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digitalmars.D.bugs - [Issue 6986] New: SortedRange[x..$] fails with unidentified __dollar

reply d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=6986

           Summary: SortedRange[x..$] fails with unidentified __dollar
           Product: D
           Version: D2
          Platform: x86_64
        OS/Version: Linux
            Status: NEW
          Severity: normal
          Priority: P2
         Component: DMD
        AssignedTo: nobody puremagic.com
        ReportedBy: jlquinn optonline.net


--- Comment #0 from Jerry Quinn <jlquinn optonline.net> 2011-11-21 22:35:06 PST
---
dmd 2.056 Linux x64

import std.range;
void foo(int[] buf) {
  auto bufsort = assumeSorted(buf);
  auto r = bufsort[1..$];
}

~/d/dmd2/linux/bin64/dmd -c range.d
range.d(5): Error: undefined identifier __dollar

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Nov 21 2011
next sibling parent d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=6986


Jonathan M Davis <jmdavisProg gmx.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |jmdavisProg gmx.com
           Platform|x86_64                      |All
         OS/Version|Linux                       |All
           Severity|normal                      |enhancement


--- Comment #1 from Jonathan M Davis <jmdavisProg gmx.com> 2011-11-21 22:57:17
PST ---
Technically, this is an enhancement request, not a bug - though it's certainly
a very desirable enhancement request. assumeSorted returns a SortedRange struct
which wraps the range which was passed to it. SortedRange does not define
opDollar, and at present, IIRC, opDollar hasn't been working correctly. So,
it's not possible for SortedRange to define opDollar, and there's no way that
your example is going to work. However, it looks like there was a commit made
to dmd about an hour ago which relates to opDollar (
https://github.com/D-Programming-Language/dmd/commit/aba0f773416e1d45d227159cb22ad0e26bb980c0
). So, it may now be possible to implement this.

But the short answer for why this doesn't work is that $ doesn't yet work for
anything other than built-in arrays, and assumeSorted doesn't return an array,
even if you pass it one (and it would defeat the purpose of assumeSort if it
did return an array).

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prev sibling next sibling parent d-bugmail puremagic.com writes:
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--- Comment #2 from Jerry Quinn <jlquinn optonline.net> 2011-11-21 23:06:36 PST
---
I'd think the simplest solution would be to do the same rewrite that happens
for builtin arrays, i.e.

x[p..$] => x.opSlice(p, x.length)

Then no opDollar is needed.

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prev sibling next sibling parent d-bugmail puremagic.com writes:
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Jonathan M Davis <jmdavisProg gmx.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
          Component|DMD                         |Phobos


--- Comment #3 from Jonathan M Davis <jmdavisProg gmx.com> 2011-11-21 23:13:04
PST ---
It doesn't work that way. opDollar is what's supposed to be used. I forget all
of the reasons why, but I believe that it has to do with cases where opDollar
would do something more complicated than simply opSlice(p, x.length). opDollar
is more flexible for some set of cases, but they're not the sort of use cases
that I normally think of, so I don't remember the exact details at the moment.
I'd have to go digging through the newsgroup archives for discussions which
related to it.

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prev sibling parent d-bugmail puremagic.com writes:
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timon.gehr gmx.ch changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |timon.gehr gmx.ch


--- Comment #4 from timon.gehr gmx.ch 2011-11-22 03:49:48 PST ---
The rewrite from $ to .length does not work if a range has no predetermined
length (eg. if it is infinite or corresponds to an input stream)

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