Re: DIP 1005 - Preliminary Review Round 1
On Saturday, 22 April 2017 at 11:54:08 UTC, Mike Parker wrote: DIP 1005 is titled "Dependency-Carrying Declarations". https://github.com/dlang/DIPs/blob/master/DIPs/DIP1005.md All review-related feedback on and discussion of the DIP should occur in this thread. Due to DConf taking place during the review period, the period will be extended by a week. The review period will end at 11:59 PM ET on May 13 (3:59 AM GMT on May 14), or when I make a post declaring it complete. The review is now closed. Thanks to all who participated.
Re: DIP 1005 - Preliminary Review Round 1
On Friday, 12 May 2017 at 14:02:20 UTC, Jonathan M Davis wrote:
On Saturday, April 22, 2017 11:54:08 Mike Parker via
Digitalmars-d wrote:
DIP 1005 is titled "Dependency-Carrying Declarations".
https://github.com/dlang/DIPs/blob/master/DIPs/DIP1005.md
All review-related feedback on and discussion of the DIP
should occur in this thread. Due to DConf taking place during
the review period, the period will be extended by a week. The
review period will end at 11:59 PM ET on May 13 (3:59 AM GMT
on May 14), or when I make a post declaring it complete.
At the end of Round 1, if further review is deemed necessary,
the DIP will be scheduled for another round. Otherwise,
because the DIP comes from a language author and no formal
review period by the language authors is necessary, the DIP
will be marked "Accepted" or "Rejected" at the author's
discretion.
An extensive discussion regarding this DIP has already taken
place [1].
Thanks in advance to all who participate.
Destroy!
[1]
http://forum.dlang.org/thread/o2psvk$1m96$1...@digitalmars.com?page=1
I've said this before in the PR for the self important idiom,
but I'll repeat my views on this here...
Aside from the exact syntax, this proposal is superior to the
self important idiom that we all know is going to cause this
DIP to be rejected in that it's more DRY. With the SII, you get
stuff like
auto foo(from!"std.datetime".SysTime lhs,
from!"std.datetime".SysTime rhs)
{
...
}
whereas with this DIP, you only have to list the import once.
With the SII, you have to repeat the imports for every symbol
whether they come from the same module or not or even if
they're the same symbol. Also UFCS doesn't work with it, which
can be problematic for template constraints. So, I think that
the DIP is better than the SII (though IMHO, the issues with
using "with" that have been brought up would need to be
addressed for this DIP to be approved). The only advantage of
SII is that we don't have to change the language to get it
(which is very cool). But on the whole, SII is worse. However,
regardless of whether this DIP or the self important idiom is
better, I think that they're both going too far - at least if
they're going to be pushed as best practice in any real way.
For a while now, We've been pushing for folks to use local
imports and scoped imports as best practice, which does make
sense on some level. You can look at a function and see which
imports it uses, and it can reduce compile times - especially
if you're using local and selective imports inside a template
which may not even be instantiated. However, it makes for a
_lot_ of extra code and is not at all DRY. Instead of simply
putting the import at the top, you have to list it in every
function that uses any symbol for it and list every single
symbol from that module that you're using, which is tedious.
And worse, as you write or refactor a function, you end up
having to maintain that list of local and selective imports,
changing them as the symbols that you use change. And after
trying to do that as best practice for a while now, I'm sick of
it. It's a maintenance nightmare. It's a lot of shuffling
around of code for minimal benefit.
It is _so_ much nicer to be able to just slap the import at the
top of the module and move on with life. You use whatever has
been imported, and occasionally when you need a symbol that
hasn't been imported, you add the import for that module, and
you're doing _way_ less shuffling around of code. You also get
shorter code, because you don't end up with all of those
repeated imports (it's especially bad when the same symbols get
used extensively throughout a module).
And we _already_ have a ridiculous number of attributes to
stick on functions in D (on top of other stuff like template
constaints), making it so that function signatures are often
way too verbose. So, adding even more to the function
signatures as would occur with this DIP or with the SII seems
to me like it's going to far. Function signatures are getting
too complicated, and IMHO, this DIP and SII simply don't pay
for that extra complication.
