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Re: Lexical byte-compilation warnings cleanup

From: Daniel Colascione
Subject: Re: Lexical byte-compilation warnings cleanup
Date: Sun, 15 Sep 2013 12:33:35 -0700
User-agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.6; rv:17.0) Gecko/20130801 Thunderbird/17.0.8

On 8/20/13 9:49 PM, Stefan Monnier wrote:
>>>> And the intention is?  The design is?  The reason is?
> Check the calling convention used by the new byte-code representation
> (used for lexically scoped code) and you'll see that there's no support
> for dynamic scoping in it.  Adding such support "natively" would
> slow down the common case too much.

I think the current design is reasonable, and the byte-compiler warning
provides some safety. We do, however, need to provide some warnings in
cl-lib, because in some cases, we _can_ dynamically bind arguments.
Consider this code:

(defvar test (cons 1 2))
(defun* bar3 () (car test))
(defun* bar2 (&key test) (bar3))
(defun* bar1 () (bar2 :test (cons 3 4)))

When bar2 parses its argument list, is _dynamically_ binds test, which
test then picks up.  bar1 returns 3. If we change test from a keyword
argument to a regular argument, bar1 then returns 1, as expected.

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