xmlvm-users

[xmlvm-users] Default values of member variables

[Markus H. <ma...@ti...>]

Hi,

take this code convert it to objc and run it:

public class Test{
    Object thisIsNotInitialized;

    void test(){
         if(thisIsNotInitialized==null)
             System.out.println("null");
    }

    public static void main(String[] args){
        new Test().test();
    }
}

I would expect to get "null" printed to the console. But that doesn't  
happen. The generated if is something like thos:

if (_op1.o != [NSNull null]) goto label0;

So it checks for [NSNull null]. But _op1.o contains 0x0 and the check  
is false. So I would guess that the initialization code of the ObjC  
variables has to be changed so that they contain [NSNull null] and not  
0x0 by default.

Hope you get what I mean.

Markus

Re: [xmlvm-users] Default values of member variables

[Panayotis K. <pan...@pa...>]

On 30 Οκτ 2009, at 8:35 μ.μ., Markus Heberling wrote:

> Hi,
>
> take this code convert it to objc and run it:
>
> public class Test{
>   Object thisIsNotInitialized;
>
>   void test(){
>        if(thisIsNotInitialized==null)
>            System.out.println("null");
>   }
>
>   public static void main(String[] args){
>       new Test().test();
>   }
> }
>
> I would expect to get "null" printed to the console. But that  
> doesn't happen. The generated if is something like thos:
>
> if (_op1.o != [NSNull null]) goto label0;
>
> So it checks for [NSNull null]. But _op1.o contains 0x0 and the  
> check is false. So I would guess that the initialization code of the  
> ObjC variables has to be changed so that they contain [NSNull null]  
> and not 0x0 by default.
>
> Hope you get what I mean.



If a selector returns nil, what is seen in Java?

Re: [xmlvm-users] Default values of member variables

[Arno P. <ar...@pu...>]

this is a tricky issue. Objective-C initializes member variables to 
'nil' by default (which, I believe, is represented by 0x0). However, in 
XMLVM we cannot map Java's null to Objective-C's nil, because nil is not 
accepted as an argument to some data structures (e.g., NSArray, 
NSDictionary, etc). That is why we map null to [NSNull null].

Now, very unfortunate, you cannot do something like this in Objective-C:

@interface Foo {
id ref = [NSNull null];
}
@end

This means, you have do some fancy code generation. This is a known 
issue in XMLVM. In the meantime, you can explicitly initialize Java 
members such as:

public class Test {
   Object ref = null;
...

Arno


Panayotis Katsaloulis wrote:
> On 30 Οκτ 2009, at 8:35 μ.μ., Markus Heberling wrote:
> 
>> Hi,
>>
>> take this code convert it to objc and run it:
>>
>> public class Test{
>>   Object thisIsNotInitialized;
>>
>>   void test(){
>>        if(thisIsNotInitialized==null)
>>            System.out.println("null");
>>   }
>>
>>   public static void main(String[] args){
>>       new Test().test();
>>   }
>> }
>>
>> I would expect to get "null" printed to the console. But that  
>> doesn't happen. The generated if is something like thos:
>>
>> if (_op1.o != [NSNull null]) goto label0;
>>
>> So it checks for [NSNull null]. But _op1.o contains 0x0 and the  
>> check is false. So I would guess that the initialization code of the  
>> ObjC variables has to be changed so that they contain [NSNull null]  
>> and not 0x0 by default.
>>
>> Hope you get what I mean.
> 
> 
> 
> If a selector returns nil, what is seen in Java?
> ------------------------------------------------------------------------------
> Come build with us! The BlackBerry(R) Developer Conference in SF, CA
> is the only developer event you need to attend this year. Jumpstart your
> developing skills, take BlackBerry mobile applications to market and stay 
> ahead of the curve. Join us from November 9 - 12, 2009. Register now!
> http://p.sf.net/sfu/devconference
> _______________________________________________
> xmlvm-users mailing list
> xml...@li...
> https://lists.sourceforge.net/lists/listinfo/xmlvm-users

Re: [xmlvm-users] Default values of member variables

[Markus H. <ma...@ti...>]

Hi,

what about this patch:

