ArrayView content is not const anymore

As in upcoming std c++ array_view, ArrayView<T> points to mutable
data, use ArrayView<const T> or alias ConstArrayView<T> for const
data.

src/array_view.hh

@@ -3,6 +3,7 @@
 
 #include <vector>
 #include <initializer_list>
+#include <type_traits>
 
 namespace Kakoune
 {
@@ -18,42 +19,42 @@ public:
     constexpr ArrayView()
         : m_pointer(nullptr), m_size(0) {}
 
-    constexpr ArrayView(const T& oneval)
+    constexpr ArrayView(T& oneval)
         : m_pointer(&oneval), m_size(1) {}
 
-    constexpr ArrayView(const T* pointer, size_t size)
+    constexpr ArrayView(T* pointer, size_t size)
         : m_pointer(pointer), m_size(size) {}
 
-    constexpr ArrayView(const T* begin, const T* end)
+    constexpr ArrayView(T* begin, T* end)
         : m_pointer(begin), m_size(end - begin) {}
 
     template<size_t N>
-    constexpr ArrayView(const T(&array)[N]) : m_pointer(array), m_size(N) {}
+    constexpr ArrayView(T(&array)[N]) : m_pointer(array), m_size(N) {}
 
     template<typename Iterator>
     constexpr ArrayView(const Iterator& begin, const Iterator& end)
         : m_pointer(&(*begin)), m_size(end - begin) {}
 
-    template<typename Alloc>
+    template<typename Alloc, typename U>
-    constexpr ArrayView(const std::vector<T, Alloc>& v)
+    constexpr ArrayView(const std::vector<U, Alloc>& v)
         : m_pointer(&v[0]), m_size(v.size()) {}
 
     constexpr ArrayView(const std::initializer_list<T>& v)
         : m_pointer(v.begin()), m_size(v.size()) {}
 
-    constexpr const T* pointer() const { return m_pointer; }
+    constexpr T* pointer() const { return m_pointer; }
     constexpr size_t size() const { return m_size; }
-    constexpr const T& operator[](size_t n) const { return *(m_pointer + n); }
+    constexpr T& operator[](size_t n) const { return *(m_pointer + n); }
 
-    constexpr const T* begin() const { return m_pointer; }
+    constexpr T* begin() const { return m_pointer; }
-    constexpr const T* end()   const { return m_pointer+m_size; }
+    constexpr T* end()   const { return m_pointer+m_size; }
 
-    using reverse_iterator = std::reverse_iterator<const T*>;
+    using reverse_iterator = std::reverse_iterator<T*>;
     constexpr reverse_iterator rbegin() const { return reverse_iterator(m_pointer+m_size); }
     constexpr reverse_iterator rend()   const { return reverse_iterator(m_pointer); }
 
-    constexpr const T& front() const { return *m_pointer; }
+    constexpr T& front() const { return *m_pointer; }
-    constexpr const T& back()  const { return *(m_pointer + m_size - 1); }
+    constexpr T& back()  const { return *(m_pointer + m_size - 1); }
 
     constexpr bool empty() const { return m_size == 0; }
 
@@ -63,10 +64,13 @@ public:
     }
 
 private:
-    const T* m_pointer;
+    T* m_pointer;
     size_t   m_size;
 };
 
+template<typename T>
+using ConstArrayView = ArrayView<const T>;
+
 }
 
 #endif // array_view_hh_INCLUDED

src/buffer.hh

@@ -164,7 +164,7 @@ public:
         ByteCoord begin;
         ByteCoord end;
     };
-    ArrayView<Change> changes_since(size_t timestamp) const;
+    ConstArrayView<Change> changes_since(size_t timestamp) const;
 
     String debug_description() const;
 private:

src/buffer.inl.hh

@@ -92,7 +92,7 @@ inline size_t Buffer::timestamp() const
     return m_changes.size();
 }
 
-inline ArrayView<Buffer::Change> Buffer::changes_since(size_t timestamp) const
+inline ConstArrayView<Buffer::Change> Buffer::changes_since(size_t timestamp) const
 {
     return { m_changes.data() + timestamp,
              m_changes.data() + m_changes.size() };

src/command_manager.cc

@@ -270,11 +270,11 @@ TokenList parse(StringView line)
 }
 
 String eval_token(const Token& token, Context& context,
-                  ArrayView<String> shell_params,
+                  ConstArrayView<String> shell_params,
                   const EnvVarMap& env_vars);
 
