Re: Any exceptions for the 15-line rule?

[Dmitry Gutov]

On 05.05.2013 9:02, Stefan Monnier wrote:
> > > -    (with-temp-buffer
> > > +        (buf (get-buffer-create "*clang-output*"))
> > > +    (with-current-buffer buf (erase-buffer))
> > > +    (with-current-buffer buf
> > So, I've merged the patch into Git repo with some modifications, but looks
> > like the above change is perfectly justified: the new code uses
> > call-process-region', which takes the region from the current buffer, so
> > using it with `with-temp-buffer' doesn't seem possible.
>
> I must be missing something because I don't see why that
> changes anything.

Before, we were just calling `call-process', which uses one buffer, for 
stdout. So we created a temp buffer, collected program output in it, 
parsed that into our data structures and the buffer could be discarded.

Now, `call-process-region' needs two buffers, for stdin and stdout. That 
means that the current buffer has to be the buffer the user's editing, 
or at least contain its contents.

So we could, I guess, save (buffer-string) to a local var, switch to a 
temp buffer, insert it and then call `call-process-region' with non-nil 
DELETE argument (or save the current point value to start parsing output 
from it), but this may be slow for large files (not sure), and using a 
separate names buffer for output is more natural.

And using `with-temp-buffer' to create a non-current buffer (for output) 
is trickier: save current buffer to a local var, `with-temp-buffer', 
save *that* buffer in another `let', use `with-current-buffer' with the 
first var, and then pass the second var to `call-process-region'.