Frames.Melt

Documentation

type family Elem t ts :: Bool where ...

Equations

Elem t '[] = False

Elem t (t ': ts) = True

Elem t (s ': ts) = Elem t ts

type family Or (a :: Bool) (b :: Bool) :: Bool where ...

Equations

Or True b = True

Or a b = b

type family Not a :: Bool where ...

Equations

Not True = False

Not False = True

type family Disjoint ss ts :: Bool where ...

Equations

Disjoint '[] ts = True

Disjoint (s ': ss) ts = Or (Not (Elem s ts)) (Disjoint ss ts)

type ElemOf ts r = RElem r ts (RIndex r ts)

class RowToColumn ts rs where

Minimal complete definition

rowToColumnAux

Methods

rowToColumnAux :: Proxy ts -> Rec f rs -> [CoRec f ts]

Instances

RowToColumn ts ([] *)

Methods

rowToColumnAux :: Proxy [*] ts -> Rec * f [*] -> [CoRec f ts]

((∈) * r ts, RowToColumn ts rs) => RowToColumn ts ((:) * r rs)

Methods

rowToColumnAux :: Proxy [*] ts -> Rec * f ((* ': r) rs) -> [CoRec f ts]

rowToColumn :: RowToColumn ts ts => Rec f ts -> [CoRec f ts]

Transform a record into a list of its fields, retaining proof that each field is part of the whole.

meltAux :: forall vs ss ts. (vs ⊆ ts, ss ⊆ ts, Disjoint ss ts ~ True, ts ≅ (vs ++ ss), ColumnHeaders vs, RowToColumn vs vs) => Record ts -> [Record (("value" :-> CoRec Identity vs) ': ss)]

type family RDeleteAll ss ts where ...

Equations

RDeleteAll '[] ts = ts

RDeleteAll (s ': ss) ts = RDeleteAll ss (RDelete s ts)

meltRow' :: forall proxy vs ts ss. (vs ⊆ ts, ss ⊆ ts, vs ~ RDeleteAll ss ts, Disjoint ss ts ~ True, ts ≅ (vs ++ ss), ColumnHeaders vs, RowToColumn vs vs) => proxy ss -> Record ts -> [Record (("value" :-> CoRec Identity vs) ': ss)]

This is melt, but the variables are at the front of the record, which reads a bit odd.

retroSnoc :: forall t ts. Record (t ': ts) -> Record (ts ++ '[t])

Turn a cons into a snoc after the fact.

meltRow :: (vs ⊆ ts, ss ⊆ ts, vs ~ RDeleteAll ss ts, Disjoint ss ts ~ True, ts ≅ (vs ++ ss), ColumnHeaders vs, RowToColumn vs vs) => proxy ss -> Record ts -> [Record (ss ++ '["value" :-> CoRec Identity vs])]

Like melt in the reshape2 package for the R language. It stacks multiple columns into a single column over multiple rows. Takes a specification of the id columns that remain unchanged. The remaining columns will be stacked.

Suppose we have a record, r :: Record [Name,Age,Weight]. If we apply melt [pr1|Name|] r, we get two values with type Record [Name, "value" :-> CoRec Identity [Age,Weight]]. The first will contain Age in the value column, and the second will contain Weight in the value column.

class HasLength ts where

Minimal complete definition

hasLength

Methods

hasLength :: proxy ts -> Int

Instances

HasLength k ([] k)

Methods

hasLength :: proxy ts -> Int

HasLength k ts => HasLength k ((:) k t ts)

Methods

hasLength :: proxy ts -> Int

melt :: forall vs ts ss proxy. (vs ⊆ ts, ss ⊆ ts, vs ~ RDeleteAll ss ts, HasLength vs, Disjoint ss ts ~ True, ts ≅ (vs ++ ss), ColumnHeaders vs, RowToColumn vs vs) => proxy ss -> FrameRec ts -> FrameRec (ss ++ '["value" :-> CoRec Identity vs])

Applies meltRow to each row of a FrameRec.