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digitalmars.D.bugs - [Issue 7389] New: Disallow or implement correct SortedRange equality

reply d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=7389

           Summary: Disallow or implement correct SortedRange equality
           Product: D
           Version: D2
          Platform: All
        OS/Version: All
            Status: NEW
          Severity: enhancement
          Priority: P2
         Component: Phobos
        AssignedTo: nobody puremagic.com
        ReportedBy: bearophile_hugs eml.cc


--- Comment #0 from bearophile_hugs eml.cc 2012-01-28 06:10:59 PST ---
Given two small unsorted arrays 'a1' and 'a2', a common natural idiom to test
that they have the same items is:
a1.sort() == a2.sort()


But currently in D2 it's a trap:


import std.algorithm: sort;
void main() {
    auto a1 = [1, 2];
    auto a2 = [2, 1];
    assert(a1.sort() == a2.sort()); // AssertError
    assert(a1.sort().release() == a2.sort().release()); // OK    
}


To avoid such bugs I suggest to statically forbid the == operation among two
SortedRange; or _better_ to implement it correctly, and allow that testing
idiom.

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parent d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=7389



--- Comment #1 from bearophile_hugs eml.cc 2012-01-28 06:19:26 PST ---
Another workaround:

import std.algorithm: sort, equal;
void main() {
    auto a1 = [1, 2];
    auto a2 = [2, 1];
    assert(equal(a1.sort(), a2.sort())); // OK
}

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