From 7c4b1543cdd87eb88dac0d64375c35c36846231b Mon Sep 17 00:00:00 2001
From: edzer <edzer.pebesma@uni-muenster.de>
Date: Tue, 16 Apr 2024 16:30:23 +0200
Subject: [PATCH] add the == and != Ops for sgbp

---
 R/sgbp.R    | 24 +++++++++++++++++-------
 man/sgbp.Rd | 12 ++++++++++++
 2 files changed, 29 insertions(+), 7 deletions(-)

diff --git a/R/sgbp.R b/R/sgbp.R
index 80fbc6dfc..59326c059 100644
--- a/R/sgbp.R
+++ b/R/sgbp.R
@@ -80,17 +80,27 @@ dim.sgbp = function(x) {
 	c(length(x), attr(x, "ncol"))
 }
 
+#' @name sgbp
+#' @param e1 object of class `sgbp`
+#' @param e2 object of class `sgbp`
 #' @export
+#' @details `==` compares only the dimension and index values, not the attributes of two `sgbp` object; use `identical` to check for equality of everything.
 Ops.sgbp = function(e1, e2) {
-	if (.Generic != "!")
-		stop("only ! operator is supported for sgbp objects")
-	nc = 1:attr(e1, "ncol")
-	sgbp(lapply(e1, function(x) setdiff(nc, x)),
-		predicate = paste0("!", attr(e1, "predicate")),
-		region.id = attr(e1, "region.id"),
-		ncol = attr(e1, "ncol"))
+	switch(.Generic, 
+	   "!" = {
+			nc = 1:attr(e1, "ncol")
+			sgbp(lapply(e1, function(x) setdiff(nc, x)),
+				predicate = paste0("!", attr(e1, "predicate")),
+				region.id = attr(e1, "region.id"),
+				ncol = attr(e1, "ncol"))
+	   },
+	   "==" = (length(e1) == length(e2)) && all(mapply(function(x,y) identical(x, y), e1, e2)), 
+	   "!=" = return(!(e1 == e2)),
+		stop("only operators !, == and != are supported for sgbp objects")
+	)
 }
 
+#' @name sgbp
 #' @export
 as.data.frame.sgbp = function(x, ...) {
 	data.frame(row.id = rep(seq_along(x), lengths(x)), col.id = unlist(x))
diff --git a/man/sgbp.Rd b/man/sgbp.Rd
index 9d12e7b41..90a744a54 100644
--- a/man/sgbp.Rd
+++ b/man/sgbp.Rd
@@ -6,6 +6,8 @@
 \alias{t.sgbp}
 \alias{as.matrix.sgbp}
 \alias{dim.sgbp}
+\alias{Ops.sgbp}
+\alias{as.data.frame.sgbp}
 \title{Methods for dealing with sparse geometry binary predicate lists}
 \usage{
 \method{print}{sgbp}(x, ..., n = 10, max_nb = 10)
@@ -15,6 +17,10 @@
 \method{as.matrix}{sgbp}(x, ...)
 
 \method{dim}{sgbp}(x)
+
+\method{Ops}{sgbp}(e1, e2)
+
+\method{as.data.frame}{sgbp}(x, ...)
 }
 \arguments{
 \item{x}{object of class \code{sgbp}}
@@ -24,10 +30,16 @@
 \item{n}{integer; maximum number of items to print}
 
 \item{max_nb}{integer; maximum number of neighbours to print for each item}
+
+\item{e1}{object of class \code{sgbp}}
+
+\item{e2}{object of class \code{sgbp}}
 }
 \description{
 Methods for dealing with sparse geometry binary predicate lists
 }
 \details{
 \code{sgbp} are sparse matrices, stored as a list with integer vectors holding the ordered \code{TRUE} indices of each row. This means that for a dense, \eqn{m \times n}{m x n} matrix \code{Q} and a list \code{L}, if \code{Q[i,j]} is \code{TRUE} then \eqn{j} is an element of \code{L[[i]]}. Reversed: when \eqn{k} is the value of \code{L[[i]][j]}, then \code{Q[i,k]} is \code{TRUE}.
+
+\code{==} compares only the dimension and index values, not the attributes of two \code{sgbp} object; use \code{identical} to check for equality of everything.
 }