Make userreg.lua more concise.

1 files changed, 37 insertions, 13 deletions

diff --git a/runtime/lua/vim/userreg.lua b/runtime/lua/vim/userreg.lua
index d1062dea73..5abcff0407 100644
--- a/runtime/lua/vim/userreg.lua
+++ b/runtime/lua/vim/userreg.lua
@@ -1,27 +1,51 @@
+-- Defualt implementation of the userregfunc. This default implementation is
+-- extensible and allows other plugins to register handlers for different
+-- registers.
+--
+-- The default handler behaves just as a normal register would.
+
 local userreg = {}
 
-userreg.store = {}
-userreg.regtable = {}
+-- Returns a "default handler" which behaves exactly like the builtin registers
+-- in Vim. Simply stores whatever was yanked and returns the last thing that was
+-- yanked.
+function userreg._default_handler()
+  local d = {}
+
+  function d.do_yank(self, content)
+    self.content = content
+  end
+
+  function d.do_put(self)
+    return self.content or {}
+  end
+
+  return d
+end
+
+-- The store for registers default handler
+userreg._regtable = {}
 
+-- Function for the userreg. This function will defer to the handler registered
+-- to the given register. If no handler is registered to the given register, the
+-- default handler is used.
 function userreg.fn(action, register, content)
+  if not userreg._regtable[register] then
+    userreg._regtable[register] = userreg._default_handler()
+  end
+
   if action == "yank" then
-    if userreg.regtable[register] then
-      userreg.regtable[register]:do_yank(content)
-    else
-      userreg.store[register] = content
-    end
+    userreg._regtable[register]:do_yank(content)
     return nil
   else 
-    if userreg.regtable[register] then
-      return userreg.regtable[register]:do_put()
-    else
-      return userreg.store[register] or {}
-    end
+    return userreg._regtable[register]:do_put()
   end
 end
 
+-- Registers a handler with a register. Future yanks and puts will defer to the
+-- handler when determining the content to put/yank.
 function userreg.register_handler(register, handler) 
-  userreg.regtable[register] = handler
+  userreg._regtable[register] = handler
 end
 
 return userreg