Re: X3 employee example with semantic actions

On 06/03/2018 09:54 AM, Maarten Verhage wrote:
> Hi Larry,
> 
>>>
>>> The documentation page: "Annotations - Decorating the ASTs" makes use of
>>> the
>>> "position_tagged" base class for an ast. It claims to provide the
>>> positions
>>> into the input (with iterators) that corresponds to a given element in
>>> the
>>> AST.
>>
>> Could you provide a link to that page.  I tried scanning the main topics
>> here:
>>
>> https://www.boost.org/doc/libs/1_67_0/libs/spirit/doc/html/index.html
>>
>> and it's not obvious to me where this "Annotations - Decorating the ASTs"
>> page might be.
>>
> 
> I didn't realize I was on some "developers" documentation area of the
> boost.org website. I used google and that brought me here:
> 
> https://www.boost.org/doc/libs/develop/libs/spirit/doc/x3/html/index.html
> 
> I also tried the annotation.cpp file there but on my gcc 5.1.0 it did
> compile fine but the printing after
> "Here's the 2nd employee" is just empty. I think you will find that. I also
> did a printf in the on_success function and that was called 10 times which
> is correct I assume, so something else went wrong.
> 
>>>
>>> Maybe this does what I want. But I don't feel a need for an on_success
>>> function.
>>>
>>> I'm going to write a fresh message asking about this position_tagged and
>>> if
>>> I can use it without that concept of annotation which I still fail to
>>> understand what that means.
>>
>> Waiting for that.  I'm unfamiliar with position_tagged and would
>> appreciation some education ;)
>>
> 
> I'm glad you put ;) along with that because I do consider myself a novice in
> Spirit. I posted it already with the title:
> [Spirit-general] X3 iterators into the input for a matching rule

Strange, I don't see it yet here:

https://sourceforge.net/p/spirit/mailman/spirit-general/

Anyway, I tried a slight modification of the previous code where the 
ast::employee just contains begin/end iterators.  The code is posted
here:

   https://gist.github.com/cppljevans/0f4351f127c2e651d8094877a9510e5a

It uses the semantic actions to simply store the input iterator
into the non-terminal's attribute.  I've no idea whether
it's better than the position_iterator other than it's
simpler to understand, it seems to me.

> 
> Regards, Maarten
> 
> 
> 
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