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Comment by mercurial | Hacker News Reader

I'll take head/tail over first/rest, but first/rest is not too bad.

I thought that for a bit until I realised tail is a bit ambiguous as it's used in the Unix space to mean the "last n" items and in some data structures as the last item pointer.

Ironically in CL LAST does what UNIX tail does.

Yeah which is where SBCL and me got into to a bad argument :)

You probably were looking for LAST1 (e.g. (first (last ...))).

But why SBCL? LAST should behave the same on all implementations.

That's just the variety of CL that I used.

I'm a fan first/rest because of Mathematica. It has four functions that all end in "st", which means I can always recall the one I need:

First, Rest, Most, Last

(Results on Range[4], respectively: 1, {2, 3, 4}, {1, 2, 3}, 4.)

Rebol comes with first & last but not the others.

  >> a: [1 2 3 4]
  == [1 2 3 4]

  >> first a
  == 1

  >> last a
  == 4

This is how you could add rest & most:

  >> rest: func [s] [next s] 
  >> most: func [s] [copy/part s back tail s]

  >> rest a
  == [2 3 4]

  >> most a                                  
  == [1 2 3]

Rebol unifies all this under what it calls a series - http://www.rebol.com/docs/core23/rebolcore-6.html

In Clojure it's almost the same: first, rest, butlast, last

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