object-oriented applications on the filesystem using simple conventions
thinobject uses (or abuses) symlinks, specifically non-resolving symlinks, in several ways.
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The type or prototype of an object is given by the value (e.g., obtained from readlink()) of the symlink named '^'.
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The value of a non-resolving symlink named '^' is the type of the thinobject object, where that type must be found in the thinobject type library identified in the TOBLIB envrironment variable. A thinobject 'type' is a directory containing executable programs -- those programs are the methods that can be run by the object. Other thinobject attributes might also be included in a type directory.
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If symlink ^ resolves to a directory, then that directory is the prototype of the thinobject object. In turn, the prototype object itself (or its prototype, and so on) must have a non-resolving ^ symlink that identifies a valid thinobject type. An object can only run methods that are defined in a thinobject type directory. Executable programs in a prototype directory are not available as methods. Other thinobject attributes in a prototype directory are available to the object with ^ pointing to that prototype.
thinobject relies on ^ symlinks -- type links -- to resolve methods for execution by an object. The type links effectively are the equivalent of the shell PATH environment variable; where the shell uses a search in the PATH (colon-delimited) directories to resolve an executable program of the given name, thinobject looks in thinobject type directories found by following ^ symlinks to resolve executable programs as methods of the object.
The thinobject handler or executive, e.g., a shell script named tob and found in PATH, gets a hook to badly-formed command line commands via the bash command_not_found_handle() function, and tries to reinterpret the bad command using the form OBJECT.METHOD. The object is resolved relative to where the command is issued, perhaps requiring substituting '.' characters with '/'. The requested method is resolved using the object's ^ type link, and is exectuted if found.
That's kind of it, I think. thinobject provides a way to find exectutable programs (methods) by following type links defined in symlinks named ^ in object directories. It gets there by parsing a command of the form OBJECT.METHOD [ARGS...] to identify the object, then its type, and then by resolving the given method via that type.