On Sunday, March 27, 2011 6:17:59 AM UTC-4, Stefan Sigurdsson wrote:
How do you guys normally manage resources when using lazy sequences?
You have to manage resources at a larger scope that encompasses all your use
of the lazy sequence. The quick-and-dirty solution is to use `doall` inside
So I have come up with a solution to my desire to move to defprotocol/
type in spite of my requirement for gen-class' init/post-init
methods :
(def protocol Resource
(open [this])
(close [this])
...
)
(deftype ResourceImpl [resource]
Resource
(open [this]...)
(close [this] (.close
How do you guys normally manage resources when using lazy sequences?
I was playing around with this question, and I looked into extending
line-seq to take a file path parameter that is coerced to reader:
(defn line-seq
([^java.io.BufferedReader rdr]
(when-let [line
Aieh, I oversimplified a bit here, and forgot about not being able to
overload with the same arity, without multimethods.
Here is the actual code I was experimenting with, which actually runs...
(defn- read-seq-
[reader extract advance]
(let [segment (extract reader)
reader (advance
Guys,
Thanks for your replies - I'm glad I posted as this is exactly what I was
looking for. I wish I had found Stuart's article when he wrote it. I had an
inkling that my gen-class struggles were out of date - now I can go and
rework all that code :-)
Problem solved.
Thanks again,
Jules
Sorry for hijacking but I wouldn't mind some clarification on the subject.
Right now I can get java classes and interfaces with defprotocol and
defrecord and the world is good.
Can somebody please educate me in the uses/needs for :gen-class and friends?
Keep in mind that I haven't really done
Hi,
On 24 Mrz., 10:40, Ulises ulises.cerv...@gmail.com wrote:
Can somebody please educate me in the uses/needs for :gen-class and friends?
You need gen-class when you want (or have to) derive from another
class. defrecord/deftype/reify don't allow that, while gen-class/proxy
do.
Sincerely
You need gen-class when you want (or have to) derive from another
class. defrecord/deftype/reify don't allow that, while gen-class/proxy
do.
I suppose this is for when you want to add fields to an already
existing class? (I'm assuming that adding methods could be done with
Stuart,
I still think in a very OO way - which is probably why I am having
difficulty with this :-)
A common OO pattern is to encapsulate complex resource acquisition/release
within a class.
I can do this with gen-class - since I control ctor args and the instances
initial state, as well as
A typical pattern for resource management is a function or macro like
`with-open-file`.
-S
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lookups one to fetch the immutable part from the .state field and one
to lookup some useful piece of data in it.
I'd like to reduce this to one lookup, directly into an immutable
field in the POJO.
Why doesn't gen-class allow e.g. :state [^Integer i ^String s ] in
a more record like way
On Wed, Mar 23, 2011 at 3:43 AM, Jules jules.gosn...@gmail.com wrote:
I only have a brief posting window this morning (I have to leave for
work) so have not researched this as well as I should before coming to
the list - so please forgive if this is a bit lame...
Should I still be using
Ahead-of-time compiled (AOT) code with `defprotocol` and `defrecord` creates
interfaces and classes you can access from Java. You don't need gen-class,
which is usually only necessary for public static void main methods and
edge-case Java interop problems.
I wrote about this on IBM
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