Add format_bulleted_list_multiline (#26)

For #21

src/format_bulleted_list.rs

@@ -12,3 +12,82 @@ pub fn format_bulleted_list(items: impl IntoIterator<Item = impl Display>) -> St
         format!("• {}", items.join("\n• "))
     }
 }
+
+/// Like [`format_bulleted_list`], except the second and subsequent lines of multi-line items are
+/// indented as well.
+pub fn format_bulleted_list_multiline(items: impl IntoIterator<Item = impl Display>) -> String {
+    format_bulleted_list(items.into_iter().map(|item| {
+        let item = item.to_string();
+        let mut lines = item.lines().peekable();
+        match lines.next() {
+            None => {
+                // ???
+                String::new()
+            }
+            Some(first) => {
+                if lines.peek().is_none() {
+                    // One line.
+                    item
+                } else {
+                    // Two or more lines.
+                    format!("{first}\n  {}", lines.join("\n  "))
+                }
+            }
+        }
+    }))
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use indoc::indoc;
+    use pretty_assertions::assert_eq;
+
+    #[test]
+    fn test_format_bulleted_list() {
+        assert_eq!(format_bulleted_list(Vec::<String>::new()), "");
+
+        assert_eq!(format_bulleted_list(["puppy"]), "• puppy");
+        assert_eq!(
+            format_bulleted_list(["puppy", "doggy"]),
+            indoc!(
+                "
+                • puppy
+                • doggy"
+            )
+        );
+    }
+
+    #[test]
+    fn test_format_bulleted_list_multiline() {
+        assert_eq!(format_bulleted_list_multiline(Vec::<String>::new()), "");
+
+        assert_eq!(format_bulleted_list_multiline(["puppy"]), "• puppy");
+        assert_eq!(
+            format_bulleted_list_multiline(["puppy", "doggy"]),
+            indoc!(
+                "
+                • puppy
+                • doggy"
+            )
+        );
+
+        assert_eq!(
+            format_bulleted_list_multiline([
+                "puppy\ndoggy",
+                "sammy\ngoldie",
+                &format_bulleted_list_multiline(["ears", "tail", "fetch!"])
+            ]),
+            indoc!(
+                "
+                • puppy
+                  doggy
+                • sammy
+                  goldie
+                • • ears
+                  • tail
+                  • fetch!"
+            )
+        );
+    }
+}

src/lib.rs

@@ -27,6 +27,7 @@ pub use app::App;
 pub use app_git::AppGit;
 pub use config::Config;
 pub use format_bulleted_list::format_bulleted_list;
+pub use format_bulleted_list::format_bulleted_list_multiline;
 pub use git::repository_url_destination;
 pub use git::AddWorktreeOpts;
 pub use git::BranchRef;