Yes, reading the source code and trying to understand why rest was being
called there is how I came up with this case.
On 2 July 2015 at 07:54, icamts <ica...@gmail.com> wrote:
> Hi Pablo,
> I think you're right. Have a look at flatten source
>
> (defn flatten
> "Takes any nested combination of sequential things (lists, vectors,
> etc.) and returns their contents as a single, flat sequence.
> (flatten nil) returns an empty sequence."
> {:added "1.2"
> :static true}
> [x]
> (filter (complement sequential?)
> (rest (tree-seq sequential? seq x))))
>
> it is the rest function that causes this behavior and it seems to be just
> an optimization to avoid filtering the first element of tree-seq that is
> known to be the whole sequence. A simpler definition of flatten seems to
> have the behavior you expected.
>
> (defn flatten1 [x] (filter (complement sequential?) (tree-seq sequential?
> seq x)))
>
>
>
>
> Il giorno mercoledì 1 luglio 2015 13:55:28 UTC+2, J. Pablo Fernández ha
> scritto:
>>
>> Hello Clojurists,
>>
>> Today I was surprised by the result of (flatten 1) which is '(). I was
>> expecting '(1) or an error. Talking in some other people in #clojure @
>> clojurians.net, not everybody agrees that '(1) is a good result but that
>> '() is somewhat surprising. Would it be better if it raised an error when
>> the attribute is not sequential?
>>
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