mixedcomparison class idea

Author: rasheedja

package.yaml

@@ -46,6 +46,7 @@ default-extensions:
   TemplateHaskell
   TupleSections
   TypeApplications
+  TypeFamilies
   NamedFieldPuns
 
 library:

simplex-method.cabal

@@ -58,7 +58,7 @@ library
   hs-source-dirs:
       src
   default-extensions:
-      DataKinds DeriveFunctor DeriveGeneric DerivingStrategies DisambiguateRecordFields DuplicateRecordFields FlexibleContexts LambdaCase OverloadedLabels OverloadedRecordDot OverloadedStrings RecordWildCards TemplateHaskell TupleSections TypeApplications NamedFieldPuns
+      DataKinds DeriveFunctor DeriveGeneric DerivingStrategies DisambiguateRecordFields DuplicateRecordFields FlexibleContexts LambdaCase OverloadedLabels OverloadedRecordDot OverloadedStrings RecordWildCards TemplateHaskell TupleSections TypeApplications TypeFamilies NamedFieldPuns
   build-depends:
       QuickCheck
     , base >=4.14 && <5
@@ -86,7 +86,7 @@ test-suite simplex-method-test
   hs-source-dirs:
       test
   default-extensions:
-      DataKinds DeriveFunctor DeriveGeneric DerivingStrategies DisambiguateRecordFields DuplicateRecordFields FlexibleContexts LambdaCase OverloadedLabels OverloadedRecordDot OverloadedStrings RecordWildCards TemplateHaskell TupleSections TypeApplications NamedFieldPuns
+      DataKinds DeriveFunctor DeriveGeneric DerivingStrategies DisambiguateRecordFields DuplicateRecordFields FlexibleContexts LambdaCase OverloadedLabels OverloadedRecordDot OverloadedStrings RecordWildCards TemplateHaskell TupleSections TypeApplications TypeFamilies NamedFieldPuns
   build-depends:
       QuickCheck
     , base >=4.14 && <5

src/Comparison/Types.hs

@@ -32,3 +32,30 @@ getMixedComparisonRHS :: MixedComparison a b -> b
 getMixedComparisonRHS (_ :<= b) = b
 getMixedComparisonRHS (_ :>= b) = b
 getMixedComparisonRHS (_ :== b) = b
+
+class MixedComparison2 c where
+  type LhsType c :: *
+  type RhsType c :: *
+
+  lhs :: c -> LhsType c
+  rhs :: c -> RhsType c
+
+  (.<=) :: c -> Bool
+  (.>=) :: c -> Bool
+
+  (.==) :: c -> Bool
+  (.==) c = (.>=) c && (.<=) c
+
+data IntComparison = IntComparison Int Int
+
+instance MixedComparison2 IntComparison where
+  type LhsType IntComparison = Int
+  type RhsType IntComparison = Int
+
+  lhs (IntComparison l _) = l
+  rhs (IntComparison _ r) = r
+
+  (.<=) (IntComparison l r) = l <= r
+  (.>=) (IntComparison l r) = l >= r
+
+  (.==) (IntComparison l r) = l == r