Add default-commands for command-groups (#351)

examples/05_command_framework/src/main.rs

@@ -170,6 +170,8 @@ fn main() {
         .group("Emoji", |g| g
             // Sets a single prefix for a group:
             .prefix("emoji")
+            // Sets a command that will be executed if only a group-prefix was passed.
+            .default_cmd(dog)
             .command("cat", |c| c
                 .desc("Sends an emoji with a cat.")
                 .batch_known_as(vec!["kitty", "neko"]) // Adds multiple aliases

src/framework/standard/command.rs

@@ -104,6 +104,7 @@ pub struct CommandGroup {
     /// A set of checks to be called prior to executing the command-group. The checks
     /// will short-circuit on the first check that returns `false`.
     pub checks: Vec<Check>,
+    pub default_command: Option<CommandOrAlias>,
 }
 
 impl Default for CommandGroup {
@@ -120,6 +121,7 @@ impl Default for CommandGroup {
             allowed_roles: Vec::new(),
             help: None,
             checks: Vec::new(),
+            default_command: None,
         }
     }
 }

src/framework/standard/create_group.rs

@@ -194,4 +194,16 @@ impl CreateGroup {
 
         self
     }
+
+    /// Adds a command for a group that will be executed if no command-name
+    /// has been passed.
+    pub fn default_cmd<C: Command + 'static>(mut self, c: C) -> Self {
+        let cmd: Arc<Command> = Arc::new(c);
+
+        self.0.default_command = Some(CommandOrAlias::Command(Arc::clone(&cmd)));
+
+        cmd.init();
+
+        self
+    }
 }

src/framework/standard/mod.rs

@@ -988,9 +988,9 @@ impl Framework for StandardFramework {
             None => return,
         };
 
-        'outer: for position in positions {
+        'outer: for (index, position) in positions.iter().enumerate() {
             let mut built = String::new();
-            let round = message.content.chars().skip(position).collect::<String>();
+            let round = message.content.chars().skip(*position).collect::<String>();
             let mut round = round.trim().split_whitespace(); // Call to `trim` causes the related bug under the main bug #206 - where the whitespace settings are ignored. The fix is implemented as an additional check inside command::positions
 
             for i in 0..self.configuration.depth {
@@ -1027,15 +1027,18 @@ impl Framework for StandardFramework {
                         // than the last matching one, this prevents picking a wrong prefix,
                         // e.g. "f" instead of "ferris" due to "f" having a lower index in the `Vec`.
                         let longest_matching_prefix_len = prefixes.iter().fold(0, |longest_prefix_len, prefix|
-                            if prefix.len() > longest_prefix_len && built.starts_with(prefix) && command_length > prefix.len() + 1 {
+                            if prefix.len() > longest_prefix_len && built.starts_with(prefix)
+                            && (index + 1 == positions.len() || command_length > prefix.len() + 1) {
                                 prefix.len()
                             } else {
                                 longest_prefix_len
                             }
                         );
 
-                        if longest_matching_prefix_len > 0 {
-                            built[(longest_matching_prefix_len + 1)..].to_string()
+                        if longest_matching_prefix_len == built.len() {
+                            String::new()
+                        } else if longest_matching_prefix_len > 0 {
+                            built[longest_matching_prefix_len + 1..].to_string()
                         } else {
                             continue;
                         }
@@ -1044,7 +1047,7 @@ impl Framework for StandardFramework {
                     };
 
                     let mut args = {
-                        let content = message.content.chars().skip(position).skip_while(|x| x.is_whitespace())
+                        let content = message.content.chars().skip(*position).skip_while(|x| x.is_whitespace())
                             .skip(command_length).collect::<String>();
 
                         Args::new(&content.trim(), &self.configuration.delimiters)
@@ -1053,7 +1056,34 @@ impl Framework for StandardFramework {
                     let before = self.before.clone();
                     let after = self.after.clone();
 
-                    if to_check == "help" {
+                    if to_check.is_empty() {
+
+                        if let Some(CommandOrAlias::Command(ref command)) = &group.default_command {
+                            let command = Arc::clone(command);
+
+                            threadpool.execute(move || {
+                                if let Some(before) = before {
+                                    if !(before)(&mut context, &message, &built) {
+                                        return;
+                                    }
+                                }
+
+                                if !command.before(&mut context, &message) {
+                                    return;
+                                }
+
+                                let result = command.execute(&mut context, &message, args);
+
+                                command.after(&mut context, &message, &result);
+
+                                if let Some(after) = after {
+                                    (after)(&mut context, &message, &built, result);
+                                }
+                            });
+
+                            return;
+                        }
+                    } else if to_check == "help" {
                         let help = self.help.clone();
 
                         if let Some(help) = help {