implicit conversion - Scala: "number" interpolation -

scala has string interpolation raw"\n" raw strings.

does have number interpolation e.g. 1px 1 pixel? nice syntax numeric units both make code more readable , make easier write safer code.

like strings, numbers have nice literal syntax , fundamental.

prefix notation px(1) not how people write units:

case class px(n: int) 

and don't think postfix notation via implicit conversion can work:

case class pixels(n: int) {  def px() = pixels(n)  def +(p: pixels) = p match {case pixels(m) => pixels(n+m)} } implicit def int2pixels(n: int) = pixels(n) 

1. it needs dot or space or parens (i.e. not (1 px) or (1)px or 1.px, not how humans write units).

2. it won't check types i.e. want explicitly cast between these numeric type-alias things , numbers (i.e. 1.px + 2 , 1 + 2.px , def inc(p: pixels) = p + pixels(1) inc(0) don't fail, because of implicit cast, when should).

you can define own string interpolation (more details here):

implicit class unithelper(val sc : stringcontext) extends anyval {   def u(args: any*): pixels = {     val pxr = """(\d.*)\s*px""".r        sc.parts.mkstring match {       case pxr(px) => pixels(px.toint)       case _ => throw new illegalargumentexception     }   } }  

usage example:

val x = u"10px" + u"20px" // x = pixels(30) 

pros:

• easy add interpolation units: em, px, pt, cm, in

cons:

• it not type safe because string interpolation runtime feature.