Eliminating some macros

[John W. Eaton]

I'm working on eliminating the macros that are generated by 
liboctave/operators/mk-ops.awk.

Currently, this script generates a set of header files that contain 
things like this

  // DO NOT EDIT -- generated by mk-ops.awk
  #if ! defined (octave_mx_cm_m_h)
  #define octave_mx_cm_m_h 1
  #include "octave-config.h"
  #include "CMatrix.h"
  #include "dMatrix.h"
  #include "mx-op-decl.h"
  MM_BIN_OP_DECLS (ComplexMatrix, ComplexMatrix, Matrix, OCTAVE_API)
  MM_CMP_OP_DECLS (ComplexMatrix, Matrix, OCTAVE_API)
  MM_BOOL_OP_DECLS (ComplexMatrix, Matrix, OCTAVE_API)
  #endif

to provide declarations of operators for mixed-type operations on 
nd-array/matrix/sparse-matrix/vector/scalar objects of various types 
(complex, real, integer).  It also generates a corresponding set of 
source files that look like this

  // DO NOT EDIT -- generated by mk-ops.awk
  #if defined (HAVE_CONFIG_H)
  #  include "config.h"
  #endif
  #include "Array-util.h"
  #include "mx-cm-m.h"
  #include "mx-op-defs.h"
  #include "boolMatrix.h"
  #include "boolNDArray.h"
  #include "CMatrix.h"
  MM_BIN_OPS (ComplexMatrix, ComplexMatrix, Matrix)
  MM_CMP_OPS (ComplexMatrix, Matrix)
  MM_BOOL_OPS (ComplexMatrix, Matrix)

to provide the actual function definitions.  My plan is to

  * Use templates instead of macros to define the functions.

  * Change the script to generate the declarations directly instead of 
using macros.

  * Preserve the non-template function signatures using inline 
functions in the header files.  These can be deprecated and eventually 
removed.  Octave itself will be fixed to use the templates directly.

  * Wrap all the functions in the octave::numeric namespace.

Questions:

  * Should the header file that declares the templates also provide the 
template definitions, or should we hide those and only instantiate these 
templates for the types we care about?  Will the build be faster if we 
use extern templates and explicit instantiation of just the templates we 
need?

  * If we choose explicit instantiation for only the types we need, 
should we continue to use a script to generate these files or should we 
just move a copy of the generated sources to the source tree and 
eliminate the script, adding new variants by hand?  (If the definitions 
are all in the header and we don't use explicit instantiation, then we 
can just eliminate the source files and script, but compiling/linking 
might be slower).

Comments?

jwe