UFCS in the presence of alias this

Apr 19, 2012

Jens Mueller

Apr 19, 2012

Timon Gehr

Apr 19, 2012

Apr 19, 2012

Apr 19, 2012

Apr 19, 2012

Apr 19, 2012

Apr 19, 2012

Hi, using UFCS with alias this behaves strange. Consider struct Foo { int _member; alias _member this; } int foo(Foo f) { return f._member; } int foo(int i) { return i; } unittest { Foo f; f.foo(); // which function will be called? Isn't it ambiguous? } Due to the alias this the function foo(int i) will be called. Is this the indented behavior? Practically, I want UFCS to just perform a syntactic rewrite from f.foo() to foo(f). When using alias this you have to define the second function. Providing only the first one results in a compile error. If you remove the alias this things work as expected (first one needs to be defined). I stumbled upon this problem when trying to define additional functions for a Tuple. Tuple has "alias field this" for falling back on TypeTuple's opIndex. Unfortunately, alias Tuple!(int) Bar; int bar(typeof(Bar.field) b) { return 1; } unittest { Bar b; b.bar(); } does not work. Jens

On 04/19/2012 11:28 AM, Jens Mueller wrote: > Hi, > > using UFCS with alias this behaves strange. > Consider > > struct Foo > { > int _member; > alias _member this; > } > > int foo(Foo f) { return f._member; } > int foo(int i) { return i; } > > unittest > { > Foo f; > f.foo(); // which function will be called? Isn't it ambiguous? > } > > Due to the alias this the function foo(int i) will be called. Is this > the indented behavior? Practically, I want UFCS to just perform a > syntactic rewrite from f.foo() to foo(f). > When using alias this you have to define the second function. Providing > only the first one results in a compile error. If you remove the alias > this things work as expected (first one needs to be defined). > > I stumbled upon this problem when trying to define additional functions > for a Tuple. Tuple has "alias field this" for falling back on > TypeTuple's opIndex. Unfortunately, > > alias Tuple!(int) Bar; > int bar(typeof(Bar.field) b) { return 1; } > > unittest > { > Bar b; > b.bar(); > } > > does not work. > > Jens This is a bug. You can report it to: http://d.puremagic.com/issues/

Timon Gehr wrote: > On 04/19/2012 11:28 AM, Jens Mueller wrote: > >Hi, > > > >using UFCS with alias this behaves strange. > >Consider > > > >struct Foo > >{ > > int _member; > > alias _member this; > >} > > > >int foo(Foo f) { return f._member; } > >int foo(int i) { return i; } > > > >unittest > >{ > > Foo f; > > f.foo(); // which function will be called? Isn't it ambiguous? > >} > > > >Due to the alias this the function foo(int i) will be called. Is this > >the indented behavior? Practically, I want UFCS to just perform a > >syntactic rewrite from f.foo() to foo(f). > >When using alias this you have to define the second function. Providing > >only the first one results in a compile error. If you remove the alias > >this things work as expected (first one needs to be defined). > > > >I stumbled upon this problem when trying to define additional functions for a Tuple. Tuple has "alias field this" for falling back on TypeTuple's opIndex. Unfortunately, > > > >alias Tuple!(int) Bar; > >int bar(typeof(Bar.field) b) { return 1; } > > > >unittest > >{ > > Bar b; > > b.bar(); > >} > > > >does not work. > > > >Jens > > This is a bug. You can report it to: http://d.puremagic.com/issues/ It's submitted. http://d.puremagic.com/issues/show_bug.cgi?id=7943 Thanks for your reply. Jens