@@ -183,11 +183,35 @@ int main(int argc, char* argv[])
      <xsl:text>
  @implementation </xsl:text>
      <xsl:value-of select="vm:fixname(@package)"/>
      <xsl:text>_</xsl:text>
      <xsl:value-of select="vm:fixname(@name)"/>
-
+
+
+    <!-- Emit constructor -->
+    <xsl:text>
+-(id)init
+{
+    if (self = [super init])
+    {
+</xsl:text>
+      <!-- Emit declarations for all non-static object fields -->
+      <xsl:for-each select="vm:field[not(@isStatic = 'true') and  
vm:isObjectRef(@type)]">
+          <xsl:text>        </xsl:text>
+        <xsl:value-of select="vm:fixname(../@package)"/>
+        <xsl:text>_</xsl:text>
+        <xsl:value-of select="vm:fixname(../@name)"/>
+        <xsl:text>_</xsl:text>
+        <xsl:value-of select="vm:fixname(@name)"/>
+        <xsl:text>=[NSNull null];
+</xsl:text>
+      </xsl:for-each>
+<xsl:text>    }
+    return self;
+}
+</xsl:text>
+
      <!-- Emit destructor -->
      <xsl:text>;

  - (void) dealloc;
  {


This creates a constructor in the ObjC-class and fills all instance  
variables of any Object-type with [NSNull null].

This seems to work in my tests, but I don't know if it might break  
anything.

Markus

Am 30.10.2009 um 20:18 schrieb Arno Puder:

>
> this is a tricky issue. Objective-C initializes member variables to
> 'nil' by default (which, I believe, is represented by 0x0). However,  
> in
> XMLVM we cannot map Java's null to Objective-C's nil, because nil is  
> not
> accepted as an argument to some data structures (e.g., NSArray,
> NSDictionary, etc). That is why we map null to [NSNull null].
>
> Now, very unfortunate, you cannot do something like this in  
> Objective-C:
>
> @interface Foo {
> id ref = [NSNull null];
> }
> @end
>
> This means, you have do some fancy code generation. This is a known
> issue in XMLVM. In the meantime, you can explicitly initialize Java
> members such as:
>
> public class Test {
>   Object ref = null;
> ...
>
> Arno
>
>
> Panayotis Katsaloulis wrote:
>> On 30 Οκτ 2009, at 8:35 μ.μ., Markus Heberling wrote:
>>
>>> Hi,
>>>
>>> take this code convert it to objc and run it:
>>>
>>> public class Test{
>>>  Object thisIsNotInitialized;
>>>
>>>  void test(){
>>>       if(thisIsNotInitialized==null)
>>>           System.out.println("null");
>>>  }
>>>
>>>  public static void main(String[] args){
>>>      new Test().test();
>>>  }
>>> }
>>>
>>> I would expect to get "null" printed to the console. But that
>>> doesn't happen. The generated if is something like thos:
>>>
>>> if (_op1.o != [NSNull null]) goto label0;
>>>
>>> So it checks for [NSNull null]. But _op1.o contains 0x0 and the
>>> check is false. So I would guess that the initialization code of the
>>> ObjC variables has to be changed so that they contain [NSNull null]
>>> and not 0x0 by default.
>>>
>>> Hope you get what I mean.
>>
>>
>>
>> If a selector returns nil, what is seen in Java?
>> ------------------------------------------------------------------------------
>> Come build with us! The BlackBerry(R) Developer Conference in SF, CA
>> is the only developer event you need to attend this year. Jumpstart  
>> your
>> developing skills, take BlackBerry mobile applications to market  
>> and stay
>> ahead of the curve. Join us from November 9 - 12, 2009. Register now!
>> http://p.sf.net/sfu/devconference
>> _______________________________________________
>> xmlvm-users mailing list
>> xml...@li...
>> https://lists.sourceforge.net/lists/listinfo/xmlvm-users
>
> ------------------------------------------------------------------------------
> Come build with us! The BlackBerry(R) Developer Conference in SF, CA
> is the only developer event you need to attend this year. Jumpstart  
> your
> developing skills, take BlackBerry mobile applications to market and  
> stay
> ahead of the curve. Join us from November 9 - 12, 2009. Register now!
> http://p.sf.net/sfu/devconference
> _______________________________________________
> xmlvm-users mailing list
> xml...@li...
> https://lists.sourceforge.net/lists/listinfo/xmlvm-users

Re: [xmlvm-users] Default values of member variables

[Wolfgang K. <wol...@xm...>]

Markus,

sorry for the late reply. At a first glance I don't see problems with
the patch you sent. Did you try running the demo applications shipped
with XMLVM to make sure that the patch did not break something or did
you only try running your small sample program?

