I personally found that using inputParser is unnecessarily complicated. For Matlab, there are always three things to check: presence, type, and range / values. Sometimes you have to assign default values. Here is a sample code that is very typical of my error checking: dayofWeek is the argument, the third in the function. (Additional comments added.) Most of this code predates the existence of assert() in Matlab. I use assertions in my later code instead of if ... error() constructs.
%Presence if nargin < 3 || isempty(dayOfWeek); dayOfWeek = ''; end %Type if ~ischar(dayOfWeek); error(MsgId.ARGUMENT_E, 'dayOfWeek must be a char array.'); end %Range days = { 'Fri' 'Sat' 'Sun' 'Mon' 'Tue' 'Wed' 'Thu' }; %A utility function I wrote that checks the value against the first arg, %and in this case, assigns the first element if argument is empty, or bad. dayOfWeek = StringUtil.checkEnum(days, dayOfWeek, 'assign'); %if I'm this far, I know I have a good, valid value for dayOfWeek