final variables in Dart
(Shameless stolen from my own Stack Overflow question and answer .) Dart has a concept of final . Most dynamic languages don't have this concept. What is final and what do I use it for? final variables can contain any value, but once assigned, a final variable can't be reassigned to any other value. For example: main() { final msg = 'hello'; msg = 'not allowed'; // **ERROR**, program won't compile } final can also be used for instance variables in an object. A final field of a class must be set before the constructor body is run. A final field will not have an implicit setter created for it, because you can't set a new value on a final variable. class Point { final num x, y; Point(this.x, this.y); } main() { var p = new Point(1, 1); print(p.x); // 1 p.x = 2; // WARNING, no such method } It's important to realize that final affects the variable, but not the object pointed to by the variable. That is, fina...
