使用inputParser类验证默认参数

Question

The inputParser class in Matlab is very useful to synthetically check arguments passed by users when calling some function. For instance:

function [] = TestValidation(varargin)
%[
    p = inputParser();
    p.addParameter('Toto', 'Hello', @isnumeric);

    p.parse(varargin{:});
%]
end

Will raise an error if user attempt to assign a non numeric value to the parameter Toto (eg TestValidation('Toto', 'Hello') ==> raises an error because Hello is not a numeric).

Anyhow calling above function without parameters (ie TestValidation() ), there is no error raised even if default value for Toto is a string (ie Hello ).

Is there a simple way to force inputParser to validate also for default values or can it be done only manually and a posteriori ?

Answer 1

It's a class, create a subclass which implements the functionality you want:

classdef myInputParser<inputParser
    methods
        function addParamValue(obj,name,default,fcn,varargin)
            assert(fcn(default));
            addParamValue@inputParser(obj,name,default,fcn,varargin{:});
        end
    end 
end

.

>> p = myInputParser();
>> p.addParamValue('Toto', 'Hello', @isnumeric);
Error using myInputParser/addParamValue
(line 4)
Assertion failed.