Boston D Meetup: Strawman Structs

[Steven Schveighoffer via Digitalmars-d-announce]

On 7/25/17 6:15 AM, Nicholas Wilson wrote:
> On Tuesday, 25 July 2017 at 09:50:46 UTC, John Colvin wrote:
>> On Sunday, 2 July 2017 at 10:35:49 UTC, Steven Schveighoffer wrote:
>>> I'll have a short presentation on a weird trick I discovered while 
>>> writing some MySQL serialization code. Hope you can attend!
>>>
>>> https://www.eventbrite.com/e/d-lang-presentation-strawman-structs-tickets-35120523431 
>>>
>>>
>>
>> Is there a written summary of the idea? Or is there a specific point 
>> in the video someone could point me to?
> 
> Basically using structs to describe layouts (among other relations) and 
> in turn use that to drive DbI automated code. The DbI is the only "code" 
> the rest is declarative using the type system.
> 
> Steven was using it to describe what columns ( name and type) a query 
> should return from a DB and the using DbI to generate the Query.
> 

Not exactly :)

I wrote a database serializer that uses introspecting members, types, 
and attributes of a struct to correctly populate members of the struct 
with data from the rows. So yes, I'm using introspection, but only for 
the serialization, the query is hand-written.

In some cases (particularly when you are joining 2 tables that have 
conflicting columns), I needed to change how the serialization worked 
(e.g. the column names had to change).

In order to do this, I created descriptors that are built from the 
combination of attributes and other introspected items. Then my thought 
was I would pass in the descriptors directly in order to control how 
serialization works.

I found it unwieldy and difficult to write the low-level descriptors by 
hand. But I thought of making a dummy or strawman struct with all the 
attributes the way I wanted, and still serializing to the real struct. 
It worked really well.

I also go over some other possible ideas for using this concept. Start 
watching from here: https://youtu.be/ZxzczSDaobw?t=18m24s

Andrei suggested doing a blog article (and actually I had started 
writing one, but it turned into this talk instead). I'll probably still 
do this.

-Steve