Merge branch 'master' into s-dash-stdin

11 files changed, 930 insertions, 554 deletions

diff --git a/src/nvim/api/buffer.c b/src/nvim/api/buffer.c
index b75a2c7211..4b6a88e5fa 100644
--- a/src/nvim/api/buffer.c
+++ b/src/nvim/api/buffer.c
@@ -1,3 +1,6 @@
+// This is an open source non-commercial project. Dear PVS-Studio, please check
+// it. PVS-Studio Static Code Analyzer for C, C++ and C#: http://www.viva64.com
+
 // Much of this code was adapted from 'if_py_both.h' from the original
 // vim source
 #include <stdbool.h>
@@ -32,7 +35,7 @@
 /// @param[out] err Error details, if any
 /// @return Line count
 Integer nvim_buf_line_count(Buffer buffer, Error *err)
-    FUNC_API_SINCE(1)
+  FUNC_API_SINCE(1)
 {
   buf_T *buf = find_buffer_by_handle(buffer, err);
 
@@ -62,7 +65,7 @@ String buffer_get_line(Buffer buffer, Integer index, Error *err)
   index = convert_index(index);
   Array slice = nvim_buf_get_lines(0, buffer, index, index+1, true, err);
 
-  if (!err->set && slice.size) {
+  if (!ERROR_SET(err) && slice.size) {
     rv = slice.items[0].data.string;
   }
 
@@ -154,7 +157,7 @@ ArrayOf(String) nvim_buf_get_lines(uint64_t channel_id,
                                    Integer end,
                                    Boolean strict_indexing,
                                    Error *err)
-    FUNC_API_SINCE(1)
+  FUNC_API_SINCE(1)
 {
   Array rv = ARRAY_DICT_INIT;
   buf_T *buf = find_buffer_by_handle(buffer, err);
@@ -168,7 +171,7 @@ ArrayOf(String) nvim_buf_get_lines(uint64_t channel_id,
   end = normalize_index(buf, end, &oob);
 
   if (strict_indexing && oob) {
-    api_set_error(err, Validation, _("Index out of bounds"));
+    api_set_error(err, kErrorTypeValidation, "Index out of bounds");
     return rv;
   }
 
@@ -184,7 +187,7 @@ ArrayOf(String) nvim_buf_get_lines(uint64_t channel_id,
     int64_t lnum = start + (int64_t)i;
 
     if (lnum > LONG_MAX) {
-      api_set_error(err, Validation, _("Line index is too high"));
+      api_set_error(err, kErrorTypeValidation, "Line index is too high");
       goto end;
     }
 
@@ -192,7 +195,7 @@ ArrayOf(String) nvim_buf_get_lines(uint64_t channel_id,
     Object str = STRING_OBJ(cstr_to_string(bufstr));
 
     // Vim represents NULs as NLs, but this may confuse clients.
-    if (channel_id != INTERNAL_CALL) {
+    if (channel_id != VIML_INTERNAL_CALL) {
       strchrsub(str.data.string.data, '\n', '\0');
     }
 
@@ -200,7 +203,7 @@ ArrayOf(String) nvim_buf_get_lines(uint64_t channel_id,
   }
 
 end:
-  if (err->set) {
+  if (ERROR_SET(err)) {
     for (size_t i = 0; i < rv.size; i++) {
       xfree(rv.items[i].data.string.data);
     }
@@ -267,7 +270,7 @@ void nvim_buf_set_lines(uint64_t channel_id,
                         Boolean strict_indexing,
                         ArrayOf(String) replacement,  // NOLINT
                         Error *err)
-    FUNC_API_SINCE(1)
+  FUNC_API_SINCE(1)
 {
   buf_T *buf = find_buffer_by_handle(buffer, err);
 
@@ -280,54 +283,58 @@ void nvim_buf_set_lines(uint64_t channel_id,
   end = normalize_index(buf, end, &oob);
 
   if (strict_indexing && oob) {
-    api_set_error(err, Validation, _("Index out of bounds"));
+    api_set_error(err, kErrorTypeValidation, "Index out of bounds");
     return;
   }
 
 
   if (start > end) {
     api_set_error(err,
-                  Validation,
-                  _("Argument \"start\" is higher than \"end\""));
+                  kErrorTypeValidation,
+                  "Argument \"start\" is higher than \"end\"");
     return;
   }
 
+  for (size_t i = 0; i < replacement.size; i++) {
+    if (replacement.items[i].type != kObjectTypeString) {
+      api_set_error(err,
+                    kErrorTypeValidation,
+                    "All items in the replacement array must be strings");
+      return;
+    }
+    // Disallow newlines in the middle of the line.
+    if (channel_id != VIML_INTERNAL_CALL) {
+      const String l = replacement.items[i].data.string;
+      if (memchr(l.data, NL, l.size)) {
+        api_set_error(err, kErrorTypeValidation,
+                      "String cannot contain newlines");
+        return;
+      }
+    }
+  }
+
   win_T *save_curwin = NULL;
   tabpage_T *save_curtab = NULL;
   size_t new_len = replacement.size;
   size_t old_len = (size_t)(end - start);
-  ssize_t extra = 0;  // lines added to text, can be negative
+  ptrdiff_t extra = 0;  // lines added to text, can be negative
   char **lines = (new_len != 0) ? xcalloc(new_len, sizeof(char *)) : NULL;
 
   for (size_t i = 0; i < new_len; i++) {
-    if (replacement.items[i].type != kObjectTypeString) {
-      api_set_error(err,
-                    Validation,
-                    _("All items in the replacement array must be strings"));
-      goto end;
-    }
-
-    String l = replacement.items[i].data.string;
+    const String l = replacement.items[i].data.string;
 
-    // Fill lines[i] with l's contents. Disallow newlines in the middle of a
-    // line and convert NULs to newlines to avoid truncation.
-    lines[i] = xmallocz(l.size);
-    for (size_t j = 0; j < l.size; j++) {
-      if (l.data[j] == '\n' && channel_id != INTERNAL_CALL) {
-        api_set_error(err, Exception, _("string cannot contain newlines"));
-        new_len = i + 1;
-        goto end;
-      }
-      lines[i][j] = (char) (l.data[j] == '\0' ? '\n' : l.data[j]);
-    }
+    // Fill lines[i] with l's contents. Convert NULs to newlines as required by
+    // NL-used-for-NUL.
+    lines[i] = xmemdupz(l.data, l.size);
+    memchrsub(lines[i], NUL, NL, l.size);
   }
 
   try_start();
-  bufref_T save_curbuf = { NULL, 0 };
+  bufref_T save_curbuf = { NULL, 0, 0 };
   switch_to_win_for_buf(buf, &save_curwin, &save_curtab, &save_curbuf);
 
   if (u_save((linenr_T)(start - 1), (linenr_T)end) == FAIL) {
-    api_set_error(err, Exception, _("Failed to save undo information"));
+    api_set_error(err, kErrorTypeException, "Failed to save undo information");
     goto end;
   }
 
@@ -337,13 +344,13 @@ void nvim_buf_set_lines(uint64_t channel_id,
   size_t to_delete = (new_len < old_len) ? (size_t)(old_len - new_len) : 0;
   for (size_t i = 0; i < to_delete; i++) {
     if (ml_delete((linenr_T)start, false) == FAIL) {
-      api_set_error(err, Exception, _("Failed to delete line"));
+      api_set_error(err, kErrorTypeException, "Failed to delete line");
       goto end;
     }
   }
 
-  if ((ssize_t)to_delete > 0) {
-    extra -= (ssize_t)to_delete;
+  if (to_delete > 0) {
+    extra -= (ptrdiff_t)to_delete;
   }
 
   // For as long as possible, replace the existing old_len with the
@@ -354,12 +361,12 @@ void nvim_buf_set_lines(uint64_t channel_id,
     int64_t lnum = start + (int64_t)i;
 
     if (lnum > LONG_MAX) {
-      api_set_error(err, Validation, _("Index value is too high"));
+      api_set_error(err, kErrorTypeValidation, "Index value is too high");
       goto end;
     }
 
     if (ml_replace((linenr_T)lnum, (char_u *)lines[i], false) == FAIL) {
-      api_set_error(err, Exception, _("Failed to replace line"));
+      api_set_error(err, kErrorTypeException, "Failed to replace line");
       goto end;
     }
     // Mark lines that haven't been passed to the buffer as they need
@@ -372,12 +379,12 @@ void nvim_buf_set_lines(uint64_t channel_id,
     int64_t lnum = start + (int64_t)i - 1;
 
     if (lnum > LONG_MAX) {
-      api_set_error(err, Validation, _("Index value is too high"));
+      api_set_error(err, kErrorTypeValidation, "Index value is too high");
       goto end;
     }
 
     if (ml_append((linenr_T)lnum, (char_u *)lines[i], 0, false) == FAIL) {
-      api_set_error(err, Exception, _("Failed to insert line"));
+      api_set_error(err, kErrorTypeException, "Failed to insert line");
       goto end;
     }
 
@@ -392,13 +399,13 @@ void nvim_buf_set_lines(uint64_t channel_id,
   // Only adjust marks if we managed to switch to a window that holds
   // the buffer, otherwise line numbers will be invalid.
   if (save_curbuf.br_buf == NULL) {
-    mark_adjust((linenr_T)start, (linenr_T)(end - 1), MAXLNUM, extra);
+    mark_adjust((linenr_T)start, (linenr_T)(end - 1), MAXLNUM, extra, false);
   }
 
-  changed_lines((linenr_T)start, 0, (linenr_T)end, extra);
+  changed_lines((linenr_T)start, 0, (linenr_T)end, (long)extra);
 
   if (save_curbuf.br_buf == NULL) {
-    fix_cursor((linenr_T)start, (linenr_T)end, extra);
+    fix_cursor((linenr_T)start, (linenr_T)end, (linenr_T)extra);
   }
 
 end:
@@ -418,7 +425,7 @@ end:
 /// @param[out] err   Error details, if any
 /// @return Variable value
 Object nvim_buf_get_var(Buffer buffer, String name, Error *err)
-    FUNC_API_SINCE(1)
+  FUNC_API_SINCE(1)
 {
   buf_T *buf = find_buffer_by_handle(buffer, err);
 
@@ -432,10 +439,11 @@ Object nvim_buf_get_var(Buffer buffer, String name, Error *err)
 /// Gets a changed tick of a buffer
 ///
 /// @param[in]  buffer  Buffer handle.
+/// @param[out] err     Error details, if any
 ///
 /// @return `b:changedtick` value.
 Integer nvim_buf_get_changedtick(Buffer buffer, Error *err)
-    FUNC_API_SINCE(2)
+  FUNC_API_SINCE(2)
 {
   const buf_T *const buf = find_buffer_by_handle(buffer, err);
 
