I don't know if you have a differente approach, but as a defn it doesn't
work
user> (import '[java.util Calendar])
java.util.Calendar
user> (defn is [s instant]
(= (.get instant Calendar/DAY_OF_WEEK)
(. Calendar s)))
CompilerException java.lang.NoSuchFieldException: s,
compiling:(NO_SOURCE_PATH:3:12)
user> (defmacro is [s instant]
`(= (.get ~instant Calendar/DAY_OF_WEEK)
(. Calendar ~s)))
#'user/is
user> (is WEDNESDAY (Calendar/getInstance))
true
I think that when you declare this as a function it will it attempt to
validate that Calendar has an 's' member, at this point that is an error,
on the other hand when the macro gets replaced the generated form is valid.
just for the fun of it, I got this working:
user> (defmacro is [s]
`#(= (.get % Calendar/DAY_OF_WEEK)
(. Calendar ~s)))
#'user/is
user> ((is WEDNESDAY) (Calendar/getInstance))
true
now I can write what I had in mind
user> (def is-friday (is FRIDAY))
#'user/is-friday
user> (is-friday (Calendar/getInstance))
false
user> (def is-wednesday (is WEDNESDAY))
#'user/is-wednesday
user> (is-wednesday (Calendar/getInstance))
true
cool xD
On Wed, Aug 14, 2013 at 11:33 AM, Jim - FooBar(); <jimpil1...@gmail.com>wrote:
> why on earth is this a macro and not a regular fn?
>
>
> Jim
>
> On 14/08/13 16:19, Daniel Meneses wrote:
>
> Hi!
>
> Thanks for your answer Sean I got it solved using clj-time
>
> Also I found the problem with my macro attempt
>
> user> (defmacro is
> [s instant]
> `(= (.get ~instant Calendar/DAY_OF_WEEK)
> (. Calendar ~s)))
> #'current-day.core/is
> user> (is FRIDAY (Calendar/getInstance))
> false
> user> (is WEDNESDAY (Calendar/getInstance))
> true
>
> I was quoting the symbol !!
>
> On Tuesday, August 13, 2013 8:21:39 PM UTC-4, Sean Corfield wrote:
>>
>> Perhaps clj-time might help you?
>>
>> https://github.com/clj-time/**clj-time<https://github.com/clj-time/clj-time>
>>
>> (ns time.core
>> (:require [clj-time.core :as time]
>> [clj-time.local :as local]
>> [clj-time.predicates :as p]))
>>
>> (p/monday? (time/now)) ;; false
>> (p/tuesday? (time/now)) ;; false
>> (p/wednesday? (time/now)) ;; true (for me in California since (time/now)
>> is UTC)
>>
>> (p/monday? (local/local-now)) ;; false
>> (p/tuesday? (local/local-now)) ;; true (for me)
>> (p/wednesday? (local/local-now)) ;; false (not yet in California)
>>
>> Sean
>>
>> On Tue, Aug 13, 2013 at 3:14 PM, Daniel Meneses Báez <dap...@gmail.com>
>> wrote:
>> > Hi :)
>> >
>> > I really want to know if there is a way to do this:
>> >
>> > (ns ...
>> > (:import [java.util Calendar]))
>> >
>> > (defsomething ;; if it is possible using a macro I'm ok with that
>> > calendar-member
>> > [member]
>> > (symbol (str "Calendar/" member)))
>> >
>> > what I want to know if an instance of Calendar "isMonday", "isFriday"
>> > "isSunday" etc...
>> >
>> > so I was thinking to write something like
>> >
>> > (defn- isss [day instant]
>> > (= (.get instant Calendar/DATE) (calendar-member day)))
>> >
>> > and then use it like (def is-friday (partial isss 'FRIDAY)) ;;
>> >
>> > am I being to crazy?
>> >
>> > btw I'm really loving the language.
>> >
>> >
>> >
>> > --
>> > Daniel Meneses Báez
>> >
>> > --
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>>
>>
>>
>> --
>> Sean A Corfield -- (904) 302-SEAN
>> An Architect's View -- http://corfield.org/
>> World Singles, LLC. -- http://worldsingles.com/
>>
>> "Perfection is the enemy of the good."
>> -- Gustave Flaubert, French realist novelist (1821-1880)
>>
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