Re: lpeg as a part of lua (was: An introduction to Lua)
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- Subject: Re: lpeg as a part of lua (was: An introduction to Lua)
- From: Sean Conner <sean@...>
- Date: 2017年10月23日 03:37:18 -0400
It was thus said that the Great Daurnimator once stated:
> On 23 October 2017 at 14:36, Sean Conner <sean@conman.org> wrote:
> > I'm thinking there's not anything that Lua patterns do that you can't do
> > in LPeg
>
> I did once sit down and rewrite the lua pattern matching functions using lpeg.
>
> If I recall correctly, the only thing I couldn't figure out was the
> `n` argument to string.gsub.
Did you try using LPeg's patt^-n? Where the pattern you generated is only
run up to n times? Something along:
function mygsub(s,luapattern,repl,n)
n = n or math.huge
local patt = convert(luapattern,repl)
patt = lpeg.Cs(
(
(lpeg.P(1) - patt)^0 -- skip portion that doesn't match
* patt -- do that pattern
)^-n -- do it up to n times
* lpeg.P(1)^0 -- return rest of string if any
)
return patt:match(s)
end
-spc (Totally untested, not sure if it will even work, yada yada ... )