FIX: finer decimal equiv? comparison than equal?

resolves: Oldes/Rebol-issues#1134

Author: Oldes

src/core/t-decimal.c

@@ -178,8 +178,8 @@ REBOOL almost_equal(REBDEC a, REBDEC b, REBCNT max_diff) {
 ***********************************************************************/
 {
 	if (mode >= 0) {
-		if (mode <= 1) return almost_equal(VAL_DECIMAL(a), VAL_DECIMAL(b), 21); //O: there was 10, but 21 is the minimum to have: (100% // 3% = 1%) == true
-		if (mode == 2) return almost_equal(VAL_DECIMAL(a), VAL_DECIMAL(b), 0);
+		if (mode == 0) return almost_equal(VAL_DECIMAL(a), VAL_DECIMAL(b), 21); //O: there was 10, but 21 is the minimum to have: (100% // 3% = 1%) == true
+		if (mode == 1) return almost_equal(VAL_DECIMAL(a), VAL_DECIMAL(b), 0);
 		return VAL_INT64(a) == VAL_INT64(b); // bits are identical
 	}
 	if (mode == -1) return VAL_DECIMAL(a) >= VAL_DECIMAL(b);

src/tests/units/compare-test.r3

@@ -111,6 +111,15 @@ Rebol [
 	--test-- "decimal! invalid compare"
 		--assert all [error? e: try [90.0 < "a" ] e/id = 'invalid-compare]
 		--assert all [error? e: try [90.0 < 1x1 ] e/id = 'invalid-compare]
+
+	--test-- "decimal! equal?/equiv?/same?"
+		;@@ https://github.com/Oldes/Rebol-issues/issues/1134
+		--assert     equal? to decimal! #{3FD3333333333333} to decimal! #{3FD3333333333333}
+		--assert     equiv? to decimal! #{3FD3333333333333} to decimal! #{3FD3333333333333}
+		--assert      same? to decimal! #{3FD3333333333333} to decimal! #{3FD3333333333333}
+		--assert     equal? to decimal! #{3FD3333333333333} to decimal! #{3FD3333333333334}
+		--assert not equiv? to decimal! #{3FD3333333333333} to decimal! #{3FD3333333333334}
+		--assert not  same? to decimal! #{3FD3333333333333} to decimal! #{3FD3333333333334}
 ===end-group===