Walter Bright wrote:
> Template and complex number fixes. New name demangler!
> 
> http://www.digitalmars.com/d/changelog.html
> 

A question: When are the implicit template properties supposed to apply? There's a interesting corner case involving properties of built-in types.

With the code

template q()
{
   const char [] q = "abc";
}

const int a = q!().length;

does not compile. Fair enough, it's looking for q!().length, not q!().q.length.

Although potentially the rule for evaluating a!().b could be: look for a!().b, if not found, look for a!().a.b
I don't think this recurses, even if a!().a was a template.

So, I tried
const int a = (q!()).length;
This doesn't compile either. Based on the error message, it seems that parentheses suppress the implicit property feature. Is this behaviour intentional? (Maybe it could be useful).

Anyway,

const int a = (q!() ~ "").length

works as expected, as does:

template strlen(char [] str)
{
   const int strlen = str.length;
}

const int a = strlen!(q!());

It certainly seems it should work. I'll check into it.

"Stewart Gordon" <smjg_1998@yahoo.com> wrote in message news:dm6rdm$57i$1@digitaldaemon.com...
> Excellent!  Only, I think you mean 28264 or 28426, not 28246.
>
> And you mistyped my name in the comment to fromMBSz.

Sorry about that. I'll fix it.

"Don Clugston" <dac@nospam.com.au> wrote in message news:dm72ee$bvp$1@digitaldaemon.com...
> With the code
>
> template q()
> {
>     const char [] q = "abc";
> }
>
> const int a = q!().length;
>
> does not compile.

I tried this with 0.140:

template q()
{
    const char [] q = "abc";
}

const int a = q!().length;

void main()
{
    printf("a = %d\n", a);
}

and got:
    a = 3
as the output.

Sorry, I got that a bit wrong. Here's a minimal test case:

--------------
template cat(int n)
{
  const int dog = n;
}

const char [] q = "qqqq";

const int thisfails = cat!(q.length).dog;
--------------
bug.d(9): no property 'length' for type 'char[]'
----------------

But if you replace the last line with:

const int a = q.length;
const int thisworks = cat!(a).dog;

it works. So it seems to be a simple order-of-evaluation bug that doesn't have anything to do with implicit template properties. I'll post it to d.D.bugs.


Walter Bright wrote:
> "Don Clugston" <dac@nospam.com.au> wrote in message
> news:dm72ee$bvp$1@digitaldaemon.com...
> 
>>With the code
>>
>>template q()
>>{
>>    const char [] q = "abc";
>>}
>>
>>const int a = q!().length;
>>
>>does not compile.
> 
> 
> I tried this with 0.140:
> 
> template q()
> {
>     const char [] q = "abc";
> }
> 
> const int a = q!().length;
> 
> void main()
> {
>     printf("a = %d\n", a);
> }
> 
> and got:
>     a = 3
> as the output.
> 
>