 String eval(StringView str, Context& context,
-            ArrayView<String> shell_params,
+            ConstArrayView<String> shell_params,
             const EnvVarMap& env_vars)
 {
     String res;
@@ -303,7 +303,7 @@ String eval(StringView str, Context& context,
 }
 
 String eval_token(const Token& token, Context& context,
-                  ArrayView<String> shell_params,
+                  ConstArrayView<String> shell_params,
                   const EnvVarMap& env_vars)
 {
     auto& content = token.content();
@@ -356,7 +356,7 @@ void CommandManager::execute_single_command(CommandParameters params,
     if (params.empty())
         return;
 
-    ArrayView<String> param_view(params.begin()+1, params.end());
+    ConstArrayView<String> param_view(params.begin()+1, params.end());
     auto command_it = find_command(context, params[0]);
     if (command_it == m_commands.end())
         throw command_not_found(params[0]);
@@ -396,7 +396,7 @@ static CharCoord find_coord(StringView str, ByteCount offset)
 
 void CommandManager::execute(StringView command_line,
                              Context& context,
-                             ArrayView<String> shell_params,
+                             ConstArrayView<String> shell_params,
                              const EnvVarMap& env_vars)
 {
     TokenList tokens = parse<true>(command_line);

src/command_manager.hh

@@ -18,7 +18,7 @@ namespace Kakoune
 {
 
 class Context;
-using CommandParameters = ArrayView<String>;
+using CommandParameters = ConstArrayView<String>;
 using Command = std::function<void (const ParametersParser& parser, Context& context)>;
 using CommandCompleter = std::function<Completions (const Context& context,
                                                     CompletionFlags,
@@ -40,7 +40,7 @@ public:
     using ArgumentCompleter = std::function<Completions (const Context&,
                                             CompletionFlags flags,
                                             const String&, ByteCount)>;
-    using ArgumentCompleterList = ArrayView<ArgumentCompleter>;
+    using ArgumentCompleterList = ConstArrayView<ArgumentCompleter>;
 
     PerArgumentCommandCompleter(ArgumentCompleterList completers)
         : m_completers(completers.begin(), completers.end()) {}
@@ -61,7 +61,7 @@ class CommandManager : public Singleton<CommandManager>
 {
 public:
     void execute(StringView command_line, Context& context,
-                 ArrayView<String> shell_params = {},
+                 ConstArrayView<String> shell_params = {},
                  const EnvVarMap& env_vars = EnvVarMap{});
 
     Completions complete(const Context& context, CompletionFlags flags,

src/commands.cc

@@ -1267,7 +1267,7 @@ const CommandDesc prompt_cmd = {
             {
                 if (event != PromptEvent::Validate)
                     return;
-                RegisterManager::instance()[reg] = ArrayView<String>(str);
+                RegisterManager::instance()[reg] = ConstArrayView<String>(str);
 
                 CommandManager::instance().execute(command, context);
             });
@@ -1449,7 +1449,7 @@ const CommandDesc set_register_cmd = {
     CommandCompleter{},
     [](const ParametersParser& parser, Context& context)
     {
-        RegisterManager::instance()[parser[0]] = ArrayView<String>(parser[1]);
+        RegisterManager::instance()[parser[0]] = ConstArrayView<String>(parser[1]);
     }
 };
 
@@ -1474,7 +1474,7 @@ public:
     RegisterRestorer(char name, const Context& context)
       : m_name(name)
     {
-        ArrayView<String> save = RegisterManager::instance()[name].values(context);
+        ConstArrayView<String> save = RegisterManager::instance()[name].values(context);
         m_save = Vector<String>(save.begin(), save.end());
     }
 
@@ -1488,7 +1488,7 @@ private:
 
 }
 
-void exec_keys(ArrayView<Key> keys, Context& context)
+void exec_keys(ConstArrayView<Key> keys, Context& context)
 {
     RegisterRestorer quote('"', context);
     RegisterRestorer slash('/', context);

src/commands.hh

@@ -10,7 +10,7 @@ namespace Kakoune
 class Context;
 
 void register_commands();
-void exec_keys(ArrayView<Key> keys, Context& context);
+void exec_keys(ConstArrayView<Key> keys, Context& context);
 
