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digitalmars.D - static import std.signals - what's wrong?

reply Vladimir Bezhenar <v04bvs gmail.com> writes:
Code:
static import std.signals;

class A {
    mixin std.signals.Signal!();
}

When I try to compile it, there is a lot of confusing messages about errors in
std/signals.d
If I remove "static" from the first line, all works ok.
Dec 01 2006
next sibling parent reply Hasan Aljudy <hasan.aljudy gmail.com> writes:
Vladimir Bezhenar wrote:

 Code:
 static import std.signals;
 
 class A {
     mixin std.signals.Signal!();
 }
 
 When I try to compile it, there is a lot of confusing messages about errors in
 std/signals.d
 If I remove "static" from the first line, all works ok.


I don't know if Walter would call that "a bug"; it's consistent with the 
specs but IMHO it's a bug. (If it's caused by what I think it is ..)

you're instantiating that template in this file, so the declarations in 
that template are "copied over" to your file, i.e. the scope where the 
mixin happens; but these declaration have dependencies, and these 
dependencies are not available in your file because your import is static.

I'm not sure if that makes any sense at all.

example:
a.d:
----------
struct A { .. }

template M()
{
    A a; //this declaration depends on the declaration of struct A
}

----------

b.d:
---------
static import a;

mixin a.M!(); //problem, struct A cannot be found from this scope 
(because the import is static)
------------
Dec 01 2006
parent reply Chris Nicholson-Sauls <ibisbasenji gmail.com> writes:
Hasan Aljudy wrote:

 
 
 Vladimir Bezhenar wrote:

 Code:
 static import std.signals;

 class A {
     mixin std.signals.Signal!();
 }

 When I try to compile it, there is a lot of confusing messages about 
 errors in
 std/signals.d
 If I remove "static" from the first line, all works ok.


 
 I don't know if Walter would call that "a bug"; it's consistent with the 
 specs but IMHO it's a bug. (If it's caused by what I think it is ..)
 
 you're instantiating that template in this file, so the declarations in 
 that template are "copied over" to your file, i.e. the scope where the 
 mixin happens; but these declaration have dependencies, and these 
 dependencies are not available in your file because your import is static.
 
 I'm not sure if that makes any sense at all.
 
 example:
 a.d:
 ----------
 struct A { .. }
 
 template M()
 {
    A a; //this declaration depends on the declaration of struct A
 }
 
 ----------
 
 b.d:
 ---------
 static import a;
 
 mixin a.M!(); //problem, struct A cannot be found from this scope 
 (because the import is static)
 ------------


I'm sure you are most likely correct that this is the problem he was
experiencing.  In 
fact, I think I suggested before that the imports within std.signals should
themselves 
most likely be static.  Would've prevented this problem, especially if they
were public 
static.  :)

-- Chris Nicholson-Sauls
Dec 01 2006
parent reply Hasan Aljudy <hasan.aljudy gmail.com> writes:
Chris Nicholson-Sauls wrote:

 Hasan Aljudy wrote:

 Vladimir Bezhenar wrote:

 Code:
 static import std.signals;

 class A {
     mixin std.signals.Signal!();
 }

 When I try to compile it, there is a lot of confusing messages about 
 errors in
 std/signals.d
 If I remove "static" from the first line, all works ok.


 I don't know if Walter would call that "a bug"; it's consistent with 
 the specs but IMHO it's a bug. (If it's caused by what I think it is ..)

 you're instantiating that template in this file, so the declarations 
 in that template are "copied over" to your file, i.e. the scope where 
 the mixin happens; but these declaration have dependencies, and these 
 dependencies are not available in your file because your import is 
 static.

 I'm not sure if that makes any sense at all.

 example:
 a.d:
 ----------
 struct A { .. }

 template M()
 {
    A a; //this declaration depends on the declaration of struct A
 }

 ----------

 b.d:
 ---------
 static import a;

 mixin a.M!(); //problem, struct A cannot be found from this scope 
 (because the import is static)
 ------------


 
 I'm sure you are most likely correct that this is the problem he was 
 experiencing.  In fact, I think I suggested before that the imports 
 within std.signals should themselves most likely be static.  Would've 
 prevented this problem, especially if they were public static.  :)
 
 -- Chris Nicholson-Sauls


But I think that wouldn't work if someone was to do something like:

import sslot = std.signal : Sig = Signal;
Dec 01 2006
parent Chris Nicholson-Sauls <ibisbasenji gmail.com> writes:
Hasan Aljudy wrote:

 
 
 Chris Nicholson-Sauls wrote:

 Hasan Aljudy wrote:

 Vladimir Bezhenar wrote:

 Code:
 static import std.signals;

 class A {
     mixin std.signals.Signal!();
 }

 When I try to compile it, there is a lot of confusing messages about 
 errors in
 std/signals.d
 If I remove "static" from the first line, all works ok.


 I don't know if Walter would call that "a bug"; it's consistent with 
 the specs but IMHO it's a bug. (If it's caused by what I think it is ..)

 you're instantiating that template in this file, so the declarations 
 in that template are "copied over" to your file, i.e. the scope where 
 the mixin happens; but these declaration have dependencies, and these 
 dependencies are not available in your file because your import is 
 static.

 I'm not sure if that makes any sense at all.

 example:
 a.d:
 ----------
 struct A { .. }

 template M()
 {
    A a; //this declaration depends on the declaration of struct A
 }

 ----------

 b.d:
 ---------
 static import a;

 mixin a.M!(); //problem, struct A cannot be found from this scope 
 (because the import is static)
 ------------


 I'm sure you are most likely correct that this is the problem he was 
 experiencing.  In fact, I think I suggested before that the imports 
 within std.signals should themselves most likely be static.  Would've 
 prevented this problem, especially if they were public static.  :)

 -- Chris Nicholson-Sauls


 
 But I think that wouldn't work if someone was to do something like:
 
 import sslot = std.signal : Sig = Signal;


As long as the code that is barfing on symbols with the static import scenario
doesn't 
itself make any referance to std.signal.Signal it should work fine... but
admittedly, I 
haven't tested this myself...

-- Chris Nicholson-Sauls
Dec 01 2006
prev sibling parent Bill Baxter <wbaxter gmail.com> writes:
Vladimir Bezhenar wrote:

 Code:
 static import std.signals;
 
 class A {
     mixin std.signals.Signal!();
 }
 
 When I try to compile it, there is a lot of confusing messages about errors in
 std/signals.d
 If I remove "static" from the first line, all works ok.


I filed this as a bug a while back, which Walter declared 'invalid'. 
This is 'works as designed' behavior.  I've just resubmitted it as an 
enhancement request though, as per his suggestion, so if you have 
something to add about this issue, add it there.

closed bug:  http://d.puremagic.com/issues/show_bug.cgi?id=506
open enhancment: http://d.puremagic.com/issues/show_bug.cgi?id=625


--bb
Dec 01 2006