Re: Add null identifiers to genmatch

[Jeff Law <law at redhat dot com>]

On 11/07/2015 07:31 AM, Pedro Alves wrote:
> Hi Richard,
>
> Passerby comment below.
>
> On 11/07/2015 01:21 PM, Richard Sandiford wrote:
> > -/* Lookup the identifier ID.  */
> > +/* Lookup the identifier ID.  Allow "null" if ALLOW_NULL.  */
> >
> >   id_base *
> > -get_operator (const char *id)
> > +get_operator (const char *id, bool allow_null = false)
> >   {
> > +  if (allow_null && strcmp (id, "null") == 0)
> > +    return null_id;
> > +
> >     id_base tem (id_base::CODE, id);
>
> Boolean params are best avoided if possible, IMO.  In this case,
> it seems this could instead be a new wrapper function, like:
This hasn't been something we've required for GCC.    I've come across 
this recommendation a few times over the last several months as I 
continue to look at refactoring and best practices for codebases such as 
GCC.

By encoding the boolean in the function's signature, it (IMHO) does make 
the code a bit easier to read, primarily because you don't have to go 
lookup the tense of the boolean).  The problem is when the boolean is 
telling us some property an argument, but there's more than one argument 
and other similar situations.

I wonder if the real benefit is in the refactoring necessary to do 
things in this way without a ton of code duplication.

Jeff