On 2006.01.24 21:19, Gioele Barabucci wrote:
> Hi,
>
> why does class_eval behave differently is you pass a string or a block to it?
> This simple test
>
> | class A
> | def test_str; p self.class.class_eval("@@v"); end
> | def test_blk; p self.class.class_eval { @@v }; end
> | end
> |
> | class B < A
> | def initialize; @@v = "v.B"; end
> | end
> |
> | B.new.test_str
> | B.new.test_blk
>
> gives this (unexpected?) result
>
> | $ ruby ./cv2.rb
> | "v.B"
> | ./cv2.rb:3:in `test_blk': uninitialized class variable @@v in A (NameError)
> | from ./cv2.rb:3:in `class_eval'
> | from ./cv2.rb:3:in `class_eval'
> | from ./cv2.rb:3:in `test_blk'
> | from ./cv2.rb:11
Reason for that is that all blocks are closures (they 'enclose' the
scope they were defined in). In this case, @@v is bound to the @@v
in class A at the time you create the block.
> Gioele <dev@gioelebarabucci.com>
E