On Monday, 11 February 2013 at 18:59:37 UTC, Johannes Pfau wrote:
When debugging gdc I've found some at least for me interesting
behavior which I'm trying to understand now:
----
auto testFunction() {
int a = 41;
int nestedFunc() { return ++a; }
struct NestedStruct {
int answer() { return nestedFunc(); }
}
return NestedStruct();
}
writeln(testFunction().answer());
----
This is valid D code, creates a closure.
----
class testClass
{
int a = 41;
int nestedFunc() { return ++a; }
struct NestedStruct {
int answer() { return nestedFunc(); }
}
auto getStruct() { return NestedStruct(); }
}
writeln((new TestClass()).getStruct().answer);
----
This does not compile:
test.d(33): Error: this for nestedFunc needs to be type
testClass not
type NestedStruct
Is this intended? It seems to be very similar to the function
closure
code. Couldn't NestedStruct just get a pointer to the testClass
to
access its variables? Or am I missing something?
Everything works fine if NestedStruct is a class and not a
struct so I
guess this functionality was disabled deliberately. But why?
And why
wasn't using a nested struct in functions in a similar way
disallowed as
well?
I recently wrote an article partly on this topic which may be of
interest to you. Apologies if it is not. See part one: neutrons.
http://forum.dlang.org/thread/[email protected]
