diff --git a/setup/resources.py b/setup/resources.py
index 31c80aa453..2704351d88 100644
--- a/setup/resources.py
+++ b/setup/resources.py
@@ -319,7 +319,7 @@ class Resources(Command):  # {{{
         from calibre.gui2.tweak_book.function_replace import builtin_functions
         for func in builtin_functions():
             try:
-                src = u''.join(inspect.getsourcelines(func)[0])
+                src = ''.join(inspect.getsourcelines(func)[0][1:])
             except Exception:
                 continue
             src = src.replace('def ' + func.func_name, 'def replace')
diff --git a/src/calibre/gui2/tweak_book/function_replace.py b/src/calibre/gui2/tweak_book/function_replace.py
index 5442dfae86..5ca71c505c 100644
--- a/src/calibre/gui2/tweak_book/function_replace.py
+++ b/src/calibre/gui2/tweak_book/function_replace.py
@@ -121,41 +121,44 @@ class FunctionBox(EditWithComplete):
 
 # Builtin functions ##########################################################
 
-def builtin(func, name, *args):
-    func.name = name
-    func.imports = args
+def builtin(name, *args):
+    def f(func):
+        func.name = name
+        func.imports = args
+        return func
+    return f
 
+@builtin('Upper-case text', upper, apply_func_to_match_groups)
 def replace_uppercase(match, number, file_name, metadata, dictionaries, functions, *args, **kwargs):
     '''Make matched text upper case. If the regular expression contains groups,
     only the text in the groups will be changed, otherwise the entire text is
     changed.'''
     return apply_func_to_match_groups(match, upper)
-builtin(replace_uppercase, 'Upper-case text', upper, apply_func_to_match_groups)
 
+@builtin('Lower-case text', lower, apply_func_to_match_groups)
 def replace_lowercase(match, number, file_name, metadata, dictionaries, functions, *args, **kwargs):
     '''Make matched text lower case. If the regular expression contains groups,
     only the text in the groups will be changed, otherwise the entire text is
     changed.'''
     return apply_func_to_match_groups(match, lower)
-builtin(replace_lowercase, 'Lower-case text', lower, apply_func_to_match_groups)
 
+@builtin('Capitalize text', capitalize, apply_func_to_match_groups)
 def replace_capitalize(match, number, file_name, metadata, dictionaries, functions, *args, **kwargs):
     '''Capitalize matched text. If the regular expression contains groups,
     only the text in the groups will be changed, otherwise the entire text is
     changed.'''
     return apply_func_to_match_groups(match, capitalize)
-builtin(replace_capitalize, 'Capitalize text', capitalize, apply_func_to_match_groups)
 
+@builtin('Title-case text', titlecase, apply_func_to_match_groups)
 def replace_titlecase(match, number, file_name, metadata, dictionaries, functions, *args, **kwargs):
     '''Title-case matched text. If the regular expression contains groups,
     only the text in the groups will be changed, otherwise the entire text is
     changed.'''
     return apply_func_to_match_groups(match, titlecase)
-builtin(replace_titlecase, 'Title-case text', titlecase, apply_func_to_match_groups)
 
+@builtin('Swap the case of text', swapcase, apply_func_to_match_groups)
 def replace_swapcase(match, number, file_name, metadata, dictionaries, functions, *args, **kwargs):
     '''Swap the case of the matched text. If the regular expression contains groups,
     only the text in the groups will be changed, otherwise the entire text is
     changed.'''
     return apply_func_to_match_groups(match, swapcase)
-builtin(replace_swapcase, 'Swap the case of text', swapcase, apply_func_to_match_groups)