@@ -446,6 +454,26 @@ Integer nvim_buf_get_changedtick(Buffer buffer, Error *err)
   return buf->b_changedtick;
 }
 
+/// Gets a list of dictionaries describing buffer-local mappings.
+/// The "buffer" key in the returned dictionary reflects the buffer
+/// handle where the mapping is present.
+///
+/// @param  mode       Mode short-name ("n", "i", "v", ...)
+/// @param  buffer     Buffer handle
+/// @param[out]  err   Error details, if any
+/// @returns Array of maparg()-like dictionaries describing mappings
+ArrayOf(Dictionary) nvim_buf_get_keymap(Buffer buffer, String mode, Error *err)
+    FUNC_API_SINCE(3)
+{
+  buf_T *buf = find_buffer_by_handle(buffer, err);
+
+  if (!buf) {
+    return (Array)ARRAY_DICT_INIT;
+  }
+
+  return keymap_array(mode, buf);
+}
+
 /// Sets a buffer-scoped (b:) variable
 ///
 /// @param buffer     Buffer handle
@@ -453,7 +481,7 @@ Integer nvim_buf_get_changedtick(Buffer buffer, Error *err)
 /// @param value      Variable value
 /// @param[out] err   Error details, if any
 void nvim_buf_set_var(Buffer buffer, String name, Object value, Error *err)
-    FUNC_API_SINCE(1)
+  FUNC_API_SINCE(1)
 {
   buf_T *buf = find_buffer_by_handle(buffer, err);
 
@@ -470,7 +498,7 @@ void nvim_buf_set_var(Buffer buffer, String name, Object value, Error *err)
 /// @param name       Variable name
 /// @param[out] err   Error details, if any
 void nvim_buf_del_var(Buffer buffer, String name, Error *err)
-    FUNC_API_SINCE(1)
+  FUNC_API_SINCE(1)
 {
   buf_T *buf = find_buffer_by_handle(buffer, err);
 
@@ -531,7 +559,7 @@ Object buffer_del_var(Buffer buffer, String name, Error *err)
 /// @param[out] err   Error details, if any
 /// @return Option value
 Object nvim_buf_get_option(Buffer buffer, String name, Error *err)
-    FUNC_API_SINCE(1)
+  FUNC_API_SINCE(1)
 {
   buf_T *buf = find_buffer_by_handle(buffer, err);
 
@@ -550,7 +578,7 @@ Object nvim_buf_get_option(Buffer buffer, String name, Error *err)
 /// @param value      Option value
 /// @param[out] err   Error details, if any
 void nvim_buf_set_option(Buffer buffer, String name, Object value, Error *err)
-    FUNC_API_SINCE(1)
+  FUNC_API_SINCE(1)
 {
   buf_T *buf = find_buffer_by_handle(buffer, err);
 
@@ -563,11 +591,15 @@ void nvim_buf_set_option(Buffer buffer, String name, Object value, Error *err)
 
 /// Gets the buffer number
 ///
+/// @deprecated The buffer number now is equal to the object id,
+///             so there is no need to use this function.
+///
 /// @param buffer     Buffer handle
 /// @param[out] err   Error details, if any
 /// @return Buffer number
 Integer nvim_buf_get_number(Buffer buffer, Error *err)
-    FUNC_API_SINCE(1)
+  FUNC_API_SINCE(1)
+  FUNC_API_DEPRECATED_SINCE(2)
 {
   Integer rv = 0;
   buf_T *buf = find_buffer_by_handle(buffer, err);
@@ -585,7 +617,7 @@ Integer nvim_buf_get_number(Buffer buffer, Error *err)
 /// @param[out] err   Error details, if any
 /// @return Buffer name
 String nvim_buf_get_name(Buffer buffer, Error *err)
-    FUNC_API_SINCE(1)
+  FUNC_API_SINCE(1)
 {
   String rv = STRING_INIT;
   buf_T *buf = find_buffer_by_handle(buffer, err);
@@ -603,7 +635,7 @@ String nvim_buf_get_name(Buffer buffer, Error *err)
 /// @param name       Buffer name
 /// @param[out] err   Error details, if any
 void nvim_buf_set_name(Buffer buffer, String name, Error *err)
-    FUNC_API_SINCE(1)
+  FUNC_API_SINCE(1)
 {
   buf_T *buf = find_buffer_by_handle(buffer, err);
 
@@ -624,7 +656,7 @@ void nvim_buf_set_name(Buffer buffer, String name, Error *err)
   }
 
   if (ren_ret == FAIL) {
-    api_set_error(err, Exception, _("Failed to rename buffer"));
+    api_set_error(err, kErrorTypeException, "Failed to rename buffer");
   }
 }
 
@@ -633,10 +665,12 @@ void nvim_buf_set_name(Buffer buffer, String name, Error *err)
 /// @param buffer Buffer handle
 /// @return true if the buffer is valid, false otherwise
 Boolean nvim_buf_is_valid(Buffer buffer)
-    FUNC_API_SINCE(1)
+  FUNC_API_SINCE(1)
 {
   Error stub = ERROR_INIT;
-  return find_buffer_by_handle(buffer, &stub) != NULL;
+  Boolean ret = find_buffer_by_handle(buffer, &stub) != NULL;
+  api_clear_error(&stub);
+  return ret;
 }
 
 /// Inserts a sequence of lines to a buffer at a certain index
@@ -665,7 +699,7 @@ void buffer_insert(Buffer buffer,
 /// @param[out] err   Error details, if any
 /// @return (row, col) tuple
 ArrayOf(Integer, 2) nvim_buf_get_mark(Buffer buffer, String name, Error *err)
-    FUNC_API_SINCE(1)
+  FUNC_API_SINCE(1)
 {
   Array rv = ARRAY_DICT_INIT;
   buf_T *buf = find_buffer_by_handle(buffer, err);
@@ -675,7 +709,8 @@ ArrayOf(Integer, 2) nvim_buf_get_mark(Buffer buffer, String name, Error *err)
   }
 
   if (name.size != 1) {
-    api_set_error(err, Validation, _("Mark name must be a single character"));
+    api_set_error(err, kErrorTypeValidation,
+                  "Mark name must be a single character");
     return rv;
   }
 
@@ -693,7 +728,7 @@ ArrayOf(Integer, 2) nvim_buf_get_mark(Buffer buffer, String name, Error *err)
   }
 
   if (posp == NULL) {
-    api_set_error(err, Validation, _("Invalid mark name"));
+    api_set_error(err, kErrorTypeValidation, "Invalid mark name");
     return rv;
   }
 
@@ -705,29 +740,29 @@ ArrayOf(Integer, 2) nvim_buf_get_mark(Buffer buffer, String name, Error *err)
 
 /// Adds a highlight to buffer.
 ///
-/// This can be used for plugins which dynamically generate highlights to a
-/// buffer (like a semantic highlighter or linter). The function adds a single
+/// Useful for plugins that dynamically generate highlights to a buffer
+/// (like a semantic highlighter or linter). The function adds a single
 /// highlight to a buffer. Unlike matchaddpos() highlights follow changes to
 /// line numbering (as lines are inserted/removed above the highlighted line),
 /// like signs and marks do.
 ///
-/// "src_id" is useful for batch deletion/updating of a set of highlights. When
-/// called with src_id = 0, an unique source id is generated and returned.
-/// Succesive calls can pass in it as "src_id" to add new highlights to the same
-/// source group. All highlights in the same group can then be cleared with
-/// nvim_buf_clear_highlight. If the highlight never will be manually deleted
-/// pass in -1 for "src_id".
+/// `src_id` is useful for batch deletion/updating of a set of highlights. When
+/// called with `src_id = 0`, an unique source id is generated and returned.
+/// Successive calls can pass that `src_id` to associate new highlights with
+/// the same source group. All highlights in the same group can be cleared
+/// with `nvim_buf_clear_highlight`. If the highlight never will be manually
+/// deleted, pass `src_id = -1`.
 ///
-/// If "hl_group" is the empty string no highlight is added, but a new src_id
+/// If `hl_group` is the empty string no highlight is added, but a new `src_id`
 /// is still returned. This is useful for an external plugin to synchrounously
-/// request an unique src_id at initialization, and later asynchronously add and
-/// clear highlights in response to buffer changes.
+/// request an unique `src_id` at initialization, and later asynchronously add
+/// and clear highlights in response to buffer changes.
 ///
 /// @param buffer     Buffer handle
 /// @param src_id     Source group to use or 0 to use a new group,
 ///                   or -1 for ungrouped highlight
 /// @param hl_group   Name of the highlight group to use
-/// @param line       Line to highlight
+/// @param line       Line to highlight (zero-indexed)
 /// @param col_start  Start of range of columns to highlight
 /// @param col_end    End of range of columns to highlight,
 ///                   or -1 to highlight to end of line
@@ -740,7 +775,7 @@ Integer nvim_buf_add_highlight(Buffer buffer,
                                Integer col_start,
                                Integer col_end,
                                Error *err)
-    FUNC_API_SINCE(1)
+  FUNC_API_SINCE(1)
 {
   buf_T *buf = find_buffer_by_handle(buffer, err);
   if (!buf) {
@@ -748,18 +783,22 @@ Integer nvim_buf_add_highlight(Buffer buffer,
   }
 
   if (line < 0 || line >= MAXLNUM) {
-    api_set_error(err, Validation, _("Line number outside range"));
+    api_set_error(err, kErrorTypeValidation, "Line number outside range");
     return 0;
   }
   if (col_start < 0 || col_start > MAXCOL) {
-    api_set_error(err, Validation, _("Column value outside range"));
+    api_set_error(err, kErrorTypeValidation, "Column value outside range");
     return 0;
   }
   if (col_end < 0 || col_end > MAXCOL) {
     col_end = MAXCOL;
   }
 
-  int hlg_id = syn_name2id((char_u *)(hl_group.data ? hl_group.data : ""));
+  int hlg_id = 0;
+  if (hl_group.size > 0) {
+    hlg_id = syn_check_group((char_u *)hl_group.data, (int)hl_group.size);
+  }
+
   src_id = bufhl_add_hl(buf, (int)src_id, hlg_id, (linenr_T)line+1,
                         (colnr_T)col_start+1, (colnr_T)col_end);
   return src_id;
@@ -781,7 +820,7 @@ void nvim_buf_clear_highlight(Buffer buffer,
                               Integer line_start,
                               Integer line_end,
                               Error *err)
-    FUNC_API_SINCE(1)
+  FUNC_API_SINCE(1)
 {
   buf_T *buf = find_buffer_by_handle(buffer, err);
   if (!buf) {
@@ -789,7 +828,7 @@ void nvim_buf_clear_highlight(Buffer buffer,
   }
 
   if (line_start < 0 || line_start >= MAXLNUM) {
-    api_set_error(err, Validation, _("Line number outside range"));
+    api_set_error(err, kErrorTypeValidation, "Line number outside range");
     return;
   }
   if (line_end < 0 || line_end > MAXLNUM) {
diff --git a/src/nvim/api/private/defs.h b/src/nvim/api/private/defs.h
index 223aab09dc..2144c80d6a 100644
--- a/src/nvim/api/private/defs.h
+++ b/src/nvim/api/private/defs.h
@@ -5,12 +5,16 @@
 #include <stdbool.h>
 #include <string.h>
 
