implicit Questions
3
Solved
I would like to propagate a request context implicitly in a system of collaborating actors.
To simplify and present the situation, my system has multiple actors and the messages passed to these ac...
Concision asked 6/4, 2013 at 15:11
4
Solved
I read a lot of tutorials about CFLAGS and also looked in the official docs. Everywhere they say CFLAGS is implicit but still pass it explicitly in their example makefile to the compiler:
CFLAGS=-...
2
Solved
This is a simple question.
Why was not the method related to Int resided in Int?
Instead Scala bothers to put related methods into RichInt and rely on implicit conversion so as to have them work ...
2
As a beginner in J I am often confronted with tacit programs which seem quite byzantine compared to the more familiar explicit form.
Now just because I find interpretation hard does not mean that...
Blayze asked 12/4, 2015 at 16:7
3
Solved
Suppose I have the code:
class A(implicit s:String = "foo"){println(s)}
object X {
implicit val s1 = "hello"
}
object Y {
import X._
// do something with X
implicit val s2 = "hi"
val a = ne...
Guffaw asked 28/2, 2015 at 9:18
1
I just ran into a strange disparity between functions and objects (scala 2.10):
implicit def conv(c: Int => String) : (PrintStream => Int => Unit) = p => v => p.println(c(v))
def f(...
Assign asked 11/2, 2015 at 9:7
2
Solved
I've not been able to come up with how to encode Obj in Scala:
{-# LANGUAGE ExistentialQuantification #-}
data Obj = forall a. (Show a) => Obj a
instance Show Obj where show (Obj a) = "Obj " ...
Lobule asked 25/1, 2015 at 14:49
5
Solved
im currently reading a book about programming Android and there is a nice little reference guide on Java in the beginning chapters. However, I stumpled upon something about implicit parameters that...
Wharfinger asked 8/4, 2012 at 19:55
2
Solved
Is there a way for me to define the same implicit ordering for two different classes?
I tried to do something along the following lines but it doesn't detect the ordering.
abstract class Common
c...
3
The type class pattern in Scala involves defining a trait such as:
trait Show[T] {
def show(obj: T): String
}
Then you can define instantiations of this type class as such:
object Show {
impl...
1
Solved
Please refer to the source code below. All source code is defined in the same package. When I define all of the code within a single source file ShowMain.scala, I get a compile error, however when ...
Effie asked 24/8, 2014 at 4:37
1
Having used a Scala library that liberally exposes the reliance on implicits to the caller, I had experienced friction around this mechanism, as Scala makes it quite hard at times to debug implicit...
9
Solved
I want to be better about knowing when I should cast. What are the implicit type conversion rules in C++ when adding, multiplying, etc. For example,
int + float = ?
int * float = ?
float * int = ?...
2
Solved
Case classes do not seem to have an implicit ordering in scala.
scala> case class A(i:Int)
defined class A
scala> implicitly[Ordering[A]]
<console>:10: error: No implicit Ordering def...
Greenfinch asked 23/7, 2014 at 17:37
4
Basically, if I want something like this,
double b = sin(2.2);
but accidentally write something like this,
double b = sin(2.2f);
there is no error or even warning message, even though this cl...
Southey asked 29/6, 2014 at 18:22
1
I'm currently working with a codebase that requires an explicit parameter to have implicit scope for parts of its implementation:
class UsesAkka(system: ActorSystem) {
implicit val systemImplicit...
7
Solved
Why when i use this:
int a = 1;
methodWithParamString(a + "");
a is cast to String, bu i can't use toString() on integer?
int a = 1;
methodWithParamString(a.toString());
Doesn't this: a+"" wo...
3
Solved
I have a following function:
def getIntValue(x: Int)(implicit y: Int ) : Int = {x + y}
I see above declaration everywhere. I understand what above function is doing. It is a currying function wh...
Nordgren asked 8/5, 2014 at 15:27
2
Solved
If I have two Options such as
val a = Option(2)
val b = Option(1)
I can write
List(a,b).sorted
and it sorts correctly by inserting an implicit Ordering. How can I get a reference to this Ord...
Sweepings asked 25/4, 2014 at 3:55
1
Solved
So I've made some utility classes and implicit conversions for them. However, it works fine when converting from a Seq but not from a Set, although the code is the same, and those two traits seem r...
1
Solved
Other answers suggest using "-Xlog-implicits" option for debugging "diverging implicit expansion" errors. However, it also logs a lot of implicits in places unrelated to these errors. Is there some...
Hartwell asked 13/12, 2013 at 12:24
1
Solved
I've been reading some stuff on Scala type level programming. Mainly the Apocalisp blog, and also a youtube talk by Alexander Lehmann.
I am a bit stuck on something which I guess is probably very ...
1
Solved
I am new to Scala, and when I look at different projects, I see two styles for dealing with implicit arguments
scala]]>def sum[A](xs:List[A])(implicit m:Monoid[A]): A = xs.foldLeft(m.mzero)(m.m...
2
Solved
I was reading about type classes where implicit objects were mentioned:
object Math {
trait NumberLike[T] {
def plus(x: T, y: T): T
def divide(x: T, y: Int): T
def minus(x: T, y: T): T
}
obj...
2
Solved
I have a custom class with implement both the == and the implicit for boolean operator.
Is this the correct way to handle all possible, if ==/!= statements and get the expected result?
Like this:
...
Elemental asked 31/1, 2014 at 16:55
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