The only real benefit I see from this DIP or the SII is the
speed up in compilation time that can go with them, but that's
just because it's effectively making some of the imports lazy -
and Walter has already talked on multiple occasions about
making imports lazy, which would then solve the problem, only
better, because then you could just slap the import at the top
of the module and have it be lazy rather than having to have
all of this extra muck in your function signatures or having to
have all of those local and selective imports. So, I'd like to
see fully lazy imports be implemented like Walter has wanted to
do and have that be the solution rather than marking up
functions even further.
If folks want to do this stuff in their own code, then that's
their prerogative, but I really don't
Re: DIP 1005 - Preliminary Review Round 1
On Saturday, April 22, 2017 11:54:08 Mike Parker via Digitalmars-d wrote:
> DIP 1005 is titled "Dependency-Carrying Declarations".
>
> https://github.com/dlang/DIPs/blob/master/DIPs/DIP1005.md
>
> All review-related feedback on and discussion of the DIP should
> occur in this thread. Due to DConf taking place during the review
> period, the period will be extended by a week. The review period
> will end at 11:59 PM ET on May 13 (3:59 AM GMT on May 14), or
> when I make a post declaring it complete.
>
> At the end of Round 1, if further review is deemed necessary, the
> DIP will be scheduled for another round. Otherwise, because the
> DIP comes from a language author and no formal review period by
> the language authors is necessary, the DIP will be marked
> "Accepted" or "Rejected" at the author's discretion.
>
> An extensive discussion regarding this DIP has already taken
> place [1].
>
> Thanks in advance to all who participate.
>
> Destroy!
>
> [1]
> http://forum.dlang.org/thread/o2psvk$1m96$1...@digitalmars.com?page=1
I've said this before in the PR for the self important idiom, but I'll
repeat my views on this here...
Aside from the exact syntax, this proposal is superior to the self important
idiom that we all know is going to cause this DIP to be rejected in that
it's more DRY. With the SII, you get stuff like
auto foo(from!"std.datetime".SysTime lhs, from!"std.datetime".SysTime rhs)
{
...
}
whereas with this DIP, you only have to list the import once. With the SII,
you have to repeat the imports for every symbol whether they come from the
same module or not or even if they're the same symbol. Also UFCS doesn't
work with it, which can be problematic for template constraints. So, I think
that the DIP is better than the SII (though IMHO, the issues with using
"with" that have been brought up would need to be addressed for this DIP to
be approved). The only advantage of SII is that we don't have to change the
language to get it (which is very cool). But on the whole, SII is worse.
However, regardless of whether this DIP or the self important idiom is
better, I think that they're both going too far - at least if they're going
to be pushed as best practice in any real way.
For a while now, We've been pushing for folks to use local imports and
scoped imports as best practice, which does make sense on some level. You
can look at a function and see which imports it uses, and it can reduce
compile times - especially if you're using local and selective imports
inside a template which may not even be instantiated. However, it makes for
a _lot_ of extra code and is not at all DRY. Instead of simply putting the
import at the top, you have to list it in every function that uses any
symbol for it and list every single symbol from that module that you're
using, which is tedious. And worse, as you write or refactor a function, you
end up having to maintain that list of local and selective imports, changing
them as the symbols that you use change. And after trying to do that as best
practice for a while now, I'm sick of it. It's a maintenance nightmare. It's
a lot of shuffling around of code for minimal benefit.
It is _so_ much nicer to be able to just slap the import at the top of the
module and move on with life. You use whatever has been imported, and
occasionally when you need a symbol that hasn't been imported, you add the
import for that module, and you're doing _way_ less shuffling around of
code. You also get shorter code, because you don't end up with all of those
repeated imports (it's especially bad when the same symbols get used
extensively throughout a module).
And we _already_ have a ridiculous number of attributes to stick on
functions in D (on top of other stuff like template constaints), making it
so that function signatures are often way too verbose. So, adding even more
to the function signatures as would occur with this DIP or with the SII
seems to me like it's going to far. Function signatures are getting too
complicated, and IMHO, this DIP and SII simply don't pay for that extra
complication.
The only real benefit I see from this DIP or the SII is the speed up in
compilation time that can go with them, but that's just because it's
effectively making some of the imports lazy - and Walter has already talked
on multiple occasions about making imports lazy, which would then solve the
problem, only better, because then you could just slap the import at the top
of the module and have it be lazy rather than having to have all of this
extra muck in your function signatures or having to have all of those local
and selective imports. So, I'd like to see fully lazy imports be implemented
like Walter has wanted to do and have that be the solution rather than
marking up functions even further.
