Re: super(...) in mixin template
On Wednesday, 5 March 2014 at 04:05:56 UTC, luminousone wrote: On Tuesday, 4 March 2014 at 12:04:12 UTC, John Colvin wrote: On Tuesday, 4 March 2014 at 12:01:46 UTC, John Colvin wrote: On Tuesday, 4 March 2014 at 10:37:02 UTC, Steve Teale wrote: On Tuesday, 4 March 2014 at 07:23:29 UTC, Jacob Carlborg wrote: Perhaps you already figured this out but template mixins can only mixin declarations, not expression or statements. -- /Jacob Carlborg Damn! Yup, first sentence of the documentation. Wishful reading. Thanks. Steve You can of course mixin a function (either nested inside the constructor or as a member or even a free funtion) containing whatever you want and then call that. That won't help you with calling super() though, you can only call super from another constructor. You'd have to use a string mixin as that truly can inject arbitrary code. This opens a question: Should functions nested in constructors be given all the same powers that a constructor has (calling super, initializing const/immutable data etc)? http://d.puremagic.com/issues/show_bug.cgi?id=3332 I don't see how that's relevant? The crux of that request/bug is about overload resolution.
Re: super(...) in mixin template
On Tuesday, 4 March 2014 at 07:23:29 UTC, Jacob Carlborg wrote: Perhaps you already figured this out but template mixins can only mixin declarations, not expression or statements. -- /Jacob Carlborg Damn! Yup, first sentence of the documentation. Wishful reading. Thanks. Steve
Re: super(...) in mixin template
On Tuesday, 4 March 2014 at 10:37:02 UTC, Steve Teale wrote: On Tuesday, 4 March 2014 at 07:23:29 UTC, Jacob Carlborg wrote: Perhaps you already figured this out but template mixins can only mixin declarations, not expression or statements. -- /Jacob Carlborg Damn! Yup, first sentence of the documentation. Wishful reading. Thanks. Steve You can of course mixin a function (either nested inside the constructor or as a member or even a free funtion) containing whatever you want and then call that. That won't help you with calling super() though, you can only call super from another constructor. You'd have to use a string mixin as that truly can inject arbitrary code.
Re: super(...) in mixin template
On Tuesday, 4 March 2014 at 12:01:46 UTC, John Colvin wrote: On Tuesday, 4 March 2014 at 10:37:02 UTC, Steve Teale wrote: On Tuesday, 4 March 2014 at 07:23:29 UTC, Jacob Carlborg wrote: Perhaps you already figured this out but template mixins can only mixin declarations, not expression or statements. -- /Jacob Carlborg Damn! Yup, first sentence of the documentation. Wishful reading. Thanks. Steve You can of course mixin a function (either nested inside the constructor or as a member or even a free funtion) containing whatever you want and then call that. That won't help you with calling super() though, you can only call super from another constructor. You'd have to use a string mixin as that truly can inject arbitrary code. This opens a question: Should functions nested in constructors be given all the same powers that a constructor has (calling super, initializing const/immutable data etc)?
Re: super(...) in mixin template
On Tuesday, 4 March 2014 at 12:04:12 UTC, John Colvin wrote: On Tuesday, 4 March 2014 at 12:01:46 UTC, John Colvin wrote: On Tuesday, 4 March 2014 at 10:37:02 UTC, Steve Teale wrote: On Tuesday, 4 March 2014 at 07:23:29 UTC, Jacob Carlborg wrote: Perhaps you already figured this out but template mixins can only mixin declarations, not expression or statements. -- /Jacob Carlborg Damn! Yup, first sentence of the documentation. Wishful reading. Thanks. Steve You can of course mixin a function (either nested inside the constructor or as a member or even a free funtion) containing whatever you want and then call that. That won't help you with calling super() though, you can only call super from another constructor. You'd have to use a string mixin as that truly can inject arbitrary code. This opens a question: Should functions nested in constructors be given all the same powers that a constructor has (calling super, initializing const/immutable data etc)? http://d.puremagic.com/issues/show_bug.cgi?id=3332 I would bet you can't call super from a mixin.
