Hylograph.Internal.Attribute

data Attribute datum

Type-safe attribute with datum phantom type

Attributes can be:

• Static: Same value for all elements
• Data-driven: Value computed from datum (with source metadata)
• Indexed: Value computed from datum and index (with source metadata)

The phantom type datum ensures attributes are only applied to selections with matching data types.

The AttrSource field enables interpreters to inspect attribute origins without evaluating the functions.

Constructors

• StaticAttr AttributeName AttributeValue
• DataAttr AttributeName AttrSource (datum -> AttributeValue)
• IndexedAttr AttributeName AttrSource (datum -> Int -> AttributeValue)
• AnimatedAttr { config :: AnimationConfig, fromValue :: Maybe (AnimatedValue datum), name :: AttributeName, toValue :: AnimatedValue datum }
• AnimatedCompound { config :: AnimationConfig, fromValues :: Array (AnimatedValue datum), generator :: Array Number -> String, name :: AttributeName, toValues :: Array (AnimatedValue datum) }

  Animated compound attribute for paths and other generated strings

  Animates multiple numeric values and calls a generator function to produce the final string value. Used for:

  • linkVertical (4 numbers → path string)
  • sankeyLink (6 numbers → path string)
  • arc (4 numbers → arc path)

  The generator receives interpolated values in the same order as fromValues/toValues.

Instances

• Show (Attribute datum)
• Contravariant Attribute

  Contravariant instance for Attribute

  Attributes consume data (they're data sinks), making them naturally contravariant. This enables attribute reuse via cmap:

  -- Define attribute for specific type
  radiusAttr :: Attribute Number
  radiusAttr = DataAttr (AttributeName "r") NumberValue
  
  -- Adapt to work with richer type
  type Circle = { radius :: Number, x :: Number, y :: Number }
  circleRadiusAttr :: Attribute Circle
  circleRadiusAttr = cmap _.radius radiusAttr
  

  The key insight: cmap composes the projection function with the attribute's data accessor, allowing attributes written for simple types to work with complex types via field selection.

newtype AttributeName

Attribute names (SVG/HTML properties)

We use a newtype to prevent typos and enable IDE autocomplete. The String inside is the actual DOM attribute name.

Constructors

• AttributeName String

Instances

• Eq AttributeName
• Ord AttributeName
• Show AttributeName

data AttributeValue

Attribute values

We support the most common value types. The ADT ensures type safety when setting attributes.

Constructors

• StringValue String
• NumberValue Number
• BooleanValue Boolean

Instances

• Eq AttributeValue
• Ord AttributeValue
• Show AttributeValue

data AttrSource

Source metadata for attributes

Describes where the attribute value comes from, enabling interpreters like MetaAST to show meaningful information about attribute bindings.

This is automatically captured when using the DSL (field, num, etc.) but is UnknownSource for raw PureScript functions (escape hatches).

Constructors

• UnknownSource
• StaticSource String
• FieldSource String
• ExprSource String
• IndexSource
• OpaqueSource

Instances

• Eq AttrSource
• Ord AttrSource
• Show AttrSource

data AnimatedValue datum

Animated value specification

Describes where the animation value comes from:

• StaticAnimValue: Constant number
• DataAnimValue: Computed from datum
• IndexedAnimValue: Computed from datum and element index

Constructors

• StaticAnimValue Number
• DataAnimValue (datum -> Number)
• IndexedAnimValue (datum -> Int -> Number)

Instances

• Show (AnimatedValue datum)

type AnimationConfig = { delay :: Milliseconds, duration :: Milliseconds, easing :: EasingType }

Configuration for a single animated attribute

Specifies timing, easing, and delay for the animation.

data EasingType

Enumeration of easing types for animations

Note: This mirrors Hylograph.Transition.Easing.EasingType but is defined here to avoid circular dependencies. The Manager module will convert between them.

Constructors

• Linear
• QuadIn
• QuadOut
• QuadInOut
• CubicIn
• CubicOut
• CubicInOut
• SinIn
• SinOut
• SinInOut
• ExpIn
• ExpOut
• ExpInOut
• CircleIn
• CircleOut
• CircleInOut
• BackIn
• BackOut
• BackInOut
• ElasticIn
• ElasticOut
• ElasticInOut
• BounceIn
• BounceOut
• BounceInOut

Instances

• Eq EasingType
• Ord EasingType
• Show EasingType

type Milliseconds = Number

Time in milliseconds for animation configuration

defaultAnimationConfig :: AnimationConfig

Default animation configuration: 300ms, QuadOut, no delay