Case classes with toStrings that print label names

Overview
The Labeled ToString project provides several traits you can mix into case classes in order to get toString representations that include parameter labels. That means you get Person(name=John Doe,age=30) instead of Person(John Doe,30).

Example
Here's a normal case class:

  case class Person(name: String, age: Int)
  Person("John Doe", 30).toString
  //result is "Person(John Doe,30)"

Here's our labeled case class:

  import com.yuvimasory.tostring._
  case class Person(name: String, age: Int) extends LabeledToStringDef
  Person("John Doe", 30).toString
  //result is  "Person(name=John Doe,age=30)"

Choosing a trait
The com.yuvimasory.tostring package provides three traits: LabeledToStringDef, LabeledToStringVal, and LabeledToStringLazyVal. They override the default case class's toString method with a def, val, and lazy val, respectively.

• If you're not sure which to use, start with LabeledToStringDef, which works in all cases.
• Consider LabeledToStringVal if you know the case class's parameters are either immutable (e.g., primitive types, immutable collections), or have string representations that never change (e.g., arrays).
• Try LabeledToStringLazyVal if you meet the criteria for LabeledToStringVal and want lazy initialization.
• Both of the *Val traits may run slightly faster (since they don't have to recompute toString every time it's needed) at the cost of more memory usage.
• You must use LabeledToStringDef if your case classes are Squeryl tables. If you don't Squeryl will generate bogus SQL.

Performance
The ToString traits use Apache Commons Lang under the hood, which uses reflection to find the parameter lables. Surprisingly, there does not seem to be any performance cost for this. In fact, using these traits actually results in code faster than the default case class toString. Try the tests yourself by running sbt run.

Warning

• These traits do not produce the right strings in the REPL yet due to the way the REPL wraps code and mangles names.
• These traits do not work if you add bodies to your case classes (i.e., additional methods or fields).