If folks want to do this stuff in their own code, then that's their
prerogative, but I really don't want to see this sort of thing become "best
practice." As it stands, I think that the local and
Re: DIP 1005 - Preliminary Review Round 1
On Saturday, 6 May 2017 at 10:38:25 UTC, Mike Parker wrote: On Saturday, 22 April 2017 at 11:54:08 UTC, Mike Parker wrote: All review-related feedback on and discussion of the DIP should occur in this thread. Due to DConf taking place during the review period, the period will be extended by a week. The review period will end at 11:59 PM ET on May 13 (3:59 AM GMT on May 14), or when I make a post declaring it complete. Reminder: There are two weeks remaining in the review period. Sorry, *One Week* remaining.
Re: DIP 1005 - Preliminary Review Round 1
On Saturday, 22 April 2017 at 11:54:08 UTC, Mike Parker wrote: All review-related feedback on and discussion of the DIP should occur in this thread. Due to DConf taking place during the review period, the period will be extended by a week. The review period will end at 11:59 PM ET on May 13 (3:59 AM GMT on May 14), or when I make a post declaring it complete. Reminder: There are two weeks remaining in the review period.
Re: DIP 1005 - Preliminary Review Round 1
On Sunday, 23 April 2017 at 12:03:47 UTC, Andrei Alexandrescu wrote: On 4/22/17 4:52 PM, Joakim wrote: Why is this still up for review? Mostly out of a sense of conformity. We asked Michael to give no special treatment of DIPs originating from us, and this one was open, so he put it up for review. It is likely it will end up rejected in favor of https://github.com/dlang/druntime/pull/1756. The DIP mentions dependency-tracking tools, an important consideration. For both the DIP and the PR it'd be worth identifying if changes will be required in D dependency-tracking tools (dmd/ldc/gdc --deps; rdmd --make-depends) or 3rd party tools in common use. --Jon
Re: DIP 1005 - Preliminary Review Round 1
On Sunday, 23 April 2017 at 19:25:09 UTC, Andrej Mitrovic wrote: With this syntax, the import is executed only if the declared name (process) is actually looked up. I don't believe the workaround with the `from` template fixes this. Not sure what DMD does, but SDC sure would do it only if used.
Re: DIP 1005 - Preliminary Review Round 1
On Sunday, 23 April 2017 at 16:39:35 UTC, deadalnix wrote: It's just one per module. Templates are only instantiated once per new set of arguments. There may be some gain here, but I doubt this is worth adding a new language feature. Ah, good point. Though there's still merit to this DIP such as this: With this syntax, the import is executed only if the declared name (process) is actually looked up. I don't believe the workaround with the `from` template fixes this.
Re: DIP 1005 - Preliminary Review Round 1
On Sunday, 23 April 2017 at 12:03:47 UTC, Andrei Alexandrescu
wrote:
On 4/22/17 4:52 PM, Joakim wrote:
On Saturday, 22 April 2017 at 11:54:08 UTC, Mike Parker wrote:
DIP 1005 is titled "Dependency-Carrying Declarations".
https://github.com/dlang/DIPs/blob/master/DIPs/DIP1005.md
All review-related feedback on and discussion of the DIP
should occur in this thread. Due to DConf taking place during
the review period, the period will be extended by a week. The
review period will end at 11:59 PM ET on May 13 (3:59 AM GMT
on May 14), or when I make a post declaring it complete.
At the end of Round 1, if further review is deemed necessary,
the DIP will be scheduled for another round. Otherwise,
because the DIP comes from a language author and no formal
review period by the language authors is necessary, the DIP
will be marked "Accepted" or "Rejected" at the author's
discretion.
An extensive discussion regarding this DIP has already taken
place [1].
Thanks in advance to all who participate.
Destroy!
[1]
http://forum.dlang.org/thread/o2psvk$1m96$1...@digitalmars.com?page=1
I thought this DIP was invalidated by the self-important
workaround?
http://forum.dlang.org/post/o72kq8$ggc$1...@digitalmars.com
https://github.com/dlang/druntime/pull/1756#issuecomment-277463742
Why is this still up for review?
