Re: Fleece: fast Lua to JSON

[Joshua Jensen <josh.jjensen@...>]

----- Original Message -----
From: Alexander Gladysh
Date: 3/19/2011 6:49 PM
> Note that, as I see, this module accesses Lua table internals
> directly, and, therefore, is not compatible with LuaJIT or any other
> third-party Lua implementation.
>
> I would very much like to see comparison of this module performance
> with fine-tuned LuaJIT2/FFI implementation. (In hope that it will
> prove that such... unorthodox measures are... unnecessary.)
Sorry, as much as I like LuaJIT2/FFI and want to use it everywhere, it 
simply does not exist on all the platforms I need to be.  It may one day.

Relying on the FFI is every bit as bad, in my opinion, as accessing the 
table structure directly.  The FFI locks you to LuaJIT in the same way 
that direct table internal access locks you to Lua 5.x itself.
> P.S. Honestly, when I hear that something works below Lua API, I reach
> for a gun. Henning, not to start a holywar, but I'm very interested in
> the... design motivation for this.
I can't speak for the reasoning behind this converter.  I can, however, 
state that LuaPlus accessing Lua's internals directly make it quite a 
bit faster than Lua's API itself.  One example is here:

http://lua-users.org/lists/lua-l/2011-01/msg00932.html

Note, in particular, that the lua_fastref() code directly accesses the 
table internals.  Note also that the design is the same as luaL_ref(), 
but instead of calling "heavyweight" Lua APIs, it goes straight to the 
source.

-Josh