Safe Haskell	None
Language	Haskell2010

DataFrame.Typed.Schema

Contents

Type families for schema manipulation
Maybe-stripping families
Join schema families
GroupBy helpers
KnownSchema class
Helpers

Synopsis

type family Lookup (name :: Symbol) (cols :: [Type]) where ...
type family HasName (name :: Symbol) (cols :: [Type]) :: Bool where ...
type family RemoveColumn (name :: Symbol) (cols :: [Type]) :: [Type] where ...
type family Impute (name :: Symbol) (cols :: [Type]) :: [Type] where ...
type family SubsetSchema (names :: [Symbol]) (cols :: [Type]) :: [Type] where ...
type family ExcludeSchema (names :: [Symbol]) (cols :: [Type]) :: [Type] where ...
type family RenameInSchema (old :: Symbol) (new :: Symbol) (cols :: [Type]) :: [Type] where ...
type family RenameManyInSchema (pairs :: [(Symbol, Symbol)]) (cols :: [Type]) :: [Type] where ...
type family Append (xs :: [k]) (ys :: [k]) :: [k] where ...
type family Snoc (xs :: [k]) (x :: k) :: [k] where ...
type family Reverse (xs :: [Type]) :: [Type] where ...
type family ColumnNames (cols :: [Type]) :: [Symbol] where ...
type family AssertAbsent (name :: Symbol) (cols :: [Type]) where ...
type family AssertPresent (name :: Symbol) (cols :: [Type]) where ...
type family AssertAllPresent (name :: [Symbol]) (cols :: [Type]) where ...
type family IsElem (x :: Symbol) (xs :: [Symbol]) :: Bool where ...
type family StripAllMaybe (cols :: [Type]) :: [Type] where ...
type family StripMaybeAt (name :: Symbol) (cols :: [Type]) :: [Type] where ...
type family SharedNames (left :: [Type]) (right :: [Type]) :: [Symbol] where ...
type family UniqueLeft (left :: [Type]) (rightNames :: [Symbol]) :: [Type] where ...
type family InnerJoinSchema (keys :: [Symbol]) (left :: [Type]) (right :: [Type]) :: [Type] where ...
type family LeftJoinSchema (keys :: [Symbol]) (left :: [Type]) (right :: [Type]) :: [Type] where ...
type family RightJoinSchema (keys :: [Symbol]) (left :: [Type]) (right :: [Type]) :: [Type] where ...
type family FullOuterJoinSchema (keys :: [Symbol]) (left :: [Type]) (right :: [Type]) :: [Type] where ...
type family WrapMaybe (cols :: [Type]) :: [Type] where ...
type family WrapMaybeColumns (names :: [Symbol]) (cols :: [Type]) :: [Type] where ...
type family CollidingColumns (left :: [Type]) (right :: [Type]) (keys :: [Symbol]) :: [Type] where ...
type family GroupKeyColumns (keys :: [Symbol]) (cols :: [Type]) :: [Type] where ...
class KnownSchema (cols :: [Type]) where
- schemaEvidence :: [(Text, SomeTypeRep)]
class AllKnownSymbol (names :: [Symbol]) where
- symbolVals :: [Text]

Type families for schema manipulation

type family Lookup (name :: Symbol) (cols :: [Type]) where ... Source #

Look up the element type of a column by name.

Equations

Lookup name (Column name a ': _1) = a
Lookup name (Column _1 _2 ': rest) = Lookup name rest
Lookup name ('[] :: [Type]) = TypeError (('Text "Column '" ':<>: 'Text name) ':<>: 'Text "' not found in schema") :: Type

type family HasName (name :: Symbol) (cols :: [Type]) :: Bool where ... Source #

Check whether a column name exists in a schema (type-level Bool).

Equations

HasName name (Column name _1 ': _2) = 'True
HasName name (Column _1 _2 ': rest) = HasName name rest
HasName name ('[] :: [Type]) = 'False

type family RemoveColumn (name :: Symbol) (cols :: [Type]) :: [Type] where ... Source #

Remove a column by name from a schema.

Equations

RemoveColumn name (Column name _1 ': rest) = rest
RemoveColumn name (col ': rest) = col ': RemoveColumn name rest
RemoveColumn name ('[] :: [Type]) = '[] :: [Type]

type family Impute (name :: Symbol) (cols :: [Type]) :: [Type] where ... Source #

Unwrap a Maybe from a type after we impute values.

Equations

Impute name (Column name (Maybe a) ': rest) = Column name a ': rest
Impute name (Column name _1 ': rest) = TypeError (('Text "Column '" ':<>: 'Text name) ':<>: 'Text "' is not of kind Maybe *") :: [Type]
Impute name (col ': rest) = col ': Impute name rest
Impute name ('[] :: [Type]) = '[] :: [Type]

type family SubsetSchema (names :: [Symbol]) (cols :: [Type]) :: [Type] where ... Source #

Select a subset of columns by a list of names.

Equations

SubsetSchema ('[] :: [Symbol]) cols = '[] :: [Type]
SubsetSchema (n ': ns) cols = Column n (Lookup n cols) ': SubsetSchema ns cols

type family ExcludeSchema (names :: [Symbol]) (cols :: [Type]) :: [Type] where ... Source #

Exclude columns by a list of names.

