add examples

src/patch/mod.rs

@@ -570,6 +570,26 @@ fn make_cpu(cmod: &Hash) -> Result<CpuBuilder> {
 }
 
 /// Find left and right indices of enumeration token in specification string
+///
+/// # Panics
+///
+/// Panics if the expression contains no or more than one token.
+///
+/// # Examples
+///
+/// ```
+/// let cases = [
+///     ("RELOAD?", (6, 0)),
+///     ("TMR[1-57]_MUX", (3, 4)),
+///     ("DT[1-3]?", (2, 0)),
+///     ("GPIO[ABCDE]", (4, 0)),
+///     ("CSPT[1][7-9],CSPT[2][0-5]", (4, 0)),
+/// ];
+/// for (spec, (li, ri)) in cases {
+///     assert_eq!(patch::spec_ind(spec), (li, ri));
+/// }
+/// ```
+///
 fn spec_ind(spec: &str) -> (usize, usize) {
     let spec = spec.split(',').next().unwrap_or(spec);
     let re =