From cac275d0ec7fa575bdff79fbea09b5a11d379b4d Mon Sep 17 00:00:00 2001
From: Lukas Pietzschmann <lukas.pietzschmann@uni-ulm.de>
Date: Wed, 17 Jul 2024 15:30:11 +0200
Subject: [PATCH] Removed SetEq and moved two functions around

---
 .../Internal/AstProcessingSteps/Evaluate.hs      | 11 +++++++++--
 src/Math/Haskellator/Internal/Units.hs           | 16 +++-------------
 2 files changed, 12 insertions(+), 15 deletions(-)

diff --git a/src/Math/Haskellator/Internal/AstProcessingSteps/Evaluate.hs b/src/Math/Haskellator/Internal/AstProcessingSteps/Evaluate.hs
index c904089..fe84820 100644
--- a/src/Math/Haskellator/Internal/AstProcessingSteps/Evaluate.hs
+++ b/src/Math/Haskellator/Internal/AstProcessingSteps/Evaluate.hs
@@ -37,9 +37,9 @@ execVal :: Value Dimension -> SimpleAstFold (Value Dimension)
 execVal = return
 
 execBinOp :: Value Dimension -> Op -> Value Dimension -> SimpleAstFold (Value Dimension)
-execBinOp lhs Plus  rhs | unit lhs =~= unit rhs = return $ combineValues (+) lhs rhs
+execBinOp lhs Plus  rhs | unit lhs == unit rhs = return $ combineValues (+) lhs rhs
                         | otherwise = throwError $ Error RuntimeError $ "Cannot add units " ++ show (unit lhs) ++ " and " ++ show (unit rhs)
-execBinOp lhs Minus rhs | unit lhs =~= unit rhs = return $ combineValues (-) lhs rhs
+execBinOp lhs Minus rhs | unit lhs == unit rhs = return $ combineValues (-) lhs rhs
                         | otherwise = throwError $ Error RuntimeError $ "Cannot subtract units " ++ show (unit lhs) ++ " and " ++ show (unit rhs)
 execBinOp lhs Mult  rhs = do
     let u = mergeUnits (unit lhs) (unit rhs)
@@ -107,3 +107,10 @@ findPair x (y:ys) | dimUnit x == dimUnit y = ([(x, y)], ([], ys))
 
 filterZeroPower :: Dimension -> Dimension
 filterZeroPower = filter ((/=0) . power)
+
+mapValue :: (Double -> Double) -> Value u -> Value u
+mapValue f (Value v u) = Value (f v) u
+
+combineValues :: Eq u => (Double -> Double -> Double) -> Value u -> Value u -> Value u
+combineValues f (Value v1 u1) (Value v2 u2) | u1 == u2  = Value (v1 `f` v2) u1
+                                            | otherwise = error "Cannot map values with different units"
diff --git a/src/Math/Haskellator/Internal/Units.hs b/src/Math/Haskellator/Internal/Units.hs
index a75c767..23b4ea9 100644
--- a/src/Math/Haskellator/Internal/Units.hs
+++ b/src/Math/Haskellator/Internal/Units.hs
@@ -68,19 +68,12 @@ instance Eq UnitExp where
     (UnitExp Multiplier _) == (UnitExp Multiplier _) = True
     (UnitExp u1 e1) == (UnitExp u2 e2)               = u1 == u2 && e1 == e2
 
-mapValue :: (Double -> Double) -> Value u -> Value u
-mapValue f (Value v u) = Value (f v) u
-
-combineValues :: SetEq u => (Double -> Double -> Double) -> Value u -> Value u -> Value u
-combineValues f (Value v1 u1) (Value v2 u2) | u1 =~= u2  = Value (v1 `f` v2) u1
-                                            | otherwise = error "Cannot map values with different units"
-
-class SetEq a where
-    (=~=) :: a -> a -> Bool
-
 -- | A dimension is a list of exponentiated units
 type Dimension = [UnitExp]
 
+instance {-# OVERLAPPING #-} Eq Dimension where
+    a == b = all (`elem` b) a && all (`elem` a) b
+
 instance {-# OVERLAPPING #-} Show Dimension where
     show xs = write $ divide xs ([],[])
               where
@@ -98,6 +91,3 @@ instance {-# OVERLAPPING #-} Show Dimension where
 divide::Dimension -> (Dimension,Dimension) -> (Dimension, Dimension)
 divide (uExp@(UnitExp _ e):xs) (pos,neg) = if e<0 then divide xs (pos,neg ++ [uExp]) else divide xs (pos ++ [uExp], neg)
 divide [] (pos,neg) = (pos,neg)
-
-instance SetEq Dimension where
-    (=~=) a b = all (`elem` b) a && all (`elem` a) b