http://d.puremagic.com/issues/show_bug.cgi?id=2477

           Summary: Trailing comma in array literal sometimes accepted,
                    sometimes not
           Product: D
           Version: 1.037
          Platform: PC
        OS/Version: Windows
            Status: NEW
          Severity: normal
          Priority: P2
         Component: DMD
        AssignedTo: bugzilla@digitalmars.com
        ReportedBy: wbaxter@gmail.com


void main() {
    int[] data = [1,2,3,];  // OK

    data = [ 1,2,3, ];  // fails
/+
// error messages
trailcomma.d(20): found ';' when expecting ','
trailcomma.d(29): found 'EOF' when expecting ','
trailcomma.d(29): found 'EOF' when expecting ','
trailcomma.d(29): found 'EOF' when expecting ','
trailcomma.d(29): found 'EOF' when expecting ','
trailcomma.d(29): found 'EOF' when expecting ','
trailcomma.d(29): found 'EOF' when expecting ','
trailcomma.d(29): found 'EOF' when expecting ','
trailcomma.d(29): found 'EOF' when expecting ','
trailcomma.d(29): found 'EOF' when expecting ','
trailcomma.d(29): found 'EOF' when expecting ','
trailcomma.d(29): found 'EOF' when expecting ','
trailcomma.d(29): found 'EOF' when expecting ','
trailcomma.d(29): found 'EOF' when expecting ','
trailcomma.d(29): found 'EOF' when expecting ','
trailcomma.d(29): found 'EOF' when expecting ','
trailcomma.d(29): found 'EOF' when expecting ','
trailcomma.d(29): found 'EOF' when expecting ','
trailcomma.d(29): found 'EOF' when expecting ','
trailcomma.d(29): found 'EOF' when expecting ','
trailcomma.d(29): found 'EOF' when expecting ','
+/
}

The repetition of the EOF error message 20 times is also rather odd.

I don't know if trailing comma is spec'ed as being allowed or not (I much prefer allowing it), but either way it should be consistent.


-- 

http://d.puremagic.com/issues/show_bug.cgi?id=2477


smjg@iname.com changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |smjg@iname.com
           Keywords|                            |diagnostic, spec




------- Comment #1 from smjg@iname.com  2008-11-30 19:20 -------
The problem is that the spec is inconsistent.  In the first case, it's not an array literal, but an array initializer.

ArrayInitializer:
        [ ]
        [ ArrayMemberInitializations ]

ArrayMemberInitializations:
        ArrayMemberInitialization
        ArrayMemberInitialization ,
        ArrayMemberInitialization , ArrayMemberInitializations

versus

ArrayLiteral:
        [ ArgumentList ]

ArgumentList:
        AssignExpression
        AssignExpression , ArgumentList


Making these consistent is technically an enhancement request rather than a bug.  I nearly set this to enhancement, but the second issue (repetition of the error message) qualifies as a bug IMO.


-- 

http://d.puremagic.com/issues/show_bug.cgi?id=2477





------- Comment #2 from wbaxter@gmail.com  2008-11-30 19:38 -------
Thanks for the spec digging, Stewart.  So I see three options:

1) change the ArrayMemberInitializations production to:

ArrayMemberInitializations:
        ArrayMemberInitialization
        ArrayMemberInitialization , ArrayMemberInitializations

(get rid of the trailing comma case for initializations)

2) change the ArrayLiteral productions to

ArrayLiteral:
        [ ArrayLiteralMemberList ]

ArrayLiteralMemberList:
        AssignExpression
        AssignExpression ,
        AssignExpression , ArrayLiteralMemberList

3) Just make all argument lists have an optional trailing comma.  This is based on the thinking that if allowing a trailing comma is a nice feature for arrays, then why not general argument lists (which can be used as general array constructors with typesafe variadic A[]... style parameters.)?

ArgumentList:
        AssignExpression
        AssignExpression ,
        AssignExpression , ArgumentList

I vote for #2.


