rename octave_value value extractors that accept error message args * ov.h, ov.cc (octave_value::xcell_value, octave_value::xstring_value, octave_value::xcellstr_value): Rename functions that accept error message args. Handle error directly. Only forward to functions that don't attempt type conversion. Change all uses. * ov-base.h, ov-base.cc (octave_base_value::xstring_value): Don't do type conversion. (octave_base_value::cell_value, octave_base_value::cellstr_value): Delete versions that accept error message args. * ov-str-mat.h, ov-str-mat.cc (octave_char_matrix_str::string_value, octave_char_matrix_str::cell_value): Delete.

--- a/libinterp/corefcn/conv2.cc	Thu Nov 12 19:27:25 2015 -0800
+++ b/libinterp/corefcn/conv2.cc	Fri Nov 13 14:10:26 2015 -0500
@@ -329,7 +329,7 @@
       return retval;
     }
   else if (nargin == 3)
-    shape = args(2).string_value ("convn: SHAPE must be a string");
+    shape = args(2).xstring_value ("convn: SHAPE must be a string");
 
   if (shape == "full")
     ct = convn_full;