Spreadsheet: Add a 'choose' function

Base/res/js/Spreadsheet/runtime.js

@@ -128,6 +128,12 @@ function select(criteria, t, f) {
     return f;
 }
 
+function choose(index, ...args) {
+    if (index > args.length) return undefined;
+    if (index < 0) return undefined;
+    return args[index];
+}
+
 function now() {
     return new Date();
 }
@@ -299,6 +305,19 @@ select.__documentation = JSON.stringify({
     },
 });
 
+choose.__documentation = JSON.stringify({
+    name: "choose",
+    argc: 1,
+    argnames: ["index"],
+    doc: "Selects an argument by the given `index`, starting at zero",
+    examples: {
+        "choose(A3, 'Sun', 'Mon', 'Tue', 'Wed', 'Thu', 'Fri', 'Sat')":
+            "Get the day name by the number in A3",
+        "choose(randRange(0, 2), 'Well', 'Hello', 'Friends')":
+            "Randomly pick one of the three words 'well', 'hello' and 'friends'",
+    },
+});
+
 now.__documentation = JSON.stringify({
     name: "now",
     argc: 0,