On 08/08/2017 08:34 PM, Johan Engelen wrote:
How would you express the function interface intent that a reference
to a class may not be null?
For a function "void foo(Klass)", calling "foo(null)" is valid. How do I
express that that is invalid? (let's leave erroring with a compile error
aside for now)
Something equivalent to C++'s pass by reference: "void foo(Klass&)".
A contract might be the best you can do:
----
void foo(Klass k)
in { assert(k !is null); }
body {}
----
Or throw an exception.
(note: I mean D classes, for structs "ref" works)
But you can pass null in a ref parameter:
----
void f(ref int x) @safe {}
void main() @safe
{
int* p = null;
f(*p);
}
----
