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/libinterp/octave-value/ov-struct.cc
+++ b/libinterp/octave-value/ov-struct.cc
@@ -2066,9 +2066,9 @@
   return retval;
 }
 
-DEFUN (nfields, args, ,
+DEFUN (numfields, args, ,
        "-*- texinfo -*-\n\
-@deftypefn {Built-in Function} {} nfields (@var{s})\n\
+@deftypefn {Built-in Function} {} numfields (@var{s})\n\
 Return the number of fields of the structure @var{s}.\n\
 @seealso{fieldnames}\n\
 @end deftypefn")