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digitalmars.D.bugs - [Issue 10394] New: opBinaryRight!"in" and tuple

reply d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=10394

           Summary: opBinaryRight!"in" and tuple
           Product: D
           Version: D2
          Platform: All
        OS/Version: All
            Status: NEW
          Severity: regression
          Priority: P2
         Component: DMD
        AssignedTo: nobody puremagic.com
        ReportedBy: justin economicmodeling.com



13:48:39 PDT ---
The following code compiles with 2.062 but not with 2.063:
-------------------------------------------------------
import std.typetuple;

struct Cube
{
    alias Address = TypeTuple!(int, int);
    //alias Address = int;

    int* opBinaryRight(string op)(Address where)
    {
        return null;
    }
}

void main()
{
    Cube cube;
    cube.Address addr;
    auto ptr = addr in cube;
}
---------------------------------------------------------
In 2.063, DMD produces the following:
cube.d(18): Error: rvalue of in expression must be an associative array, not
Cube

Flipping the comments on the two "alias Address" lines causes the sample to
compile under both, so the problem is triggered by the use of a tuple as the
left side of the "in" operator.  Using DMD with -v indicates the trouble is
during the semantic3 phase.

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Jun 17 2013
next sibling parent d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=10394


Andrej Mitrovic <andrej.mitrovich gmail.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |andrej.mitrovich gmail.com



15:52:18 PDT ---
You could use Tuple from std.typecons instead and it will work.

It seems to me what's going on is auto-expansion of a TypeTuple into two
arguments, and opBinaryRight (or opIn_r) simply can't accept more than one
argument.

I don't know why that even worked before, it might have been an accepts-invalid
bug in 2.062 and earlier. Kenji Hara will probably know more.

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Jun 17 2013
prev sibling next sibling parent d-bugmail puremagic.com writes:
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16:08:36 PDT ---


 You could use Tuple from std.typecons instead and it will work.
 
 It seems to me what's going on is auto-expansion of a TypeTuple into two
 arguments, and opBinaryRight (or opIn_r) simply can't accept more than one
 argument.
 
 I don't know why that even worked before, it might have been an accepts-invalid
 bug in 2.062 and earlier. Kenji Hara will probably know more.


From my perspective it'd be somewhat unfortunate to lose the ability to do
this.  We make extensive use of "in" as a complement to indexing the same way
associative arrays do: indexing returns the thing or throws if not present
while "in" returns a pointer to the thing or null if not present. Because we
use indexing with multiple "keys" it's nice to have a symmetric way of using
"in".

As for your suggestion to use Tuple, we usually provide an overload for that as
well, particularly because tuples can't be returned from functions.

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15:45:23 PDT ---
An update on this issue: we have worked around this by switching away from "in"
to a method-based approach, so this is no longer blocking for the reporter.  I
think this issue remains valid until it's decided whether the "in" operator (or
operators in general) will allow a tuple on the left hand side.  Here's a
simplified example that matches with our use case:
-----------------------------
struct Graph(T, Address...)
{
    struct Node
    {
        Address address;
        T payload;
    }

   ...

   Node* opBinaryRight(string op)(Address address) if (op == "in)
   {
       ...
   }
}

void main()
{
    Graph!(double, int, string) graph;
    auto node = ...procure a node from somwhere...

    // node.address is preferred to tuple(node.address)
    if (auto inGraph = node.address in graph)
    {
        ...
    }
}
-----------------------------

As I said, we have worked around this because it's not unreasonable for binary
operators to only allow one value on each side, but it was also nice to have
this kind of syntax in 2.062 and previous.

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Jul 15 2013
prev sibling next sibling parent d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=10394


Kenji Hara <k.hara.pg gmail.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |pull



https://github.com/D-Programming-Language/dmd/pull/2497

I still have a doubt that this should be fixed... Even if the dmd
implementation will be fixed in 2.064 release, we should continue discussion
about the combination of operator-overloading and built-in tuple behavior.

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Aug 25 2013
prev sibling next sibling parent d-bugmail puremagic.com writes:
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Commits pushed to master at https://github.com/D-Programming-Language/dmd

https://github.com/D-Programming-Language/dmd/commit/c4ca9257ed2863f8ef2c1be31e8690f2363a3ab9
fix Issue 10394 - opBinaryRight!"in" and tuple

https://github.com/D-Programming-Language/dmd/commit/73ca1a9b83ef6fcd8922fb7c5d6b2c0a0b576ca9


[REG2.064a] Issue 10394 - opBinaryRight!"in" and tuple

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Aug 27 2013
prev sibling parent d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=10394


Walter Bright <bugzilla digitalmars.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
                 CC|                            |bugzilla digitalmars.com
         Resolution|                            |FIXED


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