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 <
abonnaireserge...@gmail.com> 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.ya...@gmail.com> 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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