On Jan 12, 10:31 am, Stuart Sierra <the.stuart.sie...@gmail.com>
wrote:
> On Jan 12, 12:11 am, Mark Fredrickson <mark.m.fredrick...@gmail.com>
> wrote:
>
> > I can't imagine this idea will be met warmly, but I have a suggestion.
> > It requires ending maps and vectors as functions of keys. Instead,
> > make the first argument to a collection be a function which is mapped
> > to across the collection. Any additional arguments are passed to the
> > function on each invocation. For maps and hashes, this would only be
> > applied to the values. Keys would remain the same.
>
> > Some examples:
> > ('(1 2 3) * 2) => (2 4 6)
> > ({:greet "hello" :farewell "goodbye"} str " Mark") => {:greet "hello
> > Mark" :farewell "goodbye Mark"}
>
> Hi Mark,
>
> I find the callable map VERY useful, and would hate to lose it. You
> can use maps for lots of things besides keyword=>value structures, and
> the callable map becomes more valuable in those situations.
>
> Your first example can be written almost as succinctly with map:
>
> (map #(* % 2) '(1 2 3))
> ;;=> (2 4 6)
>
> The second is a little more complicated, but still doable:
>
> (reduce (fn [m [k v]] (assoc m k (str v " Mark")))
> {} {:greet "hello" :farewell "goodbye"})
> ;;=> {:farewell "goodbye Mark", :greet "hello Mark"}
>
I'd just like to add to this discussion that maps and vectors are
functions not just because it's neat or possible, with the
implementation one of many possibilities, but because they are
associative, and associative collections are inherently functions of
their keys/indices.
Lists/seqs are not associative, thus not functions.
Rich
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