Re: Is Lua used as a data representation language?

[steve donovan <steve.j.donovan@...>]

On Sun, Jan 6, 2013 at 12:55 AM, Javier Guerra Giraldez
<javier@guerrag.com> wrote:
> or against, if you want to prove your configs always terminate.

Yep, we have to go to some trouble to ensure that untrusted Lua is not harmful.

Whereas LON/LTIN is deliberately very restricted, and would have a
small C parser that C programs could use without Lua itself.

I like to think of APIs in terms of what the programmer sees.  So I'm
free to dream up a hypothetical library 'john' (LTIN John, you see ;))

So with this data

{
  names = {'Janes','Mary'},
  ages = {25,32}
}

it goes like this:

John *j = john_parse(ltin_text);
char *err = NULL;
char **strings;
double *ages;
int n1 = john_get_tag_string_array(j,"names",&strings,&err);
int n2 = john_get_tag_double_array(j,"ages",&ages,&err);
if (err != NULL) {  // conversion/type error
   fprintf(stderr,"error: %s\n",err);
  return;
}
if (n1 != n2) { // logical error
  fprintf(stderr,"error: names and ages array not the same size\n");
  return;
}

Of course, lots of details about allocation strategy and whether
get_tag should take key paths like "foo.bar", but that's the basic
idea.

Currently, we're just playing ping-pong, knocking the ball lazily
across the room. Either we'll get bored or someone will give the ball
a good whack.

steve d.