Use const identifer in uuid macro

src/macros.rs

@@ -20,6 +20,13 @@ macro_rules! define_uuid_macro {
                 };
                 OUTPUT
             }};
+            ($uuid:ident) => {{
+                const OUTPUT: $crate::Uuid = match $crate::Uuid::try_parse($uuid) {
+                    $crate::__macro_support::Ok(u) => u,
+                    $crate::__macro_support::Err(_) => panic!("invalid UUID"),
+                };
+                OUTPUT
+            }};
         }
     }
 }
@@ -50,6 +57,12 @@ define_uuid_macro! {
 /// # use uuid::uuid;
 /// let uuid = uuid!("urn:uuid:F9168C5E-CEB2-4faa-B6BF-329BF39FA1E4");
 /// ```
+/// Using a const variable:
+/// ```
+/// # use uuid::uuid;
+/// const UUID_STR: &str = "12345678-1234-5678-1234-567812345678";
+/// let UUID = uuid!(UUID_STR);
+/// ```
 ///
 /// ## Compilation Failures
 ///
@@ -71,22 +84,5 @@ define_uuid_macro! {
 ///     |                              ^
 /// ```
 ///
-/// Tokens that aren't string literals are also rejected:
-///
-/// ```compile_fail
-/// # use uuid::uuid;
-/// let uuid_str: &str = "550e8400e29b41d4a716446655440000";
-/// let uuid = uuid!(uuid_str);
-/// ```
-///
-/// Provides the following compilation error:
-///
-/// ```txt
-/// error: expected string literal
-///   |
-///   |     let uuid = uuid!(uuid_str);
-///   |                      ^^^^^^^^
-/// ```
-///
 /// [uuid::Uuid]: https://docs.rs/uuid/*/uuid/struct.Uuid.html
 }