Equations

ExcludeSchema names ('[] :: [Type]) = '[] :: [Type]
ExcludeSchema names (Column n a ': rest) = If (IsElem n names) (ExcludeSchema names rest) (Column n a ': ExcludeSchema names rest)

type family RenameInSchema (old :: Symbol) (new :: Symbol) (cols :: [Type]) :: [Type] where ... Source #

Rename a column in the schema.

Equations

RenameInSchema old new (Column old a ': rest) = Column new a ': rest
RenameInSchema old new (col ': rest) = col ': RenameInSchema old new rest
RenameInSchema old new ('[] :: [Type]) = TypeError (('Text "Cannot rename: column '" ':<>: 'Text old) ':<>: 'Text "' not found") :: [Type]

type family RenameManyInSchema (pairs :: [(Symbol, Symbol)]) (cols :: [Type]) :: [Type] where ... Source #

Rename multiple columns.

Equations

RenameManyInSchema ('[] :: [(Symbol, Symbol)]) cols = cols
RenameManyInSchema ('(old, new) ': rest) cols = RenameManyInSchema rest (RenameInSchema old new cols)

type family Append (xs :: [k]) (ys :: [k]) :: [k] where ... Source #

Append two type-level lists.

Equations

Append ('[] :: [k]) (ys :: [k]) = ys
Append (x ': xs :: [k]) (ys :: [k]) = x ': Append xs ys

type family Snoc (xs :: [k]) (x :: k) :: [k] where ... Source #

Add type to the end of a list.

Equations

Snoc ('[] :: [k]) (x :: k) = '[x]
Snoc (y ': ys :: [k]) (x :: k) = y ': Snoc ys x

type family Reverse (xs :: [Type]) :: [Type] where ... Source #

Reverse a type-level list.

Equations

Reverse xs = ReverseAcc xs ('[] :: [Type])

type family ColumnNames (cols :: [Type]) :: [Symbol] where ... Source #

Extract column names as a type-level list of Symbols.

Equations

ColumnNames ('[] :: [Type]) = '[] :: [Symbol]
ColumnNames (Column n _1 ': rest) = n ': ColumnNames rest

type family AssertAbsent (name :: Symbol) (cols :: [Type]) where ... Source #

Assert that a column name is absent from the schema (for derive/insert).

Equations

AssertAbsent name cols = AssertAbsentHelper name (HasName name cols) cols

type family AssertPresent (name :: Symbol) (cols :: [Type]) where ... Source #

Assert that a column name is present in the schema.

Equations

AssertPresent name cols = AssertPresentHelper name (HasName name cols) cols

type family AssertAllPresent (name :: [Symbol]) (cols :: [Type]) where ... Source #

Assert that a column name is present in the schema.

Equations

AssertAllPresent (name ': rest) cols = If (HasName name cols) (AssertAllPresent rest cols) (TypeError (('Text "Column '" ':<>: 'Text name) ':<>: 'Text "' not found in schema") :: Constraint)
AssertAllPresent ('[] :: [Symbol]) cols = ()

type family IsElem (x :: Symbol) (xs :: [Symbol]) :: Bool where ... Source #

Type-level elem for Symbols

Equations

IsElem x ('[] :: [Symbol]) = 'False
IsElem x (x ': _1) = 'True
IsElem x (_1 ': xs) = IsElem x xs

Maybe-stripping families

type family StripAllMaybe (cols :: [Type]) :: [Type] where ... Source #

Strip Maybe from all columns. Used by filterAllJust.

Column "x" (Maybe Double) becomes Column "x" Double. Column "y" Int stays Column "y" Int.

Equations

StripAllMaybe ('[] :: [Type]) = '[] :: [Type]
StripAllMaybe (Column n (Maybe a) ': rest) = Column n a ': StripAllMaybe rest
StripAllMaybe (Column n a ': rest) = Column n a ': StripAllMaybe rest

type family StripMaybeAt (name :: Symbol) (cols :: [Type]) :: [Type] where ... Source #

Strip Maybe from a single named column. Used by filterJust.

StripMaybeAt "x" '[Column "x" (Maybe Double), Column "y" Int] = '[Column "x" Double, Column "y" Int]

Equations

StripMaybeAt name (Column name (Maybe a) ': rest) = Column name a ': rest
StripMaybeAt name (Column name a ': rest) = Column name a ': rest
StripMaybeAt name (col ': rest) = col ': StripMaybeAt name rest
StripMaybeAt name ('[] :: [Type]) = TypeError (('Text "Column '" ':<>: 'Text name) ':<>: 'Text "' not found in schema") :: [Type]

Join schema families

type family SharedNames (left :: [Type]) (right :: [Type]) :: [Symbol] where ... Source #

Extract column names that appear in both schemas.

Equations

SharedNames ('[] :: [Type]) right = '[] :: [Symbol]
SharedNames (Column n _1 ': rest) right = If (HasName n right) (n ': SharedNames rest right) (SharedNames rest right)

type family UniqueLeft (left :: [Type]) (rightNames :: [Symbol]) :: [Type] where ... Source #

Columns from left whose names do NOT appear in right.

