How to dynamically execute code stored in a string variable

I do a small toolbox to ease ODE simulation. The script until now works well like this:

(example)

ev1 = @(T,Y)ev1(T,Y,a);
options = odeset('Events',ev1,... ...);

But given that the script should read plenty of event functions and make a list for a pop-up so the user could select them easy, I want it to check in a certain folder for all the files that are functions. The user will simply create the files like this:

% eventFile @(T,Y)ev1(T,Y,...other parameters...);
function [value,isterminal,direction+ = .... ....
      ... ...
end

the program would read the first line of all the files and if it finds eventFile keyword will save the @(T,Y.....; in a string. Can this string be converted or be used to construct an object like this: ev1 = @(T,Y)ev1(T,Y,a); so I can put it in the odeset 'Event' parameter, just like ev1 in the first example?

If you think this could be done in a different way and I should completely change my plans please tell me.

I tried to make this short and clear, but if I wasn't clear enough, tell me and I will try to explain my problem better.

Later edit: the previous title was "How can I convert a strings like "@(T,Y)event(T,Y,a)" in a function object just like ev = @(T,Y)event(T,Y,a);"

Answer 1

[per isakson]

"an object like this ev1 = @(T,Y)ev1(T,Y,a); " &nbsp that is an Anonymous Functions

Try

    >> ev1 = @(t,y) fprintf('ev1: %d, %d\n', t, y )
    >> str = '@(T,Y) ev1(T,Y)';
    >> foo = eval( str );
    >> foo(1,2)

returns

    ev1: 1, 2

[mihai]

Thank you! This eval function is amazing... I didn't expected it to exist.

Now, I know the question I made is not so general.. should I edit it? Any advice for a better title?

[per isakson]

I think this is a justifiable use of &nbsp eval. &nbsp However, it should be the used only as a last resort.

• Why is it advised to avoid using the "eval" function?
• Alternatives to the eval Function

Maybe, "How to dynamically execute code stored in a string variable" would be a better title.