Re: [C++-11] User defined literals

[Ed Smith-Rowland <3dw4rd at verizon dot net>]

On 10/05/2011 05:08 PM, Jason Merrill wrote:
> On 10/05/2011 11:55 AM, Ed Smith-Rowland wrote:
> > +         int num_parms = TREE_VEC_LENGTH (parameter_list);
> > +         if (num_parms != 1)
> > +           ok = false;
> > +         else
> > +           {
> > +             tree parm_list = TREE_VEC_ELT (parameter_list, 0);
> > +             tree parm = INNERMOST_TEMPLATE_PARMS (parm_list);
>
> This is backwards; you want to do INNERMOST_TEMPLATE_PARMS before 
> looking at the number of parms or pulling out the one at index 0.
Now I'm confused.  In an earlier email you said (3/30/2011 in response 
to how to check template parms):
----------------------------------------------------------------------------------------
If you're looking at the PARM_DECL for the template parameter, you want 
to check that TREE_TYPE (decl) is char_type_node and that 
TEMPLATE_PARM_PARAMETER_PACK (DECL_INITIAL (decl)) is true.  Does that 
help?
----------------------------------------------------------------------------------------
Also, In spite of the documentation cp_parser_template_parameter_list 
returns a TREE_VEC not a TREE_LIST.  This happens inside 
end_template_parm_list called inside the former.  So parameter_list is a 
TREE_VEC, parm_list is a TREE_LIST, parm is a PARM_DECL, etc.
> > +struct GTY(()) tree_userdef_literal {
> > +  struct tree_common common;
>
> I think you can use tree_base instead of tree_common here, since you 
> aren't using TREE_TYPE or TREE_CHAIN.
Done.
> > One thing doesn't work.  Earlier I had said that friend declarations 
> > failed.  Not true.  What fails is defining the function body in the 
> > class definition.  The function is simply not recorded.  I'm trying 
> > to track this down but pointers would be helpful.  If I write the 
> > function body outside the class definition friend works perfectly.
>
> > About friends.  The lookup for user-defined literal operators isn't 
> > ADL.  They are a lot like normal functions because of the suffix-id 
> > as opposed to operator<< in this regard.  Thus a friend literal 
> > operator should be accessible both as an explicit operator call and 
> > via a literal.  Both are tested and except as noted above about 
> > inline defs the tests pass.
>
> A function that is only declared in a friend declaration can only be 
> found by ADL, so that doesn't sound like a failure to me; it sounds 
> like it's working the way it should.  However, if you declare the 
> function earlier and then define it in the friend declaration it ought 
> to work.
Ok.  Then things really do work all around.  I almost never use friend.  ;-)
> Jason
I'm still looking for a fix for duplicate errors/warnings coming from 
cp_parser_operator.  I tried cp_parser_error and lost the errors.  I'll 
look for different code paths for the two invocations and see if I can 
either move something up or see if something is set differently between 
the two that would be useful for a flag.

Then I think this thing is really done.

Ed

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