495 lines
9.7 KiB
Text
495 lines
9.7 KiB
Text
/*
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* (c) copyright 1987 by the Vrije Universiteit, Amsterdam, The Netherlands.
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* See the copyright notice in the ACK home directory, in the file "Copyright".
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*/
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/* $Header$ */
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/* DECLARATION SYNTAX PARSER */
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{
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#include <alloc.h>
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#include "nobitfield.h"
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#include "debug.h"
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#include "arith.h"
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#include "LLlex.h"
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#include "idf.h"
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#include "type.h"
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#include "struct.h"
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#include "field.h"
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#include "decspecs.h"
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#include "def.h"
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#include "declar.h"
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#include "label.h"
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#include "expr.h"
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#include "sizes.h"
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#include "level.h"
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extern char options[];
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}
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/* 8 */
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declaration
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{struct decspecs Ds;}
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:
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{Ds = null_decspecs;}
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decl_specifiers(&Ds)
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init_declarator_list(&Ds)?
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';'
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;
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/* A `decl_specifiers' describes a sequence of a storage_class_specifier,
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an unsigned_specifier, a size_specifier and a simple type_specifier,
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which may occur in arbitrary order and each of which may be absent;
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at least one of them must be present, however, since the totally
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empty case has already be dealt with in `external_definition'.
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This means that something like:
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unsigned extern int short xx;
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is perfectly good C.
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On top of that, multiple occurrences of storage_class_specifiers,
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unsigned_specifiers and size_specifiers are errors, but a second
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type_specifier should end the decl_specifiers and be treated as
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the name to be declared (see the thin ice in RM11.1).
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Such a language is not easily expressed in a grammar; enumeration
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of the permutations is unattractive. We solve the problem by
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having a regular grammar for the "soft" items, handling the single
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occurrence of the type_specifier in the grammar (we have no choice),
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collecting all data in a `struct decspecs' and turning that data
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structure into what we want.
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The existence of declarations like
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short typedef yepp;
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makes all hope of writing a specific grammar for typedefs illusory.
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*/
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decl_specifiers /* non-empty */ (register struct decspecs *ds;)
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/* Reads a non-empty decl_specifiers and fills the struct
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decspecs *ds.
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*/
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:
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[
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other_specifier(ds)+
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[%if (DOT != IDENTIFIER || AHEAD == IDENTIFIER)
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/* the thin ice in R.M. 11.1 */
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single_type_specifier(ds) other_specifier(ds)*
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empty
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]
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single_type_specifier(ds) other_specifier(ds)*
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]
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{do_decspecs(ds);}
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;
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/* 8.1 */
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other_specifier(register struct decspecs *ds;):
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[ AUTO | STATIC | EXTERN | TYPEDEF | REGISTER ]
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{ if (ds->ds_sc_given)
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error("repeated storage class specifier");
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ds->ds_sc_given = 1;
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ds->ds_sc = DOT;
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}
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[ SHORT | LONG ]
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{ if (ds->ds_size)
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error("repeated size specifier");
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ds->ds_size = DOT;
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}
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UNSIGNED
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{ if (ds->ds_unsigned)
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error("unsigned specified twice");
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ds->ds_unsigned = 1;
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}
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;
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/* 8.2 */
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type_specifier(struct type **tpp;)
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/* Used in struct/union declarations and in casts; only the
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type is relevant.
