Add a new API for converting between interface_key and string characters.

It's necessary now that the simple linear arrangement is broken.

Lua API.rst

@@ -1591,6 +1591,17 @@ Basic painting functions:
   Returns the string that should be used to represent the given
   logical keybinding on the screen in texts like "press Key to ...".
 
+* ``dfhack.screen.keyToChar(key)``
+
+  Returns the integer character code of the string input
+  character represented by the given logical keybinding,
+  or *nil* if not a string input key.
+
+* ``dfhack.screen.charToKey(charcode)``
+
+  Returns the keybinding representing the given string input
+  character, or *nil* if impossible.
+
 The "pen" argument used by functions above may be represented by
 a table with the following possible fields:
 

library/LuaApi.cpp

@@ -1924,6 +1924,28 @@ static int screen_doSimulateInput(lua_State *L)
     return 0;
 }
 
+static int screen_keyToChar(lua_State *L)
+{
+    auto keycode = (df::interface_key)luaL_checkint(L, 1);
+    int charcode = Screen::keyToChar(keycode);
+    if (charcode >= 0)
+        lua_pushinteger(L, charcode);
+    else
+        lua_pushnil(L);
+    return 1;
+}
+
+static int screen_charToKey(lua_State *L)
+{
+    auto charcode = (char)luaL_checkint(L, 1);
+    df::interface_key keycode = Screen::charToKey(charcode);
+    if (keycode)
+        lua_pushinteger(L, keycode);
+    else
+        lua_pushnil(L);
+    return 1;
+}
+
 }
 
 static const luaL_Reg dfhack_screen_funcs[] = {
@@ -1938,6 +1960,8 @@ static const luaL_Reg dfhack_screen_funcs[] = {
     { "dismiss", screen_dismiss },
     { "isDismissed", screen_isDismissed },
     { "_doSimulateInput", screen_doSimulateInput },
+    { "keyToChar", screen_keyToChar },
+    { "charToKey", screen_charToKey },
     { NULL, NULL }
 };
 

library/include/modules/Screen.h

@@ -195,6 +195,11 @@ namespace DFHack
         /// Retrieve the string representation of the bound key.
         DFHACK_EXPORT std::string getKeyDisplay(df::interface_key key);
 
+        /// Return the character represented by this key, or -1
+        DFHACK_EXPORT int keyToChar(df::interface_key key);
+        /// Return the key code matching this character, or NONE
+        DFHACK_EXPORT df::interface_key charToKey(char code);
+
         /// A painter class that implements a clipping area and cursor/pen state
         struct DFHACK_EXPORT Painter : ViewRect {
             df::coord2d gcursor;

library/modules/Screen.cpp

@@ -413,6 +413,29 @@ string Screen::getKeyDisplay(df::interface_key key)
     return "?";
 }
 
+int Screen::keyToChar(df::interface_key key)
+{
+    if (key < interface_key::STRING_A000 ||
+        key > interface_key::STRING_A255)
+        return -1;
+
+    if (key < interface_key::STRING_A128)
+        return key - interface_key::STRING_A000;
+
+    return key - interface_key::STRING_A128 + 128;
+}
+
+df::interface_key Screen::charToKey(char code)
+{
+    int val = (unsigned char)code;
+    if (val < 127)
+        return df::interface_key(interface_key::STRING_A000 + val);
+    else if (val == 127)
+        return interface_key::NONE;
+    else
+        return df::interface_key(interface_key::STRING_A128 + (val-128));
+}
+
 /*
  * Base DFHack viewscreen.
  */
@@ -654,10 +677,10 @@ int dfhack_lua_viewscreen::do_input(lua_State *L)
         lua_pushboolean(L, true);
         lua_rawset(L, -3);
 
