Initial data commit

Task/Validate-International-Securities-Identification-Number/D/validate-international-securities-identification-number.d

@@ -0,0 +1,40 @@
+import std.stdio;
+
+void main() {
+    auto isins = [
+        "US0378331005",
+        "US0373831005",
+        "U50378331005",
+        "US03378331005",
+        "AU0000XVGZA3",
+        "AU0000VXGZA3",
+        "FR0000988040",
+    ];
+    foreach (isin; isins) {
+        writeln(isin, " is ", ISINvalidate(isin) ? "valid" : "not valid");
+    }
+}
+
+bool ISINvalidate(string isin) {
+    import std.array : appender;
+    import std.conv : to;
+    import std.regex : matchFirst;
+    import std.string : strip, toUpper;
+
+    isin = isin.strip.toUpper;
+
+    if (isin.matchFirst(`^[A-Z]{2}[A-Z0-9]{9}\d$`).empty) {
+        return false;
+    }
+
+    auto sb = appender!string;
+    foreach (c; isin[0..12]) {
+        sb.put(
+            [c].to!int(36)
+               .to!string
+        );
+    }
+
+    import luhn;
+    return luhnTest(sb.data);
+}