Deprecate nfields and replace with numfields. * NEWS: Announce deprecation of nfields and addition of new function numfields. * container.txi: Add numfields to the manual. * oct-map.cc (octave_map::cat): Change %!tests to use numfields. * ov-struct.cc (Fnumfields): Function renamed from nfields. * scripts/deprecated/nfields.m: Add m-file which warns about nfields deprecation. * scripts/deprecated/module.mk: Add nfields.m to build system. * fieldnames.m: Change seealso link to point to numfields. * __isequal__.m: Use numfields to simplify code. * imwrite.m: Replace 'isempty (fieldnames (fmt))' with 'numfields (fmt) > 0' for clarity. * imageIO.m: Replace 'isempty (fieldnames (fmt))' with 'numfields (fmt) > 0' for clarity. * importdata.m: Use numfields to simplify code. * assert.m: Use numfields to simplify code.

--- a/scripts/image/imwrite.m	Sat Mar 01 22:11:32 2014 -0800
+++ b/scripts/image/imwrite.m	Sun Mar 02 12:56:11 2014 -0800
@@ -100,7 +100,7 @@
   fmt = imformats (ext);
   ## When there is no match, fmt will be a 1x1 structure with
   ## no fields, so we can't just use `isempty (fmt)'.
-  if (isempty (fieldnames (fmt)))
+  if (numfields (fmt) > 0)
     if (isempty (ext))
       error ("imwrite: no extension found for %s to identify the image format",
              filename);