Re: [Vala] Safe call operator
On Mo, 2012-02-20 at 07:28 +0100, pancake wrote: > i really like the idea of having the elvis operator and the safe navigation > operator in Vala. Elvis is already supported, just with different syntax: ?? (same as in C#) > > fmi : http://groovy.codehaus.org/Operators > > is this going to be added at some point into the compiler? > > On Feb 1, 2012, at 21:08, Jim Nelson wrote: > > > I was going to mention that as well. Null handling in Java is not > > analogous to Vala's strategy, if for no other reason than there's no NPE. > > > > It looks to me the idea of a future Vala that emphasizes code correctness > > is that it will catch things like this: > > > > Xyxxy? x = get_xyzzy(); > > int result = x.foo(); > > > > The compiler will flag that last line as problematic. I think it will, at > > least. I don't really know. But it seems to me that if null-checking is > > going to be enforced by the compiler, it's not too much to ask the language > > to supply good tools for doing that checking. The nullable operator is one > > step in that direction, but I've coded many lines where I needed something > > like the Elvis operator (and the associated operators suggested by Project > > Coin). > > > > I'll also point out that (according to the Project Coin page) the reason > > the null-safety operators were turned down by the Java committee was that > > the Checker framework was added to Java and that Groovy, the inspiration > > for the proposed syntax, uses dynamic typing, which makes the operators > > more flexible. But the first is not going to happen for Vala (I've not > > heard of any such framework) and the second could be made to argue against > > the nullable operator, which was, in fact, added to Vala. > > > > I think the Elvis operator (and its cousins) should get real consideration > > and not be dismissed merely because Java didn't take them. > > > > -- Jim > > > > > > > > On Tue, Jan 31, 2012 at 7:27 AM, Artem Tarasov > > wrote: > > > >>> As a starter, Java rejected that syntax. > >> > >> Yeah, but in Java at least a NullPointerException is thrown when null > >> dereferencing occurs. In Vala the only option to provide null-safety > >> is explicit checking for null after each method call in a chain. > >> ___ > >> vala-list mailing list > >> vala-list@gnome.org > >> http://mail.gnome.org/mailman/listinfo/vala-list > >> > > ___ > > vala-list mailing list > > vala-list@gnome.org > > http://mail.gnome.org/mailman/listinfo/vala-list > ___ > vala-list mailing list > vala-list@gnome.org > http://mail.gnome.org/mailman/listinfo/vala-list > ___ vala-list mailing list vala-list@gnome.org http://mail.gnome.org/mailman/listinfo/vala-list
Re: [Vala] Safe call operator
i really like the idea of having the elvis operator and the safe navigation operator in Vala. fmi : http://groovy.codehaus.org/Operators is this going to be added at some point into the compiler? On Feb 1, 2012, at 21:08, Jim Nelson wrote: > I was going to mention that as well. Null handling in Java is not > analogous to Vala's strategy, if for no other reason than there's no NPE. > > It looks to me the idea of a future Vala that emphasizes code correctness > is that it will catch things like this: > > Xyxxy? x = get_xyzzy(); > int result = x.foo(); > > The compiler will flag that last line as problematic. I think it will, at > least. I don't really know. But it seems to me that if null-checking is > going to be enforced by the compiler, it's not too much to ask the language > to supply good tools for doing that checking. The nullable operator is one > step in that direction, but I've coded many lines where I needed something > like the Elvis operator (and the associated operators suggested by Project > Coin). > > I'll also point out that (according to the Project Coin page) the reason > the null-safety operators were turned down by the Java committee was that > the Checker framework was added to Java and that Groovy, the inspiration > for the proposed syntax, uses dynamic typing, which makes the operators > more flexible. But the first is not going to happen for Vala (I've not > heard of any such framework) and the second could be made to argue against > the nullable operator, which was, in fact, added to Vala. > > I think the Elvis operator (and its cousins) should get real consideration > and not be dismissed merely because Java didn't take them. > > -- Jim > > > > On Tue, Jan 31, 2012 at 7:27 AM, Artem Tarasov > wrote: > >>> As a starter, Java rejected that syntax. >> >> Yeah, but in Java at least a NullPointerException is thrown when null >> dereferencing occurs. In Vala the only option to provide null-safety >> is explicit checking for null after each method call in a chain. >> ___ >> vala-list mailing list >> vala-list@gnome.org >> http://mail.gnome.org/mailman/listinfo/vala-list >> > ___ > vala-list mailing list > vala-list@gnome.org > http://mail.gnome.org/mailman/listinfo/vala-list ___ vala-list mailing list vala-list@gnome.org http://mail.gnome.org/mailman/listinfo/vala-list
Re: [Vala] Safe call operator
