Re: Lua Digest, Vol 174, Issue 1

[Jerome Vuarand <jerome.vuarand@...>]

2009/9/28 Mike Zraly <mzraly@gmail.com>:
> On Mon, Sep 28, 2009 at 7:47 AM, <lua-request@bazar2.conectiva.com.br>
> wrote:
>>
>> Date: Sun, 27 Sep 2009 13:45:26 -0400
>> From: Norman Ramsey <nr@cs.tufts.edu>
>> Subject: Re: Lua for large apps (was: Lua for GUI toolkit wrapping?)
>> To: Lua list <lua@bazar2.conectiva.com.br>
>> Message-ID: <20090927174526.EAB8E600166C6@labrador.cs.tufts.edu>
>>
>>  > Static typing and compile-time checks (including warnings to the max)
>> are
>>  > indispensable. The alternative for dynamically typed languages are
>>  > tests.
>>
>> Actually another quite respectable alternative is program analysis.
>> I ran into Kostis Sagonas at the airport and it seems he has had some
>> very good results using something he calls 'success types' for Erlang
>> programs.  I would love to see similar technology applied to Lua.
>>
>> A paper is at
>>
>>   http://user.it.uu.se/~kostis/Papers/contracts.pdf
>>
>> Norman
>
> Actually, it might be an interesting idea to provide an interface to set
> (some) and get (all)
> information about a function object within the lua language itself.  One
> might use this to
> expose annotations like type assertions, comment strings, and perhaps even
> more low-level
> information like the function's name and source location and whether or not
> the function calls
> yield directly.

You can already associate any kind of information to a function by
using it as a weak key in a Lua table. However you need access to the
debug library to access built-in informations, or simply to allow a
function to get a reference to itself to use as a key in the weak
tables I mentioned.

> Couple with access to the calling function object, and transitively to the
> entire call stack,
> one might be able to do some interesting things at runtime.

Still with debug.getinfo you can get access to the whole stack.