-- Wolfgang


Markus Heberling wrote:
> Hi,
>
> what about this patch:
>
> @@ -183,11 +183,35 @@ int main(int argc, char* argv[])
>      <xsl:text>
>  @implementation </xsl:text>
>      <xsl:value-of select="vm:fixname(@package)"/>
>      <xsl:text>_</xsl:text>
>      <xsl:value-of select="vm:fixname(@name)"/>
> -
> +
> +
> +    <!-- Emit constructor -->
> +    <xsl:text>
> +-(id)init
> +{
> +    if (self = [super init])
> +    {
> +</xsl:text>
> +      <!-- Emit declarations for all non-static object fields -->
> +      <xsl:for-each select="vm:field[not(@isStatic = 'true') and
> vm:isObjectRef(@type)]">
> +          <xsl:text>        </xsl:text>
> +        <xsl:value-of select="vm:fixname(../@package)"/>
> +        <xsl:text>_</xsl:text>
> +        <xsl:value-of select="vm:fixname(../@name)"/>
> +        <xsl:text>_</xsl:text>
> +        <xsl:value-of select="vm:fixname(@name)"/>
> +        <xsl:text>=[NSNull null];
> +</xsl:text>
> +      </xsl:for-each>
> +<xsl:text>    }
> +    return self;
> +}
> +</xsl:text>
> +
>      <!-- Emit destructor -->
>      <xsl:text>;
>
>  - (void) dealloc;
>  {
>
>
> This creates a constructor in the ObjC-class and fills all instance
> variables of any Object-type with [NSNull null].
>
> This seems to work in my tests, but I don't know if it might break
> anything.
>
> Markus
>
> Am 30.10.2009 um 20:18 schrieb Arno Puder:
>
>>
>> this is a tricky issue. Objective-C initializes member variables to
>> 'nil' by default (which, I believe, is represented by 0x0). However, in
>> XMLVM we cannot map Java's null to Objective-C's nil, because nil is not
>> accepted as an argument to some data structures (e.g., NSArray,
>> NSDictionary, etc). That is why we map null to [NSNull null].
>>
>> Now, very unfortunate, you cannot do something like this in Objective-C:
>>
>> @interface Foo {
>> id ref = [NSNull null];
>> }
>> @end
>>
>> This means, you have do some fancy code generation. This is a known
>> issue in XMLVM. In the meantime, you can explicitly initialize Java
>> members such as:
>>
>> public class Test {
>>   Object ref = null;
>> ...
>>
>> Arno
>>
>>
>> Panayotis Katsaloulis wrote:
>>> On 30 Οκτ 2009, at 8:35 μ.μ., Markus Heberling wrote:
>>>
>>>> Hi,
>>>>
>>>> take this code convert it to objc and run it:
>>>>
>>>> public class Test{
>>>>  Object thisIsNotInitialized;
>>>>
>>>>  void test(){
>>>>       if(thisIsNotInitialized==null)
>>>>           System.out.println("null");
>>>>  }
>>>>
>>>>  public static void main(String[] args){
>>>>      new Test().test();
>>>>  }
>>>> }
>>>>
>>>> I would expect to get "null" printed to the console. But that
>>>> doesn't happen. The generated if is something like thos:
>>>>
>>>> if (_op1.o != [NSNull null]) goto label0;
>>>>
>>>> So it checks for [NSNull null]. But _op1.o contains 0x0 and the
>>>> check is false. So I would guess that the initialization code of the
>>>> ObjC variables has to be changed so that they contain [NSNull null]
>>>> and not 0x0 by default.
>>>>
>>>> Hope you get what I mean.
>>>
>>>
>>>
>>> If a selector returns nil, what is seen in Java?
>>> ------------------------------------------------------------------------------
>>>
>>> Come build with us! The BlackBerry(R) Developer Conference in SF, CA
>>> is the only developer event you need to attend this year. Jumpstart
>>> your
>>> developing skills, take BlackBerry mobile applications to market and
>>> stay
>>> ahead of the curve. Join us from November 9 - 12, 2009. Register now!
>>> http://p.sf.net/sfu/devconference
>>> _______________________________________________
>>> xmlvm-users mailing list
>>> xml...@li...
>>> https://lists.sourceforge.net/lists/listinfo/xmlvm-users
>>
>> ------------------------------------------------------------------------------
>>
>> Come build with us! The BlackBerry(R) Developer Conference in SF, CA
>> is the only developer event you need to attend this year. Jumpstart your
>> developing skills, take BlackBerry mobile applications to market and
>> stay
>> ahead of the curve. Join us from November 9 - 12, 2009. Register now!
>> http://p.sf.net/sfu/devconference
>> _______________________________________________
>> xmlvm-users mailing list
>> xml...@li...
>> https://lists.sourceforge.net/lists/listinfo/xmlvm-users
>
> ------------------------------------------------------------------------
>
> ------------------------------------------------------------------------------
> Come build with us! The BlackBerry(R) Developer Conference in SF, CA
> is the only developer event you need to attend this year. Jumpstart your
> developing skills, take BlackBerry mobile applications to market and stay 
> ahead of the curve. Join us from November 9 - 12, 2009. Register now!
> http://p.sf.net/sfu/devconference
> ------------------------------------------------------------------------
>
> _______________________________________________
> xmlvm-users mailing list
> xml...@li...
> https://lists.sourceforge.net/lists/listinfo/xmlvm-users
>   

