and obviously I would like it to throw here instead :) but hey, that's just
me - overly obsessed with fail-fast rather that performance first or
tolerance
On Fri, Mar 1, 2013 at 9:12 PM, AtKaaZ <atk...@gmail.com> wrote:
> user=> (contains? "abc" 1.5)
> true
>
> looks like for that, it's coerced to int
>
> else if(key instanceof Number && (coll instanceof String ||
> coll.getClass().isArray())) {
> int n = ((Number) key).intValue();
> return n >= 0 && n < count(coll);
> }
> => (int 1.4)
> 1
> => (int 1.6)
> 1
> => (.intValue 1.4)
> 1
> => (.intValue 1.6)
> 1
>
>
>
> On Fri, Mar 1, 2013 at 9:05 PM, Michael Gardner <gardne...@gmail.com>wrote:
>
>> On Mar 1, 2013, at 13:36 , AtKaaZ <atk...@gmail.com> wrote:
>>
>> > I don't think I understand what you mean (could you rephrase/example?),
>> I cannot think of a case when I wouldn't want it to throw when I'm passing
>> a non-number (contains? [:a :b :c] :a), I mean, rather than just silently
>> ignoring.
>>
>> I'm talking about a case where you have one or more associative
>> containers of unknown types, and you want to be able to generically ask
>> them whether they contain a particular key. E.g.:
>>
>> (defn has-foo? [c] ;; c is only known to be Associative
>> (contains? c :foo))
>>
>> Insofar as a vector can be viewed as a kind of associative container, one
>> might expect/desire this code to just return false if c happens to be a
>> vector. One could see this as a question about the contract promised by the
>> Associative interface: is is always OK to ask an Associative container
>> whether it contains a given key, or are implementations free to accept only
>> certain kinds of keys? I could go either way on that personally, but I
>> can't find any docs that support one interpretation or the other.
>>
>> > It;s not unlike this:
>> > => (contains? '(:a :b :c) :a)
>> > IllegalArgumentException contains? not supported on type:
>> clojure.lang.PersistentList clojure.lang.RT.contains (RT.java:724)
>> >
>> > it throws because, it's similarly better than just ignoring it and
>> propagating the bug somewhere else.
>>
>> Different case, because lists aren't Associative.
>>
>> > In a way, it's already so for String:
>> > => (contains? "aaa" 1)
>> > true
>> > => (contains? "aaa" 3)
>> > false
>> > => (contains? "aaa" "a")
>> > IllegalArgumentException contains? not supported on type:
>> java.lang.String clojure.lang.RT.contains (RT.java:724)
>> > => (contains? "aaa" 'a)
>> > IllegalArgumentException contains? not supported on type:
>> java.lang.String clojure.lang.RT.contains (RT.java:724)
>>
>> This one's actually quite surprising to me. I don't know why 'contains?
>> throws when given a String and a non-numeric argument, since that's
>> inconsistent with its behavior on vectors (and the exception's description
>> seems inaccurate, since 'contains? *is* supported on Strings). Even more
>> strangely:
>>
>> user=> (contains? "abc" 1.5)
>> true
>>
>> I have no explanation for this.
>>
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>>
>
>
> --
> Please correct me if I'm wrong or incomplete,
> even if you think I'll subconsciously hate it.
>
>
--
Please correct me if I'm wrong or incomplete,
even if you think I'll subconsciously hate it.
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