typeof and block statements

[simendsjo]

On 12.08.2010 16:19, Steven Schveighoffer wrote:
> On Thu, 12 Aug 2010 09:56:07 -0400, simendsjo
> <simen.endsjo at pandavre.com> wrote:
>
>> On 12.08.2010 15:30, Steven Schveighoffer wrote:
>>> On Thu, 12 Aug 2010 09:13:54 -0400, simendsjo
>>> <simen.endsjo at pandavre.com> wrote:
>>>
>>>> The spec doesn't mention anything about block statements in typeof
>>>> declarations.
>>>>
>>>> //typeof({1}) a; // found } expecting ;
>>>> //typeof({1}()) b; // same as a
>>>> typeof(1) c; // int
>>>
>>> {...} is a function literal, a lambda function if you will.
>>
>> I thought parameterless delegates were written () {}..
>>
>>> Your lambda function contains a syntax error, the single line in it does
>>> not end in a semicolon.
>>>
>>> Of course, if you made it:
>>>
>>> {1;}
>>>
>>> I think it might fail anyways, because 1; is not a statement.
>>
>> Why doesn't this work then?
>> typeof({return 1;}()) a; // found 'a' when expecting ';' following
>> statement
>
> First, this compiles for me. Not sure why it doesn't for you.
>
> Second, stringof is your friend. Coupled with pragma(msg, ...) It allows
> you to "view" the type of an expression at compile time:
>
> pragma(msg, typeof({return 1;}()).stringof);
>
> Which when compiled on dmd 2.047 linux, prints:
>
> int
>

Tested with dmd 2.048 on win7.

pragma(msg, "module:"~typeof({return 1;}()).stringof);

void main()
{
	pragma(msg, "main:"~typeof({return 1;}()).stringof);
	//typeof({return 1;}()) a; // found 'a' when expecting ';' following 
statement
}

prints
module:int
main:int



>>> I see a syntax error there, r.popFront is not a property, so it should
>>> look like this:
>>>
>>> r.popFront();
>>>
>>> It only works right now because mandatory () for non-properties is not
>>> implemented in the compiler yet.
>>
>> So once this is implemented, this template is always false?
>
> Once mandatory parens for non-properties is implemented, the code will
> be changed to r.popFront();
>
> -Steve