Re: Infinity as index

[Sean Conner <sean@...>]

It was thus said that the Great Lukas Prokop once stated:
> > On Thu, Apr 24, 2014 at 11:22 AM, Thiago L. <fakedme@gmail.com> wrote:
> >> On 24/04/2014 12:41, steve donovan wrote:
> >>> [...]
> >> Well something like what I said... I would actually expect str:sub(inf)
> >> to expand to str:sub(#str+1) and str:sub(-inf,inf) to expand to
> >> str:sub(0,#str+1)... or something...
> >
> > This is a really basic question (maybe so much so as to be off-topic):
> >
> > What is all of this useful for? Where do you guys come across this in real
> > life?
> 
> For my part, I was developing on the markdown parser and had a pattern
> like this:
> 
>     [[ Parsing recursive HTML5 tag structures ]]
>     1. Initialize "from, to = 1, 1/0"

  You could do

	from, to = 1, math.huge

as math.huge is +inf.  But seeing how that doesn't work with string.sub(),
how about?

	from, to = 1 , 2^31-1

(at least for Lua <= 5.2).  

> x = "1234567890"
> y = x:sub(1,2^31-1)
> print(y)
1234567890
> 

  -spc