Thanks both.
On Wednesday, 6 August 2014 12:02:59 UTC+1, Ambrose Bonnaire-Sergeant wrote:
>
> The `new` reader macro must resolve its first argument at compile time.
>
> That's why (new (symbol s)) doesn't work.
>
> Thanks,
> Ambrose
>
>
> On Wed, Aug 6, 2014 at 6:55 PM, Colin Yates <colin...@gmail.com
> <javascript:>> wrote:
>
>> Ah OK, I didn't realise I needed to get into Java interop.
>>
>> For education - can you (or anyone) explain me as to why what I was
>> trying didn't work?
>>
>> Thanks Ambrose.
>>
>>
>> On 6 August 2014 11:50, Ambrose Bonnaire-Sergeant <abonnair...@gmail.com
>> <javascript:>> wrote:
>>
>>> Hi Colin,
>>>
>>> If you must call the Java constructor, you need reflection.
>>>
>>> user=> (defrecord B [c])
>>> user.B
>>> user=> (def s "user.B")
>>> #'user/s
>>> user=> (.newInstance (first (.getDeclaredConstructors (Class/forName
>>> s))) (object-array [1]))
>>> #user.B{:c 1}
>>>
>>> Thanks,
>>> Ambrose
>>>
>>>
>>> On Wed, Aug 6, 2014 at 6:37 PM, Colin Yates <colin...@gmail.com
>>> <javascript:>> wrote:
>>>
>>>> Hi,
>>>>
>>>> tldr; if I have a (defrecord MyRecord) in ns a.b.c and I have a string
>>>> "a.b.c.MyRecord" how I can invoke (a.b.c.MyRecord.) (or (new
>>>> a.b.c.MyRecord)?
>>>>
>>>> I thought this was going to be as simple as (defn cfn "a.b.c.MyRecord")
>>>> ((symbol cfn).) but that throws an ArityException: wrong number of args
>>>> (0)
>>>> passed to Symbol. I
>>>>
>>>> I have a protocol with a number of implementations. Each installation
>>>> will have a single implementation and will chose one based on an
>>>> environment variable. At runtime I need to look at that environment
>>>> variable which defines the fully qualified implementation of a protocol.
>>>> I
>>>> then need to instantiate that record.
>>>>
>>>> Architecturally equivalent to a simple plugin system. I could alias
>>>> them all but that requires knowing about all the implementations which is
>>>> a
>>>> no-go.
>>>>
>>>> This is where I feel the pain of not having OSGi :).
>>>>
>>>> Thanks all!
>>>>
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>>>
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