Re: [OT] Re: More idiomatic way to use map like this?
What about the times when one simply must use loop/recur for performance
reasons? Although, one thought I had on that was to write a functional
version, and if it's a performance bottleneck, write a loop/recur version
and call the latter in performance-critical areas, but also have tests that
check that both versions have the same semantics.
On Sat, May 4, 2013 at 1:54 AM, Alex Baranosky
alexander.barano...@gmail.com wrote:
I concur with Timothy's assessment. Really well stated and illustrated
use of reduce with a named reduce function.
On Fri, May 3, 2013 at 10:52 PM, Timothy Baldridge
tbaldri...@gmail.comwrote:
In general, loop/recur shouldn't be considered idiomatic, IMO. Instead,
try for a more functional style:
due = 100
cards = cards.map do |card|
card.applied_balance = max(0, due - card.balance)
due -= card.applied_balance
becomes (untested):
(defn apply-balance-1 [{:keys [due] :as accum} [card-id balance]]
(let [applied (max (- due balance))]
(- accum
(assoc-in [:applied card-id] applied)
(assoc-in [:due] due
(reduce apply-balance-1
{:due 100}
{:card-id-1 4404.00
:card-id-2 3020.00
etc})
Often I have found that using reduce forces me to break functions into
several parts. If I used loop/recur, normally the function prelude,
postlude and loop block are all smashed into a single function. With reduce
+ a do-step-1 function (as seen above) we can more easily reason about what
is happening. The code is then easier to test as well, as we can test the
calculations apart from the loop logic.
When I'm performing Clojure code reviews, I often consider loop/recur to
be a code smell.
Timothy
On Fri, May 3, 2013 at 3:53 PM, Armando Blancas abm221...@gmail.comwrote:
On Friday, May 3, 2013 1:15:24 PM UTC-7, Robert Pitts wrote:
Armando was a good citizen and sent along a plain-text version as well
– https://groups.google.com/**group/clojure/msg/**
6aae8287bc55d436?dmode=source**output=gplainnoredirecthttps://groups.google.com/group/clojure/msg/6aae8287bc55d436?dmode=sourceoutput=gplainnoredirect
That must have been Google Groups doing the right thing... nice feature.
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You
Re: [OT] Re: More idiomatic way to use map like this?
I don't think that it's productive to discuss idiomatic code and performance in
the same breath.
People do all sorts of nasty stuff when trying to squeeze performance juice out
of their code. In my experience it's rare to see performance-related idioms
beyond the obvious language-level constructs like type hints and indeed
loop/recur. When serious performance concerns come into play, idioms are often
broken via the use of clever tricks.
In the case of loop/recur I think I agree with Tim, Alex, and company.
What you're bringing up is a special case, so to your question I would respond
with a question: What makes a context-specific performance-related concern
idiomatic? My guess is very little.
In summary I would say that loop/recur is idiomatic when there is a serious,
verifiable performance concern, but the overarching idiom is to prefer reduce
as it's more consistent with Clojure's philosophy and design. Loop/recur is
kind of like swearing. Reduce is typical conversation.
2c,
--
{:∂evin :√valters}
On Saturday, May 4, 2013 at 2:43 PM, Cedric Greevey wrote:
What about the times when one simply must use loop/recur for performance
reasons? Although, one thought I had on that was to write a functional
version, and if it's a performance bottleneck, write a loop/recur version and
call the latter in performance-critical areas, but also have tests that check
that both versions have the same semantics.
On Sat, May 4, 2013 at 1:54 AM, Alex Baranosky alexander.barano...@gmail.com
(mailto:alexander.barano...@gmail.com) wrote:
I concur with Timothy's assessment. Really well stated and illustrated use
of reduce with a named reduce function.
