Commits on Jan 9, 2024

1. Reduce iterations in concatenate! …

   This commit should reduce the amount of iterations in concatenate to N
   where N is the sum of the lengths of the input lists.
   
   The previous implementation iterated from the beginning in each
   concatenation because of `last-pair`.
   
   This implementation is significantly faster in this extreme case:
   
   (concatenate! `(,(iota 50000) ,@(map list (iota 500))))
   
   >> Previous implementation:
   real	0m0.671s
   user	0m0.658s
   sys	0m0.013s
   
   >> This implementation:
   real	0m0.175s
   user	0m0.174s
   sys	0m0.001s
   
   The tests is done using `time`, which is not reliable at all, but using
   `(trace last-pair)` shows accurately what happens with the iterations.

   

   ekaitz-zarraga committed Jan 9, 2024
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