Category talk:Wren-check: Difference between revisions

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@@ Line 104: / Line 104: @@
     static posInt(name, value)        { int(name, value, 1) }
     static nonNegInt(name, value)     { int(name, value, 0) }
-    static safeInt(name, value)       { int(name, value, Num.minSafeInteger, Num.maxSafeInteger) }
+    static safeInt(name, value)       { int(name, value, "a 'safe' integer") }
-    static posSafeInt(name, value)    { int(name, value, 1, Num.maxSafeInteger) }
+    static posSafeInt(name, value)    { int(name, value, "a positive 'safe' integer" }
-    static nonNegSafeInt(name, value) { int(name, value, 0, Num.maxSafeInteger) }
+    static nonNegSafeInt(name, value) { int(name, value, "a non-negative 'safe' integer" }
     static nonZeroSafeInt(name, value) {
@@ Line 297: / Line 297: @@
     static ok(condition) { ok(condition, "Condition is not met.") }
+}
+/*
+   SafeInt is a class containing self-explanatory static methods to check
+   integer arithmetic is 'safe' i.e. within the ± 2^53 limit.
+*/
+class SafeInt {
+    static add(i, j) {
+        Check.safeInt("Argument", i)
+        Check.safeInt("Argument", j)
+        var res = i + j
+        Check.safeInt("Result", res)
+        return res
+    }
+    static sub(i, j) {
+        Check.safeInt("Argument", i)
+        Check.safeInt("Argument", j)
+        var res = i - j
+        Check.safeInt("Result", res)
+        return res
+    }
+    static mul(i, j) {
+        Check.safeInt("Argument", i)
+        Check.safeInt("Argument", j)
+        var res = i * j
+        Check.safeInt("Result", res)
+        return res
+    }
+    static pow(i, j) {
+        Check.safeInt("Argument", i)
+        Check.safeInt("Argument", j)
+        var res = i.pow(j)
+        Check.safeInt("Result", res)
+        return res
+    }
+}
+/* SafeInts checks the safety of arithmetic operations for a list of integers. */
+class SafeInts {
+    static sum(a)  { a.reduce(0) { |acc, x| SafeInt.add(acc, x) } }
+    static prod(a) { a.reduce(1) { |acc, x| SafeInt.mul(acc, x) } }
 }