Re: Bug or not? "Functions cannot return a function"
On Thursday, 17 November 2016 at 03:10:33 UTC, Jonathan M Davis wrote: Regardless, optional parens are one of those features that seems really nice in some situations and gets really annoying in others, and you hit one of those spots where it's annoying. I would be feasible to only recognize parenthesis-less calls as calls in UFCS situations. The increase in sema-complexity is not high.
Re: Bug or not? "Functions cannot return a function"
On Thursday, November 17, 2016 02:53:50 Meta via Digitalmars-d wrote: > On Thursday, 17 November 2016 at 02:47:50 UTC, Stefan Koch wrote: > > I think you are doing a parenthesis-less call. > > I swear optional parens is going to drive me insane. Why > @property wasn't just fixed instead of the current horribly > broken and unintuitive situation, I'll never know. The number one reason? Because folks hated the extra parens with UFCS. e.g. with optional parens, you get stuff like auto r = range.map!foo.filter!(a => a < 5); whereas without them you have to do auto r = range.map!foo().filter!(a => a < 5)(); With UFCS and ranges, you end up with a lot of situations where you use parens for the template argument, and a lot of folks thought that then having to put the empty parens on the end was just ugly. If we didn't have UFCS, then optional parens used with non-property functions would be a lot less appealing. But once UFCS was added, any chance of having strong property enforcement for @property pretty much died. As it stands, we really should fix @property for callables so that you can use @property to have a property function which returns a callable and is called without the extra parens, or we should arguably just get rid of @property. Regardless, optional parens are one of those features that seems really nice in some situations and gets really annoying in others, and you hit one of those spots where it's annoying. - Jonathan M Davis
Re: Bug or not? "Functions cannot return a function"
On Thursday, 17 November 2016 at 02:47:50 UTC, Stefan Koch wrote: I think you are doing a parenthesis-less call. I swear optional parens is going to drive me insane. Why @property wasn't just fixed instead of the current horribly broken and unintuitive situation, I'll never know.
Re: Bug or not? "Functions cannot return a function"
On Thursday, 17 November 2016 at 02:15:49 UTC, Meta wrote:
On Thursday, 17 November 2016 at 02:14:43 UTC, Meta wrote:
On Thursday, 17 November 2016 at 01:48:51 UTC, Jonathan M
Davis wrote:
Well, you _can't_ return a function. You could return a
function pointer or a delegate, but not a function. What
would it even mean to return a function?
Well, it works. This compiles:
auto bug(alias f)()
{
return f;
}
void fun() {}
void main()
{
bug!fun(); //Fine
}
Should be:
void main()
{
bug!fun(); //Fine
}
I think you are doing a parenthesis-less call.
Re: Bug or not? "Functions cannot return a function"
On Thursday, 17 November 2016 at 02:14:43 UTC, Meta wrote:
On Thursday, 17 November 2016 at 01:48:51 UTC, Jonathan M Davis
wrote:
Well, you _can't_ return a function. You could return a
function pointer or a delegate, but not a function. What would
it even mean to return a function?
Well, it works. This compiles:
auto bug(alias f)()
{
return f;
}
void fun() {}
void main()
{
bug!fun(); //Fine
}
Should be:
void main()
{
bug!fun(); //Fine
}
Re: Bug or not? "Functions cannot return a function"
On Thursday, 17 November 2016 at 01:48:51 UTC, Jonathan M Davis
wrote:
Well, you _can't_ return a function. You could return a
function pointer or a delegate, but not a function. What would
it even mean to return a function?
Well, it works. This compiles:
auto bug(alias f)()
{
return f;
}
void fun() {}
void main()
{
bug!fun(); //Error: functions cannot return a function
}
So why can't I return cast(typeof(f))? Furthermore, it gives me
the exact same error when I change it to `return *`.
Re: Bug or not? "Functions cannot return a function"
On Thursday, 17 November 2016 at 01:27:45 UTC, Meta wrote:
auto bug(alias f)()
{
return cast(typeof(f))
}
void fun() {}
void main()
{
bug!fun(); //Error: functions cannot return a function
}
Got a bit ahead of myself. Found this in DMD 2.072.0.
Re: Bug or not? "Functions cannot return a function"
On Thursday, November 17, 2016 01:27:45 Meta via Digitalmars-d wrote:
> auto bug(alias f)()
> {
> return cast(typeof(f))
> }
>
> void fun() {}
>
> void main()
> {
> bug!fun(); //Error: functions cannot return a function
> }
Well, you _can't_ return a function. You could return a function pointer or
a delegate, but not a function. What would it even mean to return a
function?
Why don't you just return ? I don't understand why you're doing the cast.
should give you a pointer to f, so you have a function pointer that you
can then call later (though you'd need to assign the result of bug!fun() to
a variable, since it does nothing otherwise).
- Jonathan M Davis
