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From Gordon Smith <gsmit...@hotmail.com>
Subject Re: AW: [Falcon] Constructor NS (was: [Falcon] starting up)
Date Sun, 05 Oct 2014 16:24:14 GMT
It's a bit different in that the AVM is strict about access modifiers; you cannot use reflection
to call a private method from outside its class. However I know developers have wanted non-public
constructors for a long time and most won't care if they're not enforced at runtime, so I
don't object to the compiler enhancement. I just wanted to mention something that folks should
be aware of.

Another thing to be aware of is that this mean there will be source code that compiles under
a Falcon that doesn't compile under the old compiler. Would we change the old compiler as
we'll or not bother? I'd say don't bother.

- Gordon

> On Oct 5, 2014, at 8:09 AM, "Christofer Dutz" <christofer.dutz@c-ware.de> wrote:
> 
> But in java this is not much different. Unless you explicitly tell your Java VM to be
strict, you can get a private constructor via Reflection, make this accesslible at runtime
and instantiate it, no matter what the source-code says. Same with the type of generics. 
> 
> So I guess it would be a great addition to Flex to at least have features checked by
the compiler, even if the runtime doesn't enforce it.
> 
> Chris
> 
> 
> -----Ursprüngliche Nachricht-----
> Von: Gordon Smith [mailto:gsmithsf@hotmail.com] 
> Gesendet: Sonntag, 5. Oktober 2014 04:36
> An: dev@flex.apache.org
> Betreff: Re: [Falcon] Constructor NS (was: [Falcon] starting up)
> 
> In general the ActionScript Virtual Machine enforces access modifiers (so that, for example,
something marked private is truly inaccessible by any means outside the class) but I don't
think the AVM enforces non-public constructors. I'm guessing that a constructor in the ABC
is public regardless of what the source code says, which would mean that the constructor could
be invoked by any code via reflection. If this is the case, I'm not convinced we should pretend
that constructors can be non-public.
> 
> - Gordon
> 
> Sent from my iPad
> 
>>> On Oct 4, 2014, at 4:14 PM, "OmPrakash Muppirala" <bigosmallm@gmail.com>
wrote:
>>> 
>>> On Oct 4, 2014 12:55 PM, "Frédéric THOMAS" <webdoublefx@hotmail.com>
wrote:
>>> 
>>> Hi,
>>> 
>>> I started to check if it was possible to have private and protected
>> constructor in Falcon and I have to admit it was tricky especially 
>> because I never seen a compiler from inside before but it is 
>> apparently possible, I've been able to compile successfully:
>>> package myLib {
>>> public class CTORTest {
>>>   private var _p:int;
>>> 
>>>   private function CTORTest(p:int) {
>>>       _p = p;
>>>   }
>>> 
>>>   private function anotherFct():CTORTest {
>>>       return new CTORTest(10);
>>>   }
>>> }
>>> }
>>> and using the compiled lib:
>>> 
>>> <?xml version="1.0"?>
>>> <s:Application xmlns:fx="http://ns.adobe.com/mxml/2009"
>> xmlns:s="library://ns.adobe.com/flex/spark"
>> creationComplete="creationCompleteHandler(event)">
>>>   <fx:Script><![CDATA[
>>>       import mx.events.FlexEvent;
>>> 
>>>       import myLib.CTORTest;
>>> 
>>>       private function creationCompleteHandler(event:FlexEvent):void {
>>>           var a:CTORTest = new CTORTest(1);
>>>       }
>>>       ]]></fx:Script>
>>> </s:Application>
>>> 
>>> gives:
>>> [Fault] exception, information=VerifyError: Error #1014: La classe
>> myLib:CTORTest::CTORTest est introuvable. (not found) with the legacy 
>> compiler
>>> and:
>>> F:\sources\falconTestDrive\shell\src\Main.mxml:9
>>> Erreur: Appel d'une méthode qui ne semble pas définie CTORTest. (Call 
>>> to
>> a undefined method)
>>>           var a:CTORTest = new CTORTest(1);
>>> 
>>> (I will customize the error message later)
>>> 
>>> I still need to check it works in the 3 possible ways to instantiate 
>>> a
>> Class [1] (at the moment it works only with 1st one), check that works 
>> with is  / instanceOf, revisit the cast function accordingly and maybe 
>> other things not yet in my mind and especially check FP won't complain using it.
>>> 
>>> /* expression = FunctionCallID(KeywordNewID(void), new_type_name,
>> ContainerID(expression*)) */
>>> /* expression = FunctionCallID(KeywordNewID(void), expression,
>> ContainerID(expression*)) */
>>> /* expression = FunctionCallID(KeywordNewID(void), vector_literal,
>> ContainerID(void)) */
>>> 
>>> In case all this works and I'm far to know it at the moment, I will 
>>> have
>> to think about implement "method overloading" otherwise I can't see 
>> any usage of a protected constructor and therefore will probably 
>> require some help for the best way to implement it.
>> 
>> Exciting to see these kind of experiments.  A really good usecase for 
>> private constructor would be to create a Singleton class, I.e a class  
>> that cannot be instantiated outside of itself.  Would that be 
>> something you can test for?
>> 
>> Thanks,
>> Om
>> 
>>> 
>>> Thanks,
>>> Frédéric THOMAS
>>> 
>>>> From: webdoublefx@hotmail.com
>>>> To: dev@flex.apache.org
>>>> Subject: RE: [Falcon] starting up
>>>> Date: Wed, 1 Oct 2014 16:57:28 +0100
>>>> 
>>>> Ah ok, thanks Gordon, I was tearing my hair out :-)
>>>> 
>>>> Frédéric THOMAS
>>>> 
>>>>> Subject: Re: [Falcon] starting up
>>>>> From: gsmithsf@hotmail.com
>>>>> Date: Wed, 1 Oct 2014 08:51:16 -0700
>>>>> To: dev@flex.apache.org
>>>>> 
>>>>> That comment is out of date. Code Model was the part of pre-Falcon
>> Flash Builder that built an abstract syntax tree to support 
>> intelligent editing. We used it as the beginning of Falcon's lexer and 
>> parser. The code is just looking at the AST to see if the constructor 
>> has a non-public namespace.
>>>>> 
>>>>> - Gordon
>>>>> 
>>>>>> On Oct 1, 2014, at 8:33 AM, "Frédéric THOMAS" <
>> webdoublefx@hotmail.com> wrote:
>>>>>> 
>>>>>> 
>>>>>> 
>>>>>> 
>>>>>> 
>>>>>> 
>>>>>> 
>>>>>> I updated it to v17.0 and check in
>> falcon\compiler\generated\dist\sdk\lib\external, is there.
>>>>>> 
>>>>>> oops, looking better, it has both, just removed the bad one, it
>> runs.
>>>>>> 
>>>>>> Now, looking at internal\as\codegen\ClassDirectiveProcessor.java,

