• "Janice Caron" <caron800 googlemail.com> Nov 30 2007
• "Stewart Gordon" <smjg_1998 yahoo.com> Nov 30 2007
• Matti Niemenmaa <see_signature for.real.address> Nov 30 2007
• "Stewart Gordon" <smjg_1998 yahoo.com> Dec 06 2007

"Janice Caron" <caron800 googlemail.com> writes:

This no longer works in D2.008.

    struct A
    {
        void f() {}

        static assert(is(f));
    }

    void main()
    {
        A a;
    }

Under D2.007, the static assert would pass, because f exists. In
D2.008, the static assert fails. Why?

More importantly, how do I test that a function exists in D2.008?

"Stewart Gordon" <smjg_1998 yahoo.com> writes:

"Janice Caron" <caron800 googlemail.com> wrote in message 
news:mailman.195.1196435027.2338.digitalmars-d puremagic.com...
 This no longer works in D2.008.

    struct A
    {
        void f() {}

        static assert(is(f));
    }


 Under D2.007, the static assert would pass, because f exists.


Because f exits?  How did you come to that conclusion?  I thought the 
halting problem was unsolvable.

 In D2.008, the static assert fails. Why?


Because a bug has been fixed.  To evaluate to true, IsExpression requires 
that its operand is a semantically valid _type_.

 More importantly, how do I test that a function exists in D2.008?


static assert(is(typeof(f) == function));

(tested only on 1.023 and 2.007 to date)

Stewart.

-- 
My e-mail address is valid but not my primary mailbox.  Please keep replies 
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Matti Niemenmaa <see_signature for.real.address> writes:

Stewart Gordon wrote:
 Under D2.007, the static assert would pass, because f exists.


 Because f exits?  How did you come to that conclusion?  I thought the
 halting problem was unsolvable.


Exists, not exits.

 In D2.008, the static assert fails. Why?


 requires that its operand is a semantically valid _type_.
 
 More importantly, how do I test that a function exists in D2.008?


 static assert(is(typeof(f) == function));


static assert (is(typeof(f)); should suffice.

-- 
E-mail address: matti.niemenmaa+news, domain is iki (DOT) fi

"Stewart Gordon" <smjg_1998 yahoo.com> writes:

"Matti Niemenmaa" <see_signature for.real.address> wrote in message 
news:fipf8u$2ro$1 digitalmars.com...
 Stewart Gordon wrote:
 Under D2.007, the static assert would pass, because f exists.


 Because f exits?  How did you come to that conclusion?  I thought the
 halting problem was unsolvable.


 Exists, not exits.


Oops.

<snip>
 More importantly, how do I test that a function exists in D2.008?


 static assert(is(typeof(f) == function));


 static assert (is(typeof(f)); should suffice.


That depends on whether it should be allowed that f exists but isn't a 
function.

Stewart.

-- 
My e-mail address is valid but not my primary mailbox.  Please keep replies 
on the 'group where everybody may benefit.