An attribute node is a declared expression representing a labeled unit of data, with optional states.

LAttributeNode is the parsed declaration whereas LAttribute is the live runtime object. Since a single declaration can name several targets, one node can produce several live attributes.

Title: "Status"                             // declaration = {
                                            //     item = {{"Title"}} }
                                            // expression -> value -> string = "Status"

Window/(Left,Right) Pane/Corner Radius: 5   // Declares two attributes;
                                            // declaration = {
                                            //     traversal = {
                                            //         {{"Window"}},
                                            //         {{"Left","Right"}, {"Pane"}} }
                                            //     item = {{"Corner"}, {"Radius"}} }
                                            // expression -> value -> number = 5

Fill: Theme/Primary                         // declaration = {
                                            //     item = {{"Fill"}} }
                                            // expression -> reference = {
                                            //     traversal = {"Theme"}
                                            //     item = "Primary" }

Text Color: #111                            // declaration = {
    @Alert: Red                             //     item = {{"Text"}, {"Color"}} }
    @Success: Green                         // expression -> value -> color = #ff111111
                                            // states = {
                                            //     { conditions = {"Alert"}
                                            //       expression -> reference = {
                                            //           item = "Red"} },
                                            //     { conditions = {"Success"}
                                            //       expression -> reference = {
                                            //           item = "Green"} }  }

// Same as above; states can go inline after the main expression or on
// separate lines in an indented block underneath.
Text Color: #111 @Alert: Red @Success: Green