Re: boolean java interopt puzzle/bug?!

2013-10-10 Thread John D. Hume 
That behavior seems like a bug to me. Do you know whether there's some good
(or stated, good or bad) reason for it?

http://grepcode.com/file/repository.grepcode.com/java/root/jdk/openjdk/7-b147/sun/reflect/UnsafeBooleanFieldAccessorImpl.java
On Oct 9, 2013 4:33 PM, "Pablo Nussembaum"  wrote:

>  Thanks for the help and clarifications.
> My problem is that I'm working on a tool, as a part of my thesis, to
> randomly execute annotated java classes to try discover its behavior.
> So if a class has a (b|B)oolean field and I read its value using
> reflection it returns (using Field.get()) a Boolean that for clojure will
> be always false.
>
> In order to solve this issue I created the follow fn:
>
> (defn- get-val
>   [^java.lang.reflect.Field f instance]
>   (let [value (.get f instance)]
> (if (instance? java.lang.Boolean value)
>   (boolean value)
>   value)))
>
> Thanks and regards,
> --
> Bauna
>
>
> On 10/06/2013 10:57 PM, Andy Fingerhut wrote:
>
> There is also this page on ClojureDocs that might shed some light on this
> quirk:
>
> http://clojuredocs.org/clojure_core/clojure.core/if
>
>
> On Sun, Oct 6, 2013 at 6:14 PM, Rob Browning  wrote:
>
>> Gary Trakhman  writes:
>>
>> > Clojure's false and true are Boolean/FALSE and Boolean/TRUE, and for
>> speed
>> > reasons (I think) anything that checks for truthiness uses java's ==,
>> which
>> > will fail on any new Boolean object.  Usually, this isn't a problem, but
>> > sometimes it is.  You can see that this assumption is pervasive by
>> looking
>> > at the implementations of 'true?' and 'false?', which use identical? and
>> > the check for != Boolean.FALSE in
>> >
>> https://github.com/clojure/clojure/blob/master/src/jvm/clojure/lang/Compiler.java#L2569
>>
>>  ...and further, my understanding is that the Boolean constructors are
>> more or less considered a mistake, and you should effectively never
>> use them.  For example:
>>
>>   http://rayfd.me/2007/01/17/the-evil-boolean-constructors/
>>
>> Hope this helps
>> --
>> Rob Browning
>> rlb @defaultvalue.org and @debian.org
>> GPG as of 2011-07-10 E6A9 DA3C C9FD 1FF8 C676 D2C4 C0F0 39E9 ED1B 597A
>> GPG as of 2002-11-03 14DD 432F AE39 534D B592 F9A0 25C8 D377 8C7E 73A4
>>
>> --
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>
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Re: boolean java interopt puzzle/bug?!

2013-10-09 Thread Pablo Nussembaum 

  
  
Thanks for the help and clarifications. 
My problem is that I'm working on a tool, as a part of my thesis, to
randomly execute annotated java classes to try discover its
behavior.
So if a class has a (b|B)oolean field and I read its value using
reflection it returns (using Field.get()) a Boolean that for clojure
will be always false.

In order to solve this issue I created the follow fn:

(defn- get-val 
  [^java.lang.reflect.Field f instance] 
  (let [value (.get f instance)]
    (if (instance? java.lang.Boolean value) 
  (boolean value)
  value)))
 
Thanks and regards,
-- 
Bauna


On 10/06/2013 10:57 PM, Andy Fingerhut
  wrote:


  There is also this page on ClojureDocs that might
shed some light on this quirk:

    http://clojuredocs.org/clojure_core/clojure.core/if
  
  

On Sun, Oct 6, 2013 at 6:14 PM, Rob
  Browning 
  wrote:
  
Gary Trakhman 
  writes:
  
  > Clojure's false and true are Boolean/FALSE and
  Boolean/TRUE, and for speed
  > reasons (I think) anything that checks for truthiness
  uses java's ==, which
  > will fail on any new Boolean object.  Usually, this
  isn't a problem, but
  > sometimes it is.  You can see that this assumption is
  pervasive by looking
  > at the implementations of 'true?' and 'false?', which
  use identical? and
  > the check for != Boolean.FALSE in
  > https://github.com/clojure/clojure/blob/master/src/jvm/clojure/lang/Compiler.java#L2569
  

...and further, my understanding is that the Boolean
constructors are
more or less considered a mistake, and you should
effectively never
use them.  For example:

  http://rayfd.me/2007/01/17/the-evil-boolean-constructors/

Hope this helps
--
Rob Browning
rlb @defaultvalue.org
and @debian.org
GPG as of 2011-07-10 E6A9 DA3C C9FD 1FF8 C676 D2C4 C0F0
39E9 ED1B 597A
GPG as of 2002-11-03 14DD 432F AE39 534D B592 F9A0 25C8
D377 8C7E 73A4
  

  
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Re: boolean java interopt puzzle/bug?!

