Tree methods

• new(message): throw an exception. Example:

var x = 3;
[x != 3, { tree|new("there was a problem"); }]|decide;

• string: returns the message passed to the exception
• get_trace: returns a list consisting of the stack trace that lead to this tree being thrown. Each entry contains an object consisting of the following properties:
  • file: the file from which this entry was made
  • name: the name of the method of this stack entry
  • line: the line number which this call originated