Re: help with string-handling

[Pedro Miller Rabinovitch <pedro@...>]

>  > What I need the most is tokenizing functions, for
> >  trimming leading/trailing spaces off a string, and removing words one at a
> >  time.
>
> How about the following:
>
> -- strip leading and trailing white space from a line
> function strip(l)
>     return gsub(l, "%s*(.*)%s*", "%1", 1)
> end

Actually, this wouldn't work. The trailing spaces are captured. Try:

     return gsub(l, "%s*(.-)%s*$", "%1", 1)

> -- remove a prefix p from s
> -- return the beheaded s and the removed prefix
> function behead(s, p)
>     local s2, z
>
>     z, z, p, s2 = strfind(s, p .. ")(.*)")

There's an open-parenthesis missing:

    z, z, p, s2 = strfind(s, "(".. p .. ")(.*)")

Otherwise, they work great.

> > I also had a problem with upvalues. I was sure I was using them 
> > correctly, but Lua kept telling me that I can't access locals out 
> > of scope... my code looked something like this:
> > (...)
> >   string, junk = gsub(string, "{.-}", x)
> > (...)
> >
> > It takes a two-letter code, surrounded by braces, and replaces it 
> > with the appropriate strings from either object passed to ssub(). 
> > This seems to be exactly like the example given in the manual in 
> > the section for upvalues, but here it just doesn't seem to work?

As far as the upvalues are concerned, your code worked fine for me. 
The only problem I detected so far was your gsub pattern. It should 
be:

  string, junk = gsub(string, "{(.-)}", x)

Regards,

	Pedro.
--
Pedro Miller Rabinovitch
Gerente Geral de Tecnologia
Cipher Technology
www.cipher.com.br