Re: New metamethod for method lookup

["Alex Davies" <alex.mania@...>]

One issue I have with the idea is there is no one way to index in Lua. 
Sometimes, even for function calls, you have to index from a variable in a 
string [].  Other times the method : call is fine.  Sometimes you just want 
to pass a different self, so . is applicable.  So for this to work you'd 
need to add a "getmethod(table, key)" function, which is a bit tacky imo, 
but would work.

Mark Hamburg wrote:
> * It simplifies the implementation of objects with both methods and 
> properties allowing method lookup > to bypass a function call. (There was 
> an alternate proposal a while back, I believe to allow a metatable > entry 
> that had to be a table and a fallback function beyond that.)

The proposal was to have a __proxy field in the metatable - on a nil result, 
the index is tried again in the __proxy value (usually a table).  If that 
fails, the __index is called.  This is an improvement in a number of ways.

1) As above, it simplifies objects with properties so that a function call 
isn't required to resolve methods.
2) __index is always treated like a function, improving virtualization.  No 
"call it - unless it's a table in which case we'll index it" special 
treatment, allowing func tables (memoized functions, class constructors, 
etc) to be used as index functions.
3) Fully encompasses the existing system, so the existing behaviour can be 
replicated.

Simple change to the VM too ;)

- Alex