Re: A die(reason) or exit function is missing, isn't it?

[Romulo Bahiense <romulo@...>]

Alex Queiroz wrote:
> Hallo,
>
> On 1/25/07, Jan Schütze <JanS@dracoblue.de> wrote:
> > This isn't only used to report an error to users on website.
> > Since I use lua for webpublishing, I have somewher ein my source a
> > function called xml_render() - this one, should use die at the end, to
> > prevent from showing header and stuff when the rest of the script is
> > executed. The issue is, that this function is called mostly somewhere in
> > a set of sets of function-sets, so its not possible (easily, without
> > making the source unreadable) to do this via using if-else-constructs.
>
>     You can catch the error before it reaches the user with pcall().

I myself use a function abort(), which is something like:

local _die = {}
function abort() error(_die) end

And to catch it (pseudo code):


local handler = gethandlerforrequest( url )
local ok, err = pcall( handler )

if not ok and err ~= _die then
    -- something bad happened. Log it
    log.error(
        'An error occurred at a random address. ' .. tostring( err )
    )
end


Note that _die isn't visible anywhere else, so no one would be able to 
mimic abort() behavior.

--rb