You are already doing exactly the right thing by having a temporary
variable.
To be precise a code fragment like:
(let [expensive-answer (some-fn x y z)
final-result { :k1 (f1 expensive-answer)
:k2 (f2 expensive-answer)
:k3 (f3 expensive-answer) } ]
final-result)
is already purely functional and very appropriate. In fact, there is even
a name for a closely-related technique:
https://refactoring.com/catalog/extractVariable.html
Alan
On Sat, May 13, 2017 at 1:26 PM, Kevin Kleinfelter <
[email protected]> wrote:
> How would one convert the following procedural logic into
> functional/Clojure?
> x = expensive-calculation
> return (f1(x), f2(x), f3(x))
>
> I'm sure I could force it by using a var to save the intermediate value,
> but that's still procedural. It seems like the pattern of reusing an
> expensive result in multiple function calls without recalculating it must
> have a functional approach, but I'm not finding it.
>
> What I really want to do is to return:
> {:key1 f1(f0(x)), :key2 f2(f0(x)), :key3 f3(f0(x))}
>
> without paying the price of executing f0 multiple times.
>
> Tnx.
>
> --
> You received this message because you are subscribed to the Google
> Groups "Clojure" group.
> To post to this group, send email to [email protected]
> Note that posts from new members are moderated - please be patient with
> your first post.
> To unsubscribe from this group, send email to
> [email protected]
> 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 [email protected].
> For more options, visit https://groups.google.com/d/optout.
>
--
You received this message because you are subscribed to the Google
Groups "Clojure" group.
To post to this group, send email to [email protected]
Note that posts from new members are moderated - please be patient with your
first post.
To unsubscribe from this group, send email to
[email protected]
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 [email protected].
For more options, visit https://groups.google.com/d/optout.