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*/
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{struct decspecs Ds; Ds = null_decspecs;}
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:
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decl_specifiers(&Ds)
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{
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if (Ds.ds_sc_given)
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error("storage class ignored");
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if (Ds.ds_sc == REGISTER)
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error("register ignored");
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}
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{*tpp = Ds.ds_type;}
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;
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single_type_specifier(register struct decspecs *ds;):
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%default TYPE_IDENTIFIER /* this includes INT, CHAR, etc. */
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{idf2type(dot.tk_idf, &ds->ds_type);}
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IDENTIFIER
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{
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error("%s is not a type identifier", dot.tk_idf->id_text);
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ds->ds_type = error_type;
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if (dot.tk_idf->id_def) {
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dot.tk_idf->id_def->df_type = error_type;
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dot.tk_idf->id_def->df_sc = TYPEDEF;
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}
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}
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struct_or_union_specifier(&ds->ds_type)
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enum_specifier(&ds->ds_type)
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;
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/* 8.3 */
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init_declarator_list(struct decspecs *ds;):
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init_declarator(ds)
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[ ',' init_declarator(ds) ]*
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;
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init_declarator(register struct decspecs *ds;)
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{
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struct declarator Dc;
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}
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:
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{
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Dc = null_declarator;
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}
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[
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declarator(&Dc)
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{
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reject_params(&Dc);
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declare_idf(ds, &Dc, level);
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}
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[
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initializer(Dc.dc_idf, ds->ds_sc)
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{ code_declaration(Dc.dc_idf, (struct expr *) 0, level, ds->ds_sc); }
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]
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]
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{remove_declarator(&Dc);}
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;
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/* 8.6: initializer */
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initializer(struct idf *idf; int sc;)
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{
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struct expr *expr = (struct expr *) 0;
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int globalflag = level == L_GLOBAL ||
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(level >= L_LOCAL && sc == STATIC);
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}
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:
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{ if (idf->id_def->df_type->tp_fund == FUNCTION) {
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error("illegal initialization of function");
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}
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}
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[
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'='
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empty
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{warning("old-fashioned initialization, insert =");}
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/* This causes trouble at declarator and at
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external_definition, q.v.
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*/
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]
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{ if (globalflag) {
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struct expr ex;
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code_declaration(idf, &ex, level, sc);
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}
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}
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initial_value(globalflag ? &(idf->id_def->df_type) : (struct type **)0,
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&expr)
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{ if (! globalflag) {
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if (idf->id_def->df_type->tp_fund == FUNCTION) {
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free_expression(expr);
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expr = 0;
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}
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#ifdef DEBUG
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print_expr("initializer-expression", expr);
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#endif DEBUG
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code_declaration(idf, expr, level, sc);
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}
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init_idf(idf);
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}
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;
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/*
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Functions yielding pointers to functions must be declared as, e.g.,
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int (*hehe(par1, par2))() char *par1, *par2; {}
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Since the function heading is read as a normal declarator,
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we just include the (formal) parameter list in the declarator
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description list dc.
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*/
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declarator(register struct declarator *dc;)
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{
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arith count;
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struct formal *fm = 0;
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}
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:
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primary_declarator(dc)
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[%while(1) /* int i (M + 2) / 4;
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is a function, not an
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old-fashioned initialization.
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*/
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'('
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formal_list(&fm) ? /* semantic check later... */
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')'
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{
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add_decl_unary(dc, FUNCTION, (arith)0, fm);
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fm = 0;
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}
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arrayer(&count)
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{add_decl_unary(dc, ARRAY, count, NO_PARAMS);}
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]*
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'*' declarator(dc)
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{add_decl_unary(dc, POINTER, (arith)0, NO_PARAMS);}
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;
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primary_declarator(register struct declarator *dc;) :
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identifier(&dc->dc_idf)
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'(' declarator(dc) ')'
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;
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arrayer(arith *sizep;)
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{ struct expr *expr; }
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:
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'['
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[
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constant_expression(&expr)
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{
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check_array_subscript(expr);
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*sizep = expr->VL_VALUE;
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free_expression(expr);
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}
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empty
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{ *sizep = (arith)-1; }
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]
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']'
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;
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formal_list (struct formal **fmp;)
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:
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formal(fmp) [ ',' formal(fmp) ]*
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;
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formal(struct formal **fmp;)
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{struct idf *idf; }
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:
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identifier(&idf)
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{
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register struct formal *new = new_formal();
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new->fm_idf = idf;
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new->next = *fmp;
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*fmp = new;
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}
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;
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/* Change 2 */
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enum_specifier(register struct type **tpp;)
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{
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struct idf *idf;
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arith l = (arith)0;
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}
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:
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ENUM
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[
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{declare_struct(ENUM, (struct idf *) 0, tpp);}
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enumerator_pack(*tpp, &l)
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identifier(&idf)
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[
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{declare_struct(ENUM, idf, tpp);}
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enumerator_pack(*tpp, &l)
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{apply_struct(ENUM, idf, tpp);}
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empty
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]
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]
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;
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enumerator_pack(register struct type *tp; arith *lp;) :
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'{'
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enumerator(tp, lp)
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[%while(AHEAD != '}') /* >>> conflict on ',' */
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','
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enumerator(tp, lp)
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]*
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','? /* optional trailing comma */
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'}'
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{tp->tp_size = int_size;}
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/* fancy implementations that put small enums in 1 byte
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or so should start here.