Re: [xmlvm-users] Default values of member variables

[Markus H. <ma...@ti...>]

Hi,

I have tested it with a port of microemulator (http://microemu.org).  
Worked fine for me there. Will try out the xmlvm demos tonight, too.

Markus

Von meinem iPhone gesendet

Am 03.11.2009 um 16:38 schrieb Wolfgang Korn <wol...@xm...>:

> Markus,
>
> sorry for the late reply. At a first glance I don't see problems  
> with the patch you sent. Did you try running the demo applications  
> shipped with XMLVM to make sure that the patch did not break  
> something or did you only try running your small sample program?
>
> -- Wolfgang
>
>
> Markus Heberling wrote:
>>
>> Hi,
>>
>> what about this patch:
>>
>> @@ -183,11 +183,35 @@ int main(int argc, char* argv[])
>>      <xsl:text>
>>  @implementation </xsl:text>
>>      <xsl:value-of select="vm:fixname(@package)"/>
>>      <xsl:text>_</xsl:text>
>>      <xsl:value-of select="vm:fixname(@name)"/>
>> -
>> +
>> +
>> +    <!-- Emit constructor -->
>> +    <xsl:text>
>> +-(id)init
>> +{
>> +    if (self = [super init])
>> +    {
>> +</xsl:text>
>> +      <!-- Emit declarations for all non-static object fields -->
>> +      <xsl:for-each select="vm:field[not(@isStatic = 'true') and  
>> vm:isObjectRef(@type)]">
>> +          <xsl:text>        </xsl:text>
>> +        <xsl:value-of select="vm:fixname(../@package)"/>
>> +        <xsl:text>_</xsl:text>
>> +        <xsl:value-of select="vm:fixname(../@name)"/>
>> +        <xsl:text>_</xsl:text>
>> +        <xsl:value-of select="vm:fixname(@name)"/>
>> +        <xsl:text>=[NSNull null];
>> +</xsl:text>
>> +      </xsl:for-each>
>> +<xsl:text>    }
>> +    return self;
>> +}
>> +</xsl:text>
>> +
>>      <!-- Emit destructor -->
>>      <xsl:text>;
>>
>>  - (void) dealloc;
>>  {
>>
>>
>> This creates a constructor in the ObjC-class and fills all instance  
>> variables of any Object-type with [NSNull null].
>>
>> This seems to work in my tests, but I don't know if it might break  
>> anything.
>>
>> Markus
>>
>> Am 30.10.2009 um 20:18 schrieb Arno Puder:
>>
>>>
>>> this is a tricky issue. Objective-C initializes member variables to
>>> 'nil' by default (which, I believe, is represented by 0x0).  
>>> However, in
>>> XMLVM we cannot map Java's null to Objective-C's nil, because nil  
>>> is not
>>> accepted as an argument to some data structures (e.g., NSArray,
>>> NSDictionary, etc). That is why we map null to [NSNull null].
>>>
>>> Now, very unfortunate, you cannot do something like this in  
>>> Objective-C:
>>>
>>> @interface Foo {
>>> id ref = [NSNull null];
>>> }
>>> @end
>>>
>>> This means, you have do some fancy code generation. This is a known
>>> issue in XMLVM. In the meantime, you can explicitly initialize Java
>>> members such as:
>>>
>>> public class Test {
>>>   Object ref = null;
>>> ...
>>>
>>> Arno
>>>
>>>
>>> Panayotis Katsaloulis wrote:
>>>> On 30 Οκτ 2009, at 8:35 μ.μ., Markus  
>>>> Heberling wrote:
>>>>
>>>>> Hi,
>>>>>
>>>>> take this code convert it to objc and run it:
>>>>>
>>>>> public class Test{
>>>>>  Object thisIsNotInitialized;
