Page Comparison

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• mixins == good
• static but not always explicit types; no casts; allow implicit downcasting but warn about all other issues; check downcast at runtime.
  unsafe: List<Object> a = List<String>? compile error. Is List<Number> castable to List<Integer>? covariance. watch out for ((Object[])(new String[1]))[0] = 3.
  I like idea of covariant method args for overriding. http://www.artima.com/scalazine/articles/scalas_type_system.html talks about Cow overriding animal eat(Food) but wanting to restrict to eat(Grass); can't in java. might need polymorphic arg dispatch. abstract types seem useful. I think Java allows us to override the return type now.

  Code Block
  class T { T foo() { return null;} } class U extends T { U foo() { return null;} }

• if generics, "reify" them (keep types around at runtime) unlike java.
• pattern matching as lib?
• keep smalltalk like (typed) syntax?

  Code Block
  at: int i put: Object value => void { ... } size => int { ... }

  I use => return type so type names make sense like ML and descendants: (int, Object => void)
  Neil Gafter's lambda notation is similar for java:

  Code Block
  ()->int[] arrayLambda = ()->new int[]{1, 2, 3};

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