+#include "nvim/func_attr.h"
+
 #define ARRAY_DICT_INIT {.size = 0, .capacity = 0, .items = NULL}
 #define STRING_INIT {.data = NULL, .size = 0}
 #define OBJECT_INIT { .type = kObjectTypeNil }
-#define ERROR_INIT { .set = false }
+#define ERROR_INIT { .type = kErrorTypeNone, .msg = NULL }
 #define REMOTE_TYPE(type) typedef handle_T type
 
+#define ERROR_SET(e) ((e)->type != kErrorTypeNone)
+
 #ifdef INCLUDE_GENERATED_DECLARATIONS
 # define ArrayOf(...) Array
 # define DictionaryOf(...) Dictionary
@@ -20,6 +24,7 @@ typedef int handle_T;
 
 // Basic types
 typedef enum {
+  kErrorTypeNone = -1,
   kErrorTypeException,
   kErrorTypeValidation
 } ErrorType;
@@ -33,13 +38,31 @@ typedef enum {
 /// Used as the message ID of notifications.
 #define NO_RESPONSE UINT64_MAX
 
-/// Used as channel_id when the call is local.
-#define INTERNAL_CALL UINT64_MAX
+/// Mask for all internal calls
+#define INTERNAL_CALL_MASK (((uint64_t)1) << (sizeof(uint64_t) * 8 - 1))
+
+/// Internal call from VimL code
+#define VIML_INTERNAL_CALL INTERNAL_CALL_MASK
+
+/// Internal call from lua code
+#define LUA_INTERNAL_CALL (VIML_INTERNAL_CALL + 1)
+
+static inline bool is_internal_call(uint64_t channel_id)
+  REAL_FATTR_ALWAYS_INLINE REAL_FATTR_CONST;
+
+/// Check whether call is internal
+///
+/// @param[in]  channel_id  Channel id.
+///
+/// @return true if channel_id refers to internal channel.
+static inline bool is_internal_call(const uint64_t channel_id)
+{
+  return !!(channel_id & INTERNAL_CALL_MASK);
+}
 
 typedef struct {
   ErrorType type;
-  char msg[1024];
-  bool set;
+  char *msg;
 } Error;
 
 typedef bool Boolean;
@@ -76,16 +99,17 @@ typedef struct {
 } Dictionary;
 
 typedef enum {
-  kObjectTypeBuffer,
-  kObjectTypeWindow,
-  kObjectTypeTabpage,
-  kObjectTypeNil,
+  kObjectTypeNil = 0,
   kObjectTypeBoolean,
   kObjectTypeInteger,
   kObjectTypeFloat,
   kObjectTypeString,
   kObjectTypeArray,
   kObjectTypeDictionary,
+  // EXT types, cannot be split or reordered, see #EXT_OBJECT_TYPE_SHIFT
+  kObjectTypeBuffer,
+  kObjectTypeWindow,
+  kObjectTypeTabpage,
 } ObjectType;
 
 struct object {
diff --git a/src/nvim/api/private/dispatch.c b/src/nvim/api/private/dispatch.c
index 9b3bcc380a..f8eebcdb10 100644
--- a/src/nvim/api/private/dispatch.c
+++ b/src/nvim/api/private/dispatch.c
@@ -1,3 +1,6 @@
+// This is an open source non-commercial project. Dear PVS-Studio, please check
+// it. PVS-Studio Static Code Analyzer for C, C++ and C#: http://www.viva64.com
+
 #include <inttypes.h>
 #include <stdbool.h>
 #include <stdint.h>
diff --git a/src/nvim/api/private/handle.c b/src/nvim/api/private/handle.c
index acb0fb332a..eb96192af2 100644
--- a/src/nvim/api/private/handle.c
+++ b/src/nvim/api/private/handle.c
@@ -1,3 +1,6 @@
+// This is an open source non-commercial project. Dear PVS-Studio, please check
+// it. PVS-Studio Static Code Analyzer for C, C++ and C#: http://www.viva64.com
+
 #include <assert.h>
 #include <stdint.h>
 
diff --git a/src/nvim/api/private/helpers.c b/src/nvim/api/private/helpers.c
index 7efa086af2..629873998e 100644
--- a/src/nvim/api/private/helpers.c
+++ b/src/nvim/api/private/helpers.c
@@ -1,3 +1,6 @@
+// This is an open source non-commercial project. Dear PVS-Studio, please check
+// it. PVS-Studio Static Code Analyzer for C, C++ and C#: http://www.viva64.com
+
 #include <assert.h>
 #include <inttypes.h>
 #include <stdbool.h>
@@ -9,17 +12,20 @@
 #include "nvim/api/private/handle.h"
 #include "nvim/msgpack_rpc/helpers.h"
 #include "nvim/ascii.h"
+#include "nvim/assert.h"
 #include "nvim/vim.h"
 #include "nvim/buffer.h"
 #include "nvim/window.h"
 #include "nvim/memory.h"
 #include "nvim/eval.h"
+#include "nvim/eval/typval.h"
 #include "nvim/map_defs.h"
 #include "nvim/map.h"
 #include "nvim/option.h"
 #include "nvim/option_defs.h"
 #include "nvim/version.h"
 #include "nvim/lib/kvec.h"
+#include "nvim/getchar.h"
 
 /// Helper structure for vim_to_object
 typedef struct {
@@ -29,9 +35,75 @@ typedef struct {
 #ifdef INCLUDE_GENERATED_DECLARATIONS
 # include "api/private/helpers.c.generated.h"
 # include "api/private/funcs_metadata.generated.h"
+# include "api/private/ui_events_metadata.generated.h"
 #endif
 
+/// Start block that may cause VimL exceptions while evaluating another code
+///
+/// Used when caller is supposed to be operating when other VimL code is being
+/// processed and that “other VimL code” must not be affected.
+///
+/// @param[out]  tstate  Location where try state should be saved.
+void try_enter(TryState *const tstate)
+{
+  *tstate = (TryState) {
+    .current_exception = current_exception,
+    .msg_list = (const struct msglist *const *)msg_list,
+    .private_msg_list = NULL,
+    .trylevel = trylevel,
+    .got_int = got_int,
+    .did_throw = did_throw,
+    .need_rethrow = need_rethrow,
+    .did_emsg = did_emsg,
+  };
+  msg_list = &tstate->private_msg_list;
+  current_exception = NULL;
+  trylevel = 1;
+  got_int = false;
+  did_throw = false;
+  need_rethrow = false;
+  did_emsg = false;
+}
+
+/// End try block, set the error message if any and restore previous state
+///
+/// @warning Return is consistent with most functions (false on error), not with
+///          try_end (true on error).
+///
+/// @param[in]  tstate  Previous state to restore.
+/// @param[out]  err  Location where error should be saved.
+///
+/// @return false if error occurred, true otherwise.
+bool try_leave(const TryState *const tstate, Error *const err)
+  FUNC_ATTR_NONNULL_ALL FUNC_ATTR_WARN_UNUSED_RESULT
+{
+  const bool ret = !try_end(err);
+  assert(trylevel == 0);
+  assert(!need_rethrow);
+  assert(!got_int);
+  assert(!did_throw);
+  assert(!did_emsg);
+  assert(msg_list == &tstate->private_msg_list);
+  assert(*msg_list == NULL);
+  assert(current_exception == NULL);
+  msg_list = (struct msglist **)tstate->msg_list;
+  current_exception = tstate->current_exception;
+  trylevel = tstate->trylevel;
+  got_int = tstate->got_int;
+  did_throw = tstate->did_throw;
+  need_rethrow = tstate->need_rethrow;
+  did_emsg = tstate->did_emsg;
+  return ret;
+}
+
 /// Start block that may cause vimscript exceptions
+///
+/// Each try_start() call should be mirrored by try_end() call.
+///
+/// To be used as a replacement of `:try … catch … endtry` in C code, in cases
+/// when error flag could not already be set. If there may be pending error
+/// state at the time try_start() is executed which needs to be preserved,
+/// try_enter()/try_leave() pair should be used instead.
 void try_start(void)
 {
   ++trylevel;
@@ -44,7 +116,9 @@ void try_start(void)
 /// @return true if an error occurred
 bool try_end(Error *err)
 {
-  --trylevel;
+  // Note: all globals manipulated here should be saved/restored in
+  // try_enter/try_leave.
+  trylevel--;
 
   // Without this it stops processing all subsequent VimL commands and
   // generates strange error messages if I e.g. try calling Test() in a
@@ -57,7 +131,7 @@ bool try_end(Error *err)
       discard_current_exception();
     }
 
-    api_set_error(err, Exception, _("Keyboard interrupt"));
+    api_set_error(err, kErrorTypeException, "Keyboard interrupt");
     got_int = false;
   } else if (msg_list != NULL && *msg_list != NULL) {
     int should_free;
@@ -65,19 +139,18 @@ bool try_end(Error *err)
                                              ET_ERROR,
                                              NULL,
                                              &should_free);
-    xstrlcpy(err->msg, msg, sizeof(err->msg));
-    err->set = true;
+    api_set_error(err, kErrorTypeException, "%s", msg);
     free_global_msglist();
 
     if (should_free) {
       xfree(msg);
     }
   } else if (did_throw) {
-    api_set_error(err, Exception, "%s", current_exception->value);
+    api_set_error(err, kErrorTypeException, "%s", current_exception->value);
     discard_current_exception();
   }
 
-  return err->set;
+  return ERROR_SET(err);
 }
 
 /// Recursively expands a vimscript value in a dict
@@ -87,14 +160,13 @@ bool try_end(Error *err)
 /// @param[out] err Details of an error that may have occurred
 Object dict_get_value(dict_T *dict, String key, Error *err)
 {
-  hashitem_T *hi = hash_find(&dict->dv_hashtab, (uint8_t *) key.data);
+  dictitem_T *const di = tv_dict_find(dict, key.data, (ptrdiff_t)key.size);
 
-  if (HASHITEM_EMPTY(hi)) {
-    api_set_error(err, Validation, _("Key not found"));
-    return (Object) OBJECT_INIT;
+  if (di == NULL) {
+    api_set_error(err, kErrorTypeValidation, "Key '%s' not found", key.data);
+    return (Object)OBJECT_INIT;
   }
 