On Fri, May 3, 2013 at 10:52 PM, Timothy Baldridge tbaldri...@gmail.com
(mailto:tbaldri...@gmail.com) wrote:
In general, loop/recur shouldn't be considered idiomatic, IMO. Instead,
try for a more functional style:
due = 100
cards = cards.map do |card|
card.applied_balance = max(0, due - card.balance)
due -= card.applied_balance
becomes (untested):
(defn apply-balance-1 [{:keys [due] :as accum} [card-id balance]]
(let [applied (max (- due balance))]
(- accum
(assoc-in [:applied card-id] applied)
(assoc-in [:due] due
(reduce apply-balance-1
{:due 100}
{:card-id-1 4404.00
:card-id-2 3020.00
etc})
Often I have found that using reduce forces me to break functions into
several parts. If I used loop/recur, normally the function prelude,
postlude and loop block are all smashed into a single function. With
reduce + a do-step-1 function (as seen above) we can more easily reason
about what is happening. The code is then easier to test as well, as we
can test the calculations apart from the loop logic.
When I'm performing Clojure code reviews, I often consider loop/recur to
be a code smell.
Timothy
On Fri, May 3, 2013 at 3:53 PM, Armando Blancas abm221...@gmail.com
(mailto:abm221...@gmail.com) wrote:
On Friday, May 3, 2013 1:15:24 PM UTC-7, Robert Pitts wrote:
Armando was a good citizen and sent along a plain-text version as
well –
https://groups.google.com/group/clojure/msg/6aae8287bc55d436?dmode=sourceoutput=gplainnoredirect
That must have been Google Groups doing the right thing... nice feature.
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To
[OT] Re: More idiomatic way to use map like this?
On Fri, May 3, 2013 at 2:32 PM, Alan Thompson thompson2...@gmail.comwrote: Hey Armando - How did you get the nice syntax highlighting into your post??? Enquiring minds wanna know. Alan If the OP's problem is solved anyway, I suppose we can go OT a bit with this thread now. AFAIK, it's done by sending the list an HTML email. I'm not sure what tools are used to generate the formatting, though, or of the netiquette of posting in HTML. Those posts render well in the Groups interface and in gmail, but for anyone using other mail clients to use the list, their mileage will vary. It probably looks like a horrendous mess to anyone using mutt, elm, or XFMail, for example. Are the majority of readers here using gmail or Groups, then? (On a related note, there are a lot of top-posted replies and I'm probably guilty of a few of them myself. The gmail web interface makes it significantly more effort to bottom-post, whereas Google Groups makes it more effort to top-post, last time I checked out its interface. I haven't seen complaints here about either type of post, though, or about HTML mail to the list, so it seems as if all three are generally accepted here.) -- -- You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups Clojure group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
Re: [OT] Re: More idiomatic way to use map like this?
Armando was a good citizen and sent along a plain-text version as well – https://groups.google.com/group/clojure/msg/6aae8287bc55d436?dmode=sourceoutput=gplainnoredirect Would still be nifty to know if there's an easy way to do this, Armando :) On Friday, May 3, 2013 3:19:48 PM UTC-4, Cedric Greevey wrote: On Fri, May 3, 2013 at 2:32 PM, Alan Thompson thomps...@gmail.comjavascript: wrote: Hey Armando - How did you get the nice syntax highlighting into your post??? Enquiring minds wanna know. Alan If the OP's problem is solved anyway, I suppose we can go OT a bit with this thread now. AFAIK, it's done by sending the list an HTML email. I'm not sure what tools are used to generate the formatting, though, or of the netiquette of posting in HTML. Those posts render well in the Groups interface and in gmail, but for anyone using other mail clients to use the list, their mileage will vary. It probably looks like a horrendous mess to anyone using mutt, elm, or XFMail, for example. Are the majority of readers here using gmail or Groups, then? (On a related note, there are a lot of top-posted replies and I'm probably guilty of a few of them myself. The gmail web interface makes it significantly more effort to bottom-post, whereas Google Groups makes it more effort to top-post, last time I checked out its interface. I haven't seen complaints here about either type of post, though, or about HTML mail to the list, so it seems as if all three are generally accepted here.) -- -- You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups Clojure group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
Re: [OT] Re: More idiomatic way to use map like this?
