[MIRROR] Added an explanatory comment to the top of decls.dm.

code/datums/repositories/decls.dm

@@ -1,4 +1,20 @@
-/var/repository/decls/decls_repository = new()
+// /decl is a subtype used for singletons that should never have more than one instance 
+// in existence at a time. If you want to use a /decl you should use a pattern like:
+//     var/decl/somedecl/mydecl = decls_repository.get_decl(/decl/somedecl)
+
+// /decls are created the first time they are fetched from decls_repository and will
+// automatically call Initialize() and such when created in this way.
+
+// decls_repository.get_decls_of_type() and decls_repository.get_decls_of_subtype()
+// can be used similarly to typesof() and subtypesof(), returning assoc instance lists.
+
+// The /decl commandments:
+//     I. Thou shalt not create a /decl with new().
+//     II. Thou shalt not del() or qdel() a /decl.
+//     III. Thou shalt not write a decl that relies on arguments supplied to New().
+//     IV. Thou shalt not call Initialize() on a /decl.
+
+var/repository/decls/decls_repository = new()
 
 /repository/decls
 	var/list/fetched_decls