-  dictitem_T *di = dict_lookup(hi);
   return vim_to_object(&di->di_tv);
 }
 
@@ -115,31 +187,32 @@ Object dict_set_var(dict_T *dict, String key, Object value, bool del,
   Object rv = OBJECT_INIT;
 
   if (dict->dv_lock) {
-    api_set_error(err, Exception, _("Dictionary is locked"));
+    api_set_error(err, kErrorTypeException, "Dictionary is locked");
     return rv;
   }
 
   if (key.size == 0) {
-    api_set_error(err, Validation, _("Empty variable names aren't allowed"));
+    api_set_error(err, kErrorTypeValidation,
+                  "Empty variable names aren't allowed");
     return rv;
   }
 
   if (key.size > INT_MAX) {
-    api_set_error(err, Validation, _("Key length is too high"));
+    api_set_error(err, kErrorTypeValidation, "Key length is too high");
     return rv;
   }
 
-  dictitem_T *di = dict_find(dict, (char_u *)key.data, (int)key.size);
+  dictitem_T *di = tv_dict_find(dict, key.data, (ptrdiff_t)key.size);
 
   if (di != NULL) {
     if (di->di_flags & DI_FLAGS_RO) {
-      api_set_error(err, Exception, _("Key is read-only: %s"), key.data);
+      api_set_error(err, kErrorTypeException, "Key is read-only: %s", key.data);
       return rv;
     } else if (di->di_flags & DI_FLAGS_FIX) {
-      api_set_error(err, Exception, _("Key is fixed: %s"), key.data);
+      api_set_error(err, kErrorTypeException, "Key is fixed: %s", key.data);
       return rv;
     } else if (di->di_flags & DI_FLAGS_LOCK) {
-      api_set_error(err, Exception, _("Key is locked: %s"), key.data);
+      api_set_error(err, kErrorTypeException, "Key is locked: %s", key.data);
       return rv;
     }
   }
@@ -148,16 +221,15 @@ Object dict_set_var(dict_T *dict, String key, Object value, bool del,
     // Delete the key
     if (di == NULL) {
       // Doesn't exist, fail
-      api_set_error(err, Validation, _("Key \"%s\" doesn't exist"), key.data);
+      api_set_error(err, kErrorTypeValidation, "Key does not exist: %s",
+                    key.data);
     } else {
       // Return the old value
       if (retval) {
         rv = vim_to_object(&di->di_tv);
       }
       // Delete the entry
-      hashitem_T *hi = hash_find(&dict->dv_hashtab, di->di_key);
-      hash_remove(&dict->dv_hashtab, hi);
-      dictitem_free(di);
+      tv_dict_item_remove(dict, di);
     }
   } else {
     // Update the key
@@ -170,20 +242,20 @@ Object dict_set_var(dict_T *dict, String key, Object value, bool del,
 
     if (di == NULL) {
       // Need to create an entry
-      di = dictitem_alloc((uint8_t *) key.data);
-      dict_add(dict, di);
+      di = tv_dict_item_alloc_len(key.data, key.size);
+      tv_dict_add(dict, di);
     } else {
       // Return the old value
       if (retval) {
         rv = vim_to_object(&di->di_tv);
       }
-      clear_tv(&di->di_tv);
+      tv_clear(&di->di_tv);
     }
 
     // Update the value
-    copy_tv(&tv, &di->di_tv);
+    tv_copy(&tv, &di->di_tv);
     // Clear the temporary variable
-    clear_tv(&tv);
+    tv_clear(&tv);
   }
 
   return rv;
@@ -202,7 +274,7 @@ Object get_option_from(void *from, int type, String name, Error *err)
   Object rv = OBJECT_INIT;
 
   if (name.size == 0) {
-    api_set_error(err, Validation, _("Empty option name"));
+    api_set_error(err, kErrorTypeValidation, "Empty option name");
     return rv;
   }
 
@@ -214,8 +286,8 @@ Object get_option_from(void *from, int type, String name, Error *err)
 
   if (!flags) {
     api_set_error(err,
-                  Validation,
-                  _("Invalid option name \"%s\""),
+                  kErrorTypeValidation,
+                  "Invalid option name \"%s\"",
                   name.data);
     return rv;
   }
@@ -233,14 +305,14 @@ Object get_option_from(void *from, int type, String name, Error *err)
       rv.data.string.size = strlen(stringval);
     } else {
       api_set_error(err,
-                    Exception,
-                    _("Unable to get value for option \"%s\""),
+                    kErrorTypeException,
+                    "Unable to get value for option \"%s\"",
                     name.data);
     }
   } else {
     api_set_error(err,
-                  Exception,
-                  _("Unknown type for option \"%s\""),
+                  kErrorTypeException,
+                  "Unknown type for option \"%s\"",
                   name.data);
   }
 
@@ -257,7 +329,7 @@ Object get_option_from(void *from, int type, String name, Error *err)
 void set_option_to(void *to, int type, String name, Object value, Error *err)
 {
   if (name.size == 0) {
-    api_set_error(err, Validation, _("Empty option name"));
+    api_set_error(err, kErrorTypeValidation, "Empty option name");
     return;
   }
 
@@ -265,8 +337,8 @@ void set_option_to(void *to, int type, String name, Object value, Error *err)
 
   if (flags == 0) {
     api_set_error(err,
-                  Validation,
-                  _("Invalid option name \"%s\""),
+                  kErrorTypeValidation,
+                  "Invalid option name \"%s\"",
                   name.data);
     return;
   }
@@ -274,15 +346,15 @@ void set_option_to(void *to, int type, String name, Object value, Error *err)
   if (value.type == kObjectTypeNil) {
     if (type == SREQ_GLOBAL) {
       api_set_error(err,
-                    Exception,
-                    _("Unable to unset option \"%s\""),
+                    kErrorTypeException,
+                    "Unable to unset option \"%s\"",
                     name.data);
       return;
     } else if (!(flags & SOPT_GLOBAL)) {
       api_set_error(err,
-                    Exception,
-                    _("Cannot unset option \"%s\" "
-                      "because it doesn't have a global value"),
+                    kErrorTypeException,
+                    "Cannot unset option \"%s\" "
+                    "because it doesn't have a global value",
                     name.data);
       return;
     } else {
@@ -291,13 +363,13 @@ void set_option_to(void *to, int type, String name, Object value, Error *err)
     }
   }
 
-  int opt_flags = (type ? OPT_LOCAL : OPT_GLOBAL);
+  int opt_flags = (type == SREQ_GLOBAL) ? OPT_GLOBAL : OPT_LOCAL;
 
   if (flags & SOPT_BOOL) {
     if (value.type != kObjectTypeBoolean) {
       api_set_error(err,
-                    Validation,
-                    _("Option \"%s\" requires a boolean value"),
+                    kErrorTypeValidation,
+                    "Option \"%s\" requires a boolean value",
                     name.data);
       return;
     }
@@ -307,16 +379,16 @@ void set_option_to(void *to, int type, String name, Object value, Error *err)
   } else if (flags & SOPT_NUM) {
     if (value.type != kObjectTypeInteger) {
       api_set_error(err,
-                    Validation,
-                    _("Option \"%s\" requires an integer value"),
+                    kErrorTypeValidation,
+                    "Option \"%s\" requires an integer value",
                     name.data);
       return;
     }
 
     if (value.data.integer > INT_MAX || value.data.integer < INT_MIN) {
       api_set_error(err,
-                    Validation,
-                    _("Value for option \"%s\" is outside range"),
+                    kErrorTypeValidation,
+                    "Value for option \"%s\" is outside range",
                     name.data);
       return;
     }
@@ -326,8 +398,8 @@ void set_option_to(void *to, int type, String name, Object value, Error *err)
   } else {
     if (value.type != kObjectTypeString) {
       api_set_error(err,
-                    Validation,
-                    _("Option \"%s\" requires a string value"),
+                    kErrorTypeValidation,
+                    "Option \"%s\" requires a string value",
                     name.data);
       return;
     }
@@ -351,7 +423,7 @@ void set_option_to(void *to, int type, String name, Object value, Error *err)
 #define TYPVAL_ENCODE_CONV_UNSIGNED_NUMBER TYPVAL_ENCODE_CONV_NUMBER
 
 #define TYPVAL_ENCODE_CONV_FLOAT(tv, flt) \
-    kv_push(edata->stack, FLOATING_OBJ((Float)(flt)))
+    kv_push(edata->stack, FLOAT_OBJ((Float)(flt)))
 
 #define TYPVAL_ENCODE_CONV_STRING(tv, str, len) \
     do { \
@@ -560,13 +632,13 @@ buf_T *find_buffer_by_handle(Buffer buffer, Error *err)
   buf_T *rv = handle_get_buffer(buffer);
 
   if (!rv) {
-    api_set_error(err, Validation, _("Invalid buffer id"));
+    api_set_error(err, kErrorTypeValidation, "Invalid buffer id");
   }
 
   return rv;
 }
 
-win_T * find_window_by_handle(Window window, Error *err)
+win_T *find_window_by_handle(Window window, Error *err)
 {
   if (window == 0) {
     return curwin;
@@ -575,13 +647,13 @@ win_T * find_window_by_handle(Window window, Error *err)
   win_T *rv = handle_get_window(window);
 
   if (!rv) {
-    api_set_error(err, Validation, _("Invalid window id"));
+    api_set_error(err, kErrorTypeValidation, "Invalid window id");
   }
 
   return rv;
 }
 
-tabpage_T * find_tab_by_handle(Tabpage tabpage, Error *err)
+tabpage_T *find_tab_by_handle(Tabpage tabpage, Error *err)
 {
   if (tabpage == 0) {
     return curtab;
@@ -590,12 +662,28 @@ tabpage_T * find_tab_by_handle(Tabpage tabpage, Error *err)
   tabpage_T *rv = handle_get_tabpage(tabpage);
 
   if (!rv) {
-    api_set_error(err, Validation, _("Invalid tabpage id"));
+    api_set_error(err, kErrorTypeValidation, "Invalid tabpage id");
   }
 
   return rv;
 }
 
+/// Allocates a String consisting of a single char. Does not support multibyte
+/// characters. The resulting string is also NUL-terminated, to facilitate
+/// interoperating with code using C strings.
+///
+/// @param char the char to convert
+/// @return the resulting String, if the input char was NUL, an
+///         empty String is returned
+String cchar_to_string(char c)
+{
+  char buf[] = { c, NUL };
+  return (String) {
+    .data = xmemdupz(buf, 1),
+    .size = (c != NUL) ? 1 : 0
+  };
+}
+
 /// Copies a C string into a String (binary safe string, characters + length).
 /// The resulting string is also NUL-terminated, to facilitate interoperating
 /// with code using C strings.
@@ -616,6 +704,23 @@ String cstr_to_string(const char *str)
     };
 }
 
