Re: Lua 5.2 beta: default module path incompatibility

[David Manura <dm.lua@...>]

On Tue, Sep 20, 2011 at 7:26 AM, liam mail <liam.list@googlemail.com> wrote:
> On 20 September 2011 12:04, Dirk Laurie <dpl@sun.ac.za> wrote:
>>  The default set in luaconf.h for both package.path and package.cpath
>>  in Lua 5.2.0 beta puts the present working directory last, whereas in
>>  Lua 5.1.4 it was put first.[...]
>> It is difficult to understand why this change has been made.  It causes
>> any application distributed with customized versions of packages that
>> happen to installed system-wide to break unless the application explicitly
>> sets the path.

Arguments for the new behavior were raised in [1,2].

Note that the path "./?.lua" is relative to the current directory, but
you'd probably rather search relative to the Lua executable (i.e. "!"
style LUA_PATH in Windows / LuaDist setprogdir [3]) or relative to the
current script [4-8].  Perl's FindBin and "use lib" [9] do this well,
and I've contemplated writing the analogue of both modules for Lua,
and submitting it to distributions like LuaForWindows, because the
need is so common.  IMO, "./?.lua" is a hack that introduces some
modes of failure.

[1] http://lua-users.org/lists/lua-l/2009-07/msg00106.html
[2] http://lua-users.org/lists/lua-l/2009-05/msg00559.html

[3] https://github.com/LuaDist/lua/blob/master/src/loadlib_rel.c#L68
[4] http://lua-users.org/lists/lua-l/2011-01/msg00920.html
[5] http://lua-users.org/lists/lua-l/2010-02/msg00683.html
[6] http://lua-users.org/lists/lua-l/2011-02/msg01364.html
[7] http://lua-users.org/lists/lua-l/2006-10/msg00189.html
[8] http://lua-users.org/lists/lua-l/2003-06/msg00399.html

[9] http://search.cpan.org/~jesse/perl/lib/FindBin.pm