On Sunday, 29 October 2017 at 20:37:21 UTC, bauss wrote:
On Sunday, 29 October 2017 at 20:15:41 UTC, Ola Fosheim Grøstad
wrote:
[...]
But casting to bool is what you use to tell whether something
is valid or not.
true = valid, false = invalid.
If you want 0 to be valid for a type then you wrap around it
with opCast.
Ex.
---
import std.stdio;
struct MyInt
{
int value;
bool opCast(T : bool)()
{
return value >= 0;
}
}
void main()
{
MyInt a = MyInt(1);
MyInt b = MyInt(0);
MyInt c = MyInt(-1);
if (a) writeln("a is valid");
if (b) writeln("b is valid");
if (c) writeln("c is valid");
}
---
Output:
a is valid
b is valid
TL;DR
This could be done by maybe monad.
int? a = 0;
if (a) writeln("a is valid");
BTW: Thanks for implementing the Elvis feature.
