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+;;; enum.el --- Enumerable protocol for Elisp -*- lexical-binding: t -*-
+;; Author: William Carroll <wpcarro@gmail.com>
+
+;;; Commentary:
+;; Heavily influenced by Elixir.
+
+;; I will not be implement every function in the Enum library, since I don't
+;; need every function.  Some of the streaming functionality may prove difficult
+;; to write in Elisp.  We shall see.
+
+;; TODO: Implement the following functions:
+;; - all?/2
+;; - any?/2
+;; - at/3
+;; - chunk_by/2
+;; - chunk_every/{2,3,4}
+;; - chunk_while/4
+;; - concat/1
+;; - concat/2
+;; - count/{1,2}
+;; - dedup/1 # prefer calling this function dedupe
+;; - dedup_by/2 # same as above
+;; - drop/2
+;; - drop_every/2
+;; - drop_while/2
+;; - each/2
+;; - empty?/1
+;; - fetch/2
+;; - fetch!/2
+;; - filter/2
+;; - find/3
+;; - find_index/2
+;; - find_value/3
+;; - flat_map/2
+;; - flat_map_reduce/3
+;; - group_by/3
+;; - intersperse/2
+;; - into/{2,3}
+;; - join/2
+;; - map/2
+;; - map_every/3
+;; - map_join/3
+;; - map_reduce/3
+;; - max/2
+;; - max_by/3
+;; - member?/2 # consider calling this contains?
+;; - min/2
+;; - min_by/2
+;; - min_max/2 # This is a great function because of O(n) time.
+;; - min_max_by/3
+;; - random/1 # Consider just sample with num=1
+;; - reduce/{2,3}
+;; - reduce_while/3
+;; - reject/2
+;; - reverse/{1,2}
+;; - reverse_slice/3
+;; - scan/{2,3}
+;; - shuffle/1
+;; - slice/{2,3}
+;; - sort/{1,2}
+;; - sort/2
+;; - sort_by/3
+;; - split/2
+;; - split_while/2
+;; - split_with/2
+;; - sum/1
+;; - take/2
+;; - take_every/2
+;; - take_random/2 # prefer calling this function sample
+;; - take_while/2
+;; - to_list/1
+;; - uniq/1 # prefer calling this unique
+;; - uniq_by/2 # prefer calling this unique-by
+;; - unzip/1
+;; - with_index/2
+;; - zip/{1,2}
+
+;; TODO: Consider how to handle dispatching by type.
+
+;; TODO: Which types should be supported herein?
+;; - linked-lists
+;; - associative-lists
+;; - cycles
+
+;; Warning: This module is a total work-in-progress, and it's quite possible
+;; that I may never even finish it.
+
+;;; Code:
+
+(defun enum/count (xs)
+  "Return the number of elements in `XS'."
+  (cond
+   ((alist/instance? xs) (alist/count xs))
+   ((list/instance?  xs) (list/length xs)))
+  )
+
+(provide 'enum)
+;;; enum.el ends here