+/// Copies buffer to an allocated String.
+/// The resulting string is also NUL-terminated, to facilitate interoperating
+/// with code using C strings.
+///
+/// @param buf the buffer to copy
+/// @param size length of the buffer
+/// @return the resulting String, if the input string was NULL, an
+///         empty String is returned
+String cbuf_to_string(const char *buf, size_t size)
+  FUNC_ATTR_NONNULL_ALL
+{
+  return (String) {
+    .data = xmemdupz(buf, size),
+    .size = size
+  };
+}
+
 /// Creates a String using the given C string. Unlike
 /// cstr_to_string this function DOES NOT copy the C string.
 ///
@@ -627,7 +732,7 @@ String cstr_as_string(char *str) FUNC_ATTR_PURE
   if (str == NULL) {
     return (String) STRING_INIT;
   }
-  return (String) {.data = str, .size = strlen(str)};
+  return (String) { .data = str, .size = strlen(str) };
 }
 
 /// Converts from type Object to a VimL value.
@@ -656,12 +761,8 @@ bool object_to_vim(Object obj, typval_T *tv, Error *err)
     case kObjectTypeWindow:
     case kObjectTypeTabpage:
     case kObjectTypeInteger:
-      if (obj.data.integer > VARNUMBER_MAX
-          || obj.data.integer < VARNUMBER_MIN) {
-        api_set_error(err, Validation, _("Integer value outside range"));
-        return false;
-      }
-
+      STATIC_ASSERT(sizeof(obj.data.integer) <= sizeof(varnumber_T),
+                    "Integer size must be <= VimL number size");
       tv->v_type = VAR_NUMBER;
       tv->vval.v_number = (varnumber_T)obj.data.integer;
       break;
@@ -682,20 +783,20 @@ bool object_to_vim(Object obj, typval_T *tv, Error *err)
       break;
 
     case kObjectTypeArray: {
-      list_T *list = list_alloc();
+      list_T *const list = tv_list_alloc();
 
       for (uint32_t i = 0; i < obj.data.array.size; i++) {
         Object item = obj.data.array.items[i];
-        listitem_T *li = listitem_alloc();
+        listitem_T *li = tv_list_item_alloc();
 
         if (!object_to_vim(item, &li->li_tv, err)) {
           // cleanup
-          listitem_free(li);
-          list_free(list);
+          tv_list_item_free(li);
+          tv_list_free(list);
           return false;
         }
 
-        list_append(list, li);
+        tv_list_append(list, li);
       }
       list->lv_refcount++;
 
@@ -705,30 +806,30 @@ bool object_to_vim(Object obj, typval_T *tv, Error *err)
     }
 
     case kObjectTypeDictionary: {
-      dict_T *dict = dict_alloc();
+      dict_T *const dict = tv_dict_alloc();
 
       for (uint32_t i = 0; i < obj.data.dictionary.size; i++) {
         KeyValuePair item = obj.data.dictionary.items[i];
         String key = item.key;
 
         if (key.size == 0) {
-          api_set_error(err, Validation,
-                        _("Empty dictionary keys aren't allowed"));
+          api_set_error(err, kErrorTypeValidation,
+                        "Empty dictionary keys aren't allowed");
           // cleanup
-          dict_free(dict);
+          tv_dict_free(dict);
           return false;
         }
 
-        dictitem_T *di = dictitem_alloc((uint8_t *)key.data);
+        dictitem_T *const di = tv_dict_item_alloc(key.data);
 
         if (!object_to_vim(item.value, &di->di_tv, err)) {
           // cleanup
-          dictitem_free(di);
-          dict_free(dict);
+          tv_dict_item_free(di);
+          tv_dict_free(dict);
           return false;
         }
 
-        dict_add(dict, di);
+        tv_dict_add(dict, di);
       }
       dict->dv_refcount++;
 
@@ -800,6 +901,17 @@ void api_free_dictionary(Dictionary value)
   xfree(value.items);
 }
 
+void api_clear_error(Error *value)
+  FUNC_ATTR_NONNULL_ALL
+{
+  if (!ERROR_SET(value)) {
+    return;
+  }
+  xfree(value->msg);
+  value->msg = NULL;
+  value->type = kErrorTypeNone;
+}
+
 Dictionary api_metadata(void)
 {
   static Dictionary metadata = ARRAY_DICT_INIT;
@@ -807,6 +919,7 @@ Dictionary api_metadata(void)
   if (!metadata.size) {
     PUT(metadata, "version", DICTIONARY_OBJ(version_dict()));
     init_function_metadata(&metadata);
+    init_ui_event_metadata(&metadata);
     init_error_type_metadata(&metadata);
     init_type_metadata(&metadata);
   }
@@ -830,6 +943,22 @@ static void init_function_metadata(Dictionary *metadata)
   PUT(*metadata, "functions", functions);
 }
 
+static void init_ui_event_metadata(Dictionary *metadata)
+{
+  msgpack_unpacked unpacked;
+  msgpack_unpacked_init(&unpacked);
+  if (msgpack_unpack_next(&unpacked,
+                          (const char *)ui_events_metadata,
+                          sizeof(ui_events_metadata),
+                          NULL) != MSGPACK_UNPACK_SUCCESS) {
+    abort();
+  }
+  Object ui_events;
+  msgpack_rpc_to_object(&unpacked.data, &ui_events);
+  msgpack_unpacked_destroy(&unpacked);
+  PUT(*metadata, "ui_events", ui_events);
+}
+
 static void init_error_type_metadata(Dictionary *metadata)
 {
   Dictionary types = ARRAY_DICT_INIT;
@@ -851,15 +980,18 @@ static void init_type_metadata(Dictionary *metadata)
   Dictionary types = ARRAY_DICT_INIT;
 
   Dictionary buffer_metadata = ARRAY_DICT_INIT;
-  PUT(buffer_metadata, "id", INTEGER_OBJ(kObjectTypeBuffer));
+  PUT(buffer_metadata, "id",
+      INTEGER_OBJ(kObjectTypeBuffer - EXT_OBJECT_TYPE_SHIFT));
   PUT(buffer_metadata, "prefix", STRING_OBJ(cstr_to_string("nvim_buf_")));
 
   Dictionary window_metadata = ARRAY_DICT_INIT;
-  PUT(window_metadata, "id", INTEGER_OBJ(kObjectTypeWindow));
+  PUT(window_metadata, "id",
+      INTEGER_OBJ(kObjectTypeWindow - EXT_OBJECT_TYPE_SHIFT));
   PUT(window_metadata, "prefix", STRING_OBJ(cstr_to_string("nvim_win_")));
 
   Dictionary tabpage_metadata = ARRAY_DICT_INIT;
-  PUT(tabpage_metadata, "id", INTEGER_OBJ(kObjectTypeTabpage));
+  PUT(tabpage_metadata, "id",
+      INTEGER_OBJ(kObjectTypeTabpage - EXT_OBJECT_TYPE_SHIFT));
   PUT(tabpage_metadata, "prefix", STRING_OBJ(cstr_to_string("nvim_tabpage_")));
 
   PUT(types, "Buffer", DICTIONARY_OBJ(buffer_metadata));
@@ -869,6 +1001,24 @@ static void init_type_metadata(Dictionary *metadata)
   PUT(*metadata, "types", DICTIONARY_OBJ(types));
 }
 
+String copy_string(String str)
+{
+  if (str.data != NULL) {
+    return (String){ .data = xmemdupz(str.data, str.size), .size = str.size };
+  } else {
+    return (String)STRING_INIT;
+  }
+}
+
+Array copy_array(Array array)
+{
+  Array rv = ARRAY_DICT_INIT;
+  for (size_t i = 0; i < array.size; i++) {
+    ADD(rv, copy_object(array.items[i]));
+  }
+  return rv;
+}
+
 /// Creates a deep clone of an object
 Object copy_object(Object obj)
 {
@@ -880,15 +1030,10 @@ Object copy_object(Object obj)
       return obj;
 
     case kObjectTypeString:
-      return STRING_OBJ(cstr_to_string(obj.data.string.data));
+      return STRING_OBJ(copy_string(obj.data.string));
 
-    case kObjectTypeArray: {
-      Array rv = ARRAY_DICT_INIT;
-      for (size_t i = 0; i < obj.data.array.size; i++) {
-        ADD(rv, copy_object(obj.data.array.items[i]));
-      }
-      return ARRAY_OBJ(rv);
-    }
+    case kObjectTypeArray:
+      return ARRAY_OBJ(copy_array(obj.data.array));
 
     case kObjectTypeDictionary: {
       Dictionary rv = ARRAY_DICT_INIT;
@@ -913,7 +1058,7 @@ static void set_option_value_for(char *key,
 {
   win_T *save_curwin = NULL;
   tabpage_T *save_curtab = NULL;
-  bufref_T save_curbuf =  { NULL, 0 };
+  bufref_T save_curbuf =  { NULL, 0, 0 };
 
   try_start();
   switch (opt_type)
@@ -926,8 +1071,8 @@ static void set_option_value_for(char *key,
           return;
         }
         api_set_error(err,
-                      Exception,
-                      _("Problem while switching windows"));
+                      kErrorTypeException,
+                      "Problem while switching windows");
         return;
       }
       set_option_value_err(key, numval, stringval, opt_flags, err);
@@ -943,7 +1088,7 @@ static void set_option_value_for(char *key,
       break;
   }
 
-  if (err->set) {
+  if (ERROR_SET(err)) {
     return;
   }
 
@@ -959,15 +1104,69 @@ static void set_option_value_err(char *key,
 {
   char *errmsg;
 
-  if ((errmsg = (char *)set_option_value((uint8_t *)key,
-                                         numval,
-                                         (uint8_t *)stringval,
-                                         opt_flags)))
-  {
+  if ((errmsg = set_option_value(key, numval, stringval, opt_flags))) {
     if (try_end(err)) {
       return;
     }
 
