Re: Is variable void?
On Tuesday, 28 November 2017 at 05:10:39 UTC, bauss wrote: null != void also...void is a completely useless concept for initialisation. what can you determine about the nothingness of void? ... nothing. writeln(typeof(void).stringof); // ?? what do I know now? nothing. vs Nullable!int x; writeln(typeof(x).stringof); // Nullable!int .. now I know something.
Re: Is variable void?
On Tuesday, 28 November 2017 at 05:10:39 UTC, bauss wrote: null != void "initialized or not?" != void
Re: Is variable void?
On Monday, 27 November 2017 at 02:12:40 UTC, codephantom wrote:
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);
}
// --
null != void
Re: Is variable void?
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);
}
// --
Re: Is variable void?
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? You can use Nullable!int
Re: Is variable void?
On Saturday, 25 November 2017 at 15:38:15 UTC, Adam D. Ruppe wrote: nope. It'd be indistinguishable from the user just happening to initialize it to some random value. Thanks. I'll got with .init instead.
Re: Is variable void?
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: nope. It'd be indistinguishable from the user just happening to initialize it to some random value.
Re: Is variable void?
On 25/11/2017 3:34 PM, 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? `` = void;`` isn't null. Don't treat it as such. It is a low level detail where you _will_ initialize it, just in a smarter way. There is no conditions tied directly to it.
Is variable void?
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?