>>>>>> I
>> see that:
>>>>>> 
>>>>>> // If a constructor has a namespace as part of it's declaration,

>>>>>> it
>> must be declared public.
>>>>>> // It is ok to omit the namespace
>>>>>> // We must check the AST, as CM treats all ctors as public no
>> matter what the user typed in
>>>>>> // so the FunctionDefinition will always be in the public 
>>>>>> namespace if( node.getActualNamespaceNode() != null &&
>>>>>>      node.getActualNamespaceNode().getName() !=
>> IASKeywordConstants.PUBLIC)
>>>>>>  problems.add(new
>> ConstructorMustBePublicProblem(node.getActualNamespaceNode()));
>>>>>> 
>>>>>> What is the CM or Code Model ?
>>>>>> 
>>>>>> Thanks,
>>>>>> Frédéric THOMAS
>>>>>> 
>>>>>>> From: aharui@adobe.com
>>>>>>> To: dev@flex.apache.org
>>>>>>> Subject: Re: [Falcon] starting up
>>>>>>> Date: Wed, 1 Oct 2014 13:36:50 +0000
>>>>>>> 
>>>>>>> Could you have an old guava.jar?
>>>>>>> 
>>>>>>>> On 10/1/14 4:32 AM, "Frédéric THOMAS" <webdoublefx@hotmail.com>
>> wrote:
>>>>>>>> 
>>>>>>>> Hi,
>>>>>>>> 
>>>>>>>> I built it with ANT an ran Falcon compc.bat from the
>> generated/dist/sdk,
>>>>>>>> does anyone knows why I get that ?
>>>>>>>> 
>>>>>>>> Exception in thread "main" java.lang.NoClassDefFoundError:
>>>>>>>> com/google/common/cache/CacheLoader
>>>>>>>> at 
>>>>>>>> org.apache.flex.compiler.clients.MXMLC.<init>(MXMLC.java:379)
>>>>>>>> at org.apache.flex.compiler.clients.COMPC.<init>(COMPC.java:54)
>>>>>>>> at
>> org.apache.flex.compiler.clients.COMPC.staticMainNoExit(COMPC.java:75)
>>>>>>>> at org.apache.flex.compiler.clients.COMPC.main(COMPC.java:63)
>>>>>>>> Caused by: java.lang.ClassNotFoundException:
>>>>>>>> com.google.common.cache.CacheLoader
>>>>>>>> at java.net.URLClassLoader$1.run(URLClassLoader.java:366)
>>>>>>>> at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
>>>>>>>> at java.security.AccessController.doPrivileged(Native Method)
 
>>>>>>>> at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
>>>>>>>> at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
>>>>>>>> at 
>>>>>>>> sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
>>>>>>>> at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
>>>>>>>> ... 4 more
>>>>>>>> 
>>>>>>>> Thanks,
>>>>>>>> Frédéric THOMAS
>>> 
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