On Tue, Apr 22, 2014 at 9:42 PM, Richard Biener <richard.guent...@gmail.com> wrote: > On April 22, 2014 8:56:56 PM CEST, Richard Sandiford > <rdsandif...@googlemail.com> wrote: >>David Malcolm <dmalc...@redhat.com> writes: >>> Alternatively we could change the is-a.h API to eliminate this >>> discrepancy, and keep the typedefs; giving something like the >>following: >>> >>> static void >>> dump_gimple_switch (pretty_printer *buffer, gimple_switch gs, int >>spc, >>> int flags) >>> [...snip...] >>> >>> [...later, within pp_gimple_stmt_1:] >>> >>> case GIMPLE_SWITCH: >>> dump_gimple_switch (buffer, as_a <gimple_switch> (gs), spc, >>flags); >>> break; >>> >>> which is concise, readable, and avoid the change in pointerness >>compared >>> to the "gimple" typedef; the local decls above would look like this: >>> gimple some_stmt; /* note how this doesn't have a star... */ >>> gimple_assign assign_stmt; /* ...and neither do these */ >>> gimple_cond assign_stmt; >>> gimple_phi phi; >>> >>> I think this last proposal is my preferred API, but it requires the >>> change to is-a.h >>> >>> Attached is a proposed change to the is-a.h API that elimintates the >>> discrepancy, allowing the use of typedefs with is-a.h (doesn't yet >>> compile, but hopefully illustrates the idea). Note how it changes >>the >>> API to match C++'s dynamic_cast<> operator i.e. you do >>> >>> Q* q = dyn_cast<Q*> (p); >>> >>> not: >>> >>> Q* q = dyn_cast<Q> (p); >> >>Thanks for being flexible. :-) I like this version too FWIW, for the >>reason you said: it really does look like a proper C++ cast. > > Indeed. I even wasn't aware it is different Than a c++ cast...
It would be nice if you can change that with a separate patch posted in a separate thread to be more visible. Also I see you introduce a const_FOO class with every FOO one. I wonder whether, now that we have C++, can address const-correctness in a less awkward way than with a typedef. Can you try to go back in time and see why we did with that in the first place? ISTR that it was "oh, if we were only using C++ we wouldn't need to jump through that hoop". Thanks, Richard. > Richard. > >>If we ever decide to get rid of the typedefs (maybe at the same time as >>using "auto") then the choice might be different, but that would be a >>much >>more systematic and easily-automated change than this one. >> >>Thanks, >>Richard > >