Mostly out of a sense of conformity. We asked Michael to give
no special treatment of DIPs originating from us, and this one
was open, so he put it up for review. It is likely it will end
up rejected in favor of
https://github.com/dlang/druntime/pull/1756.
Thanks,
Andrei
this example doenst work with the from!"modName" template, would
it work with dip1005?
module moda;
struct Foo{int i;}
module modb;
void fun(from!"moda".Foo){}
module app;
template test(alias f)
{
mixin("void test(" ~
from!"std.traits".Parameters!f.stringof[1..$-1] ~ "){}");
}
void main()
{
import moda, modb;
test!fun(Foo(5));
}
could dip1005 be introspected?
// you can make the above work with this or is there a better way?
template test(alias f)
{
import traits;
enum paramImports =
{
string res;
foreach(p; Parameters!f)
{
static if(!isBuiltinType!p) res ~= "import " ~
moduleName!p ~ ";\n";
}
return res;
}();
mixin(paramImports);
mixin("void test(" ~ Parameters!f.stringof[1..$-1] ~ "){}");
}
Re: DIP 1005 - Preliminary Review Round 1
On Saturday, 22 April 2017 at 11:54:08 UTC, Mike Parker wrote: Destroy! I'm not per se against going there but there are 2 points that needs to be considered. The first one is the "self important lookup" which obviate the need for this DIP to some extent. Second, if we are going to proceed anyway, the way this is specified is not ideal. This DIP effectively adds 2 features: 1/ The ability to use import foo as an argument to a with statement. 2/ The introducing of a with declaration in addition of a with statement. These two addition are independents as far as the spec goes and should be kept as such as to avoid an explosion of ad hoc solutions for the use case we want to enable, rather than providing building blocks that combine nicely to build such solutions.
Re: DIP 1005 - Preliminary Review Round 1
On Sunday, 23 April 2017 at 12:34:34 UTC, Andrej Mitrovic wrote: On Sunday, 23 April 2017 at 12:03:47 UTC, Andrei Alexandrescu wrote: Mostly out of a sense of conformity. We asked Michael to give no special treatment of DIPs originating from us, and this one was open, so he put it up for review. It is likely it will end up rejected in favor of https://github.com/dlang/druntime/pull/1756. Wouldn't there be a compile-time performance impact from instantiating so many templates, virtually for every parameter who's type is defined in another module? It's just one per module. Templates are only instantiated once per new set of arguments. There may be some gain here, but I doubt this is worth adding a new language feature.
Re: DIP 1005 - Preliminary Review Round 1
On 2017-04-23 14:03, Andrei Alexandrescu wrote: Mostly out of a sense of conformity. We asked Michael to give no special treatment of DIPs originating from us, and this one was open, so he put it up for review. It is likely it will end up rejected in favor of https://github.com/dlang/druntime/pull/1756. Absolutely, that's great. But I would have thought that the DIP would get retracted by the author, or do you still want to see this in the language? -- /Jacob Carlborg
Re: DIP 1005 - Preliminary Review Round 1
On Sunday, 23 April 2017 at 12:03:47 UTC, Andrei Alexandrescu wrote: Mostly out of a sense of conformity. We asked Michael to give no special treatment of DIPs originating from us, and this one was open, so he put it up for review. It is likely it will end up rejected in favor of https://github.com/dlang/druntime/pull/1756. Wouldn't there be a compile-time performance impact from instantiating so many templates, virtually for every parameter who's type is defined in another module?
