diff --git a/4coder_generated/app_functions.h b/4coder_generated/app_functions.h
index 296cb008..675e13b1 100644
--- a/4coder_generated/app_functions.h
+++ b/4coder_generated/app_functions.h
@@ -155,6 +155,7 @@ struct Application_Links;
 #define OPEN_COLOR_PICKER_SIG(n) void n(Application_Links *app, color_picker *picker)
 #define ANIMATE_SIG(n) void n(Application_Links *app)
 #define FIND_ALL_IN_RANGE_INSENSITIVE_SIG(n) Found_String_List n(Application_Links *app, Buffer_ID buffer_id, i32 start, i32 end, String key, Partition *memory)
+#define GET_VIEW_VISIBLE_RANGE_SIG(n) Range n(Application_Links *app, View_ID view_id)
 typedef GLOBAL_SET_SETTING_SIG(Global_Set_Setting_Function);
 typedef GLOBAL_SET_MAPPING_SIG(Global_Set_Mapping_Function);
 typedef CREATE_CHILD_PROCESS_SIG(Create_Child_Process_Function);
@@ -311,6 +312,7 @@ typedef GET_DEFAULT_FONT_FOR_VIEW_SIG(Get_Default_Font_For_View_Function);
 typedef OPEN_COLOR_PICKER_SIG(Open_Color_Picker_Function);
 typedef ANIMATE_SIG(Animate_Function);
 typedef FIND_ALL_IN_RANGE_INSENSITIVE_SIG(Find_All_In_Range_Insensitive_Function);
+typedef GET_VIEW_VISIBLE_RANGE_SIG(Get_View_Visible_Range_Function);
 struct Application_Links{
 #if defined(ALLOW_DEP_4CODER)
 Global_Set_Setting_Function *global_set_setting;
@@ -469,6 +471,7 @@ Get_Default_Font_For_View_Function *get_default_font_for_view;
 Open_Color_Picker_Function *open_color_picker;
 Animate_Function *animate;
 Find_All_In_Range_Insensitive_Function *find_all_in_range_insensitive;
+Get_View_Visible_Range_Function *get_view_visible_range;
 #else
 Global_Set_Setting_Function *global_set_setting_;
 Global_Set_Mapping_Function *global_set_mapping_;
@@ -626,6 +629,7 @@ Get_Default_Font_For_View_Function *get_default_font_for_view_;
 Open_Color_Picker_Function *open_color_picker_;
 Animate_Function *animate_;
 Find_All_In_Range_Insensitive_Function *find_all_in_range_insensitive_;
+Get_View_Visible_Range_Function *get_view_visible_range_;
 #endif
 void *memory;
 int32_t memory_size;
@@ -790,7 +794,8 @@ app_links->draw_clip_pop_ = Draw_Clip_Pop;\
 app_links->get_default_font_for_view_ = Get_Default_Font_For_View;\
 app_links->open_color_picker_ = Open_Color_Picker;\
 app_links->animate_ = Animate;\
-app_links->find_all_in_range_insensitive_ = Find_All_In_Range_Insensitive;} while(false)
+app_links->find_all_in_range_insensitive_ = Find_All_In_Range_Insensitive;\
+app_links->get_view_visible_range_ = Get_View_Visible_Range;} while(false)
 #if defined(ALLOW_DEP_4CODER)
 static b32 global_set_setting(Application_Links *app, Global_Setting_ID setting, i32 value){return(app->global_set_setting(app, setting, value));}
 static b32 global_set_mapping(Application_Links *app, void *data, i32 size){return(app->global_set_mapping(app, data, size));}
@@ -948,6 +953,7 @@ static Face_ID get_default_font_for_view(Application_Links *app, View_ID view_id
 static void open_color_picker(Application_Links *app, color_picker *picker){(app->open_color_picker(app, picker));}
 static void animate(Application_Links *app){(app->animate(app));}
 static Found_String_List find_all_in_range_insensitive(Application_Links *app, Buffer_ID buffer_id, i32 start, i32 end, String key, Partition *memory){return(app->find_all_in_range_insensitive(app, buffer_id, start, end, key, memory));}
+static Range get_view_visible_range(Application_Links *app, View_ID view_id){return(app->get_view_visible_range(app, view_id));}
 #else
 static b32 global_set_setting(Application_Links *app, Global_Setting_ID setting, i32 value){return(app->global_set_setting_(app, setting, value));}
 static b32 global_set_mapping(Application_Links *app, void *data, i32 size){return(app->global_set_mapping_(app, data, size));}
@@ -1105,4 +1111,5 @@ static Face_ID get_default_font_for_view(Application_Links *app, View_ID view_id
 static void open_color_picker(Application_Links *app, color_picker *picker){(app->open_color_picker_(app, picker));}
 static void animate(Application_Links *app){(app->animate_(app));}
 static Found_String_List find_all_in_range_insensitive(Application_Links *app, Buffer_ID buffer_id, i32 start, i32 end, String key, Partition *memory){return(app->find_all_in_range_insensitive_(app, buffer_id, start, end, key, memory));}
+static Range get_view_visible_range(Application_Links *app, View_ID view_id){return(app->get_view_visible_range_(app, view_id));}
 #endif
diff --git a/4coder_insertion.cpp b/4coder_insertion.cpp
index b214e250..de4e84de 100644
--- a/4coder_insertion.cpp
+++ b/4coder_insertion.cpp
@@ -39,6 +39,8 @@ insertf(Buffer_Insertion *insertion, char *format, ...){
     char temp[1024];
     
