diff --git a/include/riti.h b/include/riti.h
index a4206ae..ed1ab8e 100644
--- a/include/riti.h
+++ b/include/riti.h
@@ -280,6 +280,13 @@ RitiContext *riti_context_new_with_config(const Config *ptr);
 
 void riti_context_free(RitiContext *ptr);
 
+/*
+ Generates suggestion for `key` press.
+
+ `modifier`: state of modifier keys
+ `selection`: previously selected user selection index if available otherwise `0`.
+ It is used to preserve user's candidate selection if the key is a punctuation character in Phonetic method.
+ */
 Suggestion *riti_get_suggestion_for_key(RitiContext *ptr,
                                         uint16_t key,
                                         uint8_t modifier,
diff --git a/src/ffi.rs b/src/ffi.rs
index 512a345..c338430 100644
--- a/src/ffi.rs
+++ b/src/ffi.rs
@@ -32,6 +32,11 @@ pub extern "C" fn riti_context_free(ptr: *mut RitiContext) {
     riti_free(ptr)
 }
 
+/// Generates suggestion for `key` press.
+/// 
+/// `modifier`: state of modifier keys
+/// `selection`: previously selected user selection index if available otherwise `0`.
+/// It is used to preserve user's candidate selection if the key is a punctuation character in Phonetic method.
 #[no_mangle]
 pub extern "C" fn riti_get_suggestion_for_key(
     ptr: *mut RitiContext,
diff --git a/src/phonetic/method.rs b/src/phonetic/method.rs
index 0ac698d..2a6ecb8 100644
--- a/src/phonetic/method.rs
+++ b/src/phonetic/method.rs
@@ -89,14 +89,10 @@ impl Method for PhoneticMethod {
         let mut suggestion = self.create_suggestion(data, config);
 
         // Preserve user's selection if the keypress was a punctuation mark
-        match suggestion {
-            Suggestion::Full { selection: ref mut sel, .. } => {
-                if matches!(character, '.' | '?' | '!' | ',' | ':' | ';' | '-' | '_' | ')' | '}' | ']' | '\'' | '"') {
-                    *sel = selection.into();
-                }
+        if let Suggestion::Full { selection: ref mut sel, .. } = suggestion {
+            if matches!(character, '.' | '?' | '!' | ',' | ':' | ';' | '-' | '_' | ')' | '}' | ']' | '\'' | '"') {
+                *sel = selection.into();
             }
-
-            _ => (),
         }
 
         suggestion