I've got a utility function I've been using called
`conditionally-transform` which is a non-macro version of `test->`. I
think both cond-> and if-> have a similar problem in that, if you already
understand if/cond/-> then it gives you little insight into how the new
threading macro works.
Both these names focus on the conditional nature of the macro. Perhaps a
name based on the transformative nature of the macro: trans-> or
transform-> ? These convey the idea of threading through various
transformations.
For when->, how about non-nil-> ? I'd feel better about some-> if it came,
as you said, with other new functions that use the syllable 'some', thus
expanding the Clojure lexicon. As it stands I don't feel like some-> has a
particularly intuitive meaning.
Alex
On Fri, Nov 30, 2012 at 9:33 AM, Jay Fields <j...@jayfields.com> wrote:
> On Fri, Nov 30, 2012 at 10:37 AM, Rich Hickey <richhic...@gmail.com>
> wrote:
> > The new names being considered for let->, test-> and when-> are:
> >
> > A) let-> becomes as->
>
> I prefer ->as, but don't feel strongly about it.
>
> (-> 1
> str
> (->as one-str
> (count one-str)
> (* 2 one-str))) ;; returns 2
>
> The thing that I like about this is that it reads to me as "thread
> as", and the ordering of "->" and "as" reminds me that the args are
> slightly different from traditional threading macros (i.e. it's not
> (thread-macro x & forms).
>
> > B) test-> becomes cond->
>
> I don't like cond-> for the same reason I didn't like let->, the
> cond-> isn't easy to understand if you already understand cond and ->.
> To try to come up with a name that I like, I tried to write some
> similar code to see what I would use. I came up with the following:
>
> (->> 1
> (#(if (number? %) (str %) %))
> (#(if (string? %) (count %) %))) ;; returns 1
>
> Which led me to the following (the best I can come up with right now).
>
> (if-> 1
> number? str
> string? count) ;; returns 1
>
> I don't think this is a homerun, as the understanding of "if" and "->"
> wouldn't guarantee an understanding of this. However, I couldn't come
> up with an example of solving a similar problem with -> and cond in
> any sensible way. I don't think the shape of the arguments should
> define the name, which is the only reason you'd want to use "cond",
> imho.
>
> I also considered something that expressed "if or identity. Perhaps
> something like the following
>
> (ifoi-> 1
> number? str
> string? count) ;; ifoi stands for "if or identity".
>
> You could also use ifei->, for "if else identity"
>
> Perhaps the issue is resolved if the form can take an else fn. Then
> the original if-> example becomes
>
> (if-> 1
> number? str identity
> string? count identity)
>
> This also gives you the freedom to put any function you want in the
> else clause. I don't know if that's a good thing or not.
>
> Or, since the significant majority of us have auto-complete, perhaps
> the following works
>
> (if-else-identity-> 1
> number? str
> string? count)
>
> > C) when-> becomes some->
>
> I don't see any issue with when->, that one actually seems very clear.
> Is the issue that you want to be able to continue the threading with
> false? If so, I wouldn't overload the meaning of "some", I'd simply
> make it take a test fn - then you can use any pred you want.
>
> (->when (comp not nil) (f1) (f2))
>
> Which is even more clear if you define not-nil? in core. Then all of
> the following would easily work
>
> (->when 1 not-nil? (f1) (f2)) ; thread when not nil
> (->when 1 identity (f1) (f2)) ; thread when truthy
> (->when 1 #{1 2 3} (f1) (f2)) ; thread when the value is 1 2 or 3.
>
> note, I switched the order again, as I like the way it reads (e.g.
> "thread when 1 is not nil"), and it reminds me that this is a
> threading macro that takes more than x & forms.
>
> --
> 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 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
