Re: What is the best way to navigate #ifdef and #endif in C program

[Peter Keller]

In comp.lang.lisp Elena <egarrulo@gmail.com> wrote:
> On 4 Ago, 17:09, Peter Keller <psil...@cs.wisc.edu> wrote:
>> Specifically:http://letoverlambda.com/index.cl/guest/chap5.html#sec_4
>>
>> Would show you how to write a macro such that it adds Scheme's tail call
>> optimized "named let" into Common Lisp. ?This goes beyond the concept
>> of syntactic sugar and enters the domain of pure code transformation.
> 
> Indeed, code transformation is what sets CL's macros apart. However,
> TCO is much more than that. Read here:
> 
> http://stackoverflow.com/questions/2181852/tail-call-elimination-in-clojure

After reading that, I assert that I don't know how to take base CL
and make it tail recursive since redefining things like defun and
whatnot lead to package lock errors. Even things like define-compiler-macro
can't redefine any of the CL macros or functions.

One probably could have success if they created forms like defun-tco,
labels-tco, flet-tco, etc which kept track of their code expansions
and rewrote them to be tco. But at that point you've implemented a
tco enforced lisp dialect on top of CL.

> However, TCO could also just not be possible in CL because of its
> design:
> 
> http://www.cliki.net/Tail%20Recursion

It may be true, I don't know.

-pete