Re: Shrinking EIEIO objects

[Eric Ludlam]

On 12/30/2014 12:59 PM, Stefan Monnier wrote:
> Hi Eric,
>
> I'd like to install something like the patch below into Emacs's master.
> What it does (along with various other side changes) is shorten the
> object header from 3 fields (the constant `object', the class name, and
> an object "name" field) to just one (an interned symbol with an "eieio-"
> prefix, referring to the class object).

This seems like a fine idea.  A side effect is that the 'name' slot is 
gone.  There have received a questions about why there is a 'name' for 
objects, and really the main thing was debugging.  When you have piles 
of objects around, naming them makes it much easier to see what is going 
on.   EIEIO objects have a short hand using a #<class name> format, and 
when the various prin1 tools are enabled for edebug, that short hand is 
used in place of the vector.  This is critical when debugging semantic 
databases where the vectors contain thousands of symbols.

Your proposed solution will enable the current source forge hosted 
version of CEDET to keep going, just with warning messages, which seems 
fine.

I can convert the sourceforge version CEDET to use make-instance 
instead, which should be compatible before and after your change.  Note 
that your patch still needs to update the doc string (and presumably the 
.texi file) for make-instance as the old notes about compatibility will 
no longer be relevant.

> Among the side things it does, I'd mention:
> - add "eieio--" prefixes to a few more entities.
> - use hashtables rather than obarrays.
> - use closures instead of backquoted lambdas.
> - use call-next-method in the various definitions of `clone'.
> - redirect defmethods when called on an alias.
> - use class objects (vectors) rather than class names (symbols) at more places.

These all seem like good things too.

While reading through the patch, there was a bunch of changes related to 
doc strings and methods.  The goal was if you used help on a method, 
such as:

C-h f constructor RET

(or eieio-constructor in your patch)

it should list the core doc (generic) and doc for every class that has 
it's own implementation and custom doc.  I couldn't intuit from the 
patch what might happen as some of the doc strings looked like they were 
removed?

I hope this helps.
Eric