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Re: Implementing p0515 - spaceship operator
On Mon, Jan 8, 2018 at 5:13 PM, Jonathan Wakely <jwakely.gcc@gmail.com> wrote:
> On 8 January 2018 at 22:07, Jason Merrill wrote:
>> On Mon, Jan 8, 2018 at 4:07 PM, Tim van Deurzen <tim@kompiler.org> wrote:
>>> I've been spending some time the past few weeks implementing p0515r2,
>>> i.e. the proposal for consistent comparisons for C++ (aka the spaceship
>>> operator).
>>
>> Great!
>>
>>> I've received some very valuable help on the IRC channel, but
>>> I'm still a little bit stuck. Note, I'm completely new to the GCC
>>> codebase and am very much still getting oriented.
>>>
>>> Following advice from some of the people in IRC channel I implemented
>>> parsing the new token in libcpp and I seem to be successfully parsing it
>>> and creating a new AST node. As this feature is not in the C++ standard
>>> yet, I wanted to add a command line flag to enable usage of the new
>>> operator and ignoring it otherwise. I managed to get cc1plus to accept
>>> the parameter, but it seems that when I invoke my own g++ binary with
>>> that parameter, it complains about unknown parameters.
>>>
>>> I'm perfectly happy to dig further on my own, but I get the feeling I'm
>>> missing some documentation / resource somewhere that might help me out.
>>> Is there some documentation about adding and passing around parameters
>>> that will be used both in libcpp and the C++ front-end? What would be
>>> the best place to look to learn more about how part of GCC this is
>>> structured? I want to make sure I go about this correctly.
>>
>> There's a gccint.info documentation file, the Options node seems like
>> what you're looking for. You will want to add a new option to
>> c-family/c.opt.
>
> operator<=> is now in the working paper though, so does it need its
> own option? IMHO it should just be enabled for -std=c++2a and
> -std=gnu++2a, and not otherwise.
Ah, good point.
Jason