Question

I’m trying to avoid mutable variables as much as possible, but sometimes it just feels too hard, and I don’t want to end with an extremely complicated code

Nevertheless I found this way to do it, but it certainly feels like cheating

I’m parsing a query, and I find find a field!value, I want to translate it to field:<>value, and then go on processing, so I came out with this code to avoid mutables, or at least to have them confined…

val (operator, negated) = {
  var operator = ConditionOperator.toConditionOperator(parsedOperator)
  var negated = parsedNegated == "!"
  // field!value => field notEqual value
  if (negated && operator == ConditionOperator.Unknown) {
    negated = false
    operator = ConditionOperator.NotEqual
  }
  (operator, negated)
}

Is this the right way to do it??? or is there a more idiomatic (and clear!) way to achieve this kind of things?

Answer 1

This is indeed cheating since var is mutable!

The way to correct this is to simply return the if-statement’s result directly:

val (operator, negated) = {
  val operator = ConditionOperator.toConditionOperator(parsedOperator)
  val negated = parsedNegated == "!"
  // field!value => field notEqual value
  if (negated && operator == ConditionOperator.Unknown)
    (ConditionOperator.NotEqual, false)
  else
    (operator, negated)
}