Am 19.10.2011, 18:25 Uhr, schrieb Alex Rønne Petersen
<xtzgzo...@gmail.com>:
On 19-10-2011 18:22, Alex Rønne Petersen wrote:
On 19-10-2011 18:18, Don wrote:
In D2 prior to 2.048, sqrt(2) does not compile. The reason is that it's
ambiguous whether it is sqrt(2.0), sqrt(2.0L), or sqrt(2.0f). This also
applies to _any_ function which has overloads for more than one
floating
point type.
In D2 between versions 2.049 and the present, sqrt(2) compiles due to
the request of a small number of people (2-3, I think). But still, no
other floating point function works with integer literals.
The "bug" being fixed was
Bugzilla 4455: Taking the sqrt of an integer shouldn't require an
explicit cast.
This compiles only due to an awful, undocumented hack in std.math. It
doesn't work for any function other than sqrt. I protested strongly
against this, but accepted it only on the proviso that we would fix
integer literal conversions to floating point in _all_ cases, so that
the hack could be removed.
However, when I proposed the fix on the newsgroup (integer literals
should have a preferred conversion to double), it was *unanimously*
rejected. Those who had argued for the hack were conspicuously absent.
The hack must go.
What on earth does it matter? It's just a cast. And when typing out
floating-point literals, it *really* does not hurt to type 2.0f instead
of 2. In .NET land, people live with this just fine (see
System.Math.Sqrt). Why can't we?
I say kill the hack.
- Alex
PS: What's wrong with converting integer literals to double? It's a
lossless conversion, no?
- Alex
As long as it is not a 64-bit integer, yes.
More philosophical, I think integer math should be separate from FP math,
because it has different semantics (integer division with remainder,
overflow vs. infinity, fixed steps vs. exponent, shifting, ...). So I
think .NET handles this correctly. But converting 32-bit ints to double
shouldn't harm much either. JavaScript has no integers, only doubles. It
works.
When you come across a for loop there and think to yourself "it increments
a variant that stores a double there", you can laugh or cry. (Actually
good JS engines optimize that case, of course.)
