Re: Lua with OOP, and direct member accesses

[Stephan Herrmann <stephan@...>]

Hi,
> 
> I have a little issue with implementing OOP with Lua. The
> partcicular topic here is how to access a member of an
> object ala C++, that is without having to prepend the self.
> string before the actual member name.
I know that issue. I decided to keep the self, after trying
the approach below ;-)
 
> [...] For this, I have use tag methods that track
> accesses to globals to redirect them to a table (the current
> table), but this requires me to maintain a global variable
> with the current table, which is quite unsatisfactory.
Ok, we need that current-object stack. Right.
> Then I have to call a method at start and at end of any
> method to set/clear the current table to the "self" of the
> new method, and to get rid of that I need to use the call
> hook from the debugger interface, which is *really* dirty.
I chose to modify the methods by a settable method for
classes, like

function classSettable (c, i, v)
   if type(v) == 'function' then
	rawsettable(c, i, function (...)
		local savedObject = currentObject
		currentObject = arg[1]
		call (%v, arg)
		currentObject = savedObject
	   end
        )
   else
	rawsettable(c, i, v)
   end
end

So, provided classX has the tag for which the above
tagmethod is set as settable, each definition
  function classX:methodY (arg1, arg2) ...
gets wrapped with by a closure that takes care of the currentObject.
Looks clean to me, but the overhead may not really be worth the
optical improvement.

Cheers
Stephan

--------------------------------------------------------------------------
 Stephan Herrmann
 ----------------
 Technical University Berlin
 Software Engineering Research Group
 http://swt.cs.tu-berlin.de/~stephan
 phone: ++49 30 314 73174         
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