Equations

UniqueLeft ('[] :: [Type]) _1 = '[] :: [Type]
UniqueLeft (Column n a ': rest) rn = If (IsElem n rn) (UniqueLeft rest rn) (Column n a ': UniqueLeft rest rn)

type family InnerJoinSchema (keys :: [Symbol]) (left :: [Type]) (right :: [Type]) :: [Type] where ... Source #

Inner join result schema.

Equations

InnerJoinSchema keys left right = Append (SubsetSchema keys left) (Append (UniqueLeft left (Append keys (ColumnNames right))) (Append (UniqueLeft right (Append keys (ColumnNames left))) (CollidingColumns left right keys)))

type family LeftJoinSchema (keys :: [Symbol]) (left :: [Type]) (right :: [Type]) :: [Type] where ... Source #

Left join result schema.

Equations

LeftJoinSchema keys left right = Append (SubsetSchema keys left) (Append (UniqueLeft left (Append keys (ColumnNames right))) (Append (WrapMaybe (UniqueLeft right (Append keys (ColumnNames left)))) (CollidingColumns left right keys)))

type family RightJoinSchema (keys :: [Symbol]) (left :: [Type]) (right :: [Type]) :: [Type] where ... Source #

Right join result schema.

Equations

RightJoinSchema keys left right = Append (SubsetSchema keys right) (Append (WrapMaybe (UniqueLeft left (Append keys (ColumnNames right)))) (Append (UniqueLeft right (Append keys (ColumnNames left))) (CollidingColumns left right keys)))

type family FullOuterJoinSchema (keys :: [Symbol]) (left :: [Type]) (right :: [Type]) :: [Type] where ... Source #

Full outer join result schema.

Equations

FullOuterJoinSchema keys left right = Append (WrapMaybe (SubsetSchema keys left)) (Append (WrapMaybe (UniqueLeft left (Append keys (ColumnNames right)))) (Append (WrapMaybe (UniqueLeft right (Append keys (ColumnNames left)))) (CollidingColumns left right keys)))

type family WrapMaybe (cols :: [Type]) :: [Type] where ... Source #

Wrap column types in Maybe.

Equations

WrapMaybe ('[] :: [Type]) = '[] :: [Type]
WrapMaybe (Column n a ': rest) = Column n (Maybe a) ': WrapMaybe rest

type family WrapMaybeColumns (names :: [Symbol]) (cols :: [Type]) :: [Type] where ... Source #

Wrap selected columns in Maybe by name list.

Equations

WrapMaybeColumns names ('[] :: [Type]) = '[] :: [Type]
WrapMaybeColumns names (Column n a ': rest) = If (IsElem n names) (Column n (Maybe a) ': WrapMaybeColumns names rest) (Column n a ': WrapMaybeColumns names rest)

type family CollidingColumns (left :: [Type]) (right :: [Type]) (keys :: [Symbol]) :: [Type] where ... Source #

Columns in left whose names collide with right (excluding keys).

Equations

CollidingColumns ('[] :: [Type]) _1 _2 = '[] :: [Type]
CollidingColumns (Column n a ': rest) right keys = If (IsElem n keys) (CollidingColumns rest right keys) (If (HasName n right) (Column n (These a (Lookup n right)) ': CollidingColumns rest right keys) (CollidingColumns rest right keys))

GroupBy helpers

type family GroupKeyColumns (keys :: [Symbol]) (cols :: [Type]) :: [Type] where ... Source #

Extract Column entries from a schema whose names appear in keys.

Equations

GroupKeyColumns keys ('[] :: [Type]) = '[] :: [Type]
GroupKeyColumns keys (Column n a ': rest) = If (IsElem n keys) (Column n a ': GroupKeyColumns keys rest) (GroupKeyColumns keys rest)

KnownSchema class

class KnownSchema (cols :: [Type]) where Source #

Provides runtime evidence of a schema: a list of (name, TypeRep) pairs.

Methods

schemaEvidence :: [(Text, SomeTypeRep)] Source #

Instances

Instances details

KnownSchema ('[] :: [Type]) Source #
Instance details Defined in DataFrame.Typed.Schema Methods schemaEvidence :: [(Text, SomeTypeRep)] Source #
(KnownSymbol name, Typeable a, Columnable a, KnownSchema rest) => KnownSchema (Column name a ': rest) Source #
Instance details Defined in DataFrame.Typed.Schema Methods schemaEvidence :: [(Text, SomeTypeRep)] Source #

Helpers

class AllKnownSymbol (names :: [Symbol]) where Source #

A class that provides a list of Text values for a type-level list of Symbols.

Methods

symbolVals :: [Text] Source #

Instances

Instances details

AllKnownSymbol ('[] :: [Symbol]) Source #
Instance details Defined in DataFrame.Typed.Schema Methods symbolVals :: [Text] Source #
(KnownSymbol n, AllKnownSymbol ns) => AllKnownSymbol (n ': ns) Source #
Instance details Defined in DataFrame.Typed.Schema Methods symbolVals :: [Text] Source #