 }
 

src/file.cc

@@ -255,7 +255,7 @@ void write_buffer_to_backup_file(Buffer& buffer)
     }
 }
 
-String find_file(StringView filename, ArrayView<String> paths)
+String find_file(StringView filename, ConstArrayView<String> paths)
 {
     struct stat buf;
     if (filename.length() > 1 and filename[0] == '/')

src/file.hh

@@ -1,6 +1,7 @@
 #ifndef file_hh_INCLUDED
 #define file_hh_INCLUDED
 
+#include "array_view.hh"
 #include "completion.hh"
 #include "exception.hh"
 #include "regex.hh"
@@ -23,7 +24,6 @@ struct file_not_found : file_access_error
 };
 
 class Buffer;
-template<typename T> class ArrayView;
 class String;
 class StringView;
 
@@ -43,7 +43,7 @@ void write_buffer_to_file(Buffer& buffer, StringView filename);
 void write_buffer_to_fd(Buffer& buffer, int fd);
 void write_buffer_to_backup_file(Buffer& buffer);
 
-String find_file(StringView filename, ArrayView<String> paths);
+String find_file(StringView filename, ConstArrayView<String> paths);
 
 time_t get_fs_timestamp(StringView filename);
 

src/highlighter.hh

@@ -64,7 +64,7 @@ std::unique_ptr<SimpleHighlighter<T>> make_simple_highlighter(T func)
     return make_unique<SimpleHighlighter<T>>(std::move(func));
 }
 
-using HighlighterParameters = ArrayView<String>;
+using HighlighterParameters = ConstArrayView<String>;
 using HighlighterFactory = std::function<HighlighterAndId (HighlighterParameters params)>;
 
 struct HighlighterFactoryAndDocstring

src/highlighters.cc

@@ -822,7 +822,7 @@ void find_matches(const Buffer& buffer, RegexMatchList& matches, const Regex& re
     }
 }
 
-void update_matches(const Buffer& buffer, ArrayView<LineModification> modifs,
+void update_matches(const Buffer& buffer, ConstArrayView<LineModification> modifs,
                     RegexMatchList& matches, const Regex& regex)
 {
     // remove out of date matches and update line for others
@@ -939,7 +939,7 @@ struct RegionDesc
     }
 
     void update_matches(const Buffer& buffer,
-                        ArrayView<LineModification> modifs,
+                        ConstArrayView<LineModification> modifs,
                         RegionMatches& matches) const
     {
         Kakoune::update_matches(buffer, modifs, matches.begin_matches, m_begin);

src/input_handler.cc

@@ -342,7 +342,7 @@ private:
 class Menu : public InputMode
 {
 public:
-    Menu(InputHandler& input_handler, ArrayView<String> choices,
+    Menu(InputHandler& input_handler, ConstArrayView<String> choices,
          MenuCallback callback)
         : InputMode(input_handler),
           m_callback(callback), m_choices(choices.begin(), choices.end()),
@@ -460,7 +460,7 @@ private:
     LineEditor m_filter_editor;
 };
 
-String common_prefix(ArrayView<String> strings)
+String common_prefix(ConstArrayView<String> strings)
 {
     String res;
     if (strings.empty())
@@ -928,7 +928,7 @@ private:
         selections.sort_and_merge_overlapping();
     }
 
-    void insert(ArrayView<String> strings)
+    void insert(ConstArrayView<String> strings)
     {
         context().selections().insert(strings, InsertMode::InsertCursor);
     }
@@ -1096,7 +1096,7 @@ void InputHandler::set_prompt_face(Face prompt_face)
         prompt->set_prompt_face(prompt_face);
 }
 
-void InputHandler::menu(ArrayView<String> choices,
+void InputHandler::menu(ConstArrayView<String> choices,
                        MenuCallback callback)
 {
     change_input_mode(new InputModes::Menu(*this, choices, callback));
@@ -1153,7 +1153,7 @@ bool InputHandler::is_recording() const
 void InputHandler::stop_recording()
 {
     kak_assert(m_recording_reg != 0);
-    RegisterManager::instance()[m_recording_reg] = ArrayView<String>(m_recorded_keys);
+    RegisterManager::instance()[m_recording_reg] = ConstArrayView<String>(m_recorded_keys);
     m_recording_reg = 0;
 }
 

src/input_handler.hh

@@ -61,7 +61,7 @@ public:
     // abort or validation with corresponding MenuEvent value
     // returns to normal mode after validation if callback does
     // not change the mode itself
-    void menu(ArrayView<String> choices, MenuCallback callback);
+    void menu(ArrayView<const String> choices, MenuCallback callback);
 
