Re: lpeg.U ?

[Albert Chan <albertmcchan@...>]

> 
> On Jan 26, 2018, at 2:14 AM, Dirk Laurie <dirk.laurie@gmail.com> wrote:
> 
> 2018-01-26 0:19 GMT+02:00 albertmcchan <albertmcchan@yahoo.com>:
> 
>> Is there a lpeg.U(n) (for undo n characters) or something similar ?
> 
> You have two options.
> 
>   #p matches what p matches, but consumes no input.
> 
>   A Cg/Cb allows you to store a capture and use it later.
> 
> Actually, all the answers I could give to questions like yours are in my
> lpeg-brief article on https://github.com/dlaurie/lua-notes.
> 

Thank you, Dirk !
The official lpeg documentation is much too terse.
I like the Cg/Cb surname example, which is similar to perl back reference.

I had guessed that undo is impossible, since lpeg matching is possessive.
I was just checking if anyone did a patch for lpeg.U (or similar)

= re.match('hi', '.?..')       -- actually match 3+ characters
nil