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From: te07@edrc.cmu.edu (Thomas Epperly)
Newsgroups: comp.unix.ultrix
Subject: DECstation 3100 yacc/cc bug
Keywords: yacc cc pmax
Message-ID: <5659@pt.cs.cmu.edu>
Date: 26 Jul 89 16:50:59 GMT
Reply-To: te07@edrc.cmu.edu (Thomas Epperly)
Organization: Carnegie-Mellon University, CS/RI
Lines: 50

I have found a problem using yacc and cc on the DECstation 3100.  I
don't know enough to say which is wrong, but I know that they don't
work together like they should.  I define the following union in my
yacc input file:

excerpt from yacc input file.

%union {
  double rvalue;
  long ivalue;
  struct variable *vptr;
  struct gl_list_t *elist;
}

The C program that yacc produces include these parts:

/* some deleted lines */
# line 88 "gram.y"
typedef union  {
  double rvalue;
  long ivalue;
  struct variable *vptr;
  struct gl_list_t *elist;
} YYSTYPE;

/* some more deleted lines */
#ifndef YYSTYPE
#define YYSTYPE int                /* It redefines YYSTYPE here */
#endif
YYSTYPE yylval, yyval;
/* some more lines */

As commented above, the #ifndef YYSTYPE executes the #define YYSTYPE
int.  Therefore, I get errors everytime I use yylval.{anything}  E.g.

ccom: Warning: gram.y, line 270: struct/union or struct/union pointer required
	 gl_append_ptr(yyval.elist,g_expr_ptr);
      ---------------------------^

I have a call in with DEC, but the right people haven't called back
yet.  The work around that I am using is to include the following in
my Makefile.

.y.c:
	$(YACC) $(YFLAGS) $<
	sed -e "/#ifndef YYSTYPE/,/#endif/d" < y.tab.c > y.new.c
	rm -f y.tab.c
	mv y.new.c $@

Tom Epperly