Location of the "end" statement of the main function in a m. file?

Hello,

could someone write what is the difference between possible location of the "end" statement of the main function: before first local function vs end of a file? What is the difference?

For example: first vs. second case in this answer.

Thank you!

Marek

Answer 1

[Stephen23]

"before first local function"

any functions defined after the main function are local functions:

https://www.mathworks.com/help/matlab/matlab_prog/local-functions.html

"vs end of a file?"

any functions defined within the main function are nested functions:

https://www.mathworks.com/help/matlab/matlab_prog/nested-functions.html

These can be combined too, e.g.:

function mymain()
... code
    function mynest()
        ... code
    end % mynest()
end % mymain()
function mylocal()
... code
end % mylocal()

Nested functions have access to the parent function's workspace. Local functions do not.

Read more here: https://www.mathworks.com/help/matlab/matlab_prog/types-of-functions.html

[Marek Gradzki]

Ok, right, thanks! So I guess the main difference is about access to the variables defined in the main function.

Answer 2

[Sudheer Bhimireddy]

If you have 'end' at the end of a file, then your functions become 'Nested functions'. The variables created inside the function and their scope changes.

Read this, this and this MATLAB documentation.

Hope this helps.

[Marek Gradzki]

Yes, thanks! However, I do not understand the last sentence from the last link:

"All of the variables in nested functions or the functions that contain them must be explicitly defined. That is, you cannot call a function or script that assigns values to variables unless those variables already exist in the function workspace".

Could you give any simple example of this "forbidden situation" (when it does not work properly)?

[Bruno Luong]

function caller
a = 1;
    function c = foo(d)
        eval('b = d;'); % error "forbidden"
        c = a + b;
    end

    function c = bar(d)
        b = [];
        eval('b = d;'); % OK
        c = a + b;
    end
fprintf('bar(2) = %g\n', bar(2));
fprintf('foo(2) = %g\n', foo(2)); % this won't run
end

[Marek Gradzki]

Ok, thank you!