What's ModuleLoader ?

ModuleLoader is a system for managing and loading libraries(modules) of AppleScript.

In OS X 10.9 (Oct. 2013), built-in support of libraries was introduced to AppleScript, which called as "AppleScript Libraries". ModuleLoader is a yet another library system, which has been developed from 2006 before release of OS X 10.9, and has been maintained without interruption until now.

ModuleLoader have a similar function to "AppleScript Libraries" as follows.

• Find a library from predefined locations and load the library as a script object.

  Libraries are searched from following sub-folders under user's home directory and the root directory.

  • Library/Scripts/Modules
  • Library/Script Libraries
• Sub-libraries required by the loaded library are automatically loaded.
• The version of a library to be loaded can be specified.

To build sophisticated software, the source code should be divided into some modules for easy maintenance. To gain efficiency of programming, sharing the modules between some products is effective. Such modularized source code to share between some products is called as a library or a module.

AppleScript Libraries or ModuleLoader enable to find and load libraries by specifying its names like other high functional scripting languages (e.g. Perl, Ruby, Python and so on), and to make up a software of multiple source files and libraries. Also ModuleLoader help to share source codes between applications.

In OS X 10.8 or before, AppleScript did not have a built-in library system. A library can be loaded by "load script" command which is primitive. Because the "load script" command requires a full path to a library file, management of libraries will be problematic. And sharing sub-libraries between libraries is difficult. ModuleLoader can solve these problems.

In OS X 10.9 or later, AppleScript Libraries will be first choice to work with libraries. "AppleScript Libraries" will be sufficient in usual tasks. But ModuleLoader can work with "AppleScript Libraries" and complement following missing functions of "AppleScript Libraries".

• All libraries can be loaded and embeded at compile time.
  • Loading all libraries when compiling a script causes removing dependencies on libraries and ModuleLoader. The script can works other computers in which the libraries and ModuleLoader.osax are not installed.
• Libraries can be forced to reload anytime.
• AppleScript text source file (.applescript) , applets and droplets can be libraries.

See "Working wiht AppleScrpt Libraries" for details.