From mboxrd@z Thu Jan  1 00:00:00 1970
Message-ID: <8eec1f5d6d08659ae6c574f2c6fe581b@caldo.demon.co.uk>
To: 9fans@cse.psu.edu
Subject: Re: [9fans] useful language extension, or no?
From: forsyth@caldo.demon.co.uk
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Date: Fri, 19 Jul 2002 19:35:48 +0100
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>>Ah - I see! It hadn't realised that the scope rules now included
>>that sort of nesting. When did that happen? I guess I am going to
>>have to trade in my much loved, dog eared K&R for a book on
>>standard C one of these days...

it's a gcc-specific extension (certainly implemented THAT way).

>>Presumably $185 generates the instruction to load the frame pointer,
>>and $233 creates the jump to the actual function.

it's not the normal frame pointer but a static link pointer that
allows the nested function's code to find the right frame instance for
accessing variables in the lexically-containing function.  it's
because the implementation uses a static link that it has a problem.
there is another technique that wouldn't.  the dragon book has a
reasonable discussion of the alternatives but doesn't actually discuss
the variant that could have been used here to avoid the need for the
trampoline crud (although it mentions it in a throwaway remark).