Thanks, Justin!
Yeah, I noticed that range doesn't return an instance of
clojure.lang.LazySeq, so I added a print-method for clojure.lang.Iterate.
And that one seems to work as expected, but apparently you can't override
the print-method for clojure.lang.LazySeq.
But this doesn't seem like a good approach, anyway, because I don't want to
change the printing behavior globally.
I think I'm just going to have to forego logging arbitrary things, and
maybe implement some optional santization if necessary.
On Monday, November 2, 2020 at 12:40:48 PM UTC-8 noise...@gmail.com wrote:
> hit send too soon --
>
> also, that print-method doesn't catch all lazy values
>
> user=> (instance? clojure.lang.LazySeq (range))
> false
>
> user=> (supers (class (range)))
> #{java.lang.Iterable java.util.List clojure.lang.Obj
> clojure.lang.IPending java.io.Serializable clojure.lang.IHashEq
> java.util.Collection clojure.lang.IObj clojure.lang.Sequential
> clojure.lang.Seqable clojure.lang.IPersistentCollection
> clojure.lang.ASeq clojure.lang.IReduce java.lang.Object
> clojure.lang.ISeq clojure.lang.IMeta clojure.lang.IReduceInit}
>
> On Mon, Nov 2, 2020 at 12:36 PM Justin Smith <noise...@gmail.com> wrote:
> >
> > > The next step might be to investigate why infinite lazy seqs don't
> print as clojure.lang.LazySeq, like the finite ones.
> >
> > that printing of "clojure.lang.LazySeq@c5d38b66" relies on completely
> > realizing the input, as it relies on the hash, which relies on the
> > fully realized value
> >
> > On Mon, Nov 2, 2020 at 12:32 PM Austin Haas <aus...@pettomato.com>
> wrote:
> > >
> > > Thanks, Juan.
> > >
> > > I don't need to know the length of the seq, though, only that it is
> lazy. I don't want to realize any lazy seqs. Ideally, I'd like to be able
> to print any data structure and have all lazy seqs print just like it does
> in the example I gave above (i.e., "clojure.lang.LazySeq@c5d38b66"),
> whether it is finite or infinite.
> > >
> > > I also don't want to walk through every data structure to check if it
> contains a lazy seq, but maybe that is the only option.
> > >
> > > I've also tried:
> > >
> > > (defmethod print-method clojure.lang.LazySeq [q, w]
> > > (.write w "#clojure.lang.LazySeq"))
> > >
> > > The next step might be to investigate why infinite lazy seqs don't
> print as clojure.lang.LazySeq, like the finite ones.
> > > On Monday, November 2, 2020 at 9:22:58 AM UTC-8 jpmon...@gmail.com
> wrote:
> > >>
> > >> Hi Austin,
> > >>
> > >> Since there is no way to know the length of a lazy-seq without
> realizing it, I think your only choice is to set a limit on it by binding
> *print-length* if you are not sure about the sequence.
> > >>
> > >> Other thing you can try is bounded-count like this :
> > >>
> > >> (defn looks-finite? [xs]
> > >> (let [limit 1000]
> > >> (< (bounded-count limit xs) limit)))
> > >>
> > >> (looks-finite? (map inc (range))) ;; => false
> > >> (looks-finite? (map inc (range 100))) ;; => true
> > >>
> > >> I hope that helps.
> > >>
> > >> Juan
> > >> El domingo, 1 de noviembre de 2020 a las 20:06:39 UTC-3, Austin Haas
> escribió:
> > >>>
> > >>>
> > >>> How can I make sure that a logging function won't try to realize an
> infinite lazy seq that could be anywhere in the arguments passed to the
> logging function?
> > >>>
> > >>> Is there some way to guarantee that lazy seqs won't be realized when
> converting to a string?
> > >>>
> > >>> I know I can bind *print-length*, but I don't want to constrain
> every collection.
> > >>>
> > >>> And I know that lazy seqs aren't always realized, but that doesn't
> seem to help if they are infinite:
> > >>>
> > >>> user=> (str (map inc (range 10)))
> > >>> "clojure.lang.LazySeq@c5d38b66"
> > >>>
> > >>> user=> (str (map inc (range)))
> > >>> <never ends>
> > >>>
> > >>> Thanks.
> > >>>
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