Why not all statement are expressions ?

[Timon Gehr]

On 05/08/2012 10:46 AM, Don Clugston wrote:
> On 07/05/12 19:06, deadalnix wrote:
>> Hi,
>>
>> Working on D I noticed that some statement, notably assert, are
>> expression of type void. Why not all statement (that are not expression
>> already) are expression ?
>
> assert isn't a statement. It's an expression ( same as is() ). What
> makes you think it's a statement?
>
> The main use for a void expression is so that it can be used in a comma
> expression; this is why assert is an expression.
>
> The curious thing, which may be the source of the confusion, is that
> static assert() is a statement, while assert() is an expression. Maybe
> static assert should also be an expression rather than a statement?

static assert is a declaration.