anchor.diff:  The separator string can be customized programmatically or declaratively.
   
   Use the `separator` attribute of the `@Command` annotation to declaratively set a separator string:
  -[source,java]
  +
  +.Java
  +[source,java,role="primary"]
   ----
   @Command(separator = ":")  // declaratively set a separator
   class OptionArg {
       @Option(names = { "-f", "--file" }) String file;
   }
   ----
  -[source,java]
  +
  +.Kotlin
  +[source,kotlin,role="secondary"]
  +----
  +@Command(separator = ":")  // declaratively set a separator
  +class OptionArg {
  +    @Option(names = ["-f", "--file"]) lateinit var file: String
  +}
  +----
  +
  +.Java
  +[source,java,role="primary"]
   ----
   OptionArg optionArg = CommandLine.populateCommand(new OptionArg(), "-f:output.txt");
   assert optionArg.file.equals("output.txt");
   ----
   
  +.Kotlin
  +[source,kotlin,role="secondary"]
  +----
  +val optionArg = CommandLine.populateCommand(OptionArg(), "-f:output.txt")
  +assertEquals("output.txt", optionArg.file)
  +----
  +
   
   Alternatively, the separator string can be changed programmatically with the `CommandLine.setSeparator(String separator)` method.
   For example:
  -[source,java]
  +
  +.Java
  +[source,java,role="primary"]
   ----
   OptionArg optionArg     = new OptionArg();
   CommandLine commandLine = new CommandLine(optionArg);
  
positive.code: 
      @Option(names = "-y", arity = "0..1", description = "min 0 and max 1 parameter")
      boolean y;
  }
  ----
  
  
negative.code: }
  ----
  
  .Kotlin
  [source,kotlin,role="secondary"]
  ----
  class Anchored {
      @Parameters(index = "1+") lateinit var p1: String  // assigned index = "1" or higher
      @Parameters(index = "1+") lateinit var p2: String  // assigned index = "2" or higher
  }
  ----
  
  ==== Combining Explicit and Automatic Indexes
  If a command defines a positional parameter with an explicit index at the anchor point, then automatic indexes anchored at that point will start from the explicit index plus 1.
  For example:
  
  .Java
  [source,java,role="primary"]
  ----
  class ExplicitAndAutomaticIndexes {
      @Parameters(index = "0" ) String explicit0;  // explicit index "0" at default anchor point
      @Parameters String pAuto1;                   // assigned index "1", anchor point + 1
      @Parameters String pAuto2;                   // assigned index "2"
      @Parameters(index = "1+") String pAnchored1; // assigned index "1": no explicit index 1
      @Parameters(index = "1+") String pAnchored2; // assigned index "2"
      @Parameters(index = "2" ) String explicit2;  // explicit index "2", matching anchor for "2+"
      @Parameters(index = "2+") String pAnchored3; // assigned index "3", anchor point + 1
      @Parameters(index = "2+") String pAnchored4; // assigned index "4"
  }
  ----
  
  .Kotlin
  [source,kotlin,role="secondary"]
  ----
  class ExplicitAndAutomaticIndexes {
      @Parameters(index = "0") lateinit var explicit0: String   // explicit index "0"
                                                                 // at default anchor point
      @Parameters lateinit var pAuto1: String                   // assigned index "1",
                                                                 // anchor point + 1
      @Parameters lateinit var pAuto2: String                   // assigned index "2"
      @Parameters(index = "1+") lateinit var pAnchored1: String // assigned index "1":
                                                                 // no explicit index 1
      @Parameters(index = "1+") lateinit var pAnchored2: String // assigned index "2"
      @Parameters(index = "2") lateinit var explicit2: String   // explicit index "2",
                                                                 // matching anchor for "2+"
      @Parameters(index = "2+") lateinit var pAnchored3: String // assigned index "3",
                                                                 // anchor point + 1
      @Parameters(index = "2+") lateinit var pAnchored4: String // assigned index "4"
  }
  ----
  
  ==== Unanchored Automatic Index
  
  Sometimes you want to have indexes assigned automatically to come at the end.
  