note about the design of mx-op-defs.h

[John W. Eaton]

On 16-Feb-2009, Jaroslav Hajek wrote:

| during my recent job optimizing the reduction functions, I couldn't
| help noticing that any change within mx-inlines.cc triggered a
| horrible compilation cascade in which more than half of liboctave and
| liboctinterp was recompiled. Tracking the reason I found that
| mx-inlines.cc is #included in mx-op-defs.h and this is in turn
| included in many header files to provide declarations for various
| operations.
| For future development, it would be much better to separate the
| declarative and executive parts of mx-op-defs.h and MArray-defs.h (and
| more?). I bet this would also speed-up the compilation significantly.
| Almost certainly not worth doing for 3.2, but rather a suggestion for
| future 3.4/4.0 project.
| Right now Octave compiles IMHO quite slowly. Although slow compilation
| is kind of typical for C++, I still think that we could improve this
| somewhat by sorting out issues like the above.

I have no objections to doing this and would even consider doing it
for 3.2 since it should be a fairly straighforward change.

jwe