C++17 Init statement for if/switch
C++17 will have this feature: https://tech.io/playgrounds/2205/7-features-of-c17-that-will-simplify-your-code/init-statement-for-ifswitch What do you think about it, can we have something similar to that. Maybe something like this: int func() return 5; with(auto x = func()) if (condition(x)) do_something_with(x); else do_something_else_with(x);
Re: C++17 Init statement for if/switch
On Tuesday, 15 August 2017 at 18:55:57 UTC, Daniel Kozak wrote:
C++17 will have this feature:
https://tech.io/playgrounds/2205/7-features-of-c17-that-will-simplify-your-code/init-statement-for-ifswitch
What do you think about it, can we have something similar to
that.
Maybe something like this:
int func() return 5;
with(auto x = func()) if (condition(x))
do_something_with(x);
else
do_something_else_with(x);
this would be rewrite to
int func() return 5;
{
auto x = func();
if (condition(x))
do_something_with(x);
else
do_something_else_with(x);
}
Re: C++17 Init statement for if/switch
On Tuesday, 15 August 2017 at 19:04:32 UTC, Daniel Kozak wrote:
On Tuesday, 15 August 2017 at 18:55:57 UTC, Daniel Kozak wrote:
C++17 will have this feature:
int func() return 5;
with(auto x = func()) if (condition(x))
do_something_with(x);
else
do_something_else_with(x);
this would be rewrite to
int func() return 5;
{
auto x = func();
if (condition(x))
do_something_with(x);
else
do_something_else_with(x);
}
int func() { return 5; }
Re: C++17 Init statement for if/switch
On Tuesday, 15 August 2017 at 19:24:00 UTC, Daniel Kozak wrote:
int func() { return 5; }
int func() return 5;
was a typo in all my previous posts :)
Re: C++17 Init statement for if/switch
On 08/15/2017 08:55 PM, Daniel Kozak wrote: C++17 will have this feature: https://tech.io/playgrounds/2205/7-features-of-c17-that-will-simplify-your-code/init-statement-for-ifswitch What do you think about it, can we have something similar to that. Maybe something like this: int func() return 5; with(auto x = func()) if (condition(x)) do_something_with(x); else do_something_else_with(x); Previous discussion: http://forum.dlang.org/post/vfjlpvpwuyfqoljvp...@forum.dlang.org Andrei doesn't like the C++ way, but he seems to be ok with the `with` way: http://forum.dlang.org/post/oktru0$159b$1...@digitalmars.com Walter didn't comment. I think this has a good chance of getting in, but someone will have to write a DIP and implement it.
Re: C++17 Init statement for if/switch
On Tuesday, 15 August 2017 at 20:17:40 UTC, ag0aep6g wrote:
On 08/15/2017 08:55 PM, Daniel Kozak wrote:
C++17 will have this feature:
https://tech.io/playgrounds/2205/7-features-of-c17-that-will-simplify-your-code/init-statement-for-ifswitch
What do you think about it, can we have something similar to
that.
Maybe something like this:
int func() return 5;
with(auto x = func()) if (condition(x))
do_something_with(x);
else
do_something_else_with(x);
Previous discussion:
http://forum.dlang.org/post/vfjlpvpwuyfqoljvp...@forum.dlang.org
Andrei doesn't like the C++ way, but he seems to be ok with the
`with` way:
http://forum.dlang.org/post/oktru0$159b$1...@digitalmars.com
Walter didn't comment.
I think this has a good chance of getting in, but someone will
have to write a DIP and implement it.
I wouldn't mind writing a DIP but I haven't seen enough benefit
to warrant the change yet.
I grep'd for 'if' statements in a couple phobos modules and
didn't see too many places it could be used there.
The syntax does remind me of Andrei's scoped imports proposal:
with(import std.stdio : File) void foo(File file)
{
//...
}
I think if that proposal gets accepted it would be a natural
extension to allow both imports and declarations inside a 'with'
expression and it would get more exposure/usage among the greater
community. Without alot of usage, it will just be an esoteric
construct that looks confusing to the average developer. So I
guess it depends on whether or not you think it would gain
widespread adoption?
Re: C++17 Init statement for if/switch
On Tuesday, 15 August 2017 at 20:31:50 UTC, Jonathan Marler wrote: Without alot of usage, it will just be an esoteric construct that looks confusing to the average developer. That is correct. After a while it gets tiring to see a neverending stream of complexity added to the language while things that would actually help (like IDE support) do not get any attention. As a general rule, if it's being added to C++, it's probably a bad idea.
