Add lower limit argument to device_random (#990)

* Add lower limit argument to device_random

* Better checking

editor/extension.ts

@@ -593,6 +593,29 @@ namespace pxt.editor {
                     }
                 }
             })
+
+
+        // device_random now refers to randomRange() so we need to add the missing lower bound argument
+        U.toArray(dom.querySelectorAll("block[type=device_random]"))
+            .forEach(node => {
+                for (let i = 0; i < node.children.length; i++) {
+                    const child = node.children.item(i);
+                    if (child.tagName === "value" && child.getAttribute("name") === "min") {
+                        return;
+                    }
+                }
+                const v = node.ownerDocument.createElement("value");
+                const s = node.ownerDocument.createElement("shadow");
+                const f = node.ownerDocument.createElement("field");
+
+                v.setAttribute("name", "min");
+                v.appendChild(s);
+                s.setAttribute("type", "math_number");
+                s.appendChild(f);
+                f.setAttribute("name", "NUM");
+                f.textContent = "0";
+                node.appendChild(v);
+            });
     }
 
     initExtensionsAsync = function (opts: pxt.editor.ExtensionOptions): Promise<pxt.editor.ExtensionResult> {