2012$BG/(B4$B7n(B19$BF|(B20:48 Jens Mueller <jens.k.mueller@gmx.de>: > Timon Gehr wrote: >> On 04/19/2012 11:28 AM, Jens Mueller wrote: >> >Hi, >> > >> >using UFCS with alias this behaves strange. >> >Consider >> > >> >struct Foo >> >{ >> > int _member; >> > alias _member this; >> >} >> > >> >int foo(Foo f) { return f._member; } >> >int foo(int i) { return i; } >> > >> >unittest >> >{ >> > Foo f; >> > f.foo(); // which function will be called? Isn't it ambiguous? >> >} >> > >> >Due to the alias this the function foo(int i) will be called. Is this >> >the indented behavior? Practically, I want UFCS to just perform a >> >syntactic rewrite from f.foo() to foo(f). >> >When using alias this you have to define the second function. Providing >> >only the first one results in a compile error. If you remove the alias >> >this things work as expected (first one needs to be defined). >> > >> >I stumbled upon this problem when trying to define additional functions for a Tuple. Tuple has "alias field this" for falling back on TypeTuple's opIndex. Unfortunately, >> > >> >alias Tuple!(int) Bar; >> >int bar(typeof(Bar.field) b) { return 1; } >> > >> >unittest >> >{ >> > Bar b; >> > b.bar(); >> >} >> > >> >does not work. >> > >> >Jens >> >> This is a bug. You can report it to: http://d.puremagic.com/issues/ > > It's submitted. > http://d.puremagic.com/issues/show_bug.cgi?id=7943 > Thanks for your reply. > > Jens Posted compiler fix: https://github.com/D-Programming-Language/dmd/pull/890 Thanks for your reporting, Jens! Kenji Hara

April 19, 2012

Re: UFCS in the presence of alias this

Posted by Jens Mueller

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Jens Mueller

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kenji hara wrote:
> 2012$BG/(B4$B7n(B19$BF|(B20:48 Jens Mueller <jens.k.mueller@gmx.de>:
> > Timon Gehr wrote:
> >> On 04/19/2012 11:28 AM, Jens Mueller wrote:
> >> >Hi,
> >> >
> >> >using UFCS with alias this behaves strange.
> >> >Consider
> >> >
> >> >struct Foo
> >> >{
> >> >     int _member;
> >> >     alias _member this;
> >> >}
> >> >
> >> >int foo(Foo f) { return f._member; }
> >> >int foo(int i) { return i; }
> >> >
> >> >unittest
> >> >{
> >> >     Foo f;
> >> >     f.foo(); // which function will be called? Isn't it ambiguous?
> >> >}
> >> >
> >> >Due to the alias this the function foo(int i) will be called. Is this
> >> >the indented behavior? Practically, I want UFCS to just perform a
> >> >syntactic rewrite from f.foo() to foo(f).
> >> >When using alias this you have to define the second function. Providing
> >> >only the first one results in a compile error. If you remove the alias
> >> >this things work as expected (first one needs to be defined).
> >> >
> >> >I stumbled upon this problem when trying to define additional functions for a Tuple. Tuple has "alias field this" for falling back on TypeTuple's opIndex. Unfortunately,
> >> >
> >> >alias Tuple!(int) Bar;
> >> >int bar(typeof(Bar.field) b) { return 1; }
> >> >
> >> >unittest
> >> >{
> >> >     Bar b;
> >> >     b.bar();
> >> >}
> >> >
> >> >does not work.
> >> >
> >> >Jens
> >>
> >> This is a bug. You can report it to: http://d.puremagic.com/issues/
> >
> > It's submitted.
> > http://d.puremagic.com/issues/show_bug.cgi?id=7943
> > Thanks for your reply.
> >
> > Jens
> 
> Posted compiler fix: https://github.com/D-Programming-Language/dmd/pull/890
> 
> Thanks for your reporting, Jens!

Fabulous. Thanks a lot.

Jens

Jens: >> It's submitted. http://d.puremagic.com/issues/show_bug.cgi?id=7943 (something like, one hour passes) Kenji: > Posted compiler fix: https://github.com/D-Programming-Language/dmd/pull/890 Man, you're wonderful Kenji. You never cease to amaze me. Your ability to correct bugs is borderline incredible.

2012$BG/(B4$B7n(B20$BF|(B0:56 Philippe Sigaud <philippe.sigaud@gmail.com>: > Jens: >>> It's submitted. http://d.puremagic.com/issues/show_bug.cgi?id=7943 > > (something like, one hour passes) > > Kenji: >> Posted compiler fix: https://github.com/D-Programming-Language/dmd/pull/890 > > Man, you're wonderful Kenji. You never cease to amaze me. Your ability to correct bugs is borderline incredible. Thanks. Kenji Hara

On 04/19/2012 05:56 PM, Philippe Sigaud wrote: > Jens: >>> It's submitted. >>> http://d.puremagic.com/issues/show_bug.cgi?id=7943 > > (something like, one hour passes) > I counted 26 minutes. > Kenji: >> Posted compiler fix: >> https://github.com/D-Programming-Language/dmd/pull/890 > > Man, you're wonderful Kenji. You never cease to amaze me. Your ability > to correct bugs is borderline incredible.

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