www.digitalmars.com         C & C++   DMDScript  

digitalmars.D.learn - Template mixin problem

reply Olli Aalto <oaalto gmail.com> writes:
I already posed this question on the #D channel, but here's for the rest 
of you.

http://tango.pastebin.com/m59b8715f

Here's the error:

oaalto-desktop Projects/workspace/MixinTest> dsss build
mixins/main.d => mixin_test
mixins/HelloWorld.d(7): mixin is not defined
mixins/HelloWorld.d(8): mixin 
mixins.HelloWorld.HelloWorld.HelloSpeaker!() error instantiating
mixins/HelloWorld.d(7): mixin is not defined
mixins/HelloWorld.d(8): mixin 
mixins.HelloWorld.HelloWorld.HelloSpeaker!() error instantiating
Command /home/oaalto/D/dsss/bin/rebuild returned with code 256, aborting.
Error: Command failed, aborting.

Any ideas what's going wrong?

DMD 1.033
DSSS 0.78

O.
Dec 15 2008
parent reply Olli Aalto <oaalto gmail.com> writes:
Ok, downs figured it out on #D. You can't have mixins in templates, 
which is a big disappointment.

Removing the HelloData mixin from HelloSpeaker and all references to 
helloStr it "works".

O.
Dec 15 2008
parent reply "Bill Baxter" <wbaxter gmail.com> writes:
On Mon, Dec 15, 2008 at 5:48 PM, Olli Aalto <oaalto gmail.com> wrote:

 Ok, downs figured it out on #D. You can't have mixins in templates, which is
 a big disappointment.

 Removing the HelloData mixin from HelloSpeaker and all references to
 helloStr it "works".


Hmm, didn't know that.  But also if you import a module that uses a
mixin, the module that uses the mixin also needs to import the mixin
module.  I'm sure that didn't make any sense.

I.e. you may need to import mixins.HelloData in mixins.HelloWorld.
And maybe import all the mixin modules in in main.

--bb
Dec 15 2008
parent reply Olli Aalto <oaalto gmail.com> writes:
Bill Baxter wrote:

 On Mon, Dec 15, 2008 at 5:48 PM, Olli Aalto <oaalto gmail.com> wrote:

 Ok, downs figured it out on #D. You can't have mixins in templates, which is
 a big disappointment.

 Removing the HelloData mixin from HelloSpeaker and all references to
 helloStr it "works".


 
 Hmm, didn't know that.  But also if you import a module that uses a
 mixin, the module that uses the mixin also needs to import the mixin
 module.  I'm sure that didn't make any sense.
 
 I.e. you may need to import mixins.HelloData in mixins.HelloWorld.
 And maybe import all the mixin modules in in main.
 


Yeah, just tried that and it worked. :) I think all this makes some kind 
of sense, but having to import the module for HelloData in HelloWorld 
shouldn't be needed. It's already been mixed-in in HelloSpeaker so from 
the HelloWorld's standpoint there is no HelloData. But any way glad to 
have it working.

O.
Dec 15 2008
parent reply "Bill Baxter" <wbaxter gmail.com> writes:
On Mon, Dec 15, 2008 at 5:58 PM, Olli Aalto <oaalto gmail.com> wrote:

 Bill Baxter wrote:

 On Mon, Dec 15, 2008 at 5:48 PM, Olli Aalto <oaalto gmail.com> wrote:

 Ok, downs figured it out on #D. You can't have mixins in templates, which
 is
 a big disappointment.

 Removing the HelloData mixin from HelloSpeaker and all references to
 helloStr it "works".


 Hmm, didn't know that.  But also if you import a module that uses a
 mixin, the module that uses the mixin also needs to import the mixin
 module.  I'm sure that didn't make any sense.

 I.e. you may need to import mixins.HelloData in mixins.HelloWorld.
 And maybe import all the mixin modules in in main.


 Yeah, just tried that and it worked. :) I think all this makes some kind of
 sense, but having to import the module for HelloData in HelloWorld shouldn't
 be needed. It's already been mixed-in in HelloSpeaker so from the
 HelloWorld's standpoint there is no HelloData. But any way glad to have it
 working.


But modules are inherited privately by default.
If you use "public import blahblah" for the modules the mixins require
then you can get around the problem.

Also there is a trick that I think h3r3tic first noticed -- you can
actually put an import statement inside the template, and at least if
it gets mixed into a class, it will work.  May work in other cases
too, but not so sure about that.

--bb
Dec 15 2008
parent Olli Aalto <oaalto gmail.com> writes:
Bill Baxter wrote:

 On Mon, Dec 15, 2008 at 5:58 PM, Olli Aalto <oaalto gmail.com> wrote:

 Bill Baxter wrote:

 On Mon, Dec 15, 2008 at 5:48 PM, Olli Aalto <oaalto gmail.com> wrote:

 Ok, downs figured it out on #D. You can't have mixins in templates, which
 is
 a big disappointment.

 Removing the HelloData mixin from HelloSpeaker and all references to
 helloStr it "works".


 Hmm, didn't know that.  But also if you import a module that uses a
 mixin, the module that uses the mixin also needs to import the mixin
 module.  I'm sure that didn't make any sense.

 I.e. you may need to import mixins.HelloData in mixins.HelloWorld.
 And maybe import all the mixin modules in in main.


 Yeah, just tried that and it worked. :) I think all this makes some kind of
 sense, but having to import the module for HelloData in HelloWorld shouldn't
 be needed. It's already been mixed-in in HelloSpeaker so from the
 HelloWorld's standpoint there is no HelloData. But any way glad to have it
 working.


 
 But modules are inherited privately by default.
 If you use "public import blahblah" for the modules the mixins require
 then you can get around the problem.
 
 Also there is a trick that I think h3r3tic first noticed -- you can
 actually put an import statement inside the template, and at least if
 it gets mixed into a class, it will work.  May work in other cases
 too, but not so sure about that.
 


Yes, I know that they are private by default and that's great. My point 
here is this: (copy pasted from #D)
< Odeamus> the way I see this is that when the HelloWorld sees the mixin
for HelloSpeaker the HelloSpeaker template should already 
  contain the line "private char[] helloStr" and not the mixin

But any way I wrote couple words about what I was after here:
http://odefu.blogspot.com/2008/12/composite-oriented-programming.html

O.
Dec 15 2008