     va_list args;
+    // TODO(casey): Allen, ideally we would have our own formatted here that could handle our string type, via %S or something, so 
+    // we don't have to keep doing %.*s and passing two parameters and all that garbage.
     va_start(args, format);
     i32 result = vsprintf(temp, format, args);
     va_end(args);
@@ -97,5 +99,14 @@ insert_line_from_buffer(Buffer_Insertion *insertion, Buffer_ID buffer_id, i32 li
     return(insert_line_from_buffer(insertion, buffer_id, line, 0));
 }
 
+static b32
+insert_mirror_range(Buffer_Insertion *insertion, Buffer_ID source, i32 source_first, i32 length){
+    b32 result = mirror_buffer_insert_range(insertion->app, insertion->buffer, source, insertion->at, source_first, length);
+    if (result){
+        insertion->at += length;
+    }
+    return(result);
+}
+
 // BOTTOM
 
diff --git a/4coder_mirror.cpp b/4coder_mirror.cpp
index 580bb1d5..bf195502 100644
--- a/4coder_mirror.cpp
+++ b/4coder_mirror.cpp
@@ -597,6 +597,9 @@ mirror_buffer_insert_range(Application_Links *app, Buffer_ID mirror, Buffer_ID s
             if (mode == MirrorMode_Constructing){
                 b32 did_insert = false;
                 {
+                    // TODO(casey): Allen, this is going to be suuuuuper slow - it has to do a whole memory block
+                    // reserve just to get the temporary space.  This is the kind of thing that would be super simple and
+                    // very efficient with a stack off the app pointer.
                     Arena arena = make_arena(app, (8 << 10));
                     char *buffer = push_array(&arena, char, length);
                     if (buffer_read_range(app, source, source_first, source_first + length, buffer)){
diff --git a/4ed_api_implementation.cpp b/4ed_api_implementation.cpp
index 9eb4ade3..160b9f47 100644
--- a/4ed_api_implementation.cpp
+++ b/4ed_api_implementation.cpp
@@ -4684,9 +4684,26 @@ Get_Process_State(Application_Links *app, Buffer_ID buffer_id)
         result.is_updating = file->is_updating;
         result.return_code = file->return_code;
     }
-    
     return(result);
 }
 */
 
+API_EXPORT Range
+Get_View_Visible_Range(Application_Links *app, View_ID view_id){
+    Range result = {};
+    // TODO(casey): Allen, I leave it to you to actually compute this the way you want.  Hopefully all
+    // this sort of thing will get sorted out as the render/layout stuff becomes more disentangled.
+    Models *models = (Models*)app->cmd_context;
+    View *view = imp_get_view(models, view_id);
+    if (view_api_check_view(view)){
+        i32 view_height = rect_height(view->panel->rect_inner);
+        Full_Cursor min_cursor = view_get_render_cursor(models->system, view);
+        Full_Cursor max_cursor;
+        view_compute_cursor(app, view_id, seek_xy(min_cursor.wrapped_x, min_cursor.wrapped_y + view_height, false, false), &max_cursor);
+        result.min = min_cursor.pos;
+        result.max = max_cursor.pos;
+    }
+    return(result);
+}
+
 // BOTTOM