Re: DEFUN inside LET

[Steven Haflich <smh@mit-ems.ARPA>]

> From @SU-AI.ARPA:NGALL@G.BBN.COM Thu Jan 30 11:27:51 1986
> 
> > Also, since DEFUN is a macro, it's hard to imagine what it could expand
> > into in order to behave much differently from this.
>     
> Imagine this:
> 
> (defmacro simple-defun (name lambda-list &body body)
>   `(setf (symbol-function ',name)
>          '(lambda ,lambda-list ,@body)))
> 
> The quote in front of the lambda ensures that the lambda expression is
> defined in the null lexical environment.

Wouldn't one instead use:

  (defmacro simple-defun (name lambda-list &body body)
    `(setf (symbol-function ',name)
           (function (lambda ,lambda-list ,@body))))

This would seem to capture the lexical environment quite unambiguously.
If, as DCP suggests, a defun that captures its lexical environment is
really a "time bomb", defun could be "fixed".  But how could it be
possible to prohibit constructions like the above?