From: Brian Candler <b.candler@...>
Date: 2008-11-04T22:41:17+09:00
Subject: Passing a block to a block

I notice that if you pass a block to a block, you can't use 'yield' to
yield to that block:

$ cat yield_in_block.rb
foo = lambda { |e| puts e }
blk = lambda { |e| yield e }
blk.call(123, &foo)

$ ruby yield_in_block.rb
yield_in_block.rb:2: no block given (LocalJumpError)
        from yield_in_block.rb:3
$ ruby19 yield_in_block.rb
yield_in_block.rb:2:in `block in <main>': no block given (yield)
(LocalJumpError)
        from yield_in_block.rb:3:in `call'
        from yield_in_block.rb:3:in `<main>'

What's the reason for this? Does 'yield' only invoke the top-level block
passed into a method?

ruby1.9 is happy but only if I explicitly reference the block to yield.

foo = lambda { |e| puts e }
blk = lambda { |e,&y| y[e] }
blk.call(123, &foo)

Thanks,

Brian.
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