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Parsing templates as baseclasses
- To: Martin von Loewis <martin at mira dot isdn dot cs dot tu-berlin dot de>
- Subject: Parsing templates as baseclasses
- From: Mark Mitchell <mmitchell at usa dot net>
- Date: Sun, 1 Mar 1998 17:02:45 GMT
- Cc: egcs at cygnus dot com
- References: <199803012359.AAA06557@mira.isdn.cs.tu-berlin.de>
- Reply-To: mmitchell at usa dot net
>>>>> "Martin" == Martin von Loewis <martin@mira.isdn.cs.tu-berlin.de> writes:
Martin> I'm trying to investigate the code
As we speak, I'm engaged in the process of redoing the cp/parse.y from
scratch, based directly on the grammar in the standard, with the
addition of the GNU extensions that we currently support. This is an
unauthorized, unsanctioned project; in particular, Jason's had nothing
to do with it. I've discovered a number of odd parsing problems, and
after poking around a bit, decided that some major changes were in
order, especially now that the C++ grammar has (finally) stabilized.
So, you might want to hold off; in a week or so I expect to submit the
new (and hopefully much improved) grammar, which should be fully
ISO-conformant. On the other hand, there's no guarantee whatsoever
that this version will be in g++ any time soon; Jason will of course
have to check it over with his usual eagle eye.
Martin> namespace foo {
Martin> template <class T> class x {};
Martin> }
Martin> class y : public foo::x<int> {};
Martin> I've got the lexer to produce, for the last line
Martin> (AGGR `class') (IDENTIFIER_DEFN `y') (':')(VISSPEC)
Martin> (NSNAME)(SCOPE) (PTYPENAME `x')('<')(TYPESPEC `int')('>')
Martin> ('{')
Martin> The last line is eventually reduced -> template_type.
Martin> Then I get an error with the stack state stack now 0 1 4
Martin> 66 222 223 466 717 958 123
Martin> In the non-namespace case, the template_type is further
Martin> reduced
-> type_name -> nonnested_type -> base_class.1
Martin> Now, where should I put the support for
Martin> namespace-qualified template types? I'll have to
Martin> eventually reduce this to baseclass.1 as well, preferably
Martin> without declaring foo::x<int> a nested type (it isn't).
Martin> Also, I'd like to avoid additional conflicts in the
Martin> grammar.
Martin> Any guidance appreciated.
Martin> Martin
--
Mark Mitchell mmitchell@usa.net
Stanford University http://www.stanford.edu