Hylograph.Internal.Selection.Types

data ElementType

Element types organized by rendering context

This ADT makes the distinction between SVG and HTML elements explicit, allowing the type system to guide proper namespace handling.

Constructors

• Circle
• Rect
• Path
• Line
• Polygon
• Text
• Group
• SVG
• Defs
• LinearGradient
• Stop
• PatternFill
• Div
• Span
• Table
• Tr
• Td
• Th
• Tbody
• Thead

Instances

• Eq ElementType
• Ord ElementType
• Generic ElementType _
• Show ElementType

data JoinResult :: forall k. (Type -> Type -> k -> Type) -> Type -> k -> Typedata JoinResult sel parent datum

Result of a data join operation

The join splits data and elements into three disjoint sets:

• enter: new data that needs elements created
• update: existing elements that should be updated
• exit: old elements that should be removed

Note the type signatures enforce correct usage:

• enter is SPending (needs append)
• update is SBoundOwns (owns data, can be modified)
• exit is SExiting (should be removed) Polymorphic join result that works with any selection type wrapper This allows interpreters to use their own selection types (e.g., D3v2Selection_)

Constructors

• JoinResult { enter :: sel SPending parent datum, exit :: sel SExiting Element datum, update :: sel SBoundOwns Element datum }

data RenderContext

Output context for rendering Determines which namespace to use when creating elements

Constructors

• SVGContext
• HTMLContext

Instances

• Eq RenderContext

  CanvasContext -- Canvas 2D/WebGL rendering AudioContext -- Web Audio API ARContext -- Augmented reality / spatial StringContext -- String-based interpreters (testing, pretty-printing, etc.)

• Ord RenderContext
• Generic RenderContext _
• Show RenderContext

data SBoundInherits

data SBoundOwns

data SEmpty

Phantom types representing selection states

These are uninhabited types used only at the type level to track what operations are legal on a selection.

data SExiting

data SPending

newtype Selection (state :: Type) (parent :: Type) (datum :: Type)

A type-safe D3-style selection

The phantom type parameter state tracks what operations are legal:

• SEmpty selections can receive data via join
• SBoundOwns selections own their data binding, can be updated
• SBoundInherits selections inherit parent's data, can be updated
• SPending selections need elements appended
• SExiting selections should be removed

The parent type parameter tracks the parent element type. The datum type parameter is the data bound to each element.

Examples:

svg :: Selection SEmpty Element Unit
circles :: Selection SBoundOwnsOwns Element Number
labels :: Selection SBoundOwnsInherits Element Number  -- inherits from circles
entering :: Selection SPending SVGElement Number
leaving :: Selection SExiting SVGElement Number

Constructors

• Selection (SelectionImpl parent datum)

Instances

• Functor (Selection state parent)

  Functor instance for Selection

  Allows transforming the bound data without touching the DOM. This is pure - no effects, just data transformation.

  Examples:

  -- Transform numeric data
  doubled :: Selection SBoundOwnsOwns Element Int
  doubled = map (_ * 2) numbers
  
  -- Extract fields from records
  ages :: Selection SBoundOwnsOwns Element Int
  ages = map _.age people
  

data SelectionImpl :: forall k. k -> Type -> Typedata SelectionImpl parent datum

Internal implementation of selections (not exported to users)

This ADT ensures that each state has exactly the data it needs:

• EmptySelection: parent elements to bind data to
• BoundSelection: elements with their bound data
• PendingSelection: data waiting for elements
• ExitingSelection: elements to be removed

Constructors

• EmptySelection { document :: Document, parentElements :: Array Element }
• BoundSelection { data :: Array datum, document :: Document, elements :: Array Element, indices :: Maybe (Array Int) }
• PendingSelection { document :: Document, indices :: Maybe (Array Int), parentElements :: Array Element, pendingData :: Array datum }
• ExitingSelection { data :: Array datum, document :: Document, elements :: Array Element }

elementContext :: ElementType -> RenderContext

Determine which rendering context an element belongs to

mkBoundSelection :: forall parent datum. Array Element -> Array datum -> Maybe (Array Int) -> Document -> Selection SBoundOwns parent datum

Smart constructor for creating bound selections

Used internally to create selections with data bound to elements.