Re: LPEG documentation needs more clarification

[pygy79@...]

Actually, I read i too fastt :-)

Still, the folding capture would also handle counting arbitrary
captures more cleanly:

    cnt = Cf(Cc(0) * C(1)^0 , function(total) return total +1  end)

—Pierre-Yves

On Thu, Feb 14, 2019 at 8:00 PM <pygy79@gmail.com> wrote:
>
> On Wed, Jan 30, 2019 at 4:58 AM Sean Conner <sean@conman.org> wrote:
> >
> >
> >   I managed to generate a segfault with LPEG and I can reproduce the issue
> > with this code [1]:
> >
> > local lpeg = require "lpeg"
> > local Cg = lpeg.Cg
> > local Cc = lpeg.Cc
> > local Cb = lpeg.Cb
> > local P  = lpeg.P
> >
> > local cnt = Cg(Cc(0),'count')
> >           * (P(1) * Cg(Cb'count' / function(c) return c + 1 end,'count'))^0
> >           * Cb'count'
> >
> > print(cnt:match(string.rep("x",512+128))) -- CRASH at some point past this line
>
> LuLPeg also crashes, but for a larger string (between 512 * 51 and 512
> * 52 with Lua 5.3).
>
> Just in case, your problem can be solved with a folding capture and no
> temp Lua variable:
>
>     local cnt = Cf(
>       Cp() * P(1)^0 * Cp(),
>       function(first, last) return last - first end
>     )
>
> —Pierre-Yves