>>>>>
>>>>>  void test(){
>>>>>       if(thisIsNotInitialized==null)
>>>>>           System.out.println("null");
>>>>>  }
>>>>>
>>>>>  public static void main(String[] args){
>>>>>      new Test().test();
>>>>>  }
>>>>> }
>>>>>
>>>>> I would expect to get "null" printed to the console. But that
>>>>> doesn't happen. The generated if is something like thos:
>>>>>
>>>>> if (_op1.o != [NSNull null]) goto label0;
>>>>>
>>>>> So it checks for [NSNull null]. But _op1.o contains 0x0 and the
>>>>> check is false. So I would guess that the initialization code of  
>>>>> the
>>>>> ObjC variables has to be changed so that they contain [NSNull  
>>>>> null]
>>>>> and not 0x0 by default.
>>>>>
>>>>> Hope you get what I mean.
>>>>
>>>>
>>>>
>>>> If a selector returns nil, what is seen in Java?
>>>> --- 
>>>> --- 
>>>> --- 
>>>> --- 
>>>> ------------------------------------------------------------------
>>>> Come build with us! The BlackBerry(R) Developer Conference in SF,  
>>>> CA
>>>> is the only developer event you need to attend this year.  
>>>> Jumpstart your
>>>> developing skills, take BlackBerry mobile applications to market  
>>>> and stay
>>>> ahead of the curve. Join us from November 9 - 12, 2009. Register  
>>>> now!
>>>> http://p.sf.net/sfu/devconference
>>>> _______________________________________________
>>>> xmlvm-users mailing list
>>>> xml...@li...
>>>> https://lists.sourceforge.net/lists/listinfo/xmlvm-users
>>>
>>> --- 
>>> --- 
>>> --- 
>>> --- 
>>> ------------------------------------------------------------------
>>> Come build with us! The BlackBerry(R) Developer Conference in SF, CA
>>> is the only developer event you need to attend this year.  
>>> Jumpstart your
>>> developing skills, take BlackBerry mobile applications to market  
>>> and stay
>>> ahead of the curve. Join us from November 9 - 12, 2009. Register  
>>> now!
>>> http://p.sf.net/sfu/devconference
>>> _______________________________________________
>>> xmlvm-users mailing list
>>> xml...@li...
>>> https://lists.sourceforge.net/lists/listinfo/xmlvm-users
>>
>>
>> --- 
>> --- 
>> --- 
>> ---------------------------------------------------------------------
>> Come build with us! The BlackBerry(R) Developer Conference in SF, CA
>> is the only developer event you need to attend this year. Jumpstart  
>> your
>> developing skills, take BlackBerry mobile applications to market  
>> and stay
>> ahead of the curve. Join us from November 9 - 12, 2009. Register now!
>> http://p.sf.net/sfu/devconference
>>
>> _______________________________________________
>> xmlvm-users mailing list
>> xml...@li...
>> https://lists.sourceforge.net/lists/listinfo/xmlvm-users
>>
>
>

Re: [xmlvm-users] Default values of member variables

[Arno P. <ar...@pu...>]

Guys: sorry for the late reply from my side. To add the initialization 
in the Objective-C default constructor is a clever idea. I will take 
Markus patch and make some modifications to it (also generate the 
declaration of the default constructor in the header file and default 
initialization of static member variables).

