chartspec

type Change struct {
	// Path locates the change from the root, dotted, with list positions in brackets:
	// "columns.args[0].agg" or "filter.members[1]". A root field has no prefix.
	Path string

	// Before is the node hash on the old side: for a changed field, the node that owns
	// it; for an added, removed or re-kinded child, the child itself (zero if absent).
	Before Hash

	// After is the node hash on the new side, with the same meaning as Before.
	After Hash
}

type Hash [32]byte

type Node struct {
	// Fields are the node's scalar members: strings, bools, numbers (json.Number or
	// float64) and, for an in/not_in operand, a []any of those. A nil value, typed nils
	// such as a nil slice included, is absent; Encode leaves out a struct member at its
	// zero value.
	Fields map[string]any

	// Children references each singular child node by hash.
	Children map[string]Hash

	// Lists references each repeated child, in order, by hash.
	Lists map[string][]Hash

	// Kind names the struct the node encodes (for example chart_spec or filter_clause).
	Kind string
}

type NodeGetter func(Hash) (Node, bool)

type PaneKey struct {
	// Row is the row tuple's field keys, comma-joined.
	Row string
	// Column is the column tuple's field keys, comma-joined.
	Column string
}

type Partial struct {
	// Sketch is the quantile sketch (nil while empty).
	Sketch *ddsketch.DDSketch
	// Sum is the sum of the observations.
	Sum float64
	// Count is the number of observations.
	Count float64
	// Min is the smallest observation (meaningless while Count is 0).
	Min float64
	// Max is the largest observation (meaningless while Count is 0).
	Max float64
}

type Plan struct {
	// Marks is the mark drawn in each pane.
	Marks map[PaneKey]types.Mark
	// Panes are the pane keys, rows outer, columns inner.
	Panes []PaneKey
	// Query is the store query answering every pane.
	Query types.AggregateQuery
}

type Tree struct {
	// Nodes holds every node of the tree by hash.
	Nodes map[Hash]Node

	// Root is the hash of the chart_spec node.
	Root Hash
}

type Tuple struct {
	// Fields are the field references of the header path, outermost first.
	Fields []types.FieldRef
	// Nested marks a tuple produced (at any level) by the nest operator.
	Nested bool
}