Merging x*, w32* and mac* sources (was Re: table.el)

[Kim F. Storm]

Richard Stallman <address@hidden> writes:

>     Sharing code that should be shared is a good way to improve Emacs
>     for the end user because it ensures that when something gets
>     fixed it gets fixed at all the places where it's used.
> 
>     See src/w32*.c for examples,
> 
And mac/src/mac*.c to make matters even worse...

> That example supports my point.  It is desirable to share code between
> w32*.c and x*.c because that is a lot of code to share; therefore, a
> large benefit.  Meanwhile, the code already consists of subroutines,
> so the other code which calls this code to be shared won't need to
> change at all; therefore, one cost is small.
>
Having just gone through the pain of adding the fringe width code three
times with only minor differences -- primarily caused by the structuring
of the `output_data' union -- I couldn't agree more!
 
> The other cost is the complexity of conditionals added to the merged
> code.  I don't know what that will be, but I suspect it will be much
> smaller than the benefit.

I don't see why we can't keep the x*, w32*, and mac* files for the things
which are really different on those platforms (like the event dispatch loops,
specific display code, etc) and put the (almost) common code into com* files.

The com* files would contain some conditionals, but if we restructure the
output_data union, a lot of the existing differences will go away!

(I'm almost volounteering to do this, but currently I don't have the time).

-- 
Kim F. Storm <address@hidden> http://www.cua.dk