Re: luabind: problem retrieving values from table indexed by non-built-in classes

I switched to settable() and gettable() from the [] operator: results are the
same.

I can see in debugger that conversion routines are called to convert the
key. I guess the error is somewhere therein: there's some inconsistency
between the set... and the get... paths.

Unfortunately, it's way beyond me to figure out exactly what's wrong.


qwer1304 wrote:
> 
> Did a bit more digging and experimentation:
> 
> 1.You can access Lua tables (global or local) from C++/Luabind with keys
> that are primitive (int, string) and object (provided object wraps a valid
> entity).
> 
> 2.Trying to access tables w/ non-primitive (compound) keys from
> C++/Luabind doesn't retrieve the right value.
> 
> 3.The following happens:
> a.bind a compound class to Lua (say MyClass)
> b.create an instance of that class in Lua (say x = MyClass() )
> c.In Lua, put a value into a table at key=x (i.e., tab[x] = 1)
> d.In C++ get tab and x objects: tab = globals(L)["tab"]; x =
> globals(L)["x"];
> e.check what's in tab[x]? (it's 1, as it should be
> object_cast<int>(tab[x]) == 1)
> f.convert x to MyClass: MyClass xx = object_cast<MyClass>(x)
> g.check what's in tab[xx]? (it's nil!!!!)
> 
> 
> qwer1304 wrote:
>> 
>> 
>> I tried overloading the == operator like this:
>> struct test_param
>> {
>>     int obj;
>>     bool operator==(test_param const& rhs) const
>>     {
>>         return obj == rhs.obj;
>>     }
>> };and
>> module(L)
>>     [
>>         class_<test_param>("test_param")
>>             .def_readwrite("obj", &test_param::obj)
>>             .def(const_self == const_self)
>>     ];
>> It didn't change anything.
>> As for using a local object for a key: first, it's a valid test, which
>> still shouldn't failsecond, I moved it out from the stack to heap, but it
>> didn't change the result.
>> The weird thing is that the data is there in the table and can be
>> retrieved using iterate().
>> David
>>> From: [email protected]
>>> Date: Wed, 25 Apr 2012 16:32:28 +0100
>>> To: [email protected]
>>> Subject: Re: [luabind] luabind: problem retrieving values from table
>>> indexed by non-built-in classes
>>> 
>>> 2012/4/25 qwer 1304 <[email protected]>:
>>> > Ryan Pavlik says that his version passes now all tests.
>>> >
>>> > In any case, IMHO it's important to figure out why such a simple test
>>> as I
>>> > put in my original message fails.
>>> > I.e., I'd expect a true application to be able to enter a value into a
>>> table
>>> > for a given key in an object and to be able to retrieve it.
>>> >
>>> > As the test case shows - it cannot.
>>> >
>>> > Thx,
>>> > David
>>> >
>>> >> Date: Wed, 25 Apr 2012 16:49:45 +0200
>>> >> From: [email protected]
>>> >> To: [email protected]
>>> >> Subject: Re: [luabind] luabind: problem retrieving values from table
>>> >> indexed by non-built-in classes
>>> >
>>> >>
>>> >> The object identity test failing is a known issue as far as I know,
>>> >> the commit message from when it was added states so.
>>> >>
>>> >>
>>> >>
>>> ------------------------------------------------------------------------------
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>>> >> _______________________________________________
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>>> >
>>> >
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>>> > https://lists.sourceforge.net/lists/listinfo/luabind-user
>>> >
>>> 
>>> Personally I would take a wild stab in the dark and say your object
>>> does not have a comparison operator and what does it mean to put a
>>> stack object in a container?
>>> 
>>> Liam
>>> 
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>>  		 	   		  
>> ------------------------------------------------------------------------------
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>> Exclusive live event will cover all the ways today's security and 
>> threat landscape has changed and how IT managers can respond. Discussions 
>> will include endpoint security, mobile security and the latest in malware 
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>> _______________________________________________
>> luabind-user mailing list
>> [email protected]
>> https://lists.sourceforge.net/lists/listinfo/luabind-user
>> 
>> 
> 

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