LibLine: Allow suggestions to have trailing trivia strings

These strings would be applied when inserted into the buffer, but are
not shown as part of the suggestion.

This commit also patches up Userland/js and Shell to use this
functionality

2 files changed, 44 insertions, 17 deletions

diff --git a/Libraries/LibLine/Editor.cpp b/Libraries/LibLine/Editor.cpp
index 3958bec31d..071678d03f 100644
--- a/Libraries/LibLine/Editor.cpp
+++ b/Libraries/LibLine/Editor.cpp
@@ -299,17 +299,17 @@ String Editor::get_line(const String& prompt)
                         m_suggestions = on_tab_complete_other_token(token);
                     size_t common_suggestion_prefix { 0 };
                     if (m_suggestions.size() == 1) {
-                        m_largest_common_suggestion_prefix_length = m_suggestions[0].length();
+                        m_largest_common_suggestion_prefix_length = m_suggestions[0].text.length();
                     } else if (m_suggestions.size()) {
                         char last_valid_suggestion_char;
                         for (;; ++common_suggestion_prefix) {
-                            if (m_suggestions[0].length() <= common_suggestion_prefix)
+                            if (m_suggestions[0].text.length() <= common_suggestion_prefix)
                                 goto no_more_commons;
 
-                            last_valid_suggestion_char = m_suggestions[0][common_suggestion_prefix];
+                            last_valid_suggestion_char = m_suggestions[0].text[common_suggestion_prefix];
 
                             for (const auto& suggestion : m_suggestions) {
-                                if (suggestion.length() < common_suggestion_prefix || suggestion[common_suggestion_prefix] != last_valid_suggestion_char) {
+                                if (suggestion.text.length() < common_suggestion_prefix || suggestion.text[common_suggestion_prefix] != last_valid_suggestion_char) {
                                     goto no_more_commons;
                                 }
                             }
@@ -341,7 +341,7 @@ String Editor::get_line(const String& prompt)
                 auto current_suggestion_index = m_next_suggestion_index;
                 if (m_next_suggestion_index < m_suggestions.size()) {
                     auto can_complete = m_next_suggestion_invariant_offset < m_largest_common_suggestion_prefix_length;
-                    if (!m_last_shown_suggestion.is_null()) {
+                    if (!m_last_shown_suggestion.text.is_null()) {
                         size_t actual_offset;
                         size_t shown_length = m_last_shown_suggestion_display_length;
                         switch (m_times_tab_pressed) {
@@ -367,17 +367,20 @@ String Editor::get_line(const String& prompt)
                         m_refresh_needed = true;
                     }
                     m_last_shown_suggestion = m_suggestions[m_next_suggestion_index];
-                    m_last_shown_suggestion_display_length = m_last_shown_suggestion.length();
+                    m_last_shown_suggestion_display_length = m_last_shown_suggestion.text.length();
                     m_last_shown_suggestion_was_complete = true;
                     if (m_times_tab_pressed == 1) {
                         // This is the first time, so only auto-complete *if possible*
                         if (can_complete) {
-                            insert(m_last_shown_suggestion.substring_view(m_next_suggestion_invariant_offset, m_largest_common_suggestion_prefix_length - m_next_suggestion_invariant_offset));
+                            insert(m_last_shown_suggestion.text.substring_view(m_next_suggestion_invariant_offset, m_largest_common_suggestion_prefix_length - m_next_suggestion_invariant_offset));
                             m_last_shown_suggestion_display_length = m_largest_common_suggestion_prefix_length;
                             // do not increment the suggestion index, as the first tab should only be a *peek*
                             if (m_suggestions.size() == 1) {
                                 // if there's one suggestion, commit and forget
                                 m_times_tab_pressed = 0;
+                                // add in the trivia of the last selected suggestion
+                                insert(m_last_shown_suggestion.trailing_trivia);
+                                m_last_shown_suggestion_display_length += m_last_shown_suggestion.trailing_trivia.length();
                             }
                         } else {
                             m_last_shown_suggestion_display_length = 0;
@@ -385,7 +388,9 @@ String Editor::get_line(const String& prompt)
                         ++m_times_tab_pressed;
                         m_last_shown_suggestion_was_complete = false;
                     } else {
-                        insert(m_last_shown_suggestion.substring_view(m_next_suggestion_invariant_offset, m_last_shown_suggestion.length() - m_next_suggestion_invariant_offset));
+                        insert(m_last_shown_suggestion.text.substring_view(m_next_suggestion_invariant_offset, m_last_shown_suggestion.text.length() - m_next_suggestion_invariant_offset));
+                        // add in the trivia of the last selected suggestion
+                        insert(m_last_shown_suggestion.trailing_trivia);
                         if (m_tab_direction == TabDirection::Forward)
                             increment_suggestion_index();
                         else
@@ -399,7 +404,7 @@ String Editor::get_line(const String& prompt)
                     size_t longest_suggestion_length = 0;
 