-- 

http://d.puremagic.com/issues/show_bug.cgi?id=2477


Brian Kropf <brian.kropf@gmail.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |brian.kropf@gmail.com




--- Comment #3 from Brian Kropf <brian.kropf@gmail.com>  2009-07-17 18:24:47 PDT ---
I'd originally submitted this on the ldc bugtracker and got forwarded here (since it is using the dmd front-end).  Here's a bit more info on the issue:

When using sabledd generated code, I'm seeing an error with ldc that was not present when I used gdc. It boils down to ldc not accepting only part of the endings of array initializers having commas. The following minimal test case does not build successfully on ldc x64 (but it will if you add a comma to the end of the second array initializer (like '[ 4, 5, 6, ],'). Curiously enough it also builds cleanly if I remove the commas after the 3 and the 6 in the example.

test.d: int arr[][] = [
    [ 1, 2, 3, ], [ 4, 5, 6, ]
];

int main(char[][] args) {
    return 0;
}

Error output:

test.d(7): expression expected, not ']' test.d(7): comma expected separating
array initializers, not ; test.d(9): semicolon expected, not 'int' Error:
Command failed, aborting.

-- 
Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email
------- You are receiving this mail because: -------

http://d.puremagic.com/issues/show_bug.cgi?id=2477


Aziz Köksal <aziz.koeksal@gmail.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |aziz.koeksal@gmail.com


--- Comment #4 from Aziz Köksal <aziz.koeksal@gmail.com> 2010-04-30 06:54:22 PDT ---
I agree, ArgumentLists, ArrayLiterals etc. should allow a trailing comma, just like ParameterLists or enums.

Fixing this should be possible in 6 to 10 lines of code. Why is this issue still open?

-- 
Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email
------- You are receiving this mail because: -------

http://d.puremagic.com/issues/show_bug.cgi?id=2477


Don <clugdbug@yahoo.com.au> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |clugdbug@yahoo.com.au


--- Comment #5 from Don <clugdbug@yahoo.com.au> 2010-04-30 07:18:03 PDT ---
(In reply to comment #4)
> I agree, ArgumentLists, ArrayLiterals etc. should allow a trailing comma, just like ParameterLists or enums.
> 
> Fixing this should be possible in 6 to 10 lines of code. Why is this issue still open?

Because there are over 1000 open bugs, and nearly all of them are more important than this one. Make a patch for it, if you care about it.

-- 
Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email
------- You are receiving this mail because: -------

http://d.puremagic.com/issues/show_bug.cgi?id=2477



--- Comment #6 from Ellery Newcomer <ellery-newcomer@utulsa.edu> 2010-04-30 08:49:05 PDT ---
Created an attachment (id=615)
allow trailing commas in various places

modifications for ArrayLiteral, Arguments, TemplateParameterList, and TemplateArguments.

I haven't tested it too heavily, but the simple stuff works. There might be latent trouble in the ambiguity between ArrayInitializer and ArrayLiteral (aside from what's already present), as I'm not well versed in what happens past the parser.

-- 
Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email
------- You are receiving this mail because: -------

http://d.puremagic.com/issues/show_bug.cgi?id=2477



--- Comment #7 from Aziz Köksal <aziz.koeksal@gmail.com> 2010-04-30 09:05:23 PDT ---
Don, I know it's not extremely important. I care about it, but I can't make patches for the DMD front- or back-end. Not because I don't want to, but because I'm working on a similar project; my own D compiler, remember? :-)

Ellery, thanks for taking care of this.

-- 
Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email
------- You are receiving this mail because: -------

http://d.puremagic.com/issues/show_bug.cgi?id=2477



--- Comment #8 from Ellery Newcomer <ellery-newcomer@utulsa.edu> 2010-04-30 10:02:04 PDT ---
(In reply to comment #7)
> Don, I know it's not extremely important. I care about it, but I can't make patches for the DMD front- or back-end. Not because I don't want to, but because I'm working on a similar project; my own D compiler, remember? :-)
> 

Come to think of it, so am I, or I was. I don't care much about the licensing, though. Or releasing it, if I ever finish it.

> Ellery, thanks for taking care of this.

Only needed to change 4 lines :)

-- 
Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email
------- You are receiving this mail because: -------

http://d.puremagic.com/issues/show_bug.cgi?id=2477


Walter Bright <bugzilla@digitalmars.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |bugzilla@digitalmars.com
            Version|1.037                       |D2
         OS/Version|Windows                     |All
           Severity|normal                      |enhancement


--- Comment #9 from Walter Bright <bugzilla@digitalmars.com> 2010-08-28 13:19:43 PDT ---
Since this changes the language, I'm going to do it for D2 only and mark it as an enhancement request.

-- 
Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email
------- You are receiving this mail because: -------