dataframe-parsing 2.1.0.0 → 2.1.1.0

raw patch · 2 files changed

+38/−1 lines, 2 filesPVP ok

version bump matches the API change (PVP)

API changes (from Hackage documentation)

Files

• dataframe-parsing.cabal +1/−1
• src/DataFrame/Internal/Schema.hs +37/−0

@@ -1,6 +1,6 @@ cabal-version:      3.4 name:               dataframe-parsing-version:            2.1.0.0+version:            2.1.1.0 synopsis:           Shared text/binary parsing helpers for the dataframe ecosystem. description:     Parsing primitives used by the @dataframe@ family: CSV-friendly text

@@ -1,10 +1,14 @@ {-# LANGUAGE AllowAmbiguousTypes #-}+{-# LANGUAGE DataKinds #-} {-# LANGUAGE FlexibleContexts #-}+{-# LANGUAGE FlexibleInstances #-} {-# LANGUAGE GADTs #-} {-# LANGUAGE InstanceSigs #-} {-# LANGUAGE ScopedTypeVariables #-} {-# LANGUAGE TypeApplications #-} {-# LANGUAGE TypeFamilies #-}+{-# LANGUAGE TypeOperators #-}+{-# LANGUAGE UndecidableInstances #-}  {- | Runtime schema representation. The Template-Haskell @deriveSchema@ splice@@ -16,14 +20,18 @@     schemaType,     Schema (..),     makeSchema,+    RuntimeSchema (..), ) where +import Data.Kind (Type) import qualified Data.Map as M import Data.Maybe (isJust) import qualified Data.Proxy as P import qualified Data.Text as T import Data.Type.Equality (TestEquality (..)) import DataFrame.Internal.Column (Columnable)+import DataFrame.Typed.Types (Column)+import GHC.TypeLits (KnownSymbol, symbolVal) import Type.Reflection (typeRep)  -- | A runtime tag for a column’s element type.@@ -86,3 +94,32 @@ -- | Construct a 'Schema' from a list of @(columnName, schemaType)@ pairs. makeSchema :: [(T.Text, SchemaType)] -> Schema makeSchema = Schema . M.fromList++{- | The runtime 'Schema' behind a type-level schema — names /and/ element+types — so a reader can project to a schema's columns and skip inference for+them in one step.++Every column type must have a 'Read' instance, which 'Columnable' does not+imply; that is what lets the names carry their types across to a reader.++==== __Examples__+>>> :set -XTypeApplications -XDataKinds+>>> elements (runtimeSchema @'[Column "n" Int])+fromList [("n",Int)]+-}+class RuntimeSchema (cols :: [Type]) where+    runtimeSchema :: Schema++instance RuntimeSchema '[] where+    runtimeSchema = makeSchema []++instance+    (KnownSymbol name, Columnable a, Read a, RuntimeSchema rest) =>+    RuntimeSchema (Column name a ': rest)+    where+    runtimeSchema =+        Schema $+            M.insert+                (T.pack (symbolVal (P.Proxy @name)))+                (schemaType @a)+                (elements (runtimeSchema @rest))