I'm having a conceptual problem, thinking functionally, and I was
hoping the fine Clojurians could take a peek.
Boiled down, I need to do a combination of map and reduce on a
collection. My walker needs to look at pairs along the collection,
but then sort of inject new values and restart when
Since you're given a sorted list of intervals, you don't actually need to
restart the whole merging process from the start after each merge; you can just
replace the last interval in your output with the new, merged interval and
continue from there. So `reduce' is the perfect tool for the job;
Ahhh...excellent, I see why I was blind. =) If you just build your
reduction collection in reverse, then the head of the reduction is
always the one you want to compare with as you traverse the incoming
collection. So you either cons one item or two onto the result, and
when you're all done
On Thu, Sep 16, 2010 at 07:53, Laurent PETIT laurent.pe...@gmail.com wrote:
2010/9/16 Meikel Brandmeyer m...@kotka.de
Hi Laurent,
On 16 Sep., 15:54, Laurent PETIT laurent.pe...@gmail.com wrote:
you don't like my one-liner ? :-)
I saw your message only after I sent mine. :)
(update-in
(loop [data (sorted-map)
collection newData
meeting (first collection)]
(def key ( ))
As a general rule, def should only be used at the top level. You
probably want (let [key ...] (if ...) here.
Hey, thanks for pointing this out - I was actually just trying to
Meikel,
(recur (cond (not (nil? (data key)))
(true? true)
*ieeck* Please do (cond ... :else default-clause). Not true, or (true?
true) or other stuff.
Wow, I somehow missed the :else option in cond? I've got that (true?
true) stuff scattered all over my code - going to
On 17 September 2010 00:56, Michael Ossareh ossa...@gmail.com wrote:
Meikel,
(recur (cond (not (nil? (data key)))
(true? true)
*ieeck* Please do (cond ... :else default-clause). Not true, or (true?
true) or other stuff.
Wow, I somehow missed the :else option in cond?
On Fri, Sep 17, 2010 at 08:58, Michael Wood esiot...@gmail.com wrote:
On 17 September 2010 00:56, Michael Ossareh ossa...@gmail.com wrote:
Meikel,
(recur (cond (not (nil? (data key)))
(true? true)
*ieeck* Please do (cond ... :else default-clause). Not true, or (true?
Hi Guys,
One of the things that has struck me about clojure, by virtue of being
a lisp, is the concision of the code - I really find it very
attractive. However yesterday I found something that I couldn't work
out how to do in a concise manner. Clearly commenting the code was a
priority once I
On Wed, Sep 15, 2010 at 2:48 PM, Michael Ossareh ossa...@gmail.com wrote:
Hi Guys,
One of the things that has struck me about clojure, by virtue of being
a lisp, is the concision of the code - I really find it very
attractive. However yesterday I found something that I couldn't work
out how
On Wed, 15 Sep 2010 11:48:09 -0700
Michael Ossareh ossa...@gmail.com wrote:
Hi Guys,
One of the things that has struck me about clojure, by virtue of being
a lisp, is the concision of the code - I really find it very
attractive. However yesterday I found something that I couldn't work
out
Something along those lines :
(def t { 0 {:title some :meetings [ :d1 ]} 2 {:title some2 :meetings [
:d2 ]}})
user= (pprint (update-in t [1] (fnil update-in {:title title :meetings
[]}) [:meetings] (comp vec concat) [:d1 :d2]int (update-in t [1] (fnil
update-in {:title title :meetings []})
Hi,
maybe this does what you want. I'm not sure, since you add the new
meeting to *all* meetings? And where does the :title come from when
you add a new meeting? I assume you have a map of a meeting title and
a meeting and want to add this to the corresponding entry in the data
map. If the
Hi,
On 16 Sep., 15:36, Meikel Brandmeyer m...@kotka.de wrote:
(if (not (nil? (next collection)
You can save the nil?. (if (not (next collection))) will also work.
nil is logically false.
And of course this should be (if (next collection)). The not belongs
to the You can save part.
2010/9/16 Meikel Brandmeyer m...@kotka.de
Hi Laurent,
On 16 Sep., 15:54, Laurent PETIT laurent.pe...@gmail.com wrote:
you don't like my one-liner ? :-)
I saw your message only after I sent mine. :)
(update-in coll [k] (fnil update-in *default-value*) [:meetings] (comp
vec
concat)
My poor brain can't handle nested calls to update-in, so this is what
I came up with:
(defn add-meetings [data k meetings]
(cond
(nil? (data k)) (assoc data k {:title title :meetings meetings})
:else (update-in data [k :meetings] concat meetings)))
On Sep 16, 8:53 am, Laurent PETIT
So nested calls to update-in are needed in order to be able to provide a
specific default value, everytime just having an empty map created isn't
sufficient.
So instead of (update-in {} [:a :b] identity) which returns {:a {:b nil}} ,
you can break the key path at :a so that the default value if
And note that the pattern works at any level, and is easily readable, since
update-in flattens the arguments of the modifying function :
If you want to touch the path [:a :b :c :d] and provide specific default
values at each level if the key is not found, it's as simple as :
(update-in coll
That pattern will be a great addition to the toolbox, thank you :)
On Sep 16, 9:58 am, Laurent PETIT laurent.pe...@gmail.com wrote:
And note that the pattern works at any level, and is easily readable, since
update-in flattens the arguments of the modifying function :
If you want to touch the
On Thu, Sep 2, 2010 at 6:29 PM, HB hubaghd...@gmail.com wrote:
Usually we create some domain entities, map them with Hibernate/
iBatis.
I don't know how a Clojure application would be build without objects.
I wonder if watching this talk by Rich Hickey will help?