I hope I'll get to that sometime today.

Arno


Markus Heberling wrote:
> Hi, 
> 
> I have tested it with a port of microemulator (http://microemu.org). 
> Worked fine for me there. Will try out the xmlvm demos tonight, too. 
> 
> Markus
> 
> Von meinem iPhone gesendet
> 
> Am 03.11.2009 um 16:38 schrieb Wolfgang Korn <wol...@xm... 
> <mailto:wol...@xm...>>:
> 
>> Markus,
>>
>> sorry for the late reply. At a first glance I don't see problems with 
>> the patch you sent. Did you try running the demo applications shipped 
>> with XMLVM to make sure that the patch did not break something or did 
>> you only try running your small sample program?
>>
>> -- Wolfgang
>>
>>
>> Markus Heberling wrote:
>>> Hi,
>>>
>>> what about this patch:
>>>
>>> @@ -183,11 +183,35 @@ int main(int argc, char* argv[])
>>>      <xsl:text>
>>>  @implementation </xsl:text>
>>>      <xsl:value-of select="vm:fixname(@package)"/>
>>>      <xsl:text>_</xsl:text>
>>>      <xsl:value-of select="vm:fixname(@name)"/>
>>> -
>>> +
>>> +
>>> +    <!-- Emit constructor -->
>>> +    <xsl:text>
>>> +-(id)init
>>> +{
>>> +    if (self = [super init])
>>> +    {
>>> +</xsl:text>
>>> +      <!-- Emit declarations for all non-static object fields -->
>>> +      <xsl:for-each select="vm:field[not(@isStatic = 'true') and 
>>> vm:isObjectRef(@type)]">
>>> +          <xsl:text>        </xsl:text>
>>> +        <xsl:value-of select="vm:fixname(../@package)"/>
>>> +        <xsl:text>_</xsl:text>
>>> +        <xsl:value-of select="vm:fixname(../@name)"/>
>>> +        <xsl:text>_</xsl:text>
>>> +        <xsl:value-of select="vm:fixname(@name)"/>
>>> +        <xsl:text>=[NSNull null];
>>> +</xsl:text>
>>> +      </xsl:for-each>
>>> +<xsl:text>    }
>>> +    return self;
>>> +}
>>> +</xsl:text>
>>> +
>>>      <!-- Emit destructor -->
>>>      <xsl:text>;
>>>
>>>  - (void) dealloc;
>>>  {
>>>
>>>
>>> This creates a constructor in the ObjC-class and fills all instance 
>>> variables of any Object-type with [NSNull null].
>>>
>>> This seems to work in my tests, but I don't know if it might break 
>>> anything.
>>>
>>> Markus
>>>
>>> Am 30.10.2009 um 20:18 schrieb Arno Puder:
>>>
>>>>
>>>> this is a tricky issue. Objective-C initializes member variables to
>>>> 'nil' by default (which, I believe, is represented by 0x0). However, in
>>>> XMLVM we cannot map Java's null to Objective-C's nil, because nil is 
>>>> not
>>>> accepted as an argument to some data structures (e.g., NSArray,
>>>> NSDictionary, etc). That is why we map null to [NSNull null].
>>>>
>>>> Now, very unfortunate, you cannot do something like this in 
