bug#29866: 27.0.50; cl-loop: Calculate the array length just once

[Noam Postavsky]

Drew Adams <drew.adams@oracle.com> writes:

>> While studying this code I found easier to hack if we use gensym's
>> instead of make-symbol; otherwise, the code creates several symbols with
>> the same printed representation "--cl-var--".  For example, with
>> current code you can read expansions with something like:
>> 
>> (let* ((--cl-var-- 'foo)
>>        (--cl-var-- 'bar))
>
> That's the same variable, `--cl-var--', bound
> first to `foo' and then to `bar'.

That's a printout using print-circle and/or print-gensym set to nil.  If
those were set to t, you would get something that could be properly read
back as lisp code, e.g.:

    (let* ((#1=#:--cl-var-- 'foo)
           (#2=#:--cl-var-- 'bar))
       (frobnicate #1# #2#))