Re: DIP 1005 - Preliminary Review Round 1
On 4/22/17 4:52 PM, Joakim wrote: On Saturday, 22 April 2017 at 11:54:08 UTC, Mike Parker wrote: DIP 1005 is titled "Dependency-Carrying Declarations". https://github.com/dlang/DIPs/blob/master/DIPs/DIP1005.md All review-related feedback on and discussion of the DIP should occur in this thread. Due to DConf taking place during the review period, the period will be extended by a week. The review period will end at 11:59 PM ET on May 13 (3:59 AM GMT on May 14), or when I make a post declaring it complete. At the end of Round 1, if further review is deemed necessary, the DIP will be scheduled for another round. Otherwise, because the DIP comes from a language author and no formal review period by the language authors is necessary, the DIP will be marked "Accepted" or "Rejected" at the author's discretion. An extensive discussion regarding this DIP has already taken place [1]. Thanks in advance to all who participate. Destroy! [1] http://forum.dlang.org/thread/o2psvk$1m96$1...@digitalmars.com?page=1 I thought this DIP was invalidated by the self-important workaround? http://forum.dlang.org/post/o72kq8$ggc$1...@digitalmars.com https://github.com/dlang/druntime/pull/1756#issuecomment-277463742 Why is this still up for review? Mostly out of a sense of conformity. We asked Michael to give no special treatment of DIPs originating from us, and this one was open, so he put it up for review. It is likely it will end up rejected in favor of https://github.com/dlang/druntime/pull/1756. Thanks, Andrei
Re: DIP 1005 - Preliminary Review Round 1
On Saturday, 22 April 2017 at 11:54:08 UTC, Mike Parker wrote: DIP 1005 is titled "Dependency-Carrying Declarations". https://github.com/dlang/DIPs/blob/master/DIPs/DIP1005.md All review-related feedback on and discussion of the DIP should occur in this thread. Due to DConf taking place during the review period, the period will be extended by a week. The review period will end at 11:59 PM ET on May 13 (3:59 AM GMT on May 14), or when I make a post declaring it complete. At the end of Round 1, if further review is deemed necessary, the DIP will be scheduled for another round. Otherwise, because the DIP comes from a language author and no formal review period by the language authors is necessary, the DIP will be marked "Accepted" or "Rejected" at the author's discretion. An extensive discussion regarding this DIP has already taken place [1]. Thanks in advance to all who participate. Destroy! [1] http://forum.dlang.org/thread/o2psvk$1m96$1...@digitalmars.com?page=1 I thought this DIP was invalidated by the self-important workaround? http://forum.dlang.org/post/o72kq8$ggc$1...@digitalmars.com https://github.com/dlang/druntime/pull/1756#issuecomment-277463742 Why is this still up for review?
Re: DIP 1005 - Preliminary Review Round 1
On Saturday, 22 April 2017 at 16:14:29 UTC, Timon Gehr wrote:
Please reconsider. This is new syntax. It looks like old syntax
but behaves differently.
I suppose the biggest issue is:
-
module mod;
import std.stdio;
struct A
{
~this ( ) { writeln("dtor"); }
}
-
-
module test;
class C
{
with (import mod) A a; // declaration, lives as long as C
lives
void test ( )
{
with (import mod) // statement
{
A a; // destroyed on exit of scope
}
// a was destroyed, and is not even visible here
}
}
-
I can see how this can be a pain point. If it's a big worry then
I'd be ok with using one of the syntactic alternatives, like
'import (std.stdio);'.
Re: DIP 1005 - Preliminary Review Round 1
On 22.04.2017 18:25, Stefan Koch wrote: On Saturday, 22 April 2017 at 16:13:20 UTC, Timon Gehr wrote: This is how it works for static if, and it is also how it will work for static foreach, so it is even consistent with other language features. So you will touch up your static foreach DIP ? If so I am okay with building the implementation. Sounds good. Let's discuss this at DConf.
Re: DIP 1005 - Preliminary Review Round 1
On Saturday, 22 April 2017 at 16:13:20 UTC, Timon Gehr wrote: This is how it works for static if, and it is also how it will work for static foreach, so it is even consistent with other language features. So you will touch up your static foreach DIP ? If so I am okay with building the implementation.
Re: DIP 1005 - Preliminary Review Round 1
On 22.04.2017 18:17, Timon Gehr wrote:
On 22.04.2017 17:16, Andrej Mitrovic wrote:
On Saturday, 22 April 2017 at 11:54:08 UTC, Mike Parker wrote:
https://github.com/dlang/DIPs/blob/master/DIPs/DIP1005.md
with (Type) and with (TemplateInstance) are always declarations and do
not introduce a new scope.
Does that mean we can now do things like this?:
-
module m;
struct A { struct B { } }
with (A) B b;
-
That's a pretty cool addition.
With the current wording of the DIP, this will not work in local scopes.
Why do we need more features for declaring global variables?