>>>> Objective-C:
>>>>
>>>> @interface Foo {
>>>> id ref = [NSNull null];
>>>> }
>>>> @end
>>>>
>>>> This means, you have do some fancy code generation. This is a known
>>>> issue in XMLVM. In the meantime, you can explicitly initialize Java
>>>> members such as:
>>>>
>>>> public class Test {
>>>>   Object ref = null;
>>>> ...
>>>>
>>>> Arno
>>>>
>>>>
>>>> Panayotis Katsaloulis wrote:
>>>>> On 30 Οκτ 2009, at 8:35 μ.μ., Markus Heberling wrote:
>>>>>
>>>>>> Hi,
>>>>>>
>>>>>> take this code convert it to objc and run it:
>>>>>>
>>>>>> public class Test{
>>>>>>  Object thisIsNotInitialized;
>>>>>>
>>>>>>  void test(){
>>>>>>       if(thisIsNotInitialized==null)
>>>>>>           System.out.println("null");
>>>>>>  }
>>>>>>
>>>>>>  public static void main(String[] args){
>>>>>>      new Test().test();
>>>>>>  }
>>>>>> }
>>>>>>
>>>>>> I would expect to get "null" printed to the console. But that
>>>>>> doesn't happen. The generated if is something like thos:
>>>>>>
>>>>>> if (_op1.o != [NSNull null]) goto label0;
>>>>>>
>>>>>> So it checks for [NSNull null]. But _op1.o contains 0x0 and the
>>>>>> check is false. So I would guess that the initialization code of the
>>>>>> ObjC variables has to be changed so that they contain [NSNull null]
>>>>>> and not 0x0 by default.
>>>>>>
>>>>>> Hope you get what I mean.
>>>>>
>>>>>
>>>>>
>>>>> If a selector returns nil, what is seen in Java?
>>>>> ------------------------------------------------------------------------------ 
>>>>>
>>>>> Come build with us! The BlackBerry(R) Developer Conference in SF, CA
>>>>> is the only developer event you need to attend this year. Jumpstart 
>>>>> your
>>>>> developing skills, take BlackBerry mobile applications to market 
>>>>> and stay
>>>>> ahead of the curve. Join us from November 9 - 12, 2009. Register now!
>>>>> http://p.sf.net/sfu/devconference
>>>>> _______________________________________________
>>>>> xmlvm-users mailing list
>>>>> xml...@li... 
>>>>> <mailto:xml...@li...>
>>>>> https://lists.sourceforge.net/lists/listinfo/xmlvm-users
>>>>
>>>> ------------------------------------------------------------------------------ 
>>>>
>>>> Come build with us! The BlackBerry(R) Developer Conference in SF, CA
>>>> is the only developer event you need to attend this year. Jumpstart 
>>>> your
>>>> developing skills, take BlackBerry mobile applications to market and 
>>>> stay
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>>>
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>>
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Re: [xmlvm-users] Default values of member variables

