On Saturday, 25 November 2017 at 15:34:21 UTC, John Chapman wrote:
Is there any way of determining whether a variable has been
initialized or not? For example, if something is declared like
this:
int x = void;
can I check if it's void before I use it, say, in a function
it's been passed to?
// ----------------------------------
module test;
import std.stdio;
import std.typecons; // see:
https://dlang.org/phobos/std_typecons.html#Nullable
void main()
{
Nullable!int x; // requires: import std.typecons
assert(x.isNull);
writeln("x is ", x);
x = 1;
assert(!x.isNull);
writeln("x is ", x);
x.nullify(); // Forces x back to a null state.
assert(x.isNull);
writeln("x is ", x);
}
// ----------------------------------
