Re: How to get the attributes of a lua class, without their names, using luabind

This works for me too in such a case, but it fails if the object is a 
luabind 'class' object, as in the OP message:

class 'MyLuaClass'
function MyLuaClass:__init() end

foo = MyLuaClass()
foo.bar = "baz";
PrintAttributes(foo);



On 12/12/2015 14:48, Pavel Kovalenko wrote:
> This example works for me (but I use another fork:
> https://github.com/decimad/luabind-deboostified)
>
> lua code:
>
>     local obj = {}
>     obj.foo = function (self)
>         puts("obj:foo")
>     end
>     obj.data = 42
>
>     dump_object(obj)
>
> cpp code:
>
>     void dump_object(const luabind::object &obj)
>     {
>         for (luabind::iterator it(obj), end; it!=end; it++)
>         {
>             auto s = object_cast<std::string>(it.key());
>             puts(s.c_str());
>         }
>     }
>
> What kind of lua object are you trying to iterate over?
> On 12/12/2015 0:23 AM, jean-baptiste griffo wrote:
>> Hi,
>>
>> Well it's weird but I don't remember the exact fork I'm using, I think I
>> use this one
>> https://github.com/mrsharpoblunto/LHP/tree/master/luabind-0.7/include/luabind
>> I do not use the official release because I had some problems related to
>> size_t & x64 builds, and this fork solved it.
>>
>> Here is the c++ code, please note that at this point I'm 100% sure the
>> object on the stack is the "self" of my class instance
>>
>> //get the luabind object from the stack
>> luabind::object o(luabind::from_stack(L, lastIndex));
>>
>> for (luabind::iterator i(o), end; i != end; ++i)
>> {
>>       try
>>       {
>>           std::string strKey = luabind::object_cast<std::string>(i.key());
>>           printf("%s\n",strKey.c_str());
>>       }
>>       catch(luabind::cast_failed & e)
>>       {
>>           printf("error\n");
>>       }
>> }
>>
>> ----------
>>
>> As a result, it simply prints "error" indefinitely.
>>
>> Thanks.
>>
>>
>> On 11/12/2015 17:57, Pavel Kovalenko wrote:
>>> Hi,
>>>
>>> I don't have such problem (using luabind-deboostified fork). Could you
>>> show the code which causes an infinite loop? Which fork do you use?
>>>
>>> On 12/11/2015 3:00 PM, luabind-user-request@... wrote:
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>>>> Today's Topics:
>>>>
>>>>       1. Re: How to get the attributes of a lua class without their
>>>>          names, using luabind (Crashy)
>>>>
>>>>
>>>> ----------------------------------------------------------------------
>>>>
>>>> Message: 1
>>>> Date: Thu, 10 Dec 2015 05:07:38 -0700 (MST)
>>>> From: Crashy <jean-baptiste.griffo@...>
>>>> Subject: Re: [luabind] How to get the attributes of a lua class
>>>> 	without their names, using luabind
>>>> To: luabind-user@...
>>>> Message-ID: <1449749258848-7670726.post@...>
>>>> Content-Type: text/plain; charset=us-ascii
>>>>
>>>> Hi !
>>>>
>>>> I hate to 'bump' very old topics, but I'm facing the same problem while
>>>> writing a lua debugger.
>>>> I can access values by name, but using the iterator results in an infinite
>>>> loop.
>>>> Iterators are doing well when the object is a simple table though, it only
>>>> fails when the object is a luabind class.
>>>>
>>>> Does anybody has a solution to iterate over member variables of a luabind
>>>> class ?
>>>>
>>>> Thanks !
>>>>
>>>>
>>>> Thibault Ehrhart wrote
>>>>> Hello everyone,
>>>>>
>>>>> I have a Lua class (defined using luabind's 'class' keyword) and I'd like
>>>>> to get the value of the attributes defined in Lua, with C++.
>>>>>
>>>>> In the code below, I've defined a class, created an instance "foo" and set
>>>>> a custom attribute "bar" to that instance. Finally, I am calling a C++
>>>>> function which has to print the attributes of the instance passed as a
>>>>> parameter.
>>>>>
>>>>> Here's the Lua code :
>>>>>
>>>>>        class 'MyLuaClass'
>>>>>        function MyLuaClass:__init() end
>>>>>
>>>>>        foo = MyLuaClass()
>>>>>        foo.bar = "baz";
>>>>>        PrintAttributes(foo);
>>>>>
>>>>> And now the C++ code of the PrintAttributes function, obj is a class
>>>>> instance:
>>>>>
>>>>>        void PrintAttributes(luabind::object &obj)
>>>>>        {
>>>>>            // Direct access works
>>>>>            std::cout << obj["bar"] << std::endl; // Will print "baz" :-)
>>>>>
>>>>>            // But what if I don't know the name of the variable(s)?
>>>>>            for (luabind::iterator it(obj); it != luabind::iterator(); ++it)
>>>>>            {
>>>>>                // Doesn't work since obj is an userdata
>>>>>            }
>>>>>        }
>>>>>
>>>>> I've also tried to use class_info but it only works with properties
>>>>> defined
>>>>> in a C++ class. Is there a way to access those defined with Lua?
>>>>>
>>>>> Regards,
>>>>
>>>>
>>>>
>>>> --
>>>> View this message in context: http://lua.2524044.n2.nabble.com/How-to-get-the-attributes-of-a-lua-class-without-their-names-using-luabind-tp7654070p7670726.html
>>>> Sent from the Lua C++ Bind mailing list archive at Nabble.com.
>>>>
>>>>
>>>>
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>>>>
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