Re: OOP in daydream of nightmare of hallucination of future

[Adrian Sietsma <adrian_groups@...>]

duck wrote:
...

> I recently wrote a Lua function like this:
>
>
> local function process(self,conn)
>     self.mutex:lock() 
>     self.count = self.count+1
>     --some more housekeeping stuff
>     self.mutex:unlock()
>
>     self.handle(self,conn)
>     conn:close()
>    
>     self.mutex:lock()
>     --some more housekeeping stuff
>     self.count = self.count-1
>     self.mutex:unlock()
> end

nice and clear, i agree.

i've sometimes thought about a "with" construction (implemented using 
setfenv, i suppose). That would allow

local function process(self,conn)
    with self do
	mutex:lock()
     	count = count+1
     	--some more housekeeping stuff
     	mutex:unlock()

     	handle(self,conn)
     	conn:close()

     	mutex:lock()
     	--some more housekeeping stuff
     	count = count-1
     	mutex:unlock()
    end
end

i don't think "with" should go in lua core, but it is syntactically 
neat. setfenv does the job, but the restore to previous environment is 
not as tidy.

what about a block-local extension to setfenv() ? at index 0 maybe.
eg

a = {count = 1}
do
    setfenv(0,a)
    count = count + 1 -- a's count
end
-- environment is back to previous

Adrian