feat: todo

.gitignore

@@ -0,0 +1,25 @@
+# Various IDEs and Editors
+.vscode/
+.idea/
+**/*~
+
+# Mac OSX temporary files
+.DS_Store
+**/.DS_Store
+
+# dfx temporary files
+.dfx/
+
+# generated files
+**/declarations/
+
+# rust
+target/
+
+# frontend code
+node_modules/
+dist/
+.svelte-kit/
+
+# environment variables
+.env

dfx.json

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+{
+  "canisters": {
+    "motoko_backend": {
+      "main": "src/motoko_backend/main.mo",
+      "type": "motoko"
+    }
+  },
+  "defaults": {
+    "build": {
+      "args": "",
+      "packtool": ""
+    }
+  },
+  "output_env_file": ".env",
+  "version": 1
+}

src/motoko_backend/main.mo

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+import Text "mo:base/Text";
+import Bool "mo:base/Bool";
+import Hash "mo:base/Hash";
+import Nat "mo:base/Nat";
+import Map "mo:base/HashMap";
+import Iter "mo:base/Iter";
+actor Assistant
+    {
+        public query func greet(name : Text) : async Text 
+            {
+                return "Hello, " # name # "!";
+            };
+
+        type ToDo = 
+            {
+                description: Text;
+                completed: Bool;
+            };
+
+
+        func naturalHash(n: Nat) : Hash.Hash
+            {
+                Text.hash(Nat.toText(n))
+            };
+
+        var todos = Map.HashMap<Nat, ToDo>(0, Nat.equal, naturalHash);
+        var nextID: Nat = 0;
+
+        public query func getTodos() : async [ToDo]
+            {
+                Iter.toArray(todos.vals());
+            };
+
+        public query func addTodo(description: Text) : async Nat
+            {
+                let id = nextID;
+                todos.put(id, {description = description; completed = false});
+                nextID += 1;
+                id
+            };
+
+        public func completeToDo(id: Nat): async ()
+            {
+                ignore do ?
+                    {
+                        let description = todos.get(id)!.description;
+                        todos.put(id, {description; completed = true});
+                    };
+            };
+
+        public query func showTodos() : async Text
+            {
+                var output : Text = "\nTO-DO\n";
+                for (todo: ToDo in todos.vals())
+                    {
+                        output #= "\n" # todo.description;
+                        if (todo.completed)
+                            {
+                                output #= "+";
+                            };
+                    };
+                output # "\n"
+            };
+
+        public func clearCompleted() : async ()
+            {
+                todos := Map.mapFilter<Nat, ToDo, ToDo>(todos, Nat.equal, naturalHash, 
+                func(_, todo)
+                    {
+                        if (todo.completed) null else ?todo
+                    });
+            };
+    };