scala> Float.floatToI
On pressing tab here, it displays Float.floatToIntBits. But,
scala> Float.floatToIntBits(2f)
<console>:6: error: value floatToIntBits is not a member of object Float
Float.floatToIntBits(2f)
^
views:
142answers:
2
+5
A:
Float.floatToIntBits tries to call method on the object scala.runtime.Float (I think).
scala> Float
res2: Float.type = object scala.Float
You need java.lang.Float.floatToIntBits:
scala> java.lang.Float.floatToIntBits(2f)
res1: Int = 1073741824
Alexey Romanov
2010-08-22 17:09:46
Thanks. It works. curious to know why the method is displayed on available list of members while pressing tab in REPL?
Marimuthu Madasamy
2010-08-22 17:15:16
There are some spurious things in the REPL auto-completion ... they are just bugs which will be fixed.
soc
2010-08-23 12:30:42
+4
A:
The REPL code-completion shows methods from all the Float objects available on the path (i.e.scala.Floatscala.runtime.Float and java.lang.Float). However scala.Floatscala.runtime.Float takes precedence over java.lang.Float and hence the error.
The following works:
scala> import java.lang.{Float => JFloat}
import java.lang.{Float=>JFloat}
scala> JFloat.floatToIntBits(2f)
res5: Int = 1073741824
missingfaktor
2010-08-22 17:13:16
Is the object `scala.Float` actually defined anywhere? Searching for `float` at the API site only gives `scala.runtime.Float`, nor is there a definition in `package.scala` or `Predef.scala`...
Alexey Romanov
2010-08-22 17:20:01
@Alexey: It seems they moved `Float` from `scala` to `scala.runtime` in v2.8.
missingfaktor
2010-08-22 17:27:01
@Alexey: I think `scala.Float` is now defined as an alias to `scala.runtime.Float` in the `scala` package object. http://paste.pocoo.org/show/253212/
missingfaktor
2010-08-22 17:28:34
Well, http://lampsvn.epfl.ch/trac/scala/browser/scala/tags/R_2_8_0_final/src/library/scala/package.scala doesn't seem to have it.
Alexey Romanov
2010-08-22 17:44:04
@Alexey: The first line in the scaladoc of scala.runtime.Float(Link: scala-lang.org/api/current/scala/runtime/Float$.html) reads "A object representing object scala.Float." Not sure what that means. :(
missingfaktor
2010-08-22 17:54:42
@Alexey: I don't know for sure but I think it's like this: Neither the `scala.runtime.Float` object nor its alias in `scala` package object actually exist; They are just compiler magic.
missingfaktor
2010-08-22 18:01:50
`scala.runtime.Float` _is_ defined in http://lampsvn.epfl.ch/trac/scala/browser/scala/tags/R_2_8_0_final/src//library/scala/runtime/AnyValCompanion.scala#L77 but "compiler magic" does seem likely for `scala.Float`.
Alexey Romanov
2010-08-22 18:07:20
wish Scala REPL lists only the methods on the object which has 'precedence' because it seemed so obvious to work but the listed method resulting in error :(
Marimuthu Madasamy
2010-08-22 18:29:16
@Alexey: But the alias would be trivial to define: `val Float = scala.runtime.Float`. Why won't they define it then?
missingfaktor
2010-08-23 01:54:23
The following changeset seems to be related to the compiler magic: https://lampsvn.epfl.ch/trac/scala/changeset/21408 . I have neither found a reference in the specification nor the corresponding ticket, but I haven't searched very thoroughly.
mkneissl
2010-08-23 06:49:43