[plt-scheme] to define, or to let

On Mar 21, 2004, at 3:08 AM, Anton van Straaten wrote:

>   For list-related administrative tasks:
>   http://list.cs.brown.edu/mailman/listinfo/plt-scheme
>
> Felix Klock wrote:
>> However, for the Standard (R5RS) language, DrScheme should (at least)
>> print a warning for such uses of LETREC.
>
> I'm not sure how easy violations are to detect.  It would be easier, 
> and
> make more sense IMO, to implement the standard letrec for the PLT R5RS
> language.  I suspect that might not be popular, though.

I feel like I'm missing something here.

Isn't violation-detection just a small modification of standard 
free-variable analysis, where in this modification you do not descend 
into the bodies of LAMBDA expressions (and instead, the free-vars of a 
lambda is always the empty list)?

This sounds *cheaper* than free-variable analysis to me.

What is the difficulty here?  The need to macro-expand prior to doing 
the analysis?  Or...?

-Felix

----
"Curried food and curried functions are both acquired tastes."
  -P. Wadler