On Fri, May 31, 2013 at 6:16 AM, mukesh tiwari wrote: Data.List can be abstracted using Foldable and Traversable but
unfortunately I could not find the functions corresponding to head, take. Those are, again, more general than you want. What is the `head` of a
HashMap? (Consider that an implementation may choose to randomize the hash
function to avoid hash collision attacks.) Foldable and Traversable express
the concept of a collection which has no meaningful concept of an element's
relative position within the collection. ListLike adds the concept of
position, thereby admitting an indexing operation (and, by extension,
`head` which is index 0).
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