Symbols
| Symbol | Description |
|---|---|
<- |
Used on for-comprehensions, to separate pattern from generator |
=> |
Used for function types, function literals and import renaming |
Reserved
| Symbol | Description |
|---|---|
// /* */ |
Comments |
" """ |
Strings |
$ |
String interpolation |
' |
Indicate symbols and characters |
, |
Parameter separator |
; |
Statement separator |
( ) |
Delimit expressions and parameters |
[ ] |
Delimit type parameters |
{ } |
Delimit blocks, pattern matching lambda blocks |
. |
Method call and path separator |
# |
Used in type notations |
: |
Type ascription or context bounds |
<: >: |
Upper and lower bounds |
<% |
View bounds (deprecated) |
@ |
Annotations and variable binding on pattern matching |
backtick |
Denote constant or enable arbitrary identifiers |
_* |
Vararg expansion |
_. |
Many different meanings |
-> |
Map/tuple |
Underscore
| Symbol | Description |
|---|---|
import scala._ |
Wild card – all of Scala is imported |
import scala.{ Predef => _, _ } |
Exclusion, everything except Predef |
case _ => |
Wild card pattern – matches anything |
def f[M[_]] |
Higher kinded type parameter |
def f(m: M[_]) |
Existential type |
m _ |
Eta expansion of method into method value |
m(_) |
Partial function application |
_ + _ |
Anonymous function placeholder parameter |
_ => 5 |
Discarded parameter |
f(xs: _*) |
Sequence xs is passed as multiple parameters to f(ys: T*) |
case Seq(xs @ _*) |
Identifier xs is bound to the whole matched sequence |
