On Monday, 20 November 2017 at 06:24:31 UTC, Tobias Müller wrote:
Timon Gehr <timon.g...@gmx.ch> wrote:
I wish there was a null for int types.
AFAIU, C# will now have 'int?'.
C# had 'int?' (nullable value types) for ages.
The new thing is explicitly nullable classes (reference types).
I'm really
looking forward to use those.
int? is just syntactic sugar for Nullable<int>. It has been
around since 2005. Nullable<T> is just a struct with an
implementation similar to Nullable!T from D's std.typecons
This topic is about a new C# feature called "nullable reference
types":
1. if you declare SomeClass x, x is assumed to *not hold null
values*, that means that when you try "x = null" or x ="
somepossiblenullvalue", this will result in a compiler warning:
"Warning, x is supposed to hold a value" The warning can be
avoided by using "x = null!" or "x = somepossiblenullvalue!"
2.if you declare SomeClass? x, x is allowed to *hold null
values*, meaning that if you try "x.someFunction()", this will
result in a compiler warning: "Warning, x can be null". The
warning can be avoided in two ways:
2a. test for null: "if (x != null) { x.someFunction(); }"
2b. show the compiler that you know better:: x!.someFunction()
In fact, this is the introduction of a new operator "!", probably
named "I know better" operator.
