MrFlick

table.shingle<-function(..., as.data.frame=F) {
	dots<-list(...)
	if(is.logical(as.data.frame) && as.data.frame) {
		as.data.frame <- list(collapse=T)		
	}
	stopifnot(all(sapply(dots, class) %in% c("shingle","factor")))
	stopifnot(length(unique(sapply(dots, length)))==1)
	if(is.list(as.data.frame) && !as.data.frame$collapse) {
		for(i in which(sapply(dots, class)=="shingle")) {
			pts<-unique(sort(unlist(levels(dots[[i]]))))