-    api_set_error(err, Exception, "%s", errmsg);
+    api_set_error(err, kErrorTypeException, "%s", errmsg);
+  }
+}
+
+void api_set_error(Error *err, ErrorType errType, const char *format, ...)
+  FUNC_ATTR_NONNULL_ALL
+{
+  assert(kErrorTypeNone != errType);
+  va_list args1;
+  va_list args2;
+  va_start(args1, format);
+  va_copy(args2, args1);
+  int len = vsnprintf(NULL, 0, format, args1);
+  va_end(args1);
+  assert(len >= 0);
+  // Limit error message to 1 MB.
+  size_t bufsize = MIN((size_t)len + 1, 1024 * 1024);
+  err->msg = xmalloc(bufsize);
+  vsnprintf(err->msg, bufsize, format, args2);
+  va_end(args2);
+
+  err->type = errType;
+}
+
+/// Get an array containing dictionaries describing mappings
+/// based on mode and buffer id
+///
+/// @param  mode  The abbreviation for the mode
+/// @param  buf  The buffer to get the mapping array. NULL for global
+/// @returns An array of maparg() like dictionaries describing mappings
+ArrayOf(Dictionary) keymap_array(String mode, buf_T *buf)
+{
+  Array mappings = ARRAY_DICT_INIT;
+  dict_T *const dict = tv_dict_alloc();
+
+  // Convert the string mode to the integer mode
+  // that is stored within each mapblock
+  char_u *p = (char_u *)mode.data;
+  int int_mode = get_map_mode(&p, 0);
+
+  // Determine the desired buffer value
+  long buffer_value = (buf == NULL) ? 0 : buf->handle;
+
+  for (int i = 0; i < MAX_MAPHASH; i++) {
+    for (const mapblock_T *current_maphash = get_maphash(i, buf);
+         current_maphash;
+         current_maphash = current_maphash->m_next) {
+      // Check for correct mode
+      if (int_mode & current_maphash->m_mode) {
+        mapblock_fill_dict(dict, current_maphash, buffer_value, false);
+        ADD(mappings, vim_to_object(
+            (typval_T[]) { { .v_type = VAR_DICT, .vval.v_dict = dict } }));
+
+        tv_dict_clear(dict);
+      }
+    }
   }
+  tv_dict_free(dict);
+
+  return mappings;
 }
diff --git a/src/nvim/api/private/helpers.h b/src/nvim/api/private/helpers.h
index 9fe8c351cf..87f334ac30 100644
--- a/src/nvim/api/private/helpers.h
+++ b/src/nvim/api/private/helpers.h
@@ -6,17 +6,9 @@
 #include "nvim/api/private/defs.h"
 #include "nvim/vim.h"
 #include "nvim/memory.h"
+#include "nvim/ex_eval.h"
 #include "nvim/lib/kvec.h"
 
-#define api_set_error(err, errtype, ...) \
-  do { \
-    snprintf((err)->msg, \
-             sizeof((err)->msg), \
-             __VA_ARGS__); \
-    (err)->set = true; \
-    (err)->type = kErrorType##errtype; \
-  } while (0)
-
 #define OBJECT_OBJ(o) o
 
 #define BOOLEAN_OBJ(b) ((Object) { \
@@ -27,7 +19,7 @@
     .type = kObjectTypeInteger, \
     .data.integer = i })
 
-#define FLOATING_OBJ(f) ((Object) { \
+#define FLOAT_OBJ(f) ((Object) { \
     .type = kObjectTypeFloat, \
     .data.floating = f })
 
@@ -91,6 +83,21 @@
 #define api_free_window(value)
 #define api_free_tabpage(value)
 
+/// Structure used for saving state for :try
+///
+/// Used when caller is supposed to be operating when other VimL code is being
+/// processed and that “other VimL code” must not be affected.
+typedef struct {
+  except_T *current_exception;
+  struct msglist *private_msg_list;
+  const struct msglist *const *msg_list;
+  int trylevel;
+  int got_int;
+  int did_throw;
+  int need_rethrow;
+  int did_emsg;
+} TryState;
+
 #ifdef INCLUDE_GENERATED_DECLARATIONS
 # include "api/private/helpers.h.generated.h"
 #endif
diff --git a/src/nvim/api/tabpage.c b/src/nvim/api/tabpage.c
index 0f0c33f621..b6830d9fcf 100644
--- a/src/nvim/api/tabpage.c
+++ b/src/nvim/api/tabpage.c
@@ -1,3 +1,6 @@
+// This is an open source non-commercial project. Dear PVS-Studio, please check
+// it. PVS-Studio Static Code Analyzer for C, C++ and C#: http://www.viva64.com
+
 #include <stdbool.h>
 #include <stdint.h>
 #include <stdlib.h>
@@ -15,7 +18,7 @@
 /// @param[out] err Error details, if any
 /// @return List of windows in `tabpage`
 ArrayOf(Window) nvim_tabpage_list_wins(Tabpage tabpage, Error *err)
-    FUNC_API_SINCE(1)
+  FUNC_API_SINCE(1)
 {
   Array rv = ARRAY_DICT_INIT;
   tabpage_T *tab = find_tab_by_handle(tabpage, err);
@@ -45,7 +48,7 @@ ArrayOf(Window) nvim_tabpage_list_wins(Tabpage tabpage, Error *err)
 /// @param[out] err Error details, if any
 /// @return Variable value
 Object nvim_tabpage_get_var(Tabpage tabpage, String name, Error *err)
-    FUNC_API_SINCE(1)
+  FUNC_API_SINCE(1)
 {
   tabpage_T *tab = find_tab_by_handle(tabpage, err);
 
@@ -66,7 +69,7 @@ void nvim_tabpage_set_var(Tabpage tabpage,
                           String name,
                           Object value,
                           Error *err)
-    FUNC_API_SINCE(1)
+  FUNC_API_SINCE(1)
 {
   tabpage_T *tab = find_tab_by_handle(tabpage, err);
 
@@ -83,7 +86,7 @@ void nvim_tabpage_set_var(Tabpage tabpage,
 /// @param name     Variable name
 /// @param[out] err Error details, if any
 void nvim_tabpage_del_var(Tabpage tabpage, String name, Error *err)
-    FUNC_API_SINCE(1)
+  FUNC_API_SINCE(1)
 {
   tabpage_T *tab = find_tab_by_handle(tabpage, err);
 
@@ -142,7 +145,7 @@ Object tabpage_del_var(Tabpage tabpage, String name, Error *err)
 /// @param[out] err Error details, if any
 /// @return Window handle
 Window nvim_tabpage_get_win(Tabpage tabpage, Error *err)
-    FUNC_API_SINCE(1)
+  FUNC_API_SINCE(1)
 {
   Window rv = 0;
   tabpage_T *tab = find_tab_by_handle(tabpage, err);
@@ -170,7 +173,7 @@ Window nvim_tabpage_get_win(Tabpage tabpage, Error *err)
 /// @param[out] err Error details, if any
 /// @return Tabpage number
 Integer nvim_tabpage_get_number(Tabpage tabpage, Error *err)
-    FUNC_API_SINCE(1)
+  FUNC_API_SINCE(1)
 {
   Integer rv = 0;
   tabpage_T *tab = find_tab_by_handle(tabpage, err);
@@ -187,9 +190,11 @@ Integer nvim_tabpage_get_number(Tabpage tabpage, Error *err)
 /// @param tabpage Tabpage handle
 /// @return true if the tabpage is valid, false otherwise
 Boolean nvim_tabpage_is_valid(Tabpage tabpage)
-    FUNC_API_SINCE(1)
+  FUNC_API_SINCE(1)
 {
   Error stub = ERROR_INIT;
-  return find_tab_by_handle(tabpage, &stub) != NULL;
+  Boolean ret = find_tab_by_handle(tabpage, &stub) != NULL;
+  api_clear_error(&stub);
+  return ret;
 }
 
diff --git a/src/nvim/api/ui.c b/src/nvim/api/ui.c
index 625bcc6b4b..a9eaccfac5 100644
--- a/src/nvim/api/ui.c
+++ b/src/nvim/api/ui.c
@@ -1,3 +1,6 @@
+// This is an open source non-commercial project. Dear PVS-Studio, please check
+// it. PVS-Studio Static Code Analyzer for C, C++ and C#: http://www.viva64.com
+
 #include <assert.h>
 #include <stddef.h>
 #include <stdint.h>
@@ -12,9 +15,11 @@
 #include "nvim/api/private/defs.h"
 #include "nvim/api/private/helpers.h"
 #include "nvim/popupmnu.h"
+#include "nvim/cursor_shape.h"
 
 #ifdef INCLUDE_GENERATED_DECLARATIONS
 # include "api/ui.c.generated.h"
+# include "ui_events_remote.generated.h"
 #endif
 
 typedef struct {
@@ -25,13 +30,13 @@ typedef struct {
 static PMap(uint64_t) *connected_uis = NULL;
 
 void remote_ui_init(void)
-    FUNC_API_NOEXPORT
+  FUNC_API_NOEXPORT
 {
   connected_uis = pmap_new(uint64_t)();
 }
 
 void remote_ui_disconnect(uint64_t channel_id)
-    FUNC_API_NOEXPORT
+  FUNC_API_NOEXPORT
 {
   UI *ui = pmap_get(uint64_t)(connected_uis, channel_id);
   if (!ui) {
@@ -48,27 +53,27 @@ void remote_ui_disconnect(uint64_t channel_id)
 
 void nvim_ui_attach(uint64_t channel_id, Integer width, Integer height,
                     Dictionary options, Error *err)
-    FUNC_API_SINCE(1) FUNC_API_NOEVAL
+  FUNC_API_SINCE(1) FUNC_API_REMOTE_ONLY
 {
   if (pmap_has(uint64_t)(connected_uis, channel_id)) {
-    api_set_error(err, Exception, _("UI already attached for channel"));
+    api_set_error(err, kErrorTypeException, "UI already attached for channel");
     return;
   }
 
   if (width <= 0 || height <= 0) {
-    api_set_error(err, Validation,
-                  _("Expected width > 0 and height > 0"));
+    api_set_error(err, kErrorTypeValidation,
+                  "Expected width > 0 and height > 0");
     return;
   }
   UI *ui = xcalloc(1, sizeof(UI));
   ui->width = (int)width;
   ui->height = (int)height;
   ui->rgb = true;
-  ui->pum_external = false;
   ui->resize = remote_ui_resize;
   ui->clear = remote_ui_clear;
   ui->eol_clear = remote_ui_eol_clear;
   ui->cursor_goto = remote_ui_cursor_goto;
+  ui->mode_info_set = remote_ui_mode_info_set;
   ui->update_menu = remote_ui_update_menu;
   ui->busy_start = remote_ui_busy_start;
   ui->busy_stop = remote_ui_busy_stop;
@@ -90,9 +95,11 @@ void nvim_ui_attach(uint64_t channel_id, Integer width, Integer height,
   ui->set_icon = remote_ui_set_icon;
   ui->event = remote_ui_event;
 
