pcall-like ability without closure - exposing setjmp/longjmp

[Thomas Harning <harningt@...>]

Is there any danger in exposing setjmp/longjmp outside of the 
pcall-mechanism in Lua?

I'm investigating creating a try-catch-like system without resorting to 
closures...   Preliminary idea would be something like:

if try() do
abort() -- jumps back to try setting something denoting error
end

Handle return value optionally rethrowing...

Haven't had much time to think of semantics, but I figured I'd make sure 
that using stack manipulation like this wouldn't be fatal.
One potential case would be to implement RAII-type features for Lua.


Another item... would it be possible to make the 'pcall'/'error' system 
work in this way... so that a normal error would be caught in the 
non-function method?