• Ky-Anh Huynh (16/16) Jul 28 2018 Hi,
• Jonathan M Davis (16/32) Jul 29 2018 Well, most folks would just make those separate statements, in which cas...
• Ky-Anh Huynh (6/24) Jul 30 2018 Thanks a lot for your explantion, Jonathan.
• PaperBoy (11/27) Jul 29 2018 This is the syntax sometimes seen with language that don't have
• Ky-Anh Huynh (4/19) Jul 30 2018 This is smart:) It's not very natural I think; in English, comma

Ky-Anh Huynh <saigon example.net> writes:

Hi,

is it nice to have a trailing comma in variable declaration:

[code]
   bool
     verbose = false,
     download_only = false,
     no_confirm = false,
     show_help = false,
     show_version = false,
     list_ops = false,
     ;
[/code]

As trailing comma is possible (and it's great) for arrays, 
enum,... I wonder why we don't have this fancy thing for 
variables declaration.

Thanks for your reading.

Jonathan M Davis <newsgroup.d jmdavisprog.com> writes:

On Saturday, July 28, 2018 11:32:15 PM MDT Ky-Anh Huynh via Digitalmars-d 
wrote:
 Hi,

 is it nice to have a trailing comma in variable declaration:

 [code]
    bool
      verbose = false,
      download_only = false,
      no_confirm = false,
      show_help = false,
      show_version = false,
      list_ops = false,
      ;
 [/code]

 As trailing comma is possible (and it's great) for arrays,
 enum,... I wonder why we don't have this fancy thing for
 variables declaration.

 Thanks for your reading.


Well, most folks would just make those separate statements, in which case,
there would be no commas at all. Some folks do put multiple variable
declarations on a single line, but if you do that, a trailing comma looks
terrible. I doubt that using a single statement to declare multiple
variables but putting it on multiple lines was even a use case that was
really considered. Also, a quick test with a C++ compiler shows that it's
not legal there, so the rules we have with regard to this probably just came
from C++. AFAIK, the only significant change that D has from C/C++ with
regards to declaring multiple variables in a single statement is that the *
is considered part of the type and thus

int* a, b, c;

declares three variables of type int* in D, whereas in C/C++, it would
declare a single variable of type int* and two of type int.

- Jonathan M Davis

Ky-Anh Huynh <saigon example.net> writes:

On Sunday, 29 July 2018 at 10:46:12 UTC, Jonathan M Davis wrote:
 
 Well, most folks would just make those separate statements, in 
 which case, there would be no commas at all. Some folks do put 
 multiple variable declarations on a single line, but if you do 
 that, a trailing comma looks terrible. I doubt that using a 
 single statement to declare multiple variables but putting it 
 on multiple lines was even a use case that was really 
 considered. Also, a quick test with a C++ compiler shows that 
 it's not legal there, so the rules we have with regard to this 
 probably just came from C++. AFAIK, the only significant change 
 that D has from C/C++ with regards to declaring multiple 
 variables in a single statement is that the * is considered 
 part of the type and thus

 int* a, b, c;

 declares three variables of type int* in D, whereas in C/C++, 
 it would declare a single variable of type int* and two of type 
 int.

 - Jonathan M Davis

Thanks a lot for your explantion, Jonathan.

I understand the idea is to minimize the differences between 
C/C++ and D (FIXME.) Anyway the missing feature suprised me; I 
thought variable declaration is simply a (compile time) list, and 
as an array, leading comma was acceptable :)

PaperBoy <PaperBoy za.za> writes:

On Sunday, 29 July 2018 at 05:32:15 UTC, Ky-Anh Huynh wrote:
 Hi,

 is it nice to have a trailing comma in variable declaration:

 [code]
   bool
     verbose = false,
     download_only = false,
     no_confirm = false,
     show_help = false,
     show_version = false,
     list_ops = false,
     ;
 [/code]

 As trailing comma is possible (and it's great) for arrays, 
 enum,... I wonder why we don't have this fancy thing for 
 variables declaration.

 Thanks for your reading.

This is the syntax sometimes seen with language that don't have 
trailling comma at all.

bool
        verbose = false
      , download_only = false
      , no_confirm = false
      , show_help = false
      , show_version = false
      , list_ops = false
      ;

Ky-Anh Huynh <saigon example.net> writes:

On Sunday, 29 July 2018 at 14:47:59 UTC, PaperBoy wrote:
 As trailing comma is possible (and it's great) for arrays, 
 enum,... I wonder why we don't have this fancy thing for 
 variables declaration.

 Thanks for your reading.

 This is the syntax sometimes seen with language that don't have 
 trailling comma at all.

 bool
        verbose = false
      , download_only = false
      , no_confirm = false
      , show_help = false
      , show_version = false
      , list_ops = false
      ;

This is smart:) It's not very natural I think; in English, comma 
and punctuation would be closed to the last character (e.g., the 
dot in this sentence.)