Re: Inconsistency regarding the packagemodel, call for updates of the reference manual.

["Jérôme Vuarand" <jerome.vuarand@...>]

2007/5/17, Roberto Ierusalimschy <roberto@inf.puc-rio.br>:
> 2007/5/17, Norman Ramsey <nr@eecs.harvard.edu>:
> > Looking at the source, it does seem that if I want to provide some
> > sort of precompiled or preloaded modules, I could simply write my own
> > specialized package loader and then do
> >
> >   table.insert(package.loaders, 1, myloader)
> >
> > where 'myloader' returns a function on successful load, string on
> > error, and nil otherwise.  Then everything would be great, right?
>
> Mostly right. A returned string does not mean "error", it is just an
> explanation of "why" it could not load the module. If no loader
> is able to load the module, then all these explanations together
> are presented as the error message.

And additionnaly, if you want to mimic the stock Lua module loaders,
on error you should throw a Lua error (with error() from Lua or
lua_error() from C). As said Roberto, the absence of a module is not
an error. However, if a module is found but cannot be loaded for
whatever reason, then you can consider it is an error.

So to sum up a loader:
- return a function on success
- return a string if module is not found
- throws a Lua error otherwise