[Arno P. <ar...@pu...>]

OK, I just committed a fix for this problem. Static members were a 
little tricker but it should work now. The XMLVM demos work.

Arno


Markus Heberling wrote:
> Hi, 
> 
> I have tested it with a port of microemulator (http://microemu.org). 
> Worked fine for me there. Will try out the xmlvm demos tonight, too. 
> 
> Markus
> 
> Von meinem iPhone gesendet
> 
> Am 03.11.2009 um 16:38 schrieb Wolfgang Korn <wol...@xm... 
> <mailto:wol...@xm...>>:
> 
>> Markus,
>>
>> sorry for the late reply. At a first glance I don't see problems with 
>> the patch you sent. Did you try running the demo applications shipped 
>> with XMLVM to make sure that the patch did not break something or did 
>> you only try running your small sample program?
>>
>> -- Wolfgang
>>
>>
>> Markus Heberling wrote:
>>> Hi,
>>>
>>> what about this patch:
>>>
>>> @@ -183,11 +183,35 @@ int main(int argc, char* argv[])
>>>      <xsl:text>
>>>  @implementation </xsl:text>
>>>      <xsl:value-of select="vm:fixname(@package)"/>
>>>      <xsl:text>_</xsl:text>
>>>      <xsl:value-of select="vm:fixname(@name)"/>
>>> -
>>> +
>>> +
>>> +    <!-- Emit constructor -->
>>> +    <xsl:text>
>>> +-(id)init
>>> +{
>>> +    if (self = [super init])
>>> +    {
>>> +</xsl:text>
>>> +      <!-- Emit declarations for all non-static object fields -->
>>> +      <xsl:for-each select="vm:field[not(@isStatic = 'true') and 
>>> vm:isObjectRef(@type)]">
>>> +          <xsl:text>        </xsl:text>
>>> +        <xsl:value-of select="vm:fixname(../@package)"/>
>>> +        <xsl:text>_</xsl:text>
>>> +        <xsl:value-of select="vm:fixname(../@name)"/>
>>> +        <xsl:text>_</xsl:text>
>>> +        <xsl:value-of select="vm:fixname(@name)"/>
>>> +        <xsl:text>=[NSNull null];
>>> +</xsl:text>
>>> +      </xsl:for-each>
>>> +<xsl:text>    }
>>> +    return self;
>>> +}
>>> +</xsl:text>
>>> +
>>>      <!-- Emit destructor -->
>>>      <xsl:text>;
>>>
>>>  - (void) dealloc;
>>>  {
>>>
>>>
>>> This creates a constructor in the ObjC-class and fills all instance 
>>> variables of any Object-type with [NSNull null].
>>>
>>> This seems to work in my tests, but I don't know if it might break 
>>> anything.
>>>
>>> Markus
>>>
>>> Am 30.10.2009 um 20:18 schrieb Arno Puder:
>>>
>>>>
>>>> this is a tricky issue. Objective-C initializes member variables to
>>>> 'nil' by default (which, I believe, is represented by 0x0). However, in
>>>> XMLVM we cannot map Java's null to Objective-C's nil, because nil is 
>>>> not
>>>> accepted as an argument to some data structures (e.g., NSArray,
>>>> NSDictionary, etc). That is why we map null to [NSNull null].
>>>>
>>>> Now, very unfortunate, you cannot do something like this in 
>>>> Objective-C:
>>>>
>>>> @interface Foo {
>>>> id ref = [NSNull null];
>>>> }
>>>> @end
>>>>
>>>> This means, you have do some fancy code generation. This is a known
>>>> issue in XMLVM. In the meantime, you can explicitly initialize Java
>>>> members such as:
>>>>
>>>> public class Test {
>>>>   Object ref = null;
>>>> ...
>>>>
>>>> Arno
>>>>
>>>>
>>>> Panayotis Katsaloulis wrote:
>>>>> On 30 Οκτ 2009, at 8:35 μ.μ., Markus Heberling wrote:
>>>>>
>>>>>> Hi,
>>>>>>
>>>>>> take this code convert it to objc and run it:
>>>>>>
>>>>>> public class Test{
>>>>>>  Object thisIsNotInitialized;
>>>>>>
>>>>>>  void test(){
>>>>>>       if(thisIsNotInitialized==null)
>>>>>>           System.out.println("null");
>>>>>>  }
>>>>>>
>>>>>>  public static void main(String[] args){
>>>>>>      new Test().test();
>>>>>>  }
>>>>>> }
>>>>>>
>>>>>> I would expect to get "null" printed to the console. But that
>>>>>> doesn't happen. The generated if is something like thos:
>>>>>>
>>>>>> if (_op1.o != [NSNull null]) goto label0;
>>>>>>
>>>>>> So it checks for [NSNull null]. But _op1.o contains 0x0 and the
>>>>>> check is false. So I would guess that the initialization code of the
>>>>>> ObjC variables has to be changed so that they contain [NSNull null]
>>>>>> and not 0x0 by default.
>>>>>>
>>>>>> Hope you get what I mean.
>>>>>
>>>>>
>>>>>
>>>>> If a selector returns nil, what is seen in Java?
>>>>> ------------------------------------------------------------------------------ 
>>>>>
>>>>> Come build with us! The BlackBerry(R) Developer Conference in SF, CA
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>>>>> your
>>>>> developing skills, take BlackBerry mobile applications to market 
>>>>> and stay
>>>>> ahead of the curve. Join us from November 9 - 12, 2009. Register now!
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>>>>> xml...@li... 
>>>>> <mailto:xml...@li...>
>>>>> https://lists.sourceforge.net/lists/listinfo/xmlvm-users
>>>>
>>>> ------------------------------------------------------------------------------ 
>>>>
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>>>
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>>
>>
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