On Friday, May 3, 2013 1:15:24 PM UTC-7, Robert Pitts wrote: Armando was a good citizen and sent along a plain-text version as well – https://groups.google.com/group/clojure/msg/6aae8287bc55d436?dmode=sourceoutput=gplainnoredirect That must have been Google Groups doing the right thing... nice feature. -- -- You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups Clojure group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
Re: [OT] Re: More idiomatic way to use map like this?
In general, loop/recur shouldn't be considered idiomatic, IMO. Instead, try
for a more functional style:
due = 100
cards = cards.map do |card|
card.applied_balance = max(0, due - card.balance)
due -= card.applied_balance
becomes (untested):
(defn apply-balance-1 [{:keys [due] :as accum} [card-id balance]]
(let [applied (max (- due balance))]
(- accum
(assoc-in [:applied card-id] applied)
(assoc-in [:due] due
(reduce apply-balance-1
{:due 100}
{:card-id-1 4404.00
:card-id-2 3020.00
etc})
Often I have found that using reduce forces me to break functions into
several parts. If I used loop/recur, normally the function prelude,
postlude and loop block are all smashed into a single function. With reduce
+ a do-step-1 function (as seen above) we can more easily reason about what
is happening. The code is then easier to test as well, as we can test the
calculations apart from the loop logic.
When I'm performing Clojure code reviews, I often consider loop/recur to be
a code smell.
Timothy
On Fri, May 3, 2013 at 3:53 PM, Armando Blancas abm221...@gmail.com wrote:
On Friday, May 3, 2013 1:15:24 PM UTC-7, Robert Pitts wrote:
Armando was a good citizen and sent along a plain-text version as well –
https://groups.google.com/**group/clojure/msg/**
6aae8287bc55d436?dmode=source**output=gplainnoredirecthttps://groups.google.com/group/clojure/msg/6aae8287bc55d436?dmode=sourceoutput=gplainnoredirect
That must have been Google Groups doing the right thing... nice feature.
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Re: [OT] Re: More idiomatic way to use map like this?
I concur with Timothy's assessment. Really well stated and illustrated use
of reduce with a named reduce function.
On Fri, May 3, 2013 at 10:52 PM, Timothy Baldridge tbaldri...@gmail.comwrote:
In general, loop/recur shouldn't be considered idiomatic, IMO. Instead,
try for a more functional style:
due = 100
cards = cards.map do |card|
card.applied_balance = max(0, due - card.balance)
due -= card.applied_balance
becomes (untested):
(defn apply-balance-1 [{:keys [due] :as accum} [card-id balance]]
(let [applied (max (- due balance))]
(- accum
(assoc-in [:applied card-id] applied)
(assoc-in [:due] due
(reduce apply-balance-1
{:due 100}
{:card-id-1 4404.00
:card-id-2 3020.00
etc})
Often I have found that using reduce forces me to break functions into
several parts. If I used loop/recur, normally the function prelude,
postlude and loop block are all smashed into a single function. With reduce
+ a do-step-1 function (as seen above) we can more easily reason about what
is happening. The code is then easier to test as well, as we can test the
calculations apart from the loop logic.
When I'm performing Clojure code reviews, I often consider loop/recur to
be a code smell.
Timothy
On Fri, May 3, 2013 at 3:53 PM, Armando Blancas abm221...@gmail.comwrote:
On Friday, May 3, 2013 1:15:24 PM UTC-7, Robert Pitts wrote:
Armando was a good citizen and sent along a plain-text version as well –
https://groups.google.com/**group/clojure/msg/**
6aae8287bc55d436?dmode=source**output=gplainnoredirecthttps://groups.google.com/group/clojure/msg/6aae8287bc55d436?dmode=sourceoutput=gplainnoredirect
That must have been Google Groups doing the right thing... nice feature.
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