tasks a-s

Task/Safe-addition/E/safe-addition-1.e

@@ -0,0 +1,17 @@
+def makeInterval(a :float64, b :float64) {
+    require(a <= b)
+    def interval {
+        to least() { return a }
+        to greatest() { return b }
+        to __printOn(out) {
+            out.print("[", a, ", ", b, "]")
+        }
+        to add(other) {
+            require(a <=> b)
+            require(other.least() <=> other.greatest())
+            def result := a + other.least()
+            return makeInterval(result.previous(), result.next())
+        }
+    }
+    return interval
+}

Task/Safe-addition/E/safe-addition-2.e

@@ -0,0 +1,2 @@
+? makeInterval(1.14, 1.14) + makeInterval(2000.0, 2000.0)
+# value: [2001.1399999999999, 2001.1400000000003]