     // execute callback on next keypress and returns to normal mode
     // if callback does not change the mode itself

src/keymap_manager.cc

@@ -23,7 +23,7 @@ bool KeymapManager::is_mapped(Key key, KeymapMode mode) const
            (m_parent and m_parent->is_mapped(key, mode));
 }
 
-ArrayView<Key> KeymapManager::get_mapping(Key key, KeymapMode mode) const
+ConstArrayView<Key> KeymapManager::get_mapping(Key key, KeymapMode mode) const
 {
     auto it = m_mapping.find({key, mode});
     if (it != m_mapping.end())

src/keymap_manager.hh

@@ -1,6 +1,7 @@
 #ifndef keymap_manager_hh_INCLUDED
 #define keymap_manager_hh_INCLUDED
 
+#include "array_view.hh"
 #include "keys.hh"
 #include "hash.hh"
 #include "unordered_map.hh"
@@ -21,8 +22,6 @@ enum class KeymapMode : int
     User,
 };
 
-template<typename T> class ArrayView;
-
 class KeymapManager
 {
 public:
@@ -33,7 +32,7 @@ public:
     void unmap_key(Key key, KeymapMode mode);
 
     bool is_mapped(Key key, KeymapMode mode) const;
-    ArrayView<Key> get_mapping(Key key, KeymapMode mode) const;
+    ConstArrayView<Key> get_mapping(Key key, KeymapMode mode) const;
 private:
     KeymapManager()
         : m_parent(nullptr) {}

src/main.cc

@@ -314,7 +314,7 @@ int run_client(StringView session, StringView init_command)
 }
 
 int run_server(StringView session, StringView init_command,
-               bool ignore_kakrc, bool daemon, ArrayView<StringView> files)
+               bool ignore_kakrc, bool daemon, ConstArrayView<StringView> files)
 {
     static bool terminate = false;
     if (daemon)
@@ -416,7 +416,7 @@ int run_server(StringView session, StringView init_command,
     return 0;
 }
 
-int run_filter(StringView keystr, ArrayView<StringView> files, bool quiet)
+int run_filter(StringView keystr, ConstArrayView<StringView> files, bool quiet)
 {
     StringRegistry  string_registry;
     GlobalScope     global_scope;

src/ncurses_ui.cc

@@ -564,7 +564,7 @@ void NCursesUI::draw_menu()
     m_dirty = true;
 }
 
-void NCursesUI::menu_show(ArrayView<String> items,
+void NCursesUI::menu_show(ConstArrayView<String> items,
                           CharCoord anchor, Face fg, Face bg,
                           MenuStyle style)
 {
@@ -714,7 +714,7 @@ static CharCoord compute_pos(CharCoord anchor, CharCoord size,
 }
 
 String make_info_box(StringView title, StringView message, CharCount max_width,
-                     ArrayView<StringView> assistant)
+                     ConstArrayView<StringView> assistant)
 {
     CharCoord assistant_size;
     if (not assistant.empty())
@@ -851,7 +851,7 @@ void NCursesUI::set_ui_options(const Options& options)
             else if (it->second == "clippy")
                 m_assistant = assistant_clippy;
             else if (it->second == "none" or it->second == "off")
-                m_assistant = ArrayView<StringView>{};
+                m_assistant = ConstArrayView<StringView>{};
         }
     }
 

src/ncurses_ui.hh

@@ -28,7 +28,7 @@ public:
     bool   is_key_available() override;
     Key    get_key() override;
 
-    void menu_show(ArrayView<String> items,
+    void menu_show(ConstArrayView<String> items,
                    CharCoord anchor, Face fg, Face bg,
                    MenuStyle style) override;
     void menu_select(int selected) override;
@@ -73,7 +73,7 @@ private:
     InputCallback m_input_callback;
 
     bool m_status_on_top = false;
-    ArrayView<StringView> m_assistant;
+    ConstArrayView<StringView> m_assistant;
 
     bool m_dirty = false;
 };

src/normal.cc

@@ -1079,7 +1079,7 @@ void replay_macro(Context& context, NormalParams params)
             if (running_macros[idx])
                 throw runtime_error("recursive macros call detected");
 
