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Given a named function, how can I call this function, and not the subfunction of the same name?

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My function is passed the name of a function (as a string). It just so happens that my function contains a subfunction of that name. I want to make sure I call the external function, instead of the subfunction. How can I achieve this?
E.g. save the following in test.m:
function test
feval(evalin('base', 'str2func(''help'')'), 'help');
end
function varargout = help(varargin)
error('Should not get here!');
[varargout{1:nargout}] = deal([]);
end
Then calling test gives:
>> test
Error using test>help (line 6)
Should not get here!
Error in test (line 2)
feval(evalin('base', 'str2func(''help'')'), 'help');

  1 Comment

Oliver Woodford
Oliver Woodford on 29 May 2015
I would say what I'm seeing is unexpected behaviour. Also, putting
evalin('base', 'which(''help'')')
as the first line in the help subfunction gives:
C:\....\test.m (help) % Subfunction of test
which is unexpected too.

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Accepted Answer

Titus Edelhofer
Titus Edelhofer on 29 May 2015
Oliver,
what about this:
feval(evalin('base', '@(x) help(x)'), 'help')
This works fine. And as you noted yourself, using {:} you can expand the input variable as cell array.
Titus

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More Answers (2)

Philip Borghesani
Philip Borghesani on 29 May 2015
Edited: Philip Borghesani on 29 May 2015
There is a much simpler solution to this:
function fh=test
fh=str2func('@(x) help(x)');
fh('help')
end
...
str2func isolates any anonymous function created from the surrounding environment see Loren's Blog

  1 Comment

Oliver Woodford
Oliver Woodford on 30 May 2015
Nice! Thanks, Phil. I find it bizarre that str2func finds a different function depending on whether you use the anonymous function syntax or just the function name, though.

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Titus Edelhofer
Titus Edelhofer on 29 May 2015
Hi Oliver,
although this is not an answer to your question it might help anyway: this is one of the reasons to use function handles instead of strings denoting functions. The big advantage of a function handle is, that the function is determined in the moment the function handle in contrast to strings, where in the moment of evaluation the dispatching happens.
If you pass @help instead of 'help' to your function as input, you are sure, that the correct function is used.
Titus

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Show 2 older comments
Titus Edelhofer
Titus Edelhofer on 29 May 2015
Oliver,
what about this:
feval(evalin('base', '@(x) help(x)'), 'help')
This works fine. The "only" drawback: you need to know the number of input and output variables to build up the string ...
Titus
Oliver Woodford
Oliver Woodford on 29 May 2015
The unlikely function name thing is a workaround which I can use. I'm hoping I won't need to, though. I can use the solution above :). Although the number of input arguments aren't known, I can put them in a cell array:
feval(evalin('base', '@(x) help(x{:})'), {'help'})
If you make it an answer I'll accept it.
Alfonso Nieto-Castanon
Alfonso Nieto-Castanon on 29 May 2015
couldn't you use:
feval(evalin('base','@(varargin) help(varargin{:})'),'help')
to account for variable number of inputs?

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