Editing Nested function (section)

=== Functions as values ===

In order for local functions with [[lexically scoped]] [[non-local variable|nonlocals]] to be passed as results, the language runtime code must also implicitly pass the environment (data) that the function sees inside its encapsulating function, so that it is reachable also when the current activation of the enclosing function no longer exists.<ref>Such a combination of function code and its environment is sometimes called a [[Closure (computer programming)|closure]].</ref> This means that the environment must be stored in another memory area than (the subsequently reclaimed parts of) a chronologically based execution stack, which, in turn, implies some sort of freely [[dynamic memory allocation]]. Many older Algol based languages (or dialects thereof) does therefore not allow local functions that access nonlocals to be passed as return values, or do they not allow functions as return values at all, although passing of such functions as arguments may still be possible.