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From: Sonny To <son.c.to@gmail.com>
To: Per Bothner <per@bothner.com>
Cc: Kawa mailing list <kawa@sourceware.org>
Subject: Re: scoping rules
Date: Mon, 18 Sep 2017 08:29:00 -0000	[thread overview]
Message-ID: <CAJxjsJuXREQ4B8Ui4ZOMD7a4J=n_zS2PHVL7LjbgPq+jOopnjQ@mail.gmail.com> (raw)
In-Reply-To: <CAJxjsJvYx7RjM+jJsvVMuqz3uEhA9e7VUL1zoRXFpbWiBv6N-w@mail.gmail.com>

I was able to reproduce strange behavior with symbol scope on the jvm:

(define (run-in-ui-thread fn)
  (let ((t :: java.lang.Thread (java.lang.Thread (object (java.lang.Runnable)
                                                         ((run)::void
                                                          (fn))))))
    (t:start)))

(run-in-ui-thread (lambda ()
                    (let ( (a 1)
                           (b 2)
                           (c (+ a b)))
                      (display c))))

here's the stacktrace

/dev/stdin:37:15: warning - no declaration seen for b
#|kawa:39|# Exception in thread "Thread-4" /dev/stdin:37:13: unbound location: a
        at gnu.mapping.DynamicLocation.get(DynamicLocation.java:36)
        at atInteractiveLevel$Mn5.lambda1(stdin:37)
        at atInteractiveLevel$Mn5.lambda1$check(stdin:34)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:497)
        at gnu.mapping.CallContext$ReflectMethodHandle.invokeExact(CallContext.java:726)
        at gnu.mapping.Procedure.applyToConsumerDefault(Procedure.java:75)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:497)
        at gnu.mapping.CallContext$ReflectMethodHandle.invokeExact(CallContext.java:726)
        at gnu.kawa.functions.ApplyToArgs.applyToConsumerA2A(ApplyToArgs.java:132)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:497)
        at gnu.mapping.CallContext$ReflectMethodHandle.invokeExact(CallContext.java:726)
        at gnu.mapping.CallContext.runUntilDone(CallContext.java:586)
        at gnu.mapping.CallContext.runUntilValue(CallContext.java:669)
        at gnu.mapping.Procedure.apply1(Procedure.java:148)
        at atInteractiveLevel$Mn1$0.run(stdin:5)
        at java.lang.Thread.run(Thread.java:745)


This however works:

(run-in-ui-thread (lambda ()
                    (let ( (a 1)
                           (b 2))
                      (display (+ a b)))))



On Sun, Sep 17, 2017 at 9:49 PM, Sonny To <son.c.to@gmail.com> wrote:
> ok let me see if i can reproduce this outside of android
>
> On Sun, Sep 17, 2017 at 10:45 AM, Per Bothner <per@bothner.com> wrote:
>> On 09/17/2017 09:51 AM, Sonny To wrote:
>>>
>>> sorry for the newb question but i find this behavior odd
>>>
>>> (let ((handler (android.os.Handler (android.os.Looper:getMainLooper)))
>>>        (c context))
>>>    (handler:post (lambda ()
>>>                          (let ((t (android.widget.Toast:makeText (as
>>> android.app.Application c) "foobar"  1000)))
>>>                            (t:show))
>>>                          )))
>>>
>>> To get this example to work I had to bind c context in the top level let
>>> in the second let, I have to use c instead of context directly.
>>> (android.widget.Toast:makeText (as android.app.Application context)
>>> will complain
>>>
>>> /dev/stdin:45:93: unbound location: context
>>>
>>> it could not see the context binding.
>>> Should it not look in the environment? context is definitely in the
>>> environment because the c binding works
>>
>>
>> That does sound like a bug.  Probably the interaction of dynamic
>> (environment) name-lookup
>> combined with the use of the anonymous class.
>>
>> If you can create a simple non-Android test-case I'll take a look.
>>
>> It is recommended to include the line:
>>
>>     (define-variable context)
>>
>> as that tells the compiler to look for 'context' in the dynamic environment,
>> and avoids warnings when using --warn-undefined-variable.
>> --
>>         --Per Bothner
>> per@bothner.com   http://per.bothner.com/

  reply	other threads:[~2017-09-18  8:29 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-09-17 16:51 Sonny To
2017-09-17 17:45 ` Per Bothner
2017-09-17 18:49   ` Sonny To
2017-09-18  8:29     ` Sonny To [this message]
2017-09-18  8:31       ` Sonny To
2017-09-18 12:34       ` Sonny To

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