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digitalmars.D.bugs - [Issue 9009] New: allow foreach without identifier

reply d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=9009

           Summary: allow foreach without identifier
           Product: D
           Version: unspecified
          Platform: All
        OS/Version: All
            Status: NEW
          Severity: enhancement
          Priority: P2
         Component: DMD
        AssignedTo: nobody puremagic.com
        ReportedBy: monarchdodra gmail.com


--- Comment #0 from monarchdodra gmail.com 2012-11-12 07:57:54 PST ---
Minor enhancement request, but the language should allow using "foreach"
without specifying an iteration name. THis can be useful when you want to
iterate a fixed amount, without caring about the index. For example, when you
want to "popFrontN exactly" (popFrontN is safe, so slightly slower), you'd want
to write:

foreach( ; 0 .. n ) r.popFront();

Right now, if you do this, you get:
main.d(5): Error: basic type expected, not ;
main.d(5): Error: no identifier for declarator int

for can do without declarators, I don't see why foreach can't have the above
syntax.

Just a minor ER, but I think it would make foreach that little extra user
friendly.

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Nov 12 2012
next sibling parent d-bugmail puremagic.com writes:
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Andrej Mitrovic <andrej.mitrovich gmail.com> changed:

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--- Comment #1 from Andrej Mitrovic <andrej.mitrovich gmail.com> 2013-01-11
17:50:06 PST ---
I think this is a worthy request, although you can use "_" as an unused
iteration variable you may end up having to invent unique names with 2 or more
nested foreach loops:

foreach(_; 0 .. n ) {
    foreach(__; 0 .. m) {
        // statements
    }
}

Since foreach lowers to a for statement I think it should be possible to
implement the request.

Can we get a pre-approval from Walter/Andrei?

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Jan 11 2013
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--- Comment #2 from monarchdodra gmail.com 2013-01-13 13:56:29 PST ---
(In reply to comment #1)
 I think this is a worthy request, although you can use "_" as an unused
 iteration variable you may end up having to invent unique names with 2 or more
 nested foreach loops:
 
 foreach(_; 0 .. n ) {
     foreach(__; 0 .. m) {
         // statements
     }
 }
 
 Since foreach lowers to a for statement I think it should be possible to
 implement the request.
 
 Can we get a pre-approval from Walter/Andrei?

BTW, given the compiler error that is spit out by DMD upon writing //---- foreach ( ; 0 .. n ) //---- Error: basic type expected, not ; Error: no identifier for declarator int //---- I'd say it is either a bug that this isn't already supported anyway, or the compiler error should be re-written. -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email ------- You are receiving this mail because: -------
Jan 13 2013
prev sibling next sibling parent d-bugmail puremagic.com writes:
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bearophile_hugs eml.cc changed:

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                 CC|                            |bearophile_hugs eml.cc


--- Comment #3 from bearophile_hugs eml.cc 2013-03-06 16:15:47 PST ---
I think this is a simple nice idea. There is no point in requiring to name a
variable that will not used. It's like in function signatures:

void foo(int, int y) {}

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--- Comment #4 from Andrej Mitrovic <andrej.mitrovich gmail.com> 2013-03-07
07:08:24 PST ---
(In reply to comment #3)
 I think this is a simple nice idea. There is no point in requiring to name a
 variable that will not used. It's like in function signatures:
 
 void foo(int, int y) { }

He meant: void foo(int, int) { } -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email ------- You are receiving this mail because: -------
Mar 07 2013
prev sibling next sibling parent d-bugmail puremagic.com writes:
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Piotr Szturmaj <pszturmaj tlen.pl> changed:

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--- Comment #5 from Piotr Szturmaj <pszturmaj tlen.pl> 2013-08-25 12:50:39 PDT
---
I'd vote for version without a semicolon:

1. foreach (0 .. n)
2. foreach (range)

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Aug 25 2013
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Lionello Lunesu <lio+bugzilla lunesu.com> changed:

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                 CC|                            |lio+bugzilla lunesu.com


--- Comment #6 from Lionello Lunesu <lio+bugzilla lunesu.com> 2013-08-25
19:10:53 PDT ---
(In reply to comment #5)
 I'd vote for version without a semicolon:
 
 1. foreach (0 .. n)
 2. foreach (range)

Yes, I'd prefer that too. It's what newbies would write. foreach(; ...) is just too hard to explain to newcomers.t -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email ------- You are receiving this mail because: -------
Aug 25 2013