct declaration_statement_t {
 505         statement_base_t  base;
 506         entity_t         *declarations_begin;
 507         entity_t         *declarations_end;
 508 };
 509
 510 struct if_statement_t {
 511         statement_base_t  base;
 512         scope_t           scope;
 513         expression_t     *condition;
 514         statement_t      *true_statement;
 515         statement_t      *false_statement;
 516 };
 517
 518 struct switch_statement_t {
 519         statement_base_t        base;
 520         scope_t                 scope;
 521         expression_t           *expression;
 522         statement_t            *body;
 523         case_label_statement_t *first_case, *last_case; /**< List of all cases, including default. */
 524         case_label_statement_t *default_label;          /**< The default label if existent. */
 525 };
 526
 527 struct goto_statement_t {
 528         statement_base_t  base;
 529         label_t          *label;         /**< The destination label. */
 530         goto_statement_t *next;          /**< links all goto statements of a function */
 531 };
 532
 533 struct computed_goto_statement_t {
 534         statement_base_t  base;
 535         expression_t     *expression; /**< The expression for the computed goto. */
 536 };
 537
 538 struct case_label_statement_t {
 539         statement_base_t        base;
 540         expression_t           *expression;    /**< The case label expression, NULL for default label. */
 541         expression_t           *end_range;     /**< For GNUC case a .. b: the end range expression, NULL else. */
 542         case_label_statement_t *next;          /**< link to the next case label in switch */
 543         statement_t            *statement;
 544         ir_tarval              *first_case;
 545         ir_tarval              *last_case;
 546         bool                   is_bad;         /**< If set marked as bad to suppress warnings. */
 547         bool                   is_empty_range; /**< If set marked this as an empty range. */
 548         long                   pn;
 549 };
 550
 551 struct label_statement_t {
 552         statement_base_t   base;
 553         label_t           *label;
 554         statement_t       *statement;
 555         label_statement_t *next;    /**< links all label statements of a function */
 556 };
 557
 558 struct expression_statement_t {
 559         statement_base_t  base;
 560         expression_t     *expression;
 561 };
 562
 563 struct do_while_statement_t {
 564         statement_base_t  base;
 565         scope_t           scope;
 566         expression_t     *condition;
 567         statement_t      *body;
 568 };
 569
 570 struct for_statement_t {
 571         statement_base_t  base;
 572         scope_t           scope;
 573         expression_t     *initialisation;
 574         expression_t     *condition;
 575         expression_t     *step;
 576         statement_t      *body;
 577         bool              condition_reachable:1;
 578         bool              step_reachable:1;
 579 };
 580
 581 struct asm_argument_t {
 582         string_t        constraints;
 583         expression_t   *expression;
 584         symbol_t       *symbol;
 585         asm_argument_t *next;
 586 };
 587
 588 struct asm_clobber_t {
 589         string_t       clobber;
 590         asm_clobber_t *next;
 591 };
 592
 593 struct asm_label_t {
 594         label_t     *label;
 595         asm_label_t *next;
 596 };
 597
 598 struct asm_statement_t {
 599         statement_base_t base;
 600         string_t         asm_text;
 601         asm_argument_t  *inputs;
 602         asm_argument_t  *outputs;
 603         asm_clobber_t   *clobbers;
 604         asm_label_t     *labels;
 605         bool             is_volatile;
 606 };
 607
 608 struct ms_try_statement_t {
 609         statement_base_t  base;
 610         statement_t      *try_statement;
 611         expression_t     *except_expression; /**< non-null for except, NULL for finally */
 612         statement_t      *final_statement;
 613 };
 614
 615 struct leave_statement_t {
 616         statement_base_t  base;
 617 };
 618
 619 union statement_t {
 620         statement_kind_t          kind;
 621         statement_base_t          base;
 622         return_statement_t        returns;
 623         compound_statement_t      compound;
 624         declaration_statement_t   declaration;
 625         if_statement_t            ifs;
 626         switch_statement_t        switchs;
 627         computed_goto_statement_t computed_goto;
 628         goto_statement_t          gotos;
 629         case_label_statement_t    case_label;
 630         label_statement_t         label;
 631         expression_statement_t    expression;
 632         do_while_statement_t      do_while;
 633         for_statement_t           fors;
 634         asm_statement_t           asms;
 635         ms_try_statement_t        ms_try;
 636         leave_statement_t         leave;
 637 };
 638
 639 struct translation_unit_t {
 640         scope_t      scope;
 641         statement_t *global_asm;
 642 };
 643
 644 /**
 645  * Allocate an AST node with given size and
 646  * initialize all fields with zero.
 647  */
 648 static inline void *allocate_ast_zero(size_t size)
 649 {
 650         return memset(obstack_alloc(&ast_obstack, size), 0, size);
 651 }
 652
 653 /** If set, implicit casts are printed. */
 654 extern bool print_implicit_casts;
 655 /** If set parenthesis are printed to indicate operator precedence. */
 656 extern bool print_parenthesis;
 657
 658 #endif