refactor(meta-command): have execute be a member function

src/main.rs

@@ -1,19 +1,18 @@
 use osdb::branding::startup_msg;
 use osdb::cli::read_input;
 use osdb::command::Command;
-use osdb::meta_commands::MetaCommand;
 
 fn main() {
     startup_msg();
     while let Some(input) = read_input() {
         match input.parse() {
             Ok(cmd) => match cmd {
-                Command::MetaCommand(cmd) => match cmd {
-                    MetaCommand::Exit => {
+                Command::MetaCommand(cmd) => {
+                    if cmd.execute().should_exit {
                         println!("Good-bye");
                         break;
                     }
-                },
+                }
                 Command::Statement(stmt) => stmt.execute(),
             },
             Err(err) => eprintln!("{err}"),

src/meta_commands.rs

@@ -2,6 +2,18 @@ pub enum MetaCommand {
     Exit,
 }
 
+pub struct MetaCommandExecuteResult {
+    pub should_exit: bool,
+}
+
+impl MetaCommand {
+    pub fn execute(&self) -> MetaCommandExecuteResult {
+        match self {
+            MetaCommand::Exit => MetaCommandExecuteResult { should_exit: true },
+        }
+    }
+}
+
 pub enum MetaCommandParseError {
     Unrecognized { cmd: String },
 }