minimal evaluation

[downs]

Qian Xu wrote:
> Hi All,
> 
> Is minimal evaluation always enabled in D?
> 
> I want to write a function IsNull(), so that I can check the precondition as
> follows:
> 
>   if (isNull(foo) ||
>       isNull(foo.getBar) ||
>       isNull(foo.getBar.getBar2)
>   {
>     return false;
>   }
>   // normal code goes here
> 
> If an argument is null, the IsNull() will return false. Internally it will
> be logged to console as well.
> 
> But I am not sure, if dmd-compiler generates code without minimal evaluation
> in some cases. If minimal evaluation is not always enabled. I cannot do
> precodition check in my way. 
> 
> --Qian

Short-circuit evaluation is always enabled.

http://digitalmars.com/d/1.0/expression.html#OrOrExpression

"If the left operand, converted to type bool, evaluates to true, then the right operand is not evaluated."