feat(core/comp): add Suggest::combine method for merging suggestions

2 files changed, 17 insertions, 0 deletions

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 5fe8be1..3130abc 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -140,6 +140,8 @@ None
 
 6. **[`macros:gen_program`]** Added a `pack!(Entry = Vec<String>)` invocation inside the `__this_program_impl` module generated by `gen_program!()`. This creates a `Entry` pack type (aliasing a `Vec<String>` container) directly in the generated module, providing a default entry point type for the program that can be used by `dispatcher!()`-generated types and other chain infrastructure without requiring the user to define a separate entry pack type manually.
 
+7. **[`core`]** **[`comp`]** Added `Suggest::combine(self, other: impl Into<Suggest>) -> Self` method that merges two `Suggest` values. If both are `Suggest::Suggest`, their inner `BTreeSet`s are merged (all items from `other` are added into `self`). Otherwise, the first `Suggest::Suggest` (or `FileCompletion`) is returned unchanged, and the other value is discarded. This enables ergonomic aggregation of completion suggestions from multiple sources.
+
 #### **BREAKING CHANGES** (API CHANGES):
 
 None
diff --git a/mingling_core/src/comp/suggest.rs b/mingling_core/src/comp/suggest.rs
index 99afc54..88fa5fc 100644
--- a/mingling_core/src/comp/suggest.rs
+++ b/mingling_core/src/comp/suggest.rs
@@ -41,6 +41,21 @@ impl Suggest {
     pub fn strip_typed_argument(self, ctx: &ShellContext) -> Self {
         ctx.strip_typed_argument(self)
     }
+
+    /// Combines two `Suggest` values.
+    ///
+    /// If both values are `Suggest::Suggest`, their `BTreeSet`s are merged
+    /// (all items from `other` are added into `self`). Otherwise, the first
+    /// `Suggest::Suggest` (or `FileCompletion`) is returned unchanged.
+    pub fn combine(self, other: impl Into<Suggest>) -> Self {
+        let other = other.into();
+        match (self, other) {
+            (Suggest::Suggest(suggest), Suggest::Suggest(other)) => {
+                Suggest::Suggest(suggest.into_iter().chain(other).collect())
+            }
+            (suggest, _) => suggest,
+        }
+    }
 }
 
 impl<T> From<T> for Suggest