License	MIT
Safe Haskell	None
Language	Haskell2010

DataFrame.Typed.TH.Records

Contents

Schema inference from an existing DataFrame value
ADT-based schema derivation
Re-export for TH splices
Shared helpers (used by sibling TH modules)

Description

Record-based typed-API schema derivation. The IO-agnostic core of the DataFrame.Typed.TH family. CSV-file-based derivation lives in DataFrame.Typed.TH.CSV (in dataframe-csv-th).

Synopsis

deriveSchema :: String -> DataFrame -> DecsQ
deriveSchemaFromType :: Name -> DecsQ
deriveSchemaFromTypeWith :: SchemaOptions -> Name -> DecsQ
deriveSchemaValues :: Name -> DecsQ
data SchemaOptions = SchemaOptions {
- nameTransform :: String -> String
- schemaTypeName :: Maybe String
- generateInstance :: Bool
}
defaultSchemaOptions :: SchemaOptions
camelToSnake :: String -> String
data TypedDataFrame (cols :: [(Symbol, Type)])
getSchemaInfo :: DataFrame -> [(Text, String)]
findDuplicate :: Eq a => [a] -> Maybe a

Schema inference from an existing DataFrame value

deriveSchema :: String -> DataFrame -> DecsQ Source #

ADT-based schema derivation

deriveSchemaFromType :: Name -> DecsQ Source #

deriveSchemaFromTypeWith :: SchemaOptions -> Name -> DecsQ Source #

deriveSchemaValues :: Name -> DecsQ Source #

Derive an untyped Schema value plus per-column Expr accessors from a record type. The value-level companion to deriveSchemaFromType: $(deriveSchemaValues ''Order) generates orderSchema.

data SchemaOptions Source #

Options controlling deriveSchemaFromTypeWith.

Constructors

SchemaOptions
Fields nameTransform :: String -> String Map each record selector name to a column name. Default: `camelToSnake`. schemaTypeName :: Maybe String Override the generated type synonym name. Default: `<TypeName>Schema`. generateInstance :: Bool When `True` (default), also generate a `HasSchema` instance so the record can be turned into a `DataFrame` via `fromRecords` / `toRecords`.

defaultSchemaOptions :: SchemaOptions Source #

camelToSnake :: String -> String #

Convert a camelCase identifier to snake_case.

>>> camelToSnake "orderId"
"order_id"
>>> camelToSnake "amountUS"
"amount_u_s"
>>> camelToSnake "region"
"region"

Re-export for TH splices

data TypedDataFrame (cols :: [(Symbol, Type)]) #

A phantom-typed wrapper over the untyped DataFrame.

The type parameter cols is a type-level list of '(name, ty) pairs that tracks the schema at compile time. All operations delegate to the untyped core at runtime and update the phantom type at compile time.

Instances

Instances details

Show (TypedDataFrame cols)
Instance details Defined in DataFrame.Typed.Types Methods showsPrec :: Int -> TypedDataFrame cols -> ShowS # show :: TypedDataFrame cols -> String # showList :: [TypedDataFrame cols] -> ShowS #
ToDataFrame (TypedDataFrame cols)
Instance details Defined in DataFrame.Typed.Freeze Methods toDataFrame :: TypedDataFrame cols -> DataFrame #
Eq (TypedDataFrame cols)
Instance details Defined in DataFrame.Typed.Types Methods (==) :: TypedDataFrame cols -> TypedDataFrame cols -> Bool # (/=) :: TypedDataFrame cols -> TypedDataFrame cols -> Bool #

Shared helpers (used by sibling TH modules)

getSchemaInfo :: DataFrame -> [(Text, String)] Source #

findDuplicate :: Eq a => [a] -> Maybe a Source #