Re: Any easy/build-in construct to extract submatrices from larger matrix?

[Jerry <lanceboyle@qwest.net>]

Most submatrix needs, including Nasser's example, can be handled by
slices (or slice syntax--not sure what the difference is). Boolean
masks would not often be needed.

Why doesn't Ada provide this? It seems that one of the Ada design
principles has been to build in commonly used features rather than
force the user to write them, setting up the greater possibility of
mistakes and inefficiencies. Slices exist for 1D arrays; why not for
>1D arrays?

The reverse operation, composition, is also useful. In Matlab/Octave
(assuming compatible sizes):
C = [A, B] makes A B
and
D = [A; B] makes
  A
  B
and
[0, 0, 0, A; B, 0, 0, 0] makes
   0   0   0   A
   B   0   0   0
etc.

Which brings me to one of my least favorite Ada features, the use of
() instead of [] for array indices. Talk about a readability killer.
But I'm sure that's been beat to death many times. (No, it's not
because [] are not part of ASCII.)

Jerry