Re: Horrible compiletimes and memory usage while compiling a parser with X3

On 11/13/2016 07:50 AM, Larry Evans wrote:
> On 11/07/2016 02:44 AM, Peter Gerell wrote:
>> On 07/11/2016 12:38 PM , Joel de Guzman wrote:
>>> On 07/11/2016 1:26 AM, Mikael Asplund wrote:
>>>> This is the reason we're still on 1.60 (with a small
>>>> const-patch from 1.61), since later version have link problems which are just too hard
>>>> to debug.
>>
>>> It would be great if you post a test file that exhibits this problem you mention.
>>> This linking problem doesn't look good and must be fixed.
>>
>> Hi Joel.
>> This is the problem Mikael is referring to.
>> http://melpon.org/wandbox/permlink/X8Awj4wIZ2JqMWIw
>>
>> If KEEP_CHAR is defined the code builds with both boost 1.60 and 1.61.
>> Without KEEP_CHAR it fails with 1.61.
>>
>> The following commit introduced the problem.
>> https://github.com/boostorg/spirit/commit/a8e391bd99dddb3f9ece84bdb1bb9236b0a37cf7
>>
>> The problem seems to be that the attribute types are short-circuited for sequences of one
>> even though we explicitly request a specific binding using FUSION_DEFINE_FOR_STRUCT(ast::Start, count);
> [snip]
>
> More specifically, the change on line 178 causes the
> problem.
[snip]
> Why not revert the change on detail/sequence.hpp:178 to
> solve the problem?

Or instead of:

https://github.com/boostorg/spirit/blob/boost-1.61.0/include/boost/spirit/home/x3/operator/detail/sequence.hpp#L178

why not make the bool value dependent on whether R is *not* a rule?
A similar change would be made to:

https://github.com/boostorg/spirit/blob/boost-1.61.0/include/boost/spirit/home/x3/operator/detail/sequence.hpp#L198

WARNING: not tested.

-Larry




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