task support

spec/datatypes.md

@@ -162,4 +162,18 @@ enum LanguageType {
     LanguageType_CPP,
     LanguageType_C
 };
+```
+
+## TaskConfig
+```c++
+struct TaskConfig {
+    /// Name of the task, can have spaces unlike task_id
+    string task_name;
+
+    /// ID used when invoking the task, ex: ```ninja task:helloworld```
+    string task_id;
+
+    /// Shell script to be executed when this task is called
+    string shell_script;
+};
 ```