Re: C++17 Init statement for if/switch
On Tuesday, 15 August 2017 at 21:05:09 UTC, bachmeier wrote: On Tuesday, 15 August 2017 at 20:31:50 UTC, Jonathan Marler wrote: Without alot of usage, it will just be an esoteric construct that looks confusing to the average developer. That is correct. After a while it gets tiring to see a neverending stream of complexity added to the language while things that would actually help (like IDE support) do not get any attention. +1, though I'd go for bug-fixing over IDEs. It was ridiculous that we were spending time discussing a marginal feature like scoping imports for module-scope template constraints, ie DIP 1005, when normal scoped and selective imports are not used that much yet, as evidenced by latent bugs like this symbol leak: https://issues.dlang.org/show_bug.cgi?id=17630 As a general rule, if it's being added to C++, it's probably a bad idea. Lol. :D
Re: C++17 Init statement for if/switch
On Wednesday, 16 August 2017 at 12:58:03 UTC, Joakim wrote: That is correct. After a while it gets tiring to see a neverending stream of complexity added to the language while things that would actually help (like IDE support) do not get any attention. +1, though I'd go for bug-fixing over IDEs. I like that. Feature freeze D until *all* bug reports are closed. While that would mean no more features for several years, I think it would benefit the language in the long run, both internally (less discussions about incorrect behavior) and externally (D is a mature and stable language).
Re: C++17 Init statement for if/switch
On Wednesday, 16 August 2017 at 13:40:47 UTC, Guillaume Boucher wrote: I like that. Feature freeze D until *all* bug reports are closed. While that would mean no more features for several years, I think it would benefit the language in the long run, both internally (less discussions about incorrect behavior) and externally (D is a mature and stable language). Seems a bit much. How about new features can only be added in one of every N releases (Where N > 1)?
Re: C++17 Init statement for if/switch
On Tuesday, 15 August 2017 at 21:05:09 UTC, bachmeier wrote: On Tuesday, 15 August 2017 at 20:31:50 UTC, Jonathan Marler wrote: Without alot of usage, it will just be an esoteric construct that looks confusing to the average developer. That is correct. After a while it gets tiring to see a neverending stream of complexity added to the language while things that would actually help (like IDE support) do not get any attention. As a general rule, if it's being added to C++, it's probably a bad idea. There are two thinks of c++ that I miss a little on D: - Structured binding - Uniform initialization But in general, I agreed with you.
Re: C++17 Init statement for if/switch
On Wednesday, 16 August 2017 at 13:40:47 UTC, Guillaume Boucher wrote: On Wednesday, 16 August 2017 at 12:58:03 UTC, Joakim wrote: That is correct. After a while it gets tiring to see a neverending stream of complexity added to the language while things that would actually help (like IDE support) do not get any attention. +1, though I'd go for bug-fixing over IDEs. I like that. Feature freeze D until *all* bug reports are closed. While that would mean no more features for several years, I think it would benefit the language in the long run, both internally (less discussions about incorrect behavior) and externally (D is a mature and stable language). You'd see a fork.
Re: C++17 Init statement for if/switch
On Wednesday, 16 August 2017 at 14:19:59 UTC, SrMordred wrote:
On Tuesday, 15 August 2017 at 21:05:09 UTC, bachmeier wrote:
On Tuesday, 15 August 2017 at 20:31:50 UTC, Jonathan Marler
wrote:
Without alot of usage, it will just be an esoteric construct
that looks confusing to the average developer.
That is correct. After a while it gets tiring to see a
neverending stream of complexity added to the language while
things that would actually help (like IDE support) do not get
any attention. As a general rule, if it's being added to C++,
it's probably a bad idea.
There are two thinks of c++ that I miss a little on D:
- Structured binding
- Uniform initialization
But in general, I agreed with you.
Initialization in D is pretty uniform now though. What corners am
I missing?
It's usually:
name = (args);
Structured bindings... I think C++ did it badly, actually. They
had the {...} syntax fr object construction that worked
everywhere and using the same for deconstruction would've allowed
for quite natural tuples, which manifest almost as language-level
constructs by then (with the help of 'auto' in template
parameters).
Re: C++17 Init statement for if/switch
On Thursday, 17 August 2017 at 13:11:51 UTC, Enamex wrote:
On Wednesday, 16 August 2017 at 14:19:59 UTC, SrMordred wrote:
On Tuesday, 15 August 2017 at 21:05:09 UTC, bachmeier wrote:
[...]
There are two thinks of c++ that I miss a little on D:
- Structured binding
- Uniform initialization
But in general, I agreed with you.
Initialization in D is pretty uniform now though. What corners
am I missing?
It's usually:
name = (args);
Structured bindings... I think C++ did it badly, actually. They
had the {...} syntax fr object construction that worked
everywhere and using the same for deconstruction would've
allowed for quite natural tuples, which manifest almost as
language-level constructs by then (with the help of 'auto' in
template parameters).
Nothing too serious, just miss somethings like:
void add_vec( vec2 a, vec2 b );
add_vec( {10,20}, {20,30} );
