[ 
https://issues.apache.org/jira/browse/GROOVY-7428?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14578735#comment-14578735
 ] 

Paul King commented on GROOVY-7428:
-----------------------------------

Scala follows what Excel does:
{code}
import scala.math.pow

object HelloWorld {
  implicit class PowerInt(val i:Double) extends AnyVal {
    def ** (exp:Double):Double = pow(i,exp)
  }
  def main(args:Array[String]) {
    println(-2**4)  // => 16.0
  }
}
{code}

> Change precedence priority of ** compared to pre/post inc/dec and unary 
> plus/minus
> ----------------------------------------------------------------------------------
>
>                 Key: GROOVY-7428
>                 URL: https://issues.apache.org/jira/browse/GROOVY-7428
>             Project: Groovy
>          Issue Type: Improvement
>            Reporter: Paul King
>            Assignee: Paul King
>              Labels: breaking
>             Fix For: 2.5.0-beta-1
>
>
> Currently the precedence order is:
> {noformat}
> level 1: post inc/dec
> level 2: power
> level 3: pre inc/dec
> {noformat}
> The original intention, I believe, was always:
> {noformat}
> level 1: post inc/dec
> level 2: pre inc/dec
> level 3: power
> {noformat}
> This leads to some unintuitive behavior:
> while these are the same:
> {code}
> println (-9 + 2)  //  -7
> println ((-9) + 2)  //  -7
> {code}
> these are different:
> {code}
> println (-9 ** 2)  //  -81  actually: println (-(9 ** 2))
> println ((-9) ** 2)  //  81
> {code}
> Similar anomalies occur between {{**}} and {{++}}/{{--}}



--
This message was sent by Atlassian JIRA
(v6.3.4#6332)

Reply via email to