Re: Reading characters from stdin

[Rena <hyperhacker@...>]

On Sep 21, 2012 11:12 AM, "Matthew Wild" <mwild1@gmail.com> wrote:
>
> On 21 September 2012 15:34, Rena <hyperhacker@gmail.com> wrote:
> > (Yep, this question again. :p)
> >
> > I'm coding in a rather limited Linux-like environment: I have a text editor,
> > a terminal emulator, a Lua 5.1 interpreter, and not much else. I don't have
> > a C compiler.
> >
> > My problem is I want to read keys from stdin as soon as they're pressed,
> > without having to press enter. The only ways I know to do this involve C
> > function calls. Is there perhaps an ANSI escape code or some other crazy
> > trick I can use? Can I call some program with os.execute to change terminal
> > settings?
>
> Try this small function:
>
>     function getchar(n)
>         local stty_ret = os.execute("stty raw 2>/dev/null");
>         local ok, char;
>         if stty_ret == 0 then
>             ok, char = pcall(io.read, n or 1);
>             os.execute("stty sane");
>         else
>             ok, char = pcall(io.read, "*l");
>             if ok then
>                 char = char:sub(1, n or 1);
>             end
>         end
>         if ok then
>             return char;
>         end
>     end
>
> An improvement would be to save the current stty settings, and then
> restore them (instead of 'stty sane'). I don't know how "portable"
> this is though.
>
> Hope this helps,
> Matthew
>
> PS. The code is taken from Prosody, which is MIT licensed.
>

Thanks, I thought stty could be useful there, but I hadn't noticed the raw option.