-            ArrayView<String> reg_val = RegisterManager::instance()[name].values(context);
+            ConstArrayView<String> reg_val = RegisterManager::instance()[name].values(context);
             if (not reg_val.empty())
             {
                 running_macros[idx] = true;

src/option_types.hh

@@ -109,7 +109,7 @@ struct TupleOptionDetail
                tuple_separator + escape(option_to_string(std::get<I>(opt)), tuple_separator, '\\');
     }
 
-    static void from_string(ArrayView<String> elems, std::tuple<Types...>& opt)
+    static void from_string(ConstArrayView<String> elems, std::tuple<Types...>& opt)
     {
         option_from_string(elems[I], std::get<I>(opt));
         TupleOptionDetail<I-1, Types...>::from_string(elems, opt);
@@ -124,7 +124,7 @@ struct TupleOptionDetail<0, Types...>
         return option_to_string(std::get<0>(opt));
     }
 
-    static void from_string(ArrayView<String> elems, std::tuple<Types...>& opt)
+    static void from_string(ConstArrayView<String> elems, std::tuple<Types...>& opt)
     {
         option_from_string(elems[0], std::get<0>(opt));
     }

src/parameters_parser.hh

@@ -10,7 +10,7 @@
 namespace Kakoune
 {
 
-using ParameterList = ArrayView<String>;
+using ParameterList = ConstArrayView<String>;
 
 struct parameter_error : public runtime_error
 {

src/register.hh

@@ -13,9 +13,9 @@ class Register
 {
 public:
     virtual ~Register() {}
-    virtual Register& operator=(ArrayView<String> values) = 0;
+    virtual Register& operator=(ConstArrayView<String> values) = 0;
 
-    virtual ArrayView<String> values(const Context& context) = 0;
+    virtual ConstArrayView<String> values(const Context& context) = 0;
 };
 
 }

src/register_manager.cc

@@ -12,18 +12,18 @@ namespace Kakoune
 class StaticRegister : public Register
 {
 public:
-    Register& operator=(ArrayView<String> values) override
+    Register& operator=(ConstArrayView<String> values) override
     {
         m_content = Vector<String, MemoryDomain::Registers>(values.begin(), values.end());
         return *this;
     }
 
-    ArrayView<String> values(const Context&) override
+    ConstArrayView<String> values(const Context&) override
     {
         if (m_content.empty())
-            return ArrayView<String>(ms_empty);
+            return ConstArrayView<String>(ms_empty);
         else
-            return ArrayView<String>(m_content);
+            return ConstArrayView<String>(m_content);
     }
 protected:
     Vector<String, MemoryDomain::Registers> m_content;
@@ -41,12 +41,12 @@ public:
     DynamicRegister(RegisterRetriever function)
         : m_function(std::move(function)) {}
 
-    Register& operator=(ArrayView<String> values) override
+    Register& operator=(ConstArrayView<String> values) override
     {
         throw runtime_error("this register is not assignable");
     }
 
-    ArrayView<String> values(const Context& context) override
+    ConstArrayView<String> values(const Context& context) override
     {
         m_content = m_function(context);
         return StaticRegister::values(context);

src/remote.cc

@@ -68,7 +68,7 @@ public:
     }
 
     template<typename T>
-    void write(ArrayView<T> view)
+    void write(ConstArrayView<T> view)
     {
         write<uint32_t>(view.size());
         for (auto& val : view)
@@ -78,7 +78,7 @@ public:
     template<typename T, MemoryDomain domain>
     void write(const Vector<T, domain>& vec)
     {
-        write(ArrayView<T>(vec));
+        write(ConstArrayView<T>(vec));
     }
 
     template<typename Key, typename Val, MemoryDomain domain>
@@ -249,7 +249,7 @@ public:
     RemoteUI(int socket);
     ~RemoteUI();
 
-    void menu_show(ArrayView<String> choices,
+    void menu_show(ConstArrayView<String> choices,
                    CharCoord anchor, Face fg, Face bg,
                    MenuStyle style) override;
     void menu_select(int selected) override;
@@ -298,7 +298,7 @@ RemoteUI::~RemoteUI()
     m_socket_watcher.close_fd();
 }
 
