On Mon, Jan 12, 2009 at 11:15 AM, Michael Reid <kid.me...@gmail.com> wrote:
>
> On Sun, Jan 11, 2009 at 9:12 PM, Mark Triggs <mark.h.tri...@gmail.com> wrote:
>>
>> I've also found this useful for accessing members in nested maps. For
>> example:
>>
>> (let [me {:person {:name {:first "Mark"
>> :last "Triggs"}
>> :email "mark.h.tri...@gmail.com"}}]
>> (-> me :person :name :first))
>>
>> => "Mark"
>>
>> On Jan 12, 1:04 pm, kkw <kevin.k....@gmail.com> wrote:
>>> One use I've found for -> (though there are others I haven't come to
>>> appreciate yet) is when I have something like:
>>> (f1 (f2 (f3 (f4 x))))
>>>
>>> which can be re-written as
>>> (-> x f4 f3 f2 f1)
>>>
>>> I find the latter expression easier to read.
>>>
>>> Kev
>>>
>>> On Dec 30 2008, 2:49 pm, wubbie <sunj...@gmail.com> wrote:
>>>
>>> > Very criptic for newbie.
>>> > What does "Threads the expr through the forms." mean?
>>> > Does it create a thread to execute?
>>>
>>> > thanks
>>> > sun
>>>
>>> > On Dec 29, 10:07 pm, Paul Barry <pauljbar...@gmail.com> wrote:
>>>
>>> > > You can look up the documentation for a function/macro interactively
>>> > > from the repl:
>>>
>>> > > user=> (doc ->)
>>> > > -------------------------
>>> > > clojure.core/->
>>> > > ([x form] [x form & more])
>>> > > Macro
>>> > > Threads the expr through the forms. Inserts x as the
>>> > > second item in the first form, making a list of it if it is not a
>>> > > list already. If there are more forms, inserts the first form as the
>>> > > second item in second form, etc.
>>> > > nil
>>>
>>> > > On Dec 29, 8:27 pm, wubbie <sunj...@gmail.com> wrote:
>>>
>>> > > > Hi all,
>>>
>>> > > > Looking intoants.clj, I came across
>>> > > > (defn place [[x y]]
>>> > > > (-> world (nth x) (nth y)))
>>>
>>> > > > What -> mean here?
>>>
>>> > > > thanks
>>> > > > sun
>
> I initially stumbled on what -> is good for. But over time it makes
> more sense. I like to think of it as similar to this construct, which
> you often see in the Java world:
>
> Object result = object.doSomething().doSomethingElse().andMoreThings();
>
> Of course the doSomethings could also be get*s() or what-have-you.
While we're on this topic, don't forget the closely related doto
function which calls many functions on the same object, unlike ->
which calls many functions on the result of the previous function.
Here's the example from the doc string.
(doto (new java.util.HashMap) (.put "a" 1) (.put "b" 2))
--
R. Mark Volkmann
Object Computing, Inc.
--~--~---------~--~----~------------~-------~--~----~
You received this message because you are subscribed to the Google Groups
"Clojure" group.
To post to this group, send email to clojure@googlegroups.com
To unsubscribe from this group, send email to
clojure+unsubscr...@googlegroups.com
For more options, visit this group at
http://groups.google.com/group/clojure?hl=en
-~----------~----~----~----~------~----~------~--~---
