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   DougMerritt (log😅 = 💧log😄) (dougmerritt@mathstodon.xyz)'s status on Monday, 17-Feb-2025 17:41:27 JST DougMerritt (log😅 = 💧log😄)

   in reply to

   @screwtape @riley
   As a historical note:

   > There isn't a lot of cost (well, one cons to nil)

   Back in the days when RAM was measured in kilobytes / kilowords, some implementations did in fact have space-optimized representations for short lists represented as small arrays.

   See cdr-coding
   https://en.wikipedia.org/wiki/CDR_coding

   That might still be in some implementations today, since its savings might be significant in large structures or in aiding cache locality.
    
   The first paper may well have been L. Peter Deutsch: A LISP Machine with Very Compact Programs. IJCAI 1973, Pages 697 - 703

   This is covered in 7.13 in the classic "Anatomy of Lisp", John Allen (1937-2022), 1978 (long out of print, and the author once replied to my query saying he didn't think it was worthwhile updating it for more modern times).

   Has a lot on implemention, but tends to talk about abstractions in terms of M-Expressions, which is no longer in style.

   ACM has it online:
   https://dl.acm.org/doi/pdf/10.5555/542865

   Glowing review of "Anatomy" on goodreads: https://www.goodreads.com/book/show/1537412.Anatomy_of_LISP

   "John Allen (1937-2022) and Anatomy of LISP" by Paul McJones
   https://mcjones.org/dustydecks/archives/2024/04/11/1249/