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*/
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;
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enumerator(struct type *tp; arith *lp;)
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{
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struct idf *idf;
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struct expr *expr;
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}
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:
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identifier(&idf)
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[
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'='
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constant_expression(&expr)
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{
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*lp = expr->VL_VALUE;
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free_expression(expr);
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}
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]?
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{declare_enum(tp, idf, (*lp)++);}
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;
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/* 8.5 */
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struct_or_union_specifier(register struct type **tpp;)
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{
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int fund;
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struct idf *idfX;
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register struct idf *idf;
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}
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:
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[ STRUCT | UNION ]
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{fund = DOT;}
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[
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{
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declare_struct(fund, (struct idf *)0, tpp);
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}
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struct_declaration_pack(*tpp)
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identifier(&idfX) { idf = idfX; }
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[
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{
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declare_struct(fund, idf, tpp);
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(idf->id_struct->tg_busy)++;
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}
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struct_declaration_pack(*tpp)
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{
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(idf->id_struct->tg_busy)--;
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}
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{apply_struct(fund, idf, tpp);}
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empty
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]
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]
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;
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struct_declaration_pack(register struct type *stp;)
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{
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struct sdef **sdefp = &stp->tp_sdef;
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arith size = (arith)0;
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}
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:
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/* The size is only filled in after the whole struct has
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been read, to prevent recursive definitions.
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*/
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'{'
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struct_declaration(stp, &sdefp, &size)+
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'}'
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{stp->tp_size = align(size, stp->tp_align);}
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;
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struct_declaration(struct type *stp; struct sdef ***sdefpp; arith *szp;)
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{struct type *tp;}
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:
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type_specifier(&tp)
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struct_declarator_list(tp, stp, sdefpp, szp)
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[ /* in some standard UNIX compilers the semicolon
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is optional, would you believe!
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*/
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';'
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empty
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{warning("no semicolon after declarator");}
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]
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;
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struct_declarator_list(struct type *tp, *stp;
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struct sdef ***sdefpp; arith *szp;)
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:
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struct_declarator(tp, stp, sdefpp, szp)
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[ ',' struct_declarator(tp, stp, sdefpp, szp) ]*
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;
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struct_declarator(struct type *tp; struct type *stp;
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struct sdef ***sdefpp; arith *szp;)
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{
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struct declarator Dc;
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struct field *fd = 0;
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}
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:
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{
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Dc = null_declarator;
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}
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[
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declarator(&Dc)
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{reject_params(&Dc);}
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bit_expression(&fd)?
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{Dc.dc_idf = gen_idf();}
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bit_expression(&fd)
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]
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{add_sel(stp, declare_type(tp, &Dc), Dc.dc_idf, sdefpp, szp, fd);}
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{remove_declarator(&Dc);}
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;
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bit_expression(struct field **fd;)
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{ struct expr *expr; }
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:
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{
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*fd = new_field();
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}
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':'
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constant_expression(&expr)
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{
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(*fd)->fd_width = expr->VL_VALUE;
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free_expression(expr);
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#ifdef NOBITFIELD
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error("bitfields are not implemented");
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#endif NOBITFIELD
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}
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;
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/* 8.7 */
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cast(struct type **tpp;) {struct declarator Dc;} :
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{Dc = null_declarator;}
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'('
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type_specifier(tpp)
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abstract_declarator(&Dc)
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')'
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{*tpp = declare_type(*tpp, &Dc);}
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{remove_declarator(&Dc);}
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;
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/* This code is an abject copy of that of 'declarator', for lack of
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a two-level grammar.
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*/
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abstract_declarator(register struct declarator *dc;)
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{arith count;}
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:
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primary_abstract_declarator(dc)
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[
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'(' ')'
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{add_decl_unary(dc, FUNCTION, (arith)0, NO_PARAMS);}
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arrayer(&count)
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{add_decl_unary(dc, ARRAY, count, NO_PARAMS);}
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]*
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'*' abstract_declarator(dc)
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{add_decl_unary(dc, POINTER, (arith)0, NO_PARAMS);}
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;
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primary_abstract_declarator(struct declarator *dc;) :
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[%if (AHEAD == ')')
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empty
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'(' abstract_declarator(dc) ')'
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]
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;
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empty:
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;
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/* 8.8 */
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/* included in the IDENTIFIER/TYPE_IDENTIFIER mechanism */
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