
    =======================================================
    Known Problems In PCCTS - Last revised 14 November 1998
    =======================================================

#14. Parsing bug in dlg

    THM: I have been unable to reproduce this problem.

    Reported by Rick Howard Mijenix Corporation (rickh@mijenix.com).

    The regular expression parser (in rexpr.c) fails while
    trying to parse the following regular expression:

            {[a-zA-Z]:}(\\\\[a-zA-Z0-9]*)+

    See my comment in the following excerpt from rexpr.c:

    /*
     * <regExpr>        ::= <andExpr> ( '|' {<andExpr>} )*
     *
     * Return -1 if syntax error
     * Return  0 if none found
     * Return  1 if a regExrp was found
     */
	static
	regExpr(g)
	GraphPtr g;
	{
	    Graph g1, g2;
	
	    if ( andExpr(&g1) == -1 )
	    {
	        return -1;
	    }
	
	    while ( token == '|' )
	    {
	        int a;
	        next();
	        a = andExpr(&g2);
	        if ( a == -1 ) return -1;   /* syntax error below */
	        else if ( !a ) return 1;    /* empty alternative */
	        g1 = BuildNFA_AorB(g1, g2);
	    }
	
	    if ( token!='\0' ) return -1;
	*****
	***** It appears to fail here becuause token is 125 - the closing '}'
	***** If I change it to:
	*****    if ( token!='\0' && token!='}' && token!= ')' ) return -1;
	*****
	***** It succeeds, but I'm not sure this is the corrrect approach.
	*****
	    *g = g1;
	    return 1;
	}

#13. dlg reports an invalid range for: [\0x00-\0xff]

    Diagnosed by Piotr Eljasiak (eljasiak@no-spam.zt.gdansk.tpsa.pl):

    Fixed in MR16.

#12. Strings containing comment actions

     Sequences that looked like C style comments appearing in string
     literals are improperly parsed by antlr/dlg.

        << fprintf(out," /* obsolete */ ");

     For this case use:

        << fprintf(out," \/\* obsolete \*\/ ");

     Reported by K.J. Cummings (cummings@peritus.com).

#11. User hook for deallocation of variables on guess fail

     The mechanism outlined in Item #108 works only for
     heap allocated variables.

#10. Label re-initialization in ( X {y:Y} )*

     If a label assignment is optional and appears in a
     (...)* or (...)+ block it will not be reset to NULL
     when it is skipped by a subsequent iteration.

     Consider the example:

            ( X { y:Y })* Z

     with input:

            X Y X Z

     The first time through the block Y will be matched and
     y will be set to point to the token.  On the second
     iteration of the (...)* block there is no match for Y.
     But y will not be reset to NULL, as the user might
     expect, it will contain a reference to the Y that was
     matched in the first iteration.

     The work-around is to manually reset y:

            ( X << y = NULL; >> { y:Y } )* Z

        or

            ( X ( y:Y | << y = NULL; >> /* epsilon */ ) )* Z

     Reported by Jeff Vincent (JVincent@novell.com).

#9. PCCTAST.h PCCTSAST::setType() is a noop

#8. #tokdefs with ~Token and .

    THM: I have been unable to reproduce this problem.

    When antlr uses #tokdefs to define tokens the fields of
    #errclass and #tokclass do not get properly defined.
    When it subsequently attempts to take the complement of
    the set of tokens (using ~Token or .) it can refer to
    tokens which don't have names, generating a fatal error.

#7. DLG crashes on some invalid inputs

    THM:  In MR20 have fixed the most common cases.

    The following token defintion will cause DLG to crash.

        #token "()"

    Reported by  Mengue Olivier (dolmen@bigfoot.com).

#6. On MS systems \n\r is treated as two new lines

    Fixed.

#5. Token expressions in #tokclass

    #errclass does not support TOK1..TOK2 or ~TOK syntax.
    #tokclass does not support ~TOKEN syntax

    A workaround for #errclass TOK1..TOK2 is to use a
    #tokclass.

    Reported by Dave Watola (dwatola@amtsun.jpl.nasa.gov)

#4. A #tokdef must appear "early" in the grammar file.

    The "early" section of the grammar file is the only
    place where the following directives may appear:

        #header
        #first
        #tokdefs
        #parser

    Any other kind of statement signifiies the end of the
    "early" section.

#3. Use of PURIFY macro for C++ mode

    Item #93 of the CHANGES_FROM_1.33 describes the use of
    the PURIFY macro to zero arguments to be passed by
    upward inheritance.

        #define PURIFY(r, s) memset((char *) &(r), '\0', (s));

    This may not be the right thing to do for C++ objects that
    have constructors.  Reported by Bonny Rais (bonny@werple.net.au).

    For those cases one should #define PURIFY to be an empty macro
    in the #header or #first actions.

#2. Fixed in 1.33MR10 - See CHANGES_FROM_1.33 Item #80.

#1. The quality of support for systems with 8.3 file names leaves
    much to be desired.  Since the kit is distributed using the
    long file names and the make file uses long file names it requires
    some effort to generate.  This will probably not be changed due
    to the large number of systems already written using the long
    file names.