Simple Lua for scripts - Sumary

[Alain <alainm@...>]

Hi,

thanks to all the feedback I got from this thread. I am making here a 
sumary where I will try to put it all toghether and see if it is 
reasonable. I started with a question about a small aspect (2) and got 
much more.

1) Link Lua static into my program. (this also helps Win/Lin portability 
stability and install)

2) I can edit llex.c and make a syntaticaly simpler Lua language. I will 
check if this can do what I want.

3) Remove from Lua all possibilty of loading modules and even functions 
from Lua code. This will probably require altering the code to remove 
"loadstring" , "loadlib" and "require" (maybe some others...)

4) Use one Lua state for each window. A window in the system is one 
entity where all objects colectively execute one single task. This will 
keep things independant and problems easier to track.

4) All general libs and functions will be pre-loaded by the C program. 
Then a new environment is created to protect all globals with setfenv(). 
Then all object functions are loaded, they can only access selected 
functions and variables declared as locals (last sniplet of 
http://www.lua.org/pil/15.4.html) I could even have a GLOB local to 
access the global environment only in debug mode.

5) All object scripts share the same environment. They comunicate with 
the outside world though C functions that access the Window properties 
and databases. A single return string sets the object's value if 
apprepriate. (I believe this is a kind os community sandboxing)

6) In the editing window for object scripts, I test the code with 
loadstring() to turn the user's code into a function (to catch any 
syntax errors). A few more filtering can be done (eg: GLOB access) only 
then I accept and store the code.

MISSING: all user data should be UTF8 :() how much far from Lua is 
LuaPlus? do you recomend it?

TODO: limit execution time. Mark Hamburg sent some info that I could not 
understand. FWIK it should be done inside the VM ... (?)

Alain