Re: String indexing again

[Randy Kramer <rhkramer@...>]

Thanks! (To you and the others that replied.)

Randy Kramer

On Monday 20 December 2010 08:58:49 am Dirk Laurie wrote:
> > On Sunday 19 December 2010 11:57:19 pm Dirk Laurie wrote:
> > > Except for the long lecture you need to explain why you get this:
> > > > s='hello'; print(s[3])
> > >
> > > nil
>
> Indexing for strings was not defined at all in Lua 5.0:
> --
> Lua 5.0.3  Copyright (C) 1994-2006 Tecgraf, PUC-Rio
>
> > s='hello'; print(s[3])
>
> stdin:1: attempt to index global `s' (a string value)
> stack traceback:
>     stdin:1: in main chunk
>     [C]: ?
> --
> It is still not defined in Lua 5.1 and 5.2.  But in the meantime,
> strings have acquired a metatable, in order to allow you to write
> s:sub(3,3) instead of string.sub(s,3,3).  Since indexing for
> strings is not defined, s[3] falls through to the metatable,
> which does not have an entry with key value 3.  Therefore, as
> with all table references, nil is returned.
>
> In my opinion, this sort of non-intuitive behaviour, which needs
> very careful reading of the reference manual to understand, is
> a much greater evil than the alleged illogic and Cobol-likeness
> of making s[3] mean the third character of the string s.  But
> I promised to stop ranting about this.