-        if (key >= interface_key::STRING_A000 &&
-            key <= interface_key::STRING_A255)
+        int charval = Screen::keyToChar(key);
+        if (charval >= 0)
         {
-            lua_pushinteger(L, key - interface_key::STRING_A000);
+            lua_pushinteger(L, charval);
             lua_setfield(L, -2, "_STRING");
         }
     }

plugins/command-prompt.cpp

@@ -238,10 +238,10 @@ void viewscreen_commandpromptst::feed(std::set<df::interface_key> *events)
                 cursor_pos = entry.size();
             continue;
         }
-        if (key >= interface_key::STRING_A000 &&
-            key <= interface_key::STRING_A255)
+        int charcode = Screen::keyToChar(key);
+        if (charcode > 0)
         {
-            entry.insert(cursor_pos, 1, char(key - interface_key::STRING_A000));
+            entry.insert(cursor_pos, 1, char(charcode));
             cursor_pos++;
             set_entry(entry);
             return;

plugins/search.cpp

@@ -130,7 +130,8 @@ public:
             this->cursor_pos = get_viewscreen_cursor();
             this->primary_list = get_primary_list();
             this->select_key = get_search_select_key();
-            select_token = (df::interface_key) (ascii_to_enum_offset + select_key);
+            select_token = Screen::charToKey(select_key);
+            shift_select_token = Screen::charToKey(select_key + 'A' - 'a');
             valid = true;
             do_post_init();
         }
@@ -185,10 +186,11 @@ public:
                 return false;
             }
             df::interface_key last_token = *input->rbegin();
-            if (last_token >= interface_key::STRING_A032 && last_token <= interface_key::STRING_A126)
+            int charcode = Screen::keyToChar(last_token);
+            if (charcode >= 32 && charcode <= 126)
             {
                 // Standard character
-                search_string += last_token - ascii_to_enum_offset;
+                search_string += char(charcode);
                 do_search();
             }
             else if (last_token == interface_key::STRING_A000)
@@ -219,7 +221,7 @@ public:
             // Hotkey pressed, enter typing mode
             start_entry_mode();
         }
-        else if (input->count((df::interface_key) (select_token + shift_offset)))
+        else if (input->count(shift_select_token))
         {
             // Shift + Hotkey pressed, clear query
             clear_search();
@@ -246,7 +248,7 @@ protected:
     virtual int32_t *get_viewscreen_cursor() = 0;
     virtual vector<T> *get_primary_list() = 0;
 
-    search_generic() : ascii_to_enum_offset(interface_key::STRING_A048 - '0'), shift_offset('A' - 'a')
+    search_generic()
     {
         reset_all();
     }
@@ -412,9 +414,7 @@ private:
     bool entry_mode;
 
     df::interface_key select_token;
-    const int ascii_to_enum_offset;
-    const int shift_offset;
-
+    df::interface_key shift_select_token;
 };
 
 template <class S, class T> search_generic<S, T> *search_generic<S, T> ::lock = NULL;

plugins/uicommon.h

@@ -143,8 +143,6 @@ void OutputToggleString(int &x, int &y, const char *text, const char *hotkey, bo
         OutputString(COLOR_GREY, x, y, "Off", newline, left_margin);
 }
 
-const int ascii_to_enum_offset = interface_key::STRING_A048 - '0';
-
 inline string int_to_string(const int n)
 {
     return static_cast<ostringstream*>( &(ostringstream() << n) )->str();
@@ -792,11 +790,11 @@ public:
         {
             // Search query typing mode always on
             df::interface_key last_token = *input->rbegin();
-            if ((last_token >= interface_key::STRING_A096 && last_token <= interface_key::STRING_A123) ||
-                last_token == interface_key::STRING_A032)
+            int charcode = Screen::keyToChar(last_token);
+            if ((charcode >= 96 && charcode <= 123) || charcode == 32)
             {
                 // Standard character
-                search_string += last_token - ascii_to_enum_offset;
+                search_string += char(charcode);
                 filterDisplay();
                 centerSelection();
             }

plugins/zone.cpp

@@ -4087,8 +4087,6 @@ using df::global::ui_building_assign_items;
 
 using df::global::ui_building_in_assign;
 
-static const int ascii_to_enum_offset = interface_key::STRING_A048 - '0';
-
 void OutputString(int8_t color, int &x, int y, const std::string &text)
 {
     Screen::paintString(Screen::Pen(' ', color, 0), x, y, text);
@@ -4241,10 +4239,11 @@ public:
             }
 
             df::interface_key last_token = *input->rbegin();
-            if (last_token >= interface_key::STRING_A032 && last_token <= interface_key::STRING_A126)
+            int charcode = Screen::keyToChar(last_token);
+            if (charcode >= 32 && charcode <= 126)
             {
                 // Standard character
-                search_string += last_token - ascii_to_enum_offset;
+                search_string += char(charcode);
                 apply_filters();
             }
             else if (last_token == interface_key::STRING_A000)