On 01/04/2012 12:31 AM, Jonathan M Davis wrote:
On Tuesday, January 03, 2012 17:41:12 simendsjo wrote:
I guess this is as designed, but I'll ask anyway.
http://dlang.org/operatoroverloading.html#Cast says an expression is
rewritten to opCast "whenever a bool result is expected".
This is true for
if(e) somethingElse
and e&& somethingElse
, but not for other parts.
assert(cast(bool)e == true); // explicit cast works
assert(e == true); // Error: incompatible types for ((s) == (false)):
'S' and 'bool'
is(typeof(e) : bool); // false
Yeah. It's the same for built-in types. Take arrays and pointers for example.
They don't implicitly convert to bool, but when you use them in a condition,
they implicitly convert to bool (true if they're non-null, false if they're
null). If you want implicit conversion in general, then you need to use alias
this.
- Jonathan M Davis
The conversion is explicit. if(x) is rewritten to if(cast(bool)x) and e
&& somethingElse is rewritten to cast(bool)e && cast(bool)somethingElse.