+  memset(ui->ui_ext, 0, sizeof(ui->ui_ext));
+
   for (size_t i = 0; i < options.size; i++) {
     ui_set_option(ui, options.items[i].key, options.items[i].value, err);
-    if (err->set) {
+    if (ERROR_SET(err)) {
       xfree(ui);
       return;
     }
@@ -118,10 +125,10 @@ void ui_attach(uint64_t channel_id, Integer width, Integer height,
 }
 
 void nvim_ui_detach(uint64_t channel_id, Error *err)
-    FUNC_API_SINCE(1) FUNC_API_NOEVAL
+  FUNC_API_SINCE(1) FUNC_API_REMOTE_ONLY
 {
   if (!pmap_has(uint64_t)(connected_uis, channel_id)) {
-    api_set_error(err, Exception, _("UI is not attached for channel"));
+    api_set_error(err, kErrorTypeException, "UI is not attached for channel");
     return;
   }
   remote_ui_disconnect(channel_id);
@@ -130,16 +137,16 @@ void nvim_ui_detach(uint64_t channel_id, Error *err)
 
 void nvim_ui_try_resize(uint64_t channel_id, Integer width,
                         Integer height, Error *err)
-    FUNC_API_SINCE(1) FUNC_API_NOEVAL
+  FUNC_API_SINCE(1) FUNC_API_REMOTE_ONLY
 {
   if (!pmap_has(uint64_t)(connected_uis, channel_id)) {
-    api_set_error(err, Exception, _("UI is not attached for channel"));
+    api_set_error(err, kErrorTypeException, "UI is not attached for channel");
     return;
   }
 
   if (width <= 0 || height <= 0) {
-    api_set_error(err, Validation,
-                  _("Expected width > 0 and height > 0"));
+    api_set_error(err, kErrorTypeValidation,
+                  "Expected width > 0 and height > 0");
     return;
   }
 
@@ -151,39 +158,64 @@ void nvim_ui_try_resize(uint64_t channel_id, Integer width,
 
 void nvim_ui_set_option(uint64_t channel_id, String name,
                         Object value, Error *error)
-    FUNC_API_SINCE(1) FUNC_API_NOEVAL
+  FUNC_API_SINCE(1) FUNC_API_REMOTE_ONLY
 {
   if (!pmap_has(uint64_t)(connected_uis, channel_id)) {
-    api_set_error(error, Exception, _("UI is not attached for channel"));
+    api_set_error(error, kErrorTypeException, "UI is not attached for channel");
     return;
   }
   UI *ui = pmap_get(uint64_t)(connected_uis, channel_id);
 
   ui_set_option(ui, name, value, error);
-  if (!error->set) {
+  if (!ERROR_SET(error)) {
     ui_refresh();
   }
 }
 
-static void ui_set_option(UI *ui, String name, Object value, Error *error) {
-  if (strcmp(name.data, "rgb") == 0) {
+static void ui_set_option(UI *ui, String name, Object value, Error *error)
+{
+#define UI_EXT_OPTION(o, e) \
+  do { \
+    if (strequal(name.data, #o)) { \
+      if (value.type != kObjectTypeBoolean) { \
+        api_set_error(error, kErrorTypeValidation, #o " must be a Boolean"); \
+        return; \
+      } \
+      ui->ui_ext[(e)] = value.data.boolean; \
+      return; \
+    } \
+  } while (0)
+
+  if (strequal(name.data, "rgb")) {
     if (value.type != kObjectTypeBoolean) {
-      api_set_error(error, Validation, _("rgb must be a Boolean"));
+      api_set_error(error, kErrorTypeValidation, "rgb must be a Boolean");
       return;
     }
     ui->rgb = value.data.boolean;
-  } else if (strcmp(name.data, "popupmenu_external") == 0) {
+    return;
+  }
+
+  UI_EXT_OPTION(ext_cmdline, kUICmdline);
+  UI_EXT_OPTION(ext_popupmenu, kUIPopupmenu);
+  UI_EXT_OPTION(ext_tabline, kUITabline);
+  UI_EXT_OPTION(ext_wildmenu, kUIWildmenu);
+
+  if (strequal(name.data, "popupmenu_external")) {
+    // LEGACY: Deprecated option, use `ui_ext` instead.
     if (value.type != kObjectTypeBoolean) {
-      api_set_error(error, Validation,
-                    _("popupmenu_external must be a Boolean"));
+      api_set_error(error, kErrorTypeValidation,
+                    "popupmenu_external must be a Boolean");
       return;
     }
-    ui->pum_external = value.data.boolean;
-  } else {
-    api_set_error(error, Validation, _("No such ui option"));
+    ui->ui_ext[kUIPopupmenu] = value.data.boolean;
+    return;
   }
+
+  api_set_error(error, kErrorTypeValidation, "No such ui option");
+#undef UI_EXT_OPTION
 }
 
+/// Pushes data into UI.UIData, to be consumed later by remote_ui_flush().
 static void push_call(UI *ui, char *name, Array args)
 {
   Array call = ARRAY_DICT_INIT;
@@ -206,205 +238,23 @@ static void push_call(UI *ui, char *name, Array args)
   kv_A(data->buffer, kv_size(data->buffer) - 1).data.array = call;
 }
 
-static void remote_ui_resize(UI *ui, int width, int height)
-{
-  Array args = ARRAY_DICT_INIT;
-  ADD(args, INTEGER_OBJ(width));
-  ADD(args, INTEGER_OBJ(height));
-  push_call(ui, "resize", args);
-}
-
-static void remote_ui_clear(UI *ui)
-{
-  Array args = ARRAY_DICT_INIT;
-  push_call(ui, "clear", args);
-}
-
-static void remote_ui_eol_clear(UI *ui)
-{
-  Array args = ARRAY_DICT_INIT;
-  push_call(ui, "eol_clear", args);
-}
-
-static void remote_ui_cursor_goto(UI *ui, int row, int col)
-{
-  Array args = ARRAY_DICT_INIT;
-  ADD(args, INTEGER_OBJ(row));
-  ADD(args, INTEGER_OBJ(col));
-  push_call(ui, "cursor_goto", args);
-}
-
-static void remote_ui_update_menu(UI *ui)
-{
-  Array args = ARRAY_DICT_INIT;
-  push_call(ui, "update_menu", args);
-}
-
-static void remote_ui_busy_start(UI *ui)
-{
-  Array args = ARRAY_DICT_INIT;
-  push_call(ui, "busy_start", args);
-}
-
-static void remote_ui_busy_stop(UI *ui)
-{
-  Array args = ARRAY_DICT_INIT;
-  push_call(ui, "busy_stop", args);
-}
-
-static void remote_ui_mouse_on(UI *ui)
-{
-  Array args = ARRAY_DICT_INIT;
-  push_call(ui, "mouse_on", args);
-}
-
-static void remote_ui_mouse_off(UI *ui)
-{
-  Array args = ARRAY_DICT_INIT;
-  push_call(ui, "mouse_off", args);
-}
-
-static void remote_ui_mode_change(UI *ui, int mode)
-{
-  Array args = ARRAY_DICT_INIT;
-  if (mode == INSERT) {
-    ADD(args, STRING_OBJ(cstr_to_string("insert")));
-  } else if (mode == REPLACE) {
-    ADD(args, STRING_OBJ(cstr_to_string("replace")));
-  } else if (mode == CMDLINE) {
-    ADD(args, STRING_OBJ(cstr_to_string("cmdline")));
-  } else {
-    assert(mode == NORMAL);
-    ADD(args, STRING_OBJ(cstr_to_string("normal")));
-  }
-  push_call(ui, "mode_change", args);
-}
-
-static void remote_ui_set_scroll_region(UI *ui, int top, int bot, int left,
-                                        int right)
-{
-  Array args = ARRAY_DICT_INIT;
-  ADD(args, INTEGER_OBJ(top));
-  ADD(args, INTEGER_OBJ(bot));
-  ADD(args, INTEGER_OBJ(left));
-  ADD(args, INTEGER_OBJ(right));
-  push_call(ui, "set_scroll_region", args);
-}
-
-static void remote_ui_scroll(UI *ui, int count)
-{
-  Array args = ARRAY_DICT_INIT;
-  ADD(args, INTEGER_OBJ(count));
-  push_call(ui, "scroll", args);
-}
 
 static void remote_ui_highlight_set(UI *ui, HlAttrs attrs)
 {
   Array args = ARRAY_DICT_INIT;
-  Dictionary hl = ARRAY_DICT_INIT;
-
-  if (attrs.bold) {
-    PUT(hl, "bold", BOOLEAN_OBJ(true));
-  }
-
-  if (attrs.underline) {
-    PUT(hl, "underline", BOOLEAN_OBJ(true));
-  }
-
-  if (attrs.undercurl) {
-    PUT(hl, "undercurl", BOOLEAN_OBJ(true));
-  }
-
-  if (attrs.italic) {
-    PUT(hl, "italic", BOOLEAN_OBJ(true));
-  }
-
-  if (attrs.reverse) {
-    PUT(hl, "reverse", BOOLEAN_OBJ(true));
-  }
-
-  if (attrs.foreground != -1) {
-    PUT(hl, "foreground", INTEGER_OBJ(attrs.foreground));
-  }
-
-  if (attrs.background != -1) {
-    PUT(hl, "background", INTEGER_OBJ(attrs.background));
-  }
-
-  if (attrs.special != -1) {
-    PUT(hl, "special", INTEGER_OBJ(attrs.special));
-  }
+  Dictionary hl = hlattrs2dict(attrs);
 
   ADD(args, DICTIONARY_OBJ(hl));
   push_call(ui, "highlight_set", args);
 }
 
-static void remote_ui_put(UI *ui, uint8_t *data, size_t size)
-{
-  Array args = ARRAY_DICT_INIT;
-  String str = { .data = xmemdupz(data, size), .size = size };
-  ADD(args, STRING_OBJ(str));
-  push_call(ui, "put", args);
-}
-
-static void remote_ui_bell(UI *ui)
-{
-  Array args = ARRAY_DICT_INIT;
-  push_call(ui, "bell", args);
-}
-
-static void remote_ui_visual_bell(UI *ui)
-{
-  Array args = ARRAY_DICT_INIT;
-  push_call(ui, "visual_bell", args);
-}
-
-static void remote_ui_update_fg(UI *ui, int fg)
-{
-  Array args = ARRAY_DICT_INIT;
-  ADD(args, INTEGER_OBJ(fg));
-  push_call(ui, "update_fg", args);
-}
-
-static void remote_ui_update_bg(UI *ui, int bg)
-{
-  Array args = ARRAY_DICT_INIT;
-  ADD(args, INTEGER_OBJ(bg));
-  push_call(ui, "update_bg", args);
-}
-
-static void remote_ui_update_sp(UI *ui, int sp)
-{
-  Array args = ARRAY_DICT_INIT;
-  ADD(args, INTEGER_OBJ(sp));
-  push_call(ui, "update_sp", args);
-}
-
 static void remote_ui_flush(UI *ui)
 {
   UIData *data = ui->data;
-  channel_send_event(data->channel_id, "redraw", data->buffer);
-  data->buffer = (Array)ARRAY_DICT_INIT;
-}
-
-static void remote_ui_suspend(UI *ui)
-{
-  Array args = ARRAY_DICT_INIT;
-  push_call(ui, "suspend", args);
-}
-
-static void remote_ui_set_title(UI *ui, char *title)
-{
-  Array args = ARRAY_DICT_INIT;
-  ADD(args, STRING_OBJ(cstr_to_string(title)));
-  push_call(ui, "set_title", args);
-}
-
-static void remote_ui_set_icon(UI *ui, char *icon)
-{
-  Array args = ARRAY_DICT_INIT;
-  ADD(args, STRING_OBJ(cstr_to_string(icon)));
-  push_call(ui, "set_icon", args);
+  if (data->buffer.size > 0) {
+    rpc_send_event(data->channel_id, "redraw", data->buffer);
+    data->buffer = (Array)ARRAY_DICT_INIT;
+  }
 }
 
