This post is composed of info on scala source desugaring originating from this thread. I was afraid the information would be lost forever so here’s what I managed to salvage after a fight with markdown (tables, oh my…).
Types
| Source type | Type |
|---|---|
Int => Int | Function1[Int, Int] |
(Int, Int, Int) => Int | Function3[Int, Int, Int, Int] |
(String, Int) | Tuple2[String, Int] |
String <:< Test | <:<[String, Test] |
Values
| Source value | Desugared | Type |
|---|---|---|
null | Null | Null |
() | () | Unit |
1 | 1 | Int |
2.0f | 2.0f | Float |
3.0 | 3.0 | Double |
"hello" | "hello" | String |
'd | Symbol("d") | Symbol |
(5,6) | Tuple2(5,6) | Tuple2[Int, Int] |
(7,8,9) | Tuple3(7,8,9) | Tuple3[Int, Int, Int] |
Anonymous Function1
x: Int => x * 1
// desugared
new Function1[Int, Int] {
def apply(x: Int): Int = x * 1
}
Anonymous Function2
(_: Int) * (_: Int)
// desugared
(x1: Int, x2: Int) => x1 * x2
Type: Function2[Int, Int, Int]
Partial function explicitly typed as a Function1
{ case x: Int => x }: (Any => Int)
// desugared
new Function1[Any, Int] {
def apply(x: Any) = x match { case x: Int => x}
}
Partial function
{ case x: Int => x }: PartialFunction[Any, Int]
// desugared
new PartialFunction[Any, Int] {
def apply(x: Any) = x match { case x: Int => x}
def isDefinedAt(x: Any) = x match { case x: Int => true; case _ => false}
}
XML Syntax
<a:b><c></c></a:b>
// desugared
new xml.Elem("a", "b", null, xml.TopScope,
new xml.Elem(null, "c", null, xml.TopScope))
Type: xml.Elem
Thanks to:
This information is true as of scala 2.7. Having said that, the desugarings in 2.8 shouldn’t have changed too much.