I was going to mention that as well. Null handling in Java is not analogous to Vala's strategy, if for no other reason than there's no NPE. It looks to me the idea of a future Vala that emphasizes code correctness is that it will catch things like this: Xyxxy? x = get_xyzzy(); int result = x.foo(); The compiler will flag that last line as problematic. I think it will, at least. I don't really know. But it seems to me that if null-checking is going to be enforced by the compiler, it's not too much to ask the language to supply good tools for doing that checking. The nullable operator is one step in that direction, but I've coded many lines where I needed something like the Elvis operator (and the associated operators suggested by Project Coin). I'll also point out that (according to the Project Coin page) the reason the null-safety operators were turned down by the Java committee was that the Checker framework was added to Java and that Groovy, the inspiration for the proposed syntax, uses dynamic typing, which makes the operators more flexible. But the first is not going to happen for Vala (I've not heard of any such framework) and the second could be made to argue against the nullable operator, which was, in fact, added to Vala. I think the Elvis operator (and its cousins) should get real consideration and not be dismissed merely because Java didn't take them. -- Jim On Tue, Jan 31, 2012 at 7:27 AM, Artem Tarasov wrote: > > As a starter, Java rejected that syntax. > > Yeah, but in Java at least a NullPointerException is thrown when null > dereferencing occurs. In Vala the only option to provide null-safety > is explicit checking for null after each method call in a chain. > ___ > vala-list mailing list > vala-list@gnome.org > http://mail.gnome.org/mailman/listinfo/vala-list > ___ vala-list mailing list vala-list@gnome.org http://mail.gnome.org/mailman/listinfo/vala-list
Re: [Vala] Safe call operator
This can induce hard to debug errors. For example, something should raise an error or an execption now may return 0 only. This return value might accidentally be used by other parts of the program. When the project become larger, it's hard to trace this bug. On Tue, Jan 31, 2012 at 11:27 PM, Artem Tarasov wrote: > > As a starter, Java rejected that syntax. > > Yeah, but in Java at least a NullPointerException is thrown when null > dereferencing occurs. In Vala the only option to provide null-safety > is explicit checking for null after each method call in a chain. > ___ > vala-list mailing list > vala-list@gnome.org > http://mail.gnome.org/mailman/listinfo/vala-list > ___ vala-list mailing list vala-list@gnome.org http://mail.gnome.org/mailman/listinfo/vala-list
Re: [Vala] Safe call operator
> As a starter, Java rejected that syntax. Yeah, but in Java at least a NullPointerException is thrown when null dereferencing occurs. In Vala the only option to provide null-safety is explicit checking for null after each method call in a chain. ___ vala-list mailing list vala-list@gnome.org http://mail.gnome.org/mailman/listinfo/vala-list
Re: [Vala] Safe call operator
On Tue, Jan 31, 2012 at 3:32 PM, wrote: > Do you know the reason why it was rejected? I searched for more > information but could only find the proposals, not the rejection. > http://blogs.oracle.com/darcy/entry/project_coin_final_five -- www.debian.org - The Universal Operating System ___ vala-list mailing list vala-list@gnome.org http://mail.gnome.org/mailman/listinfo/vala-list
Re: [Vala] Safe call operator
Do you know the reason why it was rejected? I searched for more information but could only find the proposals, not the rejection. A null-safe operator (an "elvis" operator) seems like a natural complement to the nullable operator already in Vala. -- Jim On Tue, Jan 31, 2012 at 4:58 AM, Luca Bruno wrote: > On Tue, Jan 31, 2012 at 1:34 PM, Artem Tarasov > wrote: > > > There's so-called 'safe call operator' in Kotlin programming language > > which, when used in chains, resembles 'Maybe' monad from Haskell. Thus it > > makes easier to work with nullable types in some cases. Is it possible to > > add such a feature to Vala? > > > > Adding a feature is always possible, but it must be discussed first :-) > As a starter, Java rejected that syntax. > > -- > www.debian.org - The Universal Operating System > ___ vala-list mailing list vala-list@gnome.org http://mail.gnome.org/mailman/listinfo/vala-list
Re: [Vala] Safe call operator
On Tue, Jan 31, 2012 at 1:34 PM, Artem Tarasov wrote: > There's so-called 'safe call operator' in Kotlin programming language > which, when used in chains, resembles 'Maybe' monad from Haskell. Thus it > makes easier to work with nullable types in some cases. Is it possible to > add such a feature to Vala? > Adding a feature is always possible, but it must be discussed first :-) As a starter, Java rejected that syntax. -- www.debian.org - The Universal Operating System ___ vala-list mailing list vala-list@gnome.org http://mail.gnome.org/mailman/listinfo/vala-list
[Vala] Safe call operator
Hello, today I stumbled upon this page: http://confluence.jetbrains.net/display/Kotlin/Null-safety There's so-called 'safe call operator' in Kotlin programming language which, when used in chains, resembles 'Maybe' monad from Haskell. Thus it makes easier to work with nullable types in some cases. Is it possible to add such a feature to Vala? ___ vala-list mailing list vala-list@gnome.org http://mail.gnome.org/mailman/listinfo/vala-list
