Binary Modules Loader

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Difference (from prior minor revision) (major diff)

Changed: 1c1,34

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Here is an example of a module loader that loads binary modules, just like the standalone loader provided by Lua. You can use it to implement more complex loaders. (JeromeVuarand)


 module(..., package.seeall)
 
 local function load(modulename)
   local errmsg = ""
   -- Find DLL
   local symbolname = string.gsub(modulename, "%.", "_")
   local modulepath = string.gsub(modulename, "%.", "/")
   for path in string.gmatch(package.cpath, "([^;]+)") do
     local filename = string.gsub(path, "%?", modulepath)
     local file = io.open(filename, "rb")
     if file then
       file:close()
       -- Load and return the module loader
       local loader,msg = package.loadlib(filename, "luaopen_"..symbolname)
       if not loader then
         error("error loading module '"..modulename.."' from file '"..path.."':\n\t"..msg, 3)
       end
       return loader
     end
     errmsg = errmsg.."\n\tno file '"..filename.."' (checked with custom loader)"
   end
   return errmsg
 end
 
 -- Install the loader so that it's called just before the normal binary loader
 table.insert(package.loaders, 3, load)

-----

The terminology on this page could be improved. This is a "searcher function" that returns a "loader" [1]. (Alas, package.loaders is not named package.searchers.) Also, the term "binary module" might wrongly imply a Lua bytecode file; I suggest "C library" as in the refman (or "shared library"). So, I suggest renaming the page "CeeLibrarySearcherFunctionInLua?" (there are currently four other "*InLua?" pages on this wiki). --DavidManura

Here is an example of a module loader that loads binary modules, just like the standalone loader provided by Lua. You can use it to implement more complex loaders. (JeromeVuarand)

module(..., package.seeall)

local function load(modulename)
  local errmsg = ""
  -- Find DLL
  local symbolname = string.gsub(modulename, "%.", "_")
  local modulepath = string.gsub(modulename, "%.", "/")
  for path in string.gmatch(package.cpath, "([^;]+)") do
    local filename = string.gsub(path, "%?", modulepath)
    local file = io.open(filename, "rb")
    if file then
      file:close()
      -- Load and return the module loader
      local loader,msg = package.loadlib(filename, "luaopen_"..symbolname)
      if not loader then
        error("error loading module '"..modulename.."' from file '"..path.."':\n\t"..msg, 3)
      end
      return loader
    end
    errmsg = errmsg.."\n\tno file '"..filename.."' (checked with custom loader)"
  end
  return errmsg
end

-- Install the loader so that it's called just before the normal binary loader
table.insert(package.loaders, 3, load)

: The terminology on this page could be improved. This is a "searcher function" that returns a "loader" [1]. (Alas, package.loaders is not named package.searchers.) Also, the term "binary module" might wrongly imply a Lua bytecode file; I suggest "C library" as in the refman (or "shared library"). So, I suggest renaming the page "CeeLibrarySearcherFunctionInLua?" (there are currently four other "*InLua?" pages on this wiki). --DavidManura

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Last edited September 6, 2009 3:01 am GMT (diff)