Re: loading lua scripts relative to an app's path

[askok@...]

There's basically two ways to this, based on whether your 
script is launched as a filename, or via the '-l' 
(library) flag.

The '-l' solution is kind-of ugly, and a better one would 
be welcomed.   This has been mentioned on the list (at 
least) once, but no changes came about.


1. filename argument
=============

Lumikki is started by such shell script ("lumikki"):

   #!/bin/sh
   #
   lua -lstrict ./scripts/main.lua $@

This allows main.lua to use 'argv[0]' to find other 
scripts:

-- arg[0] should have our full filename, let's take the 
path out:
--
local _,_, MY_PATH= string.find( arg[0], "(.+[/\\]).-" )
assert(MY_PATH)

dofile( MY_PATH.."filters.lua" )

dofile( MY_PATH.."support.lua" )
dofile( MY_PATH.."dirtools.lua" )

dofile( MY_PATH.."depcache.lua" )
dofile( MY_PATH.."lumikki2.lua" )


2. '-l' flag
======

--
-- HAMSTER.LUA                     -- Copyright (c) 
2005-06, askok@dnainternet.net
--
-- Hamster initialisation hub.
--
-- This script is the entry point for Lua's "-l" loading 
mechanism, and can
-- handle any Lua engine incompatibility issue prior to 
loading actual
-- application scripts.
--

local main= "main"    -- main script   <--- NAMING THIS IS 
UP TO YOU

-- Finding subscripts:
--
local LUA_PATH= rawget(_G,"package") and package.path
                                      or 
os.getenv("LUA_PATH")
if not LUA_PATH then
    error "LUA_PATH environment variable not set."
end

rawset( _G, "MY_PATH", false )

for pat in string.gfind( LUA_PATH, "[^;]+" ) do
    local try= string.gsub( pat, "?", "hamster" )
    local fh= io.open(try,"r")
    if fh then
        fh:close()
        MY_PATH= string.gsub(try,"hamster%.lua","")
        break
    end
end
assert(MY_PATH)

--
-- Actual application code:
--
local m= dofile( MY_PATH..main..".lua" )

return m




On Fri, 06 Oct 2006 10:10:47 +0100
 Gavin Wraith <gavin@wra1th.plus.com> wrote:
> In message 
> <1079b050610060102g63d45083of3f8a6e0b00786f9@mail.gmail.com> 
> you wrote:
>
> > How does eveyone determine the location of scripts 
> > relative to their
> > application?  I've been racking my brain on this one and 
> > haven't found
> > a solution yet.  I tried reading the directory "./" and 
> > got the hard
> > drive's root.  Are there other ways?  I'm trying to 
> > overcome the
> > problem of my app being run on different computers and 
> > not wanting to
> > ask the user to do any more work than download the app.
>
> I use arg[0].
>
> --
> Gavin Wraith (gavin@wra1th.plus.com)
> Home page: http://www.wra1th.plus.com/