[Ecls-list] LOOP error

[Juan Jose Garcia-Ripoll]

On Feb 3, 2008 12:06 AM, Stelian Ionescu <sionescu at common-lisp.net> wrote:
> When compiling this function from KMRCL
>
> (defun remove-keyword (key arglist)
>   (loop for sublist = arglist then rest until (null sublist)
>      for (elt arg . rest) = sublist
>      unless (eq key elt) append (list elt arg)))
>
> ECL complains that "Iteration in LOOP follows body code" but the way I
> interpret section 6.1.4 of the Hyperspec is that termination clauses are
> *not* considered to be body clauses, so I think that LOOP shouldn't
> signal an error here

The hyperspec is rather clear about this issue:

loop [name-clause] {variable-clause}* {main-clause}* => result*

all for statements are variable-clause, hence they cannot appear after
a main-clause (until, unless, etc)

http://www.lisp.org/HyperSpec/Body/mac_loop.html

> SBCL, CMUCL, Clisp, GCL and ABCL all accept that and only Clisp signals a
> warning about it

LOOP is an ugly beast. I just stole that code and I doubt I can fix
that. But I insist it is not a bug, but a commonly accepted practice.

Juanjo

-- 
Facultad de Fisicas, Universidad Complutense,
Ciudad Universitaria s/n Madrid 28040 (Spain)
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