scala.compiletime
Members list
Type members
Experimental classlikes
A marker trait for erased values. vals or parameters whose type extends Erased get an implicit erased modifier.
Value members
Concrete methods
Assertion that an argument is by-name. Used for nullability checking.
Assertion that an argument is by-name. Used for nullability checking.
Attributes
- Source
- package.scala
Returns the string representation of argument code:
Returns the string representation of argument code:
inline def logged(inline p1: Any) =
("code: " + codeOf(p1), p1)
logged(identity("foo"))
// above is equivalent to:
// ("code: scala.Predef.identity("foo")", identity("foo"))
The formatting of the code is not stable across version of the compiler.
Attributes
- Note
-
only
inlinearguments will be displayed as "code". Other values may display unintutively. - Source
- package.scala
Given a constant, singleton type T, convert it to a value of the same singleton type. For example: assert(constValue[1] == 1).
Given a constant, singleton type T, convert it to a value of the same singleton type. For example: assert(constValue[1] == 1).
Attributes
- Source
- package.scala
Same as constValue but returns a None if a constant value cannot be constructed from the provided type. Otherwise returns that value wrapped in Some.
Same as constValue but returns a None if a constant value cannot be constructed from the provided type. Otherwise returns that value wrapped in Some.
Attributes
- Source
- package.scala
Given a tuple type (X1, ..., Xn), returns a tuple value (constValue[X1], ..., constValue[Xn]).
Given a tuple type (X1, ..., Xn), returns a tuple value (constValue[X1], ..., constValue[Xn]).
Attributes
- Source
- package.scala
Used as the right hand side of a given in a trait, like this
Used as the right hand side of a given in a trait, like this
given T = deferred
This signifies that the given will get a synthesized definition in all classes that implement the enclosing trait and that do not contain an explicit overriding definition of that given.
Attributes
- Source
- package.scala
Use this method when you have a type, do not have a value for it but want to pattern match on it. For example, given a type Tup <: Tuple, one can pattern-match on it as follows:
Use this method when you have a type, do not have a value for it but want to pattern match on it. For example, given a type Tup <: Tuple, one can pattern-match on it as follows:
type Tup
inline def f = {
inline erasedValue[Tup] match {
case _: EmptyTuple => ???
case _: (h *: t) => ???
}
}
This value can only be used in an inline match and the value cannot be used in the branches.
Attributes
- Source
- package.scala
The error method is used to produce user-defined compile errors during inline expansion. If an inline expansion results in a call error(msgStr) the compiler produces an error message containing the given msgStr.
The error method is used to produce user-defined compile errors during inline expansion. If an inline expansion results in a call error(msgStr) the compiler produces an error message containing the given msgStr.
error("My error message")
or
inline def errorOnThisCode(inline x: Any) =
error("My error of this code: " + codeOf(x))
Attributes
- Source
- package.scala
Checks at compiletime that the provided values is a constant after inlining and constant folding.
Checks at compiletime that the provided values is a constant after inlining and constant folding.
Usage:
inline def twice(inline n: Int): Int =
requireConst(n) // compile-time assertion that the parameter `n` is a constant
n + n
twice(1)
val m: Int = ???
twice(m) // error: expected a constant value but found: m
Attributes
- Source
- package.scala
Given a tuple T, summons each of its member types and returns them in a Tuple.
Given a tuple T, summons each of its member types and returns them in a Tuple.
Type parameters
- T
-
the tuple containing the types of the values to be summoned
Attributes
- Returns
-
the given values typed as elements of the tuple
- Source
- package.scala
Summons first given matching one of the listed cases. E.g. in
Summons first given matching one of the listed cases. E.g. in
type A
trait B
type C
inline def f = {
given B with { }
summonFrom {
case given A => 1
case given B => 2
case given C => 3
case _ => 4
}
}
the returned value would be 2.
Attributes
- Source
- package.scala
Summon a given value of type T. Usually, the argument is not passed explicitly. The summoning is delayed until the call has been fully inlined.
Summon a given value of type T. Usually, the argument is not passed explicitly. The summoning is delayed until the call has been fully inlined.
Type parameters
- T
-
the type of the value to be summoned
Attributes
- Returns
-
the given value typed as the provided type parameter
- Source
- package.scala
Used as the initializer of a mutable class or object field, like this:
Used as the initializer of a mutable class or object field, like this:
type T
var x: T = uninitialized
This signifies that the field is not initialized on its own. It is still initialized as part of the bulk initialization of the object it belongs to, which assigns zero values such as null, 0, 0.0, false to all object fields.
Attributes
- Source
- package.scala
Extensions
Extensions
Casts a value to be Matchable. This is needed if the value's type is an unconstrained type parameter and the value is the scrutinee of a match expression. This is normally disallowed since it violates parametricity and allows to uncover implementation details that were intended to be hidden. The asMatchable escape hatch should be used sparingly. It's usually better to constrain the scrutinee type to be Matchable in the first place.
Casts a value to be Matchable. This is needed if the value's type is an unconstrained type parameter and the value is the scrutinee of a match expression. This is normally disallowed since it violates parametricity and allows to uncover implementation details that were intended to be hidden. The asMatchable escape hatch should be used sparingly. It's usually better to constrain the scrutinee type to be Matchable in the first place.
Attributes
- Source
- package.scala