[issue12635] use "as" for block scope support

New submission from HaiYun Yan : use "as" for block scope support just like mozilla javascript "let" extension https://developer.mozilla.org/en/new_in_javascript_1.7#Block_scope_with_let_%28Merge_into_let_Statement%29 usage: as_clause(as_declare): "as" NAME a

[issue12473] factory func of collections.defaultdict should receive the "missing key" as args when called.

New submission from HaiYun Yan : for example: def calc(params): """ i am factoring numbers. """ # an expensive CPU cost function but # passin params and return result are both lightweight cachedcalc = collections.defaultdict(calc) result = cachedcalc