Correction: It will not work in function scopes.
Re: DIP 1005 - Preliminary Review Round 1
On 22.04.2017 17:16, Andrej Mitrovic wrote:
On Saturday, 22 April 2017 at 11:54:08 UTC, Mike Parker wrote:
https://github.com/dlang/DIPs/blob/master/DIPs/DIP1005.md
with (Type) and with (TemplateInstance) are always declarations and do
not introduce a new scope.
Does that mean we can now do things like this?:
-
module m;
struct A { struct B { } }
with (A) B b;
-
That's a pretty cool addition.
With the current wording of the DIP, this will not work in local scopes.
Why do we need more features for declaring global variables?
Re: DIP 1005 - Preliminary Review Round 1
On 22.04.2017 17:31, Andrej Mitrovic wrote: On Saturday, 22 April 2017 at 11:54:08 UTC, Mike Parker wrote: https://github.com/dlang/DIPs/blob/master/DIPs/DIP1005.md Very solid DIP! And I like the use of `with` and it's proposed extension to be allowed in declarations, rather than introducing new syntax. Please reconsider. This is new syntax. It looks like old syntax but behaves differently.
Re: DIP 1005 - Preliminary Review Round 1
On 22.04.2017 13:54, Mike Parker wrote: DIP 1005 is titled "Dependency-Carrying Declarations". https://github.com/dlang/DIPs/blob/master/DIPs/DIP1005.md All review-related feedback on and discussion of the DIP should occur in this thread. Due to DConf taking place during the review period, the period will be extended by a week. The review period will end at 11:59 PM ET on May 13 (3:59 AM GMT on May 14), or when I make a post declaring it complete. At the end of Round 1, if further review is deemed necessary, the DIP will be scheduled for another round. Otherwise, because the DIP comes from a language author and no formal review period by the language authors is necessary, the DIP will be marked "Accepted" or "Rejected" at the author's discretion. An extensive discussion regarding this DIP has already taken place [1]. Thanks in advance to all who participate. Destroy! [1] http://forum.dlang.org/thread/o2psvk$1m96$1...@digitalmars.com?page=1 "* Inside any function, all uses of with are statements and obey the current language rules. * Everywhere else, ..." "* Inside any function, with (Import ImportList) is a statement that introduces a scope. Inside the with, lookup considers the import local to the declaration (similar to the current handling of nested imports). * Everywhere else, ..." Please don't do this. "This extension removes an unforced limitation of the current with syntax (allows it to occur at top level)" No, it does not. It introduces two more incompatible syntaxes that look the same, yet are different. "The drawback of this choice is the potentially confusing handling of scopes: the with statement introduces a scope, whereas the with declaration does not." It's not merely confusing, it's frustrating. I might legitimately want to use the new feature on a local declaration. As an analogy, just imagine how frustrating it would be if 'static if' was written as 'if' with different meaning depending on the scope. Just associate actual syntax to the the scope handling. The proposal would be sane if it instead introduced a new 'static with' construct that actually has the same meaning in every context. This is how it works for static if, and it is also how it will work for static foreach, so it is even consistent with other language features.
Re: DIP 1005 - Preliminary Review Round 1
On Saturday, 22 April 2017 at 11:54:08 UTC, Mike Parker wrote: https://github.com/dlang/DIPs/blob/master/DIPs/DIP1005.md Very solid DIP! And I like the use of `with` and it's proposed extension to be allowed in declarations, rather than introducing new syntax.
Re: DIP 1005 - Preliminary Review Round 1
On Saturday, 22 April 2017 at 11:54:08 UTC, Mike Parker wrote:
https://github.com/dlang/DIPs/blob/master/DIPs/DIP1005.md
with (Type) and with (TemplateInstance) are always declarations
and do not introduce a new scope.
Does that mean we can now do things like this?:
-
module m;
struct A { struct B { } }
with (A) B b;
-
That's a pretty cool addition.
Re: DIP 1005 - Preliminary Review Round 1
On Saturday, 22 April 2017 at 11:54:08 UTC, Mike Parker wrote: DIP 1005 is titled "Dependency-Carrying Declarations". https://github.com/dlang/DIPs/blob/master/DIPs/DIP1005.md Oh, this is huge, great work! Many thanks to all authors! --Ilya
