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Re: Are nested DEFUN's illegal?
- To: email@example.com, firstname.lastname@example.org
- Subject: Re: Are nested DEFUN's illegal?
- From: haible (Bruno Haible)
- Date: Thu, 8 Dec 94 16:22:56 +0100
Mark Thomas <email@example.com> noticed the following:
> > (defun bar (x)
> (defun foo ()
> (+ x 3)))
> *** - THE-ENVIRONMENT is impossible in compiled code
This is a bug. It will be fixed in the next release.
> Note 1: Perhaps nested DEFUN forms are considered poor style, but is
> there a _technical_ reason for disallowing them?
There is no technical reason for disallowing them. Nested DEFUNs are simply
used so rarely that it wasn't noticed before you came.
> The error message refers to 'compiled code'. What code is that?
When the "defun bar" is evaluated, the macros inside of it are expanded. This
is a kind of pre-compilation. The "defun foo" wants to save its form and
environment, in order to make it possible to later (ED 'FOO). I put in an
error message because this is not possible if BAR were compiled. But - and
that's the bug - it is not compilation, but only pre-compilation which