Re: How to avoid "infinite loop"

[Elias Barrionovo <elias.tandel@...>]

On Wed, Sep 2, 2015 at 5:36 PM, Rodrigo Azevedo <rodrigoams@gmail.com> wrote:
> Is Lua a "infinite loop" safe language in any conception? (I really don't
> know the strategies involved to check/avoid these cases at implementation
> level)


Alan Turing famously proved that there is no general way [1] of
finding out whether a piece of program terminates for an arbitrary
input without actually running it and hoping for the best. It's known
as the Halting Problem: https://en.wikipedia.org/wiki/Halting_problem

However, there are certain heuristics. For instance, you could create
a graph of branches and function calls and see if there are any
cycles, but it is very error prone (add some basic metatable or ENV
trickery and the checker won't work).

Usually, what is done is to limit the total runtime of a piece of
code, which in Lua can be done using hooks and the debug library.
Others in this list may enlight you in this matter.

-- 
NI!

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