remove test code

README.md

@@ -58,4 +58,4 @@ This comes with absolutely no guarantee of support or correct function, although
 * `nn.sql` - half an RNN in SQLite, unfinished because it *apparently* can't do recursive common table expressions.
 * `alexandergriffing_spite.py` - spites sometime by doing bad numerics in Python.
 * `screensaver.html` - an attempt to replicate one of Apple's screensavers (incomplete).
-* `StringGroup.hs` - native Haskell strings are only a monoid, so I improved them to be a group instead.
+* `StringGroup.hs` - native Haskell strings are only a monoid, so I made an improved version which forms a group instead.

StringGroup.hs

@@ -26,11 +26,6 @@ instance Semigroup SString where
                 | otherwise = go xs (P x:N y:ys)
             go (x:xs) acc = go xs (x:acc)
 
-concat' [] [] = []
-concat' [] ys = ys
-concat' xs [] = xs
-concat' (x:xs) ys = x:concat' xs ys
-
 instance Monoid SString where
     mempty = SString []