rbbt.require('ggplot2')

geom_entity <- function (real.geom = NULL, mapping = NULL, data = NULL, stat = "identity",
                          position = "identity", ...) {
    rg <- real.geom(mapping = mapping, data = data, stat = stat, 
                    position = position, ...)

    rg$geom <- proto(rg$geom, { 
        draw <- function(., data, ...) {
            grobs <- list()

            for (i in 1:nrow(data)) {
                grob <- .super$draw(., data[i,], ...) 
                if (is.null(data$entity.type)) 
                    grobs[[i]] <- garnishGrob(grob, `data-entity`=data[i,]$entity)
                else
                    grobs[[i]] <- garnishGrob(grob, `data-entity`=data[i,]$entity, `data-entity-type`=data[i,]$entity.type)
            }

            ggplot2:::ggname("geom_entity", gTree(children = do.call("gList", grobs)))
        }

        draw_groups <- function(., data, ...) {
            grobs <- list()

            for (i in 1:nrow(data)) {
                grob <- .super$draw_groups(., data[i,], ...) 
                if (is.null(data$entity.type)) 
                    grobs[[i]] <- garnishGrob(grob, `data-entity`=data[i,]$entity)
                else
                    grobs[[i]] <- garnishGrob(grob, `data-entity`=data[i,]$entity, `data-entity-type`=data[i,]$entity.type)
            }

            ggplot2:::ggname("geom_entity", gTree(children = do.call("gList", grobs)))
        }
    })

    rg
}