2013-10-06 Thread Andy Fingerhut 
There is also this page on ClojureDocs that might shed some light on this
quirk:

http://clojuredocs.org/clojure_core/clojure.core/if


On Sun, Oct 6, 2013 at 6:14 PM, Rob Browning  wrote:

> Gary Trakhman  writes:
>
> > Clojure's false and true are Boolean/FALSE and Boolean/TRUE, and for
> speed
> > reasons (I think) anything that checks for truthiness uses java's ==,
> which
> > will fail on any new Boolean object.  Usually, this isn't a problem, but
> > sometimes it is.  You can see that this assumption is pervasive by
> looking
> > at the implementations of 'true?' and 'false?', which use identical? and
> > the check for != Boolean.FALSE in
> >
> https://github.com/clojure/clojure/blob/master/src/jvm/clojure/lang/Compiler.java#L2569
>
> ...and further, my understanding is that the Boolean constructors are
> more or less considered a mistake, and you should effectively never
> use them.  For example:
>
>   http://rayfd.me/2007/01/17/the-evil-boolean-constructors/
>
> Hope this helps
> --
> Rob Browning
> rlb @defaultvalue.org and @debian.org
> GPG as of 2011-07-10 E6A9 DA3C C9FD 1FF8 C676 D2C4 C0F0 39E9 ED1B 597A
> GPG as of 2002-11-03 14DD 432F AE39 534D B592 F9A0 25C8 D377 8C7E 73A4
>
> --
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Re: boolean java interopt puzzle/bug?!

2013-10-06 Thread Rob Browning 
Gary Trakhman  writes:

> Clojure's false and true are Boolean/FALSE and Boolean/TRUE, and for speed
> reasons (I think) anything that checks for truthiness uses java's ==, which
> will fail on any new Boolean object.  Usually, this isn't a problem, but
> sometimes it is.  You can see that this assumption is pervasive by looking
> at the implementations of 'true?' and 'false?', which use identical? and
> the check for != Boolean.FALSE in
> https://github.com/clojure/clojure/blob/master/src/jvm/clojure/lang/Compiler.java#L2569

...and further, my understanding is that the Boolean constructors are
more or less considered a mistake, and you should effectively never
use them.  For example:

  http://rayfd.me/2007/01/17/the-evil-boolean-constructors/

Hope this helps
-- 
Rob Browning
rlb @defaultvalue.org and @debian.org
GPG as of 2011-07-10 E6A9 DA3C C9FD 1FF8 C676 D2C4 C0F0 39E9 ED1B 597A
GPG as of 2002-11-03 14DD 432F AE39 534D B592 F9A0 25C8 D377 8C7E 73A4

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Re: boolean java interopt puzzle/bug?!

2013-10-06 Thread Gary Trakhman 
Clojure's false and true are Boolean/FALSE and Boolean/TRUE, and for speed
reasons (I think) anything that checks for truthiness uses java's ==, which
will fail on any new Boolean object.  Usually, this isn't a problem, but
sometimes it is.  You can see that this assumption is pervasive by looking
at the implementations of 'true?' and 'false?', which use identical? and
the check for != Boolean.FALSE in
https://github.com/clojure/clojure/blob/master/src/jvm/clojure/lang/Compiler.java#L2569





On Sun, Oct 6, 2013 at 5:27 PM, Pablo Nussembaum  wrote:

> Hey Devs,
> I have fighting against an issue that can summarized in the following line:
>
> user=> (not (new java.lang.Boolean false))
> false
>
> Is that behavior correct?
>
> Because if I run:
> user=> (type false)
> java.lang.Boolean
>
> Can someone help me to understand it?
>
> Thanks,
> --
> Bauna
>
> --
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boolean java interopt puzzle/bug?!

2013-10-06 Thread Pablo Nussembaum 
Hey Devs,
I have fighting against an issue that can summarized in the following line:

user=> (not (new java.lang.Boolean false))
false

Is that behavior correct?

Because if I run:
user=> (type false)
java.lang.Boolean

Can someone help me to understand it?

Thanks,
-- 
Bauna

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