fix: [And-Or] fixed And and Or operation for const (#34)

Author: jiekun

binary_op.go

@@ -191,9 +191,9 @@ func binaryOpEvalNumber(op string, left, right float64, isBool bool) float64 {
 		case "^":
 			left = binaryop.Pow(left, right)
 		case "and":
-			// Nothing to do
+			left = binaryop.And(left, right)
 		case "or":
-			// Nothing to do
+			left = binaryop.Or(left, right)
 		case "unless":
 			left = nan
 		case "default":

binaryop/funcs.go

@@ -107,3 +107,21 @@ func Ifnot(left, right float64) float64 {
 	}
 	return nan
 }
+
+// And return left if left and right is not NaN. Otherwise, NaN is returned.
+func And(left, right float64) float64 {
+	if math.IsNaN(left) || math.IsNaN(right) {
+		return nan
+	}
+	return left
+}
+
+// Or return the first non-NaN item. If both left and right are NaN, it returns NaN.
+func Or(left, right float64) float64 {
+	if !math.IsNaN(left) {
+		return left
+	} else if !math.IsNaN(right) {
+		return right
+	}
+	return nan
+}

parser_test.go

@@ -251,7 +251,16 @@ func TestParseSuccess(t *testing.T) {
 	another(`m + ON (Foo) n[5m]`, `m + on(Foo) n[5m]`)
 	same(`m + ignoring(a,b) n[5m]`)
 	another(`1 or 2`, `1`)
+	another(`1 or NaN`, `1`)
+	another(`NaN or 1`, `1`)
+	another(`(1 > 0) or 2`, `1`)
+	another(`(1 < 0) or 2`, `2`)
+	another(`(1 < 0) or (2 < 0)`, `NaN`)
+	another(`NaN or NaN`, `NaN`)
 	another(`1 and 2`, `1`)
+	another(`1 and (1 > 0)`, `1`)
+	another(`1 and (1 < 0)`, `NaN`)
+	another(`1 and NaN`, `NaN`)
 	another(`1 unless 2`, `NaN`)
 	another(`1 default 2`, `1`)
 	another(`1 default NaN`, `1`)