                     for (auto& suggestion : m_suggestions) {
-                        longest_suggestion_length = max(longest_suggestion_length, suggestion.length());
+                        longest_suggestion_length = max(longest_suggestion_length, suggestion.text.length());
                     }
 
                     size_t num_printed = 0;
@@ -423,10 +428,10 @@ String Editor::get_line(const String& prompt)
                     }
                     vt_move_absolute(max_line_count + m_origin_x, 1);
                     for (auto& suggestion : m_suggestions) {
-                        size_t next_column = num_printed + suggestion.length() + longest_suggestion_length + 2;
+                        size_t next_column = num_printed + suggestion.text.length() + longest_suggestion_length + 2;
 
                         if (next_column > m_num_columns) {
-                            auto lines = (suggestion.length() + m_num_columns - 1) / m_num_columns;
+                            auto lines = (suggestion.text.length() + m_num_columns - 1) / m_num_columns;
                             lines_used += lines;
                             putchar('\n');
                             num_printed = 0;
@@ -445,9 +450,9 @@ String Editor::get_line(const String& prompt)
 
                         if (spans_entire_line) {
                             num_printed += m_num_columns;
-                            fprintf(stderr, "%s", suggestion.characters());
+                            fprintf(stderr, "%s", suggestion.text.characters());
                         } else {
-                            num_printed += fprintf(stderr, "%-*s", static_cast<int>(longest_suggestion_length) + 2, suggestion.characters());
+                            num_printed += fprintf(stderr, "%-*s", static_cast<int>(longest_suggestion_length) + 2, suggestion.text.characters());
                         }
 
                         if (m_last_shown_suggestion_was_complete && index == current_suggestion_index) {
diff --git a/Libraries/LibLine/Editor.h b/Libraries/LibLine/Editor.h
index f5085cfcbd..ce7813d31a 100644
--- a/Libraries/LibLine/Editor.h
+++ b/Libraries/LibLine/Editor.h
@@ -53,6 +53,28 @@ struct KeyCallback {
     Function<bool(Editor&)> callback;
 };
 
+struct CompletionSuggestion {
+    // intentionally not explicit (allows suggesting bare strings)
+    CompletionSuggestion(const String& completion)
+        : text(completion)
+        , trailing_trivia("")
+    {
+    }
+    CompletionSuggestion(const StringView& completion, const StringView& trailing_trivia)
+        : text(completion)
+        , trailing_trivia(trailing_trivia)
+    {
+    }
+
+    bool operator==(const CompletionSuggestion& suggestion) const
+    {
+        return suggestion.text == text;
+    }
+
+    String text;
+    String trailing_trivia;
+};
+
 class Editor {
 public:
     Editor();
@@ -79,8 +101,8 @@ public:
 
     void register_character_input_callback(char ch, Function<bool(Editor&)> callback);
 
-    Function<Vector<String>(const String&)> on_tab_complete_first_token;
-    Function<Vector<String>(const String&)> on_tab_complete_other_token;
+    Function<Vector<CompletionSuggestion>(const String&)> on_tab_complete_first_token;
+    Function<Vector<CompletionSuggestion>(const String&)> on_tab_complete_other_token;
     Function<void(Editor&)> on_display_refresh;
 
     // FIXME: we will have to kindly ask our instantiators to set our signal handlers
@@ -195,8 +217,8 @@ private:
     size_t m_origin_y { 0 };
 
     String m_new_prompt;
-    Vector<String> m_suggestions;
-    String m_last_shown_suggestion { String::empty() };
+    Vector<CompletionSuggestion> m_suggestions;
+    CompletionSuggestion m_last_shown_suggestion { String::empty() };
     size_t m_last_shown_suggestion_display_length { 0 };
     bool m_last_shown_suggestion_was_complete { false };
     size_t m_next_suggestion_index { 0 };