Thread overview
[Issue 3000] New: iota should work with floats
May 17, 2009
dsimcha@yahoo.com
Jul 10, 2009
Brad Roberts
Jul 11, 2009
Brad Roberts
May 17, 2009
http://d.puremagic.com/issues/show_bug.cgi?id=3000

           Summary: iota should work with floats
           Product: D
           Version: 2.030
          Platform: PC
        OS/Version: Windows
            Status: NEW
          Severity: normal
          Priority: P2
         Component: Phobos
        AssignedTo: bugzilla@digitalmars.com
        ReportedBy: dsimcha@yahoo.com


import std.range;

void main() {
    auto foo = iota(0.0L, 10.0L, 1.0L);
}

The above doesn't compile and results in a bunch of long errors that aren't
particularly useful for diagnosing the cause of the problem.  The real problem
is
line 2089, range.d:

return take((end - begin + step - 1) / step, Seq(tuple(begin, step), 0u));

The problem is that, if the arguments to iota are floats, not ints, the number of elements take() is told to take is a float, not an int.  This can be fixed trivially by changing that line to:

return take(cast(size_t) ((end - begin + step - 1) / step), Seq(tuple(begin,
step), 0u));

Also, take() should probably use a ulong, not a size_t.  I could picture someone wanting to run a long monte carlo simulation, for example, by taking more than 4 billion elements from an infinite range of random numbers.

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May 18, 2009
http://d.puremagic.com/issues/show_bug.cgi?id=3000


Andrei Alexandrescu <andrei@metalanguage.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |ASSIGNED
                 CC|                            |andrei@metalanguage.com
         AssignedTo|bugzilla@digitalmars.com    |andrei@metalanguage.com




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July 07, 2009
http://d.puremagic.com/issues/show_bug.cgi?id=3000


Andrei Alexandrescu <andrei@metalanguage.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|                            |FIXED




--- Comment #1 from Andrei Alexandrescu <andrei@metalanguage.com>  2009-07-07 10:02:24 PDT ---
Fixed in future 2.032 (and checked in for the impatient).

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July 10, 2009
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Brad Roberts <braddr@puremagic.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|RESOLVED                    |REOPENED
                 CC|                            |braddr@puremagic.com
         Resolution|FIXED                       |




--- Comment #2 from Brad Roberts <braddr@puremagic.com>  2009-07-09 22:33:01 PDT ---
Should the examples be updated to include one for floats, maybe?

Also, how about adding a bit more sanity checking such as B, E, and S are all numeric types?

Also, what does 'iota' stand for?  I keep reading it as 'itoa' which is obviously wrong.

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July 11, 2009
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Andrei Alexandrescu <andrei@metalanguage.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|REOPENED                    |RESOLVED
         Resolution|                            |FIXED




--- Comment #3 from Andrei Alexandrescu <andrei@metalanguage.com>  2009-07-11 12:11:32 PDT ---
(In reply to comment #2)
> Should the examples be updated to include one for floats, maybe?

Done. Also found and fixed a couple of issues with negative ranges.

> Also, how about adding a bit more sanity checking such as B, E, and S are all numeric types?

B and E can be pointers. I did add a check that should eliminate nonsensical calls.

> Also, what does 'iota' stand for?  I keep reading it as 'itoa' which is obviously wrong.

It's an actual word of which meaning in the current context I borrowed from some STL implementations (http://www.sgi.com/tech/stl/iota.html).

Bug fixed and checked in; the fix will come in dmd 2.032.

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--- Comment #4 from Brad Roberts <braddr@puremagic.com>  2009-07-11 12:15:59 PDT ---
I thought that might be the case (regarding the name), but it wasn't obvious. And I still keep reading it with the o and t reversed. :)

Thanks for the updates.

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