Re: stldib does not like luajit

[Reuben Thomas <rrt@...>]

On Thu, 11 Sep 2008, Mike Pall wrote:

> Apparently stdlib has not been updated to use Lua 5.1 semantics
> regarding varargs.

This is true in just the one instance given (that of stdlib's string.format 
extension). Thanks to David Kantowitz for bringing this to my attention; 
I'll make a release in a few minutes with a fix.

> Anyway, stdlib has some strange code like:
>   if #arg == 0 then ...
> Which is mixing Lua 5.1 syntax (# operator) and Lua 5.0 syntax
> (arg table).

Indeed, stdlib still has code like this. But it's not incorrect: there are 
two cases where it's used:

1. It is desired to operate on the table of varargs. The code will be 
preceded with a line like this:

local arg = {...}

2. Where the code is referring to the top-level arg table of the standalone 
interpreter. From the manual:

"Before starting to run the script, lua collects all arguments in the 
command line in a global table called arg."

I don't see any hint that this is deprecated.

> There's more ugliness inside like an __index function for the string 
> metatable, overriding lots of standard functions and in general adding 
> lots of bloat.

This is very much the point of stdlib. It adds __index to the string 
metatable as a convenience, and similarly overrides the standard functions 
to add conveniences that the Lua team have not seen fit to add. Almost all 
the extensions to standard types and functions in stdlib only extend the 
existing semantics, rather than altering them. For example, string.format is 
extended so that if only one argument is given, it is printed as a string, 
i.e. "string.format (s)" becomes "string.format ("%s", s)".

Of course, there are also a lot of general-purpose functions not found in 
the built-in library.

> So I suggest to stay away from it.

I suggest rather that you criticize and improve it. stdlib was started as a 
project to build general-purpose pure-Lua libraries. Sadly, it has not 
exactly prospered, though I still maintain it. Almost all the code in it I 
wrote or gathered for particular uses. As I don't program much in Lua any 
more, I don't add to it.

One other thing of note is that I'm actually quite anti-bloat. I have only 
added things that seem to me to be widely useful (with one or two odd 
exceptions like the mbox parser, which I simply wanted to preserve), and 
that I've used in my own code. In particular, I have occasionally removed 
functions that I ended up deciding were too special-purpose, and I have 
removed several functions that were obsoleted by new features or functions 
in Lua releases.

I think stdlib is not without value: much of the code in it is reasonably 
well tested, and all of it is reasonably well documented. The design of the 
library has had quite a bit of thought put into it. There's a lot left to be 
desired: in particular, there are no systematic tests, and much of the code 
could be written more efficiently. The coding style is largely but not 
entirely consistent. The dependencies between modules are expressed, but few 
modules can be loaded without pulling in most of the library. There's no 
automatic dependency detection, which there could and should be.

If an active Lua programmer would like to take over the project, I'd be 
delighted. I think stdlib still fills an otherwise unfilled hole in the 
space of Lua libraries.

--
http://rrt.sc3d.org/ | RSA, n.  safety in numbers