On 2010-09-02, at 10:02 PM, HB wrote:
So in idiomatic Clojure applications, maps are considered like
objects?
And to operate on them we pass them to functions?
I think that considering maps as a state representation is reasonable. There
are alternatives, but that's fine-tuning I think.
, this OOP/FP is really powerful
approach (please note I'm not saying Clojure isn't good, I don't seel
flame war)
How to think in Clojure? how to achieve this shift?
Reading a bit about OOP in either Common Lisp or Dylan might help ease you into
'thinking clojure'. It can provide a bridge between
I'm only a little ways through Joy of Clojure (my first Clojure book)
but bear with me as I'm thinking aloud on what it means for me to
think in Clojure. I hope list members will forgive me if I get
things wrong - and please correct my working concept(s) as well.
One of the things that stuck out
Sean and Peter made comments that ring very true for me. I've always
had a problem with Java/Smalltalk/C# type OO. I also thought the
Common Lisp/Dylan way of generic functions and data structures made
more sense. Like Peter mentioned, I tend to think in terms of verbs
and transformations of
On Thu, Sep 2, 2010 at 11:36 PM, Peter Buckley buckmeist...@gmail.com wrote:
One of the things that stuck out for me that I heard somewhere (can't
remember exactly) was that OOP is about framing questions in terms of
nouns and FP is about framing questions in terms of verbs.
Perhaps you heard
On Thu, Sep 2, 2010 at 21:05, Miki miki.teb...@gmail.com wrote:
I'd go over SICP, though it not in Clojure but in Scheme - it will
show you how to think functional.
+1 on this.
http://mitpress.mit.edu/sicp/
--
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415-400-6772
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You received this message because you are
Really nice example Peter,
Thanks, I appreciate it.
On Sep 3, 6:36 am, Peter Buckley buckmeist...@gmail.com wrote:
I'm only a little ways through Joy of Clojure (my first Clojure book)
but bear with me as I'm thinking aloud on what it means for me to
think in Clojure. I hope list members will
I had the exact same problem transitioning from OOP to Lisp, and I can
only offer my own experiences. I finally understood lisp, by
programming a new pet project FROM SCRATCH, in the most
STRAIGHTFORWARD way possible. I originally started by porting over a
program I had written in Java, and found
On Fri, Sep 3, 2010 at 8:23 AM, Michael Ossareh ossa...@gmail.com wrote:
I'd go over SICP, though it not in Clojure but in Scheme - it will
show you how to think functional.
+1 on this.
http://mitpress.mit.edu/sicp/
i think some folks argue that
http://www.htdp.org/
is even better :-)
or at
This may help!
http://groups.csail.mit.edu/mac/classes/6.001/abelson-sussman-lectures/
These twenty video lectures by Hal Abelson and Gerald Jay Sussman are
a complete presentation of the course, given in July 1986 for Hewlett-
Packard employees, and professionally produced by Hewlett-Packard
I'm interested in Conjure webframework and I'm considering trying to
read its source code and participate later.
What do you think?
Do you other projects in mind?
This discussion is amazing guys :)
On Sep 3, 8:25 pm, CuppoJava patrickli_2...@hotmail.com wrote:
I had the exact same problem
Hey,
I finished reading Programming Clojure and Practical Clojure and
I'm hooked :)
Please count me in the Clojure club.
But I failed how to think in Clojure.
My main career is around Java web applications (Hibernate, Spring,
Lucene) and Web services.
Lets not talk about Java web frameworks
On Thu, Sep 2, 2010 at 9:29 PM, HB hubaghd...@gmail.com wrote:
Hey,
I finished reading Programming Clojure and Practical Clojure and
I'm hooked :)
Please count me in the Clojure club.
But I failed how to think in Clojure.
My main career is around Java web applications (Hibernate, Spring,
So in idiomatic Clojure applications, maps are considered like
objects?
And to operate on them we pass them to functions?
On Sep 3, 4:55 am, David Nolen dnolen.li...@gmail.com wrote:
On Thu, Sep 2, 2010 at 9:29 PM, HB hubaghd...@gmail.com wrote:
Hey,
I finished reading Programming Clojure
I highly recommend Joy of Clojure. It's a good 2nd book on clojure.
It shows you the why things are the way they are, and how to
do things the clojure way as much as possible.
On Thu, Sep 2, 2010 at 9:29 PM, HB hubaghd...@gmail.com wrote:
Hey,
I finished reading Programming Clojure and
I'd go over SICP, though it not in Clojure but in Scheme - it will
show you how to think functional.
On Sep 2, 6:29 pm, HB hubaghd...@gmail.com wrote:
Hey,
I finished reading Programming Clojure and Practical Clojure and
I'm hooked :)
Please count me in the Clojure club.
But I failed how to
I'm new to Clojure and I'm wondering how I'm supposed to be thinking
about various things. I want to use the c3p0 database connection pool
in a Clojure app. In Java, I would simply create an instance of this
class and either assign it to a static field or perhaps make it
available in a
I'm new to Clojure and I'm wondering how I'm supposed to be thinking
about various things. I want to use the c3p0 database connection pool
in a Clojure app. In Java, I would simply create an instance of this
class and either assign it to a static field or perhaps make it
available in a
Here is one way:
(let [dbc (make-db)]
(defn get-apples []
(.query dbc select * from apples)))
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On Mon, Jan 26, 2009 at 11:13 PM, Whirlycott p...@whirlycott.com wrote:
I'm new to Clojure and I'm wondering how I'm supposed to be thinking
about various things. I want to use the c3p0 database connection pool
in a Clojure app. In Java, I would simply create an instance of this
class and
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