scala.util
Members list
Packages
Type members
Classlikes
A utility object to support command line parsing for @main methods
A utility object to support command line parsing for @main methods
Attributes
- Source
- CommandLineParser.scala
- Supertypes
- Self type
-
CommandLineParser.type
A type class for types that admit numeric literals.
A type class for types that admit numeric literals.
Attributes
- Companion
- object
- Source
- FromDigits.scala
- Supertypes
- Known subtypes
-
trait Decimal[T]trait Floating[T]object BigDecimalFromDigitstrait WithRadix[T]object BigIntFromDigits
Attributes
- Companion
- trait
- Source
- FromDigits.scala
- Supertypes
- Self type
-
FromDigits.type
Attributes
- Source
- NotGiven.scala
- Supertypes
- Known subtypes
-
object NotGiven
A special class used to implement negation in implicit search.
A special class used to implement negation in implicit search.
Consider the problem of using implicit i1 for a query type D if an implicit for some other class C is available, and using an implicit i2 if no implicit value of type C is available. If we do not want to prioritize i1 and i2 by putting them in different traits we can instead define the following:
given i1: D(using ev: C) = ... given i2: D(using ev: NotGiven[C]) = ...
NotGiven is treated specially in implicit search, similar to the way logical negation is treated in Prolog: The implicit search for NotGiven[C] succeeds if and only if the implicit search for C fails.
In Scala 2 this form of negation can be simulated by setting up a conditional ambiguous implicit and an unconditional fallback, the way it is done with the default, amb1 and amb2 methods below. Due to the way these two methods are defined, NotGiven is also usable from Scala 2.
In Dotty, ambiguity is a global error, and therefore cannot be used to implement negation. Instead, NotGiven is treated natively in implicit search.
Attributes
- Companion
- object
- Source
- NotGiven.scala
- Supertypes
Attributes
- Companion
- class
- Source
- NotGiven.scala
- Supertypes
- Self type
-
NotGiven.type
A boundary that can be exited by break calls. boundary and break represent a unified and superior alternative for the scala.util.control.NonLocalReturns and scala.util.control.Breaks APIs. The main differences are:
A boundary that can be exited by break calls. boundary and break represent a unified and superior alternative for the scala.util.control.NonLocalReturns and scala.util.control.Breaks APIs. The main differences are:
- Unified names:
boundaryto establish a scope,breakto leave it.breakcan optionally return a value. - Integration with exceptions.
breaks are logically non-fatal exceptions. TheBreakexception class extendsRuntimeExceptionand is optimized so that stack trace generation is suppressed. - Better performance: breaks to enclosing scopes in the same method can be rewritten to jumps.
Example usage:
import scala.util.boundary, boundary.break
def firstIndex[T](xs: List[T], elem: T): Int =
boundary:
for (x, i) <- xs.zipWithIndex do
if x == elem then break(i)
-1
Attributes
- Source
- boundary.scala
- Supertypes
- Self type
-
boundary.type
Experimental classlikes
Type class relating a FunctionN[..., R] with an equivalent tupled function Function1[TupleN[...], R]
Type class relating a FunctionN[..., R] with an equivalent tupled function Function1[TupleN[...], R]
Type parameters
- F
-
a function type
- G
-
a tupled function type (function of arity 1 receiving a tuple as argument)
Attributes
- Experimental
- true
- Source
- TupledFunction.scala
- Supertypes