-void RemoteUI::menu_show(ArrayView<String> choices,
+void RemoteUI::menu_show(ConstArrayView<String> choices,
                          CharCoord anchor, Face fg, Face bg,
                          MenuStyle style)
 {

src/selection.cc

@@ -196,7 +196,7 @@ const Buffer::Change* backward_sorted_until(const Buffer::Change* first, const B
     return last;
 }
 
-void update_forward(ArrayView<Buffer::Change> changes, Vector<Selection>& selections, size_t& main)
+void update_forward(ConstArrayView<Buffer::Change> changes, Vector<Selection>& selections, size_t& main)
 {
     ForwardChangesTracker changes_tracker;
 
@@ -221,7 +221,7 @@ void update_forward(ArrayView<Buffer::Change> changes, Vector<Selection>& select
     kak_assert(std::is_sorted(selections.begin(), selections.end(), compare_selections));
 }
 
-void update_backward(ArrayView<Buffer::Change> changes, Vector<Selection>& selections, size_t& main)
+void update_backward(ConstArrayView<Buffer::Change> changes, Vector<Selection>& selections, size_t& main)
 {
     ForwardChangesTracker changes_tracker;
 
@@ -463,7 +463,7 @@ BufferIterator prepare_insert(Buffer& buffer, const Selection& sel, InsertMode m
     return {};
 }
 
-void SelectionList::insert(ArrayView<String> strings, InsertMode mode,
+void SelectionList::insert(ConstArrayView<String> strings, InsertMode mode,
                            bool select_inserted)
 {
     if (strings.empty())

src/selection.hh

@@ -128,7 +128,7 @@ struct SelectionList
     size_t timestamp() const { return m_timestamp; }
     void update_timestamp() { m_timestamp = m_buffer->timestamp(); }
 
-    void insert(ArrayView<String> strings, InsertMode mode,
+    void insert(ConstArrayView<String> strings, InsertMode mode,
                 bool select_inserted = false);
     void erase();
 

src/shell_manager.cc

@@ -29,7 +29,7 @@ ShellManager::ShellManager()
 }
 
 String ShellManager::eval(StringView cmdline, const Context& context,
-                          ArrayView<String> params,
+                          ConstArrayView<String> params,
                           const EnvVarMap& env_vars,
                           int* exit_status)
 {
@@ -38,7 +38,7 @@ String ShellManager::eval(StringView cmdline, const Context& context,
 
 String ShellManager::pipe(StringView input,
                           StringView cmdline, const Context& context,
-                          ArrayView<String> params,
+                          ConstArrayView<String> params,
                           const EnvVarMap& env_vars,
                           int* exit_status)
 {

src/shell_manager.hh

@@ -1,6 +1,7 @@
 #ifndef shell_manager_hh_INCLUDED
 #define shell_manager_hh_INCLUDED
 
+#include "array_view.hh"
 #include "regex.hh"
 #include "utils.hh"
 #include "env_vars.hh"
@@ -9,7 +10,6 @@ namespace Kakoune
 {
 
 class Context;
-template<typename T> class ArrayView;
 class String;
 class StringView;
 
@@ -21,13 +21,13 @@ public:
     ShellManager();
 
     String eval(StringView cmdline, const Context& context,
-                ArrayView<String> params,
+                ConstArrayView<String> params,
                 const EnvVarMap& env_vars,
                 int* exit_status = nullptr);
 
     String pipe(StringView input,
                 StringView cmdline, const Context& context,
-                ArrayView<String> params,
+                ConstArrayView<String> params,
                 const EnvVarMap& env_vars,
                 int* exit_status = nullptr);
 

src/user_interface.hh

@@ -1,6 +1,7 @@
 #ifndef user_interface_hh_INCLUDED
 #define user_interface_hh_INCLUDED
 
+#include "array_view.hh"
 #include "safe_ptr.hh"
 #include "unordered_map.hh"
 
@@ -15,7 +16,6 @@ class DisplayLine;
 struct CharCoord;
 struct Face;
 struct Key;
-template<typename T> class ArrayView;
 
 enum class MenuStyle
 {
@@ -41,7 +41,7 @@ class UserInterface : public SafeCountable
 public:
     virtual ~UserInterface() {}
 
-    virtual void menu_show(ArrayView<String> choices,
+    virtual void menu_show(ConstArrayView<String> choices,
                            CharCoord anchor, Face fg, Face bg,
                            MenuStyle style) = 0;
     virtual void menu_select(int selected) = 0;