Tiny progress in vkv editor.

SrcMod/Shell/Modules/Valve/VkvModule.cs

@@ -3,5 +3,42 @@
 [Module("vkv")]
 public static class VkvModule
 {
-    
+    [Command("create")]
+    public static void CreateVkv(string path)
+    {
+        if (File.Exists(path)) throw new($"File already exists at \"{path}\". Did you mean to run \"vkv edit\"?");
+
+        VkvNode parentNode = new VkvTreeNode()
+        {
+            { "key", new VkvSingleNode("value") }
+        };
+        string parentNodeName = "tree";
+
+        VkvModifyWhole(ref parentNode, ref parentNodeName);
+    }
+
+    private static void VkvModifyWhole(ref VkvNode node, ref string nodeName)
+    {
+        VkvDisplayNode(node, nodeName);
+    }
+    private static void VkvDisplayNode(in VkvNode? node, in string nodeName, in int indent = 0)
+    {
+        int spaceCount = indent * 4;
+
+        if (node is null) return;
+        else if (node is VkvSingleNode single)
+        {
+            Write(new string(' ', spaceCount) + $"\"{nodeName}\"  \"{single.value}\"");
+        }
+        else if (node is VkvTreeNode tree)
+        {
+            Write(new string(' ', spaceCount) + $"\"{nodeName}\"\n" + new string(' ', spaceCount) + "{");
+            foreach (KeyValuePair<string, VkvNode?> subNode in tree)
+            {
+                VkvDisplayNode(subNode.Value, subNode.Key, indent + 1);
+            }
+            Write(new string(' ', spaceCount) + "}");
+        }
+        else return;
+    }
 }