Why aren't all sequences callable, i.e. why don't they all implement
IFn? I'd like to use lists like this sometimes.
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On Sun, Jan 11, 2009 at 9:38 PM, Ethan Herdrick wrote:
>
> Why aren't all sequences callable, i.e. why don't they all implement
> IFn? I'd like to use lists like this sometimes.
When you call maps and vectors, it acts as if you're calling 'get'.
But 'get' doesn't do anything useful for lists.
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 e
On Jan 12, 12:11 am, Mark Fredrickson
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
On Jan 12, 10:31 am, Stuart Sierra
wrote:
> On Jan 12, 12:11 am, Mark Fredrickson
> 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 functi
For mapping across maps I often find the following utility helpful:
(defn map-map "Like map, but expects f to produce pairs that are
combined to produce a map output."
[f & maps] (reduce #(conj %1 %2) {} (apply map f maps)))
1:1 user=> (map-map (fn [[k v]] [k (str v " Mark")]) {:greet
"hello"
Then why are sets callable? Not that I'm complaining - I found it
handy, then came to wonder why lists aren't.
-Ethan
> 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
On Mon, Jan 12, 2009 at 5:56 PM, Jason Wolfe wrote:
>
> For mapping across maps I often find the following utility helpful:
>
> (defn map-map "Like map, but expects f to produce pairs that are
> combined to produce a map output."
> [f & maps] (reduce #(conj %1 %2) {} (apply map f maps)))
>
> 1:
A set is, in a sense, a function mapping from arbitrary objects to
Boolean values. If the object is in the set, it returns true. A list,
in the Lisp world at least, only has two elements, first and rest (car
and cdr in older Lisps). A list object isn't really a "complete"
collection the way vector
Makes sense, but (#{:a :b :c} :b) doesn't return 'true', it
returns :b. So it's not really acting like an object to boolean
mapping. Doesn't much matter, though.
By the way, I'd like to see map-map in the core.
-Ethan
On Jan 12, 5:30 pm, Stuart Sierra wrote:
> A set is, in a sense, a functio
On Wed, Jan 14, 2009 at 10:23 PM, Ethan Herdrick wrote:
>
> By the way, I'd like to see map-map in the core.
If you're referring to Jason Wolfe's suggested function, I think you
may be pretty satisfied with (into {} (map ...)) instead.
--Chouser
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