Generalise mention parsing

Fixes #396

2 files changed, 26 insertions, 1 deletions

diff --git a/src/model/misc.rs b/src/model/misc.rs
index ff0f3de..9c09a9b 100644
--- a/src/model/misc.rs
+++ b/src/model/misc.rs
@@ -156,7 +156,7 @@ macro_rules! impl_from_str {
                 type Err = $err;
 
                 fn from_str(s: &str) -> StdResult<Self, Self::Err> {
-                    Ok(match utils::parse_username(s) {
+                    Ok(match utils::parse_mention(s) {
                         Some(id) => $id(id),
                         None => s.parse::<u64>().map($id).map_err(|_| $err::InvalidFormat)?,
                     })
diff --git a/src/utils/mod.rs b/src/utils/mod.rs
index 347e19a..2d1df4a 100644
--- a/src/utils/mod.rs
+++ b/src/utils/mod.rs
@@ -261,6 +261,31 @@ pub fn parse_channel(mention: &str) -> Option<u64> {
     }
 }
 
+/// Retrieve the ID number out of a channel, role, or user mention.
+///
+/// If the mention is invalid, `None` is returned.
+///
+/// # Examples
+///
+/// ```rust
+/// use serenity::utils::parse_mention;
+///
+/// assert_eq!(parse_mention("<@136510335967297536>"), Some(136510335967297536));
+/// assert_eq!(parse_mention("<@&137235212097683456>"), Some(137235212097683456));
+/// assert_eq!(parse_mention("<#137234234728251392>"), Some(137234234728251392));
+/// ```
+pub fn parse_mention(mention: &str) -> Option<u64> {
+    if mention.starts_with("<@&") {
+        parse_role(mention)
+    } else if mention.starts_with("<@") || mention.starts_with("<@!") {
+        parse_username(mention)
+    } else if mention.starts_with("<#") {
+        parse_channel(mention)
+    } else {
+        None
+    }
+}
+
 /// Retrieves the name and Id from an emoji mention, in the form of an
 /// `EmojiIdentifier`.
 ///