2 files changed, 74 insertions, 2 deletions

diff --git a/mingling_core/src/comp/shell_ctx.rs b/mingling_core/src/comp/shell_ctx.rs
index 8efbc9d..734b5d2 100644
--- a/mingling_core/src/comp/shell_ctx.rs
+++ b/mingling_core/src/comp/shell_ctx.rs
@@ -50,8 +50,14 @@ impl TryFrom<Vec<String>> for ShellContext {
         let word_index = special_argument!(args, "-i")
             .and_then(|s| s.parse().ok())
             .unwrap_or_default();
-        let shell_flag = special_argument!(args, "-F")
-            .map_or(ShellFlag::Other("unknown".to_string()), ShellFlag::from);
+        // Distinguish "-F absent" (unknown shell) from "-F present without a value" (empty shell)
+        let has_shell_flag = args.iter().any(|arg| arg == "-F");
+        let shell_flag = if has_shell_flag {
+            special_argument!(args, "-F")
+                .map_or_else(|| ShellFlag::Other(String::new()), ShellFlag::from)
+        } else {
+            ShellFlag::Other("unknown".to_string())
+        };
 
         let all_words = command_line
             .split_whitespace()
diff --git a/mingling_core/src/comp/suggest.rs b/mingling_core/src/comp/suggest.rs
index dda5026..804d622 100644
--- a/mingling_core/src/comp/suggest.rs
+++ b/mingling_core/src/comp/suggest.rs
@@ -92,6 +92,72 @@ impl Suggest {
             self.insert(SuggestItem::WithDescription(item, desc_str.clone()));
         }
     }
+
+    /// Adds a prefix to every suggestion in the `Suggest` set.
+    ///
+    /// This method takes the current `Suggest` value and prepends the given
+    /// prefix to the suggestion text of each item. If the `Suggest` value is
+    /// [`Suggest::FileCompletion`], it is returned unchanged.
+    ///
+    /// # Arguments
+    ///
+    /// * `prefix` — The string to prepend to each suggestion. Must implement
+    ///   `Into<String>`.
+    ///
+    /// # Returns
+    ///
+    /// A new `Suggest` value where each item's suggestion text is prefixed
+    /// with the given string. For example, `["foo", "bar"]` with prefix `"--"`
+    /// becomes `["--foo", "--bar"]`.
+    pub fn add_prefix(self, prefix: impl Into<String>) -> Suggest {
+        let suggest = match self {
+            Suggest::Suggest(s) => s,
+            Suggest::FileCompletion => return Suggest::FileCompletion,
+        };
+        let prefix = prefix.into();
+        let prefixed = suggest
+            .into_iter()
+            .map(|item| {
+                let mut new_item = item;
+                new_item.set_suggest(format!("{}{}", prefix, new_item.suggest()));
+                new_item
+            })
+            .collect();
+        Suggest::Suggest(prefixed)
+    }
+
+    /// Appends a suffix to every suggestion in the `Suggest` set.
+    ///
+    /// This method takes the current `Suggest` value and appends the given
+    /// suffix to the suggestion text of each item. If the `Suggest` value is
+    /// [`Suggest::FileCompletion`], it is returned unchanged.
+    ///
+    /// # Arguments
+    ///
+    /// * `suffix` — The string to append to each suggestion. Must implement
+    ///   `Into<String>`.
+    ///
+    /// # Returns
+    ///
+    /// A new `Suggest` value where each item's suggestion text is suffixed
+    /// with the given string. For example, `["foo", "bar"]` with suffix `"="`
+    /// becomes `["foo=", "bar="]`.
+    pub fn add_suffix(self, suffix: impl Into<String>) -> Suggest {
+        let suggest = match self {
+            Suggest::Suggest(s) => s,
+            Suggest::FileCompletion => return Suggest::FileCompletion,
+        };
+        let suffix = suffix.into();
+        let suffixed = suggest
+            .into_iter()
+            .map(|item| {
+                let mut new_item = item;
+                new_item.set_suggest(format!("{}{}", new_item.suggest(), suffix));
+                new_item
+            })
+            .collect();
+        Suggest::Suggest(suffixed)
+    }
 }
 
 impl<T> From<T> for Suggest