Re: Bug in pattern matching

[Roberto Ierusalimschy <roberto@...>]

> I believe I've found a bug in the pattern matching implementation.
> Executing the code below shows that each iteration takes under 1
> second.
> 
> local pattern = "b"
> for len=10000,100000,10000 do
>   local t = os.time()
>   ("a"):rep(len):find(pattern)
>   print(len, os.time() - t)
> end
> 
> On the other hand, if the pattern string is ".*b", this is how long
> it's taking:
> 
> [...]

This is literally a textbook example: http://www.lua.org/pil/20.4.html


> [...] I think some "cleverness" is missing in the implementation.

Missing cleverness is not a bug.

-- Roberto