Jozef is correct, but to give some examples:
(ns example.core
(:require [example.other :as other]))
(= ::foo :example.core/foo)
(= ::other/foo :example.other/foo)
(not= :foo :example.core/foo)
(not= :example.core/foo :example.other/foo)
(not= :other/foo ::other/foo)
- James
On 9 August 2014 19:14, Jozef Wagner <jozef.wag...@gmail.com> wrote:
> Keep in mind that :: is just a syntax sugar that is processed by the
> reader, before the compiler kicks in. ::foo is a shorthand for
> :your.current.ns/foo. Its purpose is to make it easy to create keywords
> that do not clash with other ones.
>
> Keywords are equal (and identical) only when both of their namespaces and
> names are equal. :ns1/foo is thus not equal to :ns2/foo, nor to just :foo. ::
> is used in cases where you want to exploit this important property of
> keywords, so that your keyword won't e.g. clash with other keywords in a
> collection, contents of which you don't know.
>
> Jozef
>
>
> On Saturday, August 9, 2014 7:46:45 PM UTC+2, larry google groups wrote:
>>
>> Please forgive this stupid question, but I'm still trying to understand
>> exactly what the double "::" means. I have read that I can use (derive) to
>> establish a hierarchy and I can imagine how this would be useful for things
>> like throwing errors and catching them and logging, but I've also read that
>> "::" adds the namespace to the symbol, so I would assume that I can not
>> match ::logging from one namespace with ::logging from another?
>>
>> I'm thinking of this especially in my use of Slingshot, where I was
>> thinking of doing something like:
>>
>> (throw+ {:type ::database-problem :message "something wrong in the
>> database query"})
>>
>> and then at a higher level in my code I was going to catch it with
>> something like:
>>
>> (derive ::database-problem ::logging)
>>
>> and then using Dire:
>>
>> (dire/with-handler! #'database/remove-this-item
>> [:type ::logging]
>> (fn [e & args]
>> (timbre/log (str " database/remove-this-item: The time : "
>> (dates/current-time-as-string) ( str e))))
>>
>> but conceptually I am having trouble understanding how ::logging in one
>> namespace can match ::logging in another namespace. Perhaps I should just
>> use normal keywords?
>>
>>
>> --
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