nestedFunctions()

Programming

nestedFunctions() is a MATLAB®-compatible programming function for a nested function is defined inside another function's body using a normal "function ... end" block. it closes over the enclosing function's local variables — reading them at call time and writing mutations back to the parent on return. only variables that already existed in the parent scope before the call are written back; new variables created inside the nested function remain local. formal parameters of the nested function shadow (but do not corrupt) identically-named parent variables. limitation: the nested function must be defined (its "function" line executed) before it is called; forward references are not supported. Run it online in your browser with SimLab — free, no install, no license required.

A nested function is defined inside another function's body using a normal "function ... end" block. It closes over the enclosing function's local variables — reading them at call time and writing mutations back to the parent on return. Only variables that already existed in the parent scope before the call are written back; new variables created inside the nested function remain local. Formal parameters of the nested function shadow (but do not corrupt) identically-named parent variables. Limitation: the nested function must be defined (its "function" line executed) before it is called; forward references are not supported.

function outer()
  count = 0;
  function increment()
    count = count + 1;
  end
  increment();
end

% Canonical counter — nested fn mutates parent local
function result = makeCounter()
  count = 0;
  function increment()
    count = count + 1;
  end
  increment();
  increment();
  result = count;  % 2
end
r = makeCounter()