Add RecordOf and FieldOf for homogeneous records

purescript · Aug 10, 2017 · 8b39b00 · 8b39b00
1 parent 5b70a6f
commit 8b39b00
Showing 1 changed file with 18 additions and 0 deletions.
diff --git a/src/Type/Data/Record.purs b/src/Type/Data/Record.purs
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+module Type.Data.Record
+  ( class RecordOf
+  ) where
+
+import Type.Row (class RowToList, Cons, Nil, kind RowList)
+
+class RecordOf record fieldType
+instance recordOf
+  :: ( RowToList record fields
+     , FieldOf fields fieldType
+     )
+  => RecordOf (Record record) fieldType
+
+class FieldOf (rowList :: RowList) fieldType
+instance fieldOfCons
+  :: (FieldOf tail fieldType)
+  => FieldOf (Cons symbol fieldType tail) fieldType
+instance fieldOfNil :: FieldOf Nil fieldType