Scala class extends Trait

Question

When trying to extend an class with a trait with concrete definition like so

trait logmsg
{
  printmsg(msg : String)  = println(msg)
}

class DimensionUtils extends logmsg {
  printmsg("hello")
}

why does the repl give the following error:

**error**
defined trait logmsg
<console>:16: error: not found: value printmsg
          printmsg("hello")

this code is correct. I'm guessing you are pasting the code into the REPL, and the problem will go away if you move the first { onto the same line as trait logmsg, to prevent the REPL from taking trait logmsg by itself as a complete definition. this is one of the reasons Scala programmers never put { on a line by itself. (the other is semicolon inference.) — Seth Tisue
– Seth Tisue, Commented Oct 3, 2018 at 20:19
Moreover looking for scala style guide You should have trait starting with capital letter. In 90% situation put the parenthesis in the same line, not a new line. Remove all necessary lines. Your code can have 7 lines with the same information. — Patryk Rudnicki
– Patryk Rudnicki, Commented Oct 5, 2018 at 12:09

Vivek · Accepted Answer · 2018-10-04 12:06:03Z

1

Your Code is correct, I tried in eclipse editor by creating a Scala project, getting an answer as "hello" here is the code which runs.

object StackQ extends App {
  val obj = new DimensionUtils
}

trait log_msg {
  def printmsg(msg: String) = println(msg)
}

class DimensionUtils extends log_msg {
  printmsg("hello")
}

answered Oct 4, 2018 at 12:06

Vivek

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