I can't understand why this code is wrong, the error message is:
error: '}' expected but '.' found.
on line
this.tX = cX
code:
class Quaternion {
private var tX: Float = 0
private var tY: Float = 0
private var tZ: Float = 0
private var tW: Float = 1
def this(cX: Float, cY: Float, cZ: Float, cW: Float) {
this.tX = cX
this.tY = cY
this.tZ = cZ
this.tW = cW
}
...
Please help me fix my probably obvious mistake.
Reference like always answers it (§5.3.1 and example 5.3.3):
To prevent infinite cycles of constructor invocations, there is the restriction that every self constructor invocation must refer to a constructor definition which precedes it (i.e. it must refer to either a preceding auxiliary constructor or the primary constructor of the class).
Which in your case change it to:
def this(cX: Float, cY: Float, cZ: Float, cW: Float) {
this()
this.tX = cX
this.tY = cY
this.tZ = cZ
this.tW = cW
}
I think you should look at making this a case class, and immutable. That would look something like this (nb. generally I prefer doubles to floats):
case class Quaternion(tX: Double = 0.0, tY: Double = 0.0, tZ: Double = 0.0, tW: Double = 1.0)
Instances can then be created as per the following examples:
scala> val qDefault = Quaternion()
qDefault: Quaternion = Quaternion(0.0,0.0,0.0,1.0)
scala> val q1234 = Quaternion(1,2,3,4)
q1234: Quaternion = Quaternion(1.0,2.0,3.0,4.0)
scala> val q0101 = Quaternion(tY = 1.0)
q0101: Quaternion = Quaternion(0.0,1.0,0.0,1.0)
I would strongly recommend to use immutable case class with companion object, constructor overload or default values:
case class Quaternion(cX: Float, cY: Float, cZ: Float, cW: Float)
object Quaternion {
def apply() = new Quaternion(0,0,0,1)
}
scala> Quaternion()
res0: Quaternion = Quaternion(0.0,0.0,0.0,1.0)
or
case class Quaternion(cX: Float, cY: Float, cZ: Float, cW: Float) {
def this() = this(0,0,0,1)
}
scala> new Quaternion()
res2: Quaternion = Quaternion(0.0,0.0,0.0,1.0)
or
case class Quaternion(cX: Float = 0, cY: Float = 0, cZ: Float = 0, cW: Float = 1)
scala> Quaternion()
res0: Quaternion = Quaternion(0.0,0.0,0.0,1.0)
If you need to change var, you can always use copy method.