Re: super(...) in mixin template
On Monday, 3 March 2014 at 16:11:48 UTC, Steve Teale wrote: I did not get any takers in D Learn, so I'll try again here. Mixin templates are supposed to be instantiated in the scope where they were invoked. I have tried one that I want to invoke in the body of a constructor, but it fails when it calls super(...). Should this be so, or is it a bug? Steve Can you post a link to the thread in digitalmars.D.learn? I regularly lurk there, and I must've missed your thread.
super(...) in mixin template
I did not get any takers in D Learn, so I'll try again here. Mixin templates are supposed to be instantiated in the scope where they were invoked. I have tried one that I want to invoke in the body of a constructor, but it fails when it calls super(...). Should this be so, or is it a bug? Steve
Re: super(...) in mixin template
On Monday, 3 March 2014 at 16:11:48 UTC, Steve Teale wrote: I did not get any takers in D Learn, so I'll try again here. Mixin templates are supposed to be instantiated in the scope where they were invoked. I have tried one that I want to invoke in the body of a constructor, but it fails when it calls super(...). Should this be so, or is it a bug? Steve Have you got an example please?
Re: super(...) in mixin template
On Monday, 3 March 2014 at 16:20:22 UTC, Gary Willoughby wrote:
On Monday, 3 March 2014 at 16:11:48 UTC, Steve Teale wrote:
I did not get any takers in D Learn, so I'll try again here.
Mixin templates are supposed to be instantiated in the scope
where they were invoked. I have tried one that I want to
invoke in the body of a constructor, but it fails when it
calls super(...).
Should this be so, or is it a bug?
Steve
Have you got an example please?
There's an example below, but it is probably not necessary.
The thing is that the mixin won't compile because it's seeing
super(whatever) as an attempt to define a function.
mixin.d(35): Error: function declaration without return type.
(Note that constructors are always named 'this')
mixin.d(35): Error: no identifier for declarator super(s, t, g)
If you move the mixin definition inside a constructor, you get a
slew of other errors.
What I really want the mixin to do should I think be done after
the class hierarchy is complete - without the super call the rest
of it is hardly worth bothering.
I should also mention that the example below compiles OK if you
move the super call out of the mixin, but for some reason it
won't link - it works OK in my app, so I didn't pursue it.
import std.conv;
enum
{
COX,
WILLIAM,
GREEN
}
enum Groups
{
APPLES,
PEARS,
BANANAS
}
class App
{
this();
}
class Base
{
string name;
int type;
Groups group;
mixin template Preamble(alias NAME, alias GNAME, alias T)
{
string s = NAME~ ~to!string(nextOid);
Groups g = mixin(Groups.~GNAME);
static int t = T;
// Mixin must be syntactically correct - the following
isn't because
// we are not in a constructor
super(s, t, g);
}
this(App app, string s, int t, Groups g)
{
name = s;
type = t;
group = g;
}
}
class Intermediate : Base
{
this(App app, string s, int t, Groups g)
{
super(app, s, t, g);
}
}
class CoxPipin : Intermediate
{
static int nextOid = 0;
this(App app)
{
mixin Preamble!(CoxPipin, APPLES, COX);
// Move the super call out, and everything is fine
//super(app, s, t, g);
}
}
void main()
{
App a = new App();
Base x = new CoxPipin(a);
}
Re: super(...) in mixin template
On Tuesday, 4 March 2014 at 05:08:45 UTC, Steve Teale wrote: There's an example below, but it is probably not necessary. The thing is that the mixin won't compile because it's seeing super(whatever) as an attempt to define a function. Perhaps you already figured this out but template mixins can only mixin declarations, not expression or statements. -- /Jacob Carlborg
