Re: [PATCH] decorate: clean up and document API

From: Jonathan Tan <jonathantanmy@google.com>
Date: Dec 11, 2017, 18:32 UTC
Message-ID: <20171211103249.e34385be4688734442659e71@google.com>
In-Reply-To: <20171208095510.GA29626@sigill.intra.peff.net>

On Fri, 8 Dec 2017 04:55:11 -0500 Jeff King <peff@peff.net> wrote:

Show 17 quoted lines

> I have mixed feelings. On the one hand, compiling and running the code
> ensures that those things actually work. On the other hand, I expect you
> can make a much clearer example if instead of having running code, you
> show snippets of almost-code.
> 
> E.g.:
> 
>   struct decoration d = { NULL };
> 
>   add_decoration(&d, obj, "foo");
>   ...
>   str = lookup_decoration(obj);
> 
> pretty much gives the relevant overview, with very little boilerplate.
> Yes, it omits things like the return value of add_decoration(), but
> those sorts of details are probably better left to the function
> docstrings.

The part about iterating over all entries should probably also be shown too. Besides that, I'm OK with having a simplified example in documentation too, but I'll wait and see if others have any opinions before making any changes.

Show 7 quoted lines

> Other than that philosophical point, the documentation you added looks
> pretty good to me. Two possible improvements to the API we could do on
> top:
> 
>   1. Should there be a DECORATION_INIT macro (possibly taking the "name"
>      as an argument)? (Actually, the whole name thing seems like a
>      confusing and bad API design in the first place).

Agreed about the "name" thing. I'll add a DECORATION_INIT when I make the next reroll, but I think that having it with no argument is best (and instantiating "name" with NULL).

>   2. This is really just an oidmap to a void pointer. I wonder if we
>      ought to be wrapping that code (I think we still want some
>      interface so that the caller doesn't have to declare their own
>      structs).

It is slightly different from oidmap in that this uses "struct object *" as a key whereas oidmap uses "struct object_id", meaning that a user of "decorate" must already have objects allocated or be willing to allocate them, whereas a user of "oidmap" doesn't.

Having said that, it is true that perhaps we have too many data structures doing similar things.