 static void remote_ui_event(UI *ui, char *name, Array args, bool *args_consumed)
diff --git a/src/nvim/api/ui_events.in.h b/src/nvim/api/ui_events.in.h
new file mode 100644
index 0000000000..847b21072a
--- /dev/null
+++ b/src/nvim/api/ui_events.in.h
@@ -0,0 +1,94 @@
+#ifndef NVIM_API_UI_EVENTS_IN_H
+#define NVIM_API_UI_EVENTS_IN_H
+
+// This file is not compiled, just parsed for definitons
+#ifdef INCLUDE_GENERATED_DECLARATIONS
+# error "don't include this file, include nvim/ui.h"
+#endif
+
+#include "nvim/api/private/defs.h"
+#include "nvim/func_attr.h"
+#include "nvim/ui.h"
+
+void resize(Integer rows, Integer columns)
+  FUNC_API_SINCE(3);
+void clear(void)
+  FUNC_API_SINCE(3);
+void eol_clear(void)
+  FUNC_API_SINCE(3);
+void cursor_goto(Integer row, Integer col)
+  FUNC_API_SINCE(3);
+void mode_info_set(Boolean enabled, Array cursor_styles)
+  FUNC_API_SINCE(3);
+void update_menu(void)
+  FUNC_API_SINCE(3);
+void busy_start(void)
+  FUNC_API_SINCE(3);
+void busy_stop(void)
+  FUNC_API_SINCE(3);
+void mouse_on(void)
+  FUNC_API_SINCE(3);
+void mouse_off(void)
+  FUNC_API_SINCE(3);
+void mode_change(String mode, Integer mode_idx)
+  FUNC_API_SINCE(3);
+void set_scroll_region(Integer top, Integer bot, Integer left, Integer right)
+  FUNC_API_SINCE(3);
+void scroll(Integer count)
+  FUNC_API_SINCE(3);
+void highlight_set(HlAttrs attrs)
+  FUNC_API_SINCE(3) FUNC_API_REMOTE_IMPL FUNC_API_BRIDGE_IMPL;
+void put(String str)
+  FUNC_API_SINCE(3);
+void bell(void)
+  FUNC_API_SINCE(3);
+void visual_bell(void)
+  FUNC_API_SINCE(3);
+void flush(void)
+  FUNC_API_SINCE(3) FUNC_API_REMOTE_IMPL;
+void update_fg(Integer fg)
+  FUNC_API_SINCE(3);
+void update_bg(Integer bg)
+  FUNC_API_SINCE(3);
+void update_sp(Integer sp)
+  FUNC_API_SINCE(3);
+void suspend(void)
+  FUNC_API_SINCE(3) FUNC_API_BRIDGE_IMPL;
+void set_title(String title)
+  FUNC_API_SINCE(3);
+void set_icon(String icon)
+  FUNC_API_SINCE(3);
+
+void popupmenu_show(Array items, Integer selected, Integer row, Integer col)
+  FUNC_API_SINCE(3) FUNC_API_REMOTE_ONLY;
+void popupmenu_hide(void)
+  FUNC_API_SINCE(3) FUNC_API_REMOTE_ONLY;
+void popupmenu_select(Integer selected)
+  FUNC_API_SINCE(3) FUNC_API_REMOTE_ONLY;
+
+void tabline_update(Tabpage current, Array tabs)
+  FUNC_API_SINCE(3) FUNC_API_REMOTE_ONLY;
+
+void cmdline_show(Array content, Integer pos, String firstc, String prompt,
+                  Integer indent, Integer level)
+  FUNC_API_SINCE(3) FUNC_API_REMOTE_ONLY;
+void cmdline_pos(Integer pos, Integer level)
+  FUNC_API_SINCE(3) FUNC_API_REMOTE_ONLY;
+void cmdline_special_char(String c, Boolean shift, Integer level)
+  FUNC_API_SINCE(3) FUNC_API_REMOTE_ONLY;
+void cmdline_hide(Integer level)
+  FUNC_API_SINCE(3) FUNC_API_REMOTE_ONLY;
+void cmdline_block_show(Array lines)
+  FUNC_API_SINCE(3) FUNC_API_REMOTE_ONLY;
+void cmdline_block_append(Array lines)
+  FUNC_API_SINCE(3) FUNC_API_REMOTE_ONLY;
+void cmdline_block_hide(void)
+  FUNC_API_SINCE(3) FUNC_API_REMOTE_ONLY;
+
+void wildmenu_show(Array items)
+  FUNC_API_SINCE(3) FUNC_API_REMOTE_ONLY;
+void wildmenu_select(Integer selected)
+  FUNC_API_SINCE(3) FUNC_API_REMOTE_ONLY;
+void wildmenu_hide(void)
+  FUNC_API_SINCE(3) FUNC_API_REMOTE_ONLY;
+#endif  // NVIM_API_UI_EVENTS_IN_H
diff --git a/src/nvim/api/vim.c b/src/nvim/api/vim.c
index 413456c615..f4ccf07bec 100644
--- a/src/nvim/api/vim.c
+++ b/src/nvim/api/vim.c
@@ -1,3 +1,6 @@
+// This is an open source non-commercial project. Dear PVS-Studio, please check
+// it. PVS-Studio Static Code Analyzer for C, C++ and C#: http://www.viva64.com
+
 #include <assert.h>
 #include <stdint.h>
 #include <inttypes.h>
@@ -10,8 +13,10 @@
 #include "nvim/ascii.h"
 #include "nvim/api/private/helpers.h"
 #include "nvim/api/private/defs.h"
+#include "nvim/api/private/dispatch.h"
 #include "nvim/api/buffer.h"
 #include "nvim/msgpack_rpc/channel.h"
+#include "nvim/lua/executor.h"
 #include "nvim/vim.h"
 #include "nvim/buffer.h"
 #include "nvim/file_search.h"
@@ -22,7 +27,9 @@
 #include "nvim/memory.h"
 #include "nvim/message.h"
 #include "nvim/eval.h"
+#include "nvim/eval/typval.h"
 #include "nvim/option.h"
+#include "nvim/state.h"
 #include "nvim/syntax.h"
 #include "nvim/getchar.h"
 #include "nvim/os/input.h"
@@ -39,7 +46,7 @@
 /// @param command  Ex-command string
 /// @param[out] err Error details (including actual VimL error), if any
 void nvim_command(String command, Error *err)
-    FUNC_API_SINCE(1)
+  FUNC_API_SINCE(1)
 {
   // Run the command
   try_start();
@@ -48,6 +55,48 @@ void nvim_command(String command, Error *err)
   try_end(err);
 }
 
+/// Gets a highlight definition by name.
+///
+/// @param name Highlight group name
+/// @param rgb Export RGB colors
+/// @param[out] err Error details, if any
+/// @return Highlight definition map
+/// @see nvim_get_hl_by_id
+Dictionary nvim_get_hl_by_name(String name, Boolean rgb, Error *err)
+  FUNC_API_SINCE(3)
+{
+  Dictionary result = ARRAY_DICT_INIT;
+  int id = syn_name2id((const char_u *)name.data);
+
+  if (id == 0) {
+    api_set_error(err, kErrorTypeException, "Invalid highlight name: %s",
+                  name.data);
+    return result;
+  }
+  result = nvim_get_hl_by_id(id, rgb, err);
+  return result;
+}
+
+/// Gets a highlight definition by id. |hlID()|
+///
+/// @param hl_id Highlight id as returned by |hlID()|
+/// @param rgb Export RGB colors
+/// @param[out] err Error details, if any
+/// @return Highlight definition map
+/// @see nvim_get_hl_by_name
+Dictionary nvim_get_hl_by_id(Integer hl_id, Boolean rgb, Error *err)
+  FUNC_API_SINCE(3)
+{
+  Dictionary dic = ARRAY_DICT_INIT;
+  if (syn_get_final_id((int)hl_id) == 0) {
+    api_set_error(err, kErrorTypeException,
+                  "Invalid highlight id: %" PRId64, hl_id);
+    return dic;
+  }
+  int attrcode = syn_id2attr((int)hl_id);
+  return hl_get_attr_by_id(attrcode, rgb, err);
+}
+
 /// Passes input keys to Nvim.
 /// On VimL error: Does not fail, but updates v:errmsg.
 ///
@@ -57,7 +106,7 @@ void nvim_command(String command, Error *err)
 /// @see feedkeys()
 /// @see vim_strsave_escape_csi
 void nvim_feedkeys(String keys, String mode, Boolean escape_csi)
-    FUNC_API_SINCE(1)
+  FUNC_API_SINCE(1)
 {
   bool remap = true;
   bool insert = false;
@@ -118,51 +167,53 @@ void nvim_feedkeys(String keys, String mode, Boolean escape_csi)
 /// On VimL error: Does not fail, but updates v:errmsg.
 ///
 /// Unlike `nvim_feedkeys`, this uses a lower-level input buffer and the call
-/// is not deferred. This is the most reliable way to emulate real user input.
+/// is not deferred. This is the most reliable way to send real user input.
+///
+/// @note |keycodes| like <CR> are translated, so "<" is special.
+///       To input a literal "<", send <LT>.
 ///
 /// @param keys to be typed
 /// @return Number of bytes actually written (can be fewer than
 ///         requested if the buffer becomes full).
 Integer nvim_input(String keys)
-    FUNC_API_SINCE(1) FUNC_API_ASYNC
+  FUNC_API_SINCE(1) FUNC_API_ASYNC
 {
   return (Integer)input_enqueue(keys);
 }
 
-/// Replaces any terminal codes with the internal representation
+/// Replaces terminal codes and |keycodes| (<CR>, <Esc>, ...) in a string with
+/// the internal representation.
 ///
+/// @param str        String to be converted.
+/// @param from_part  Legacy Vim parameter. Usually true.
+/// @param do_lt      Also translate <lt>. Ignored if `special` is false.
+/// @param special    Replace |keycodes|, e.g. <CR> becomes a "\n" char.
 /// @see replace_termcodes
 /// @see cpoptions
 String nvim_replace_termcodes(String str, Boolean from_part, Boolean do_lt,
                               Boolean special)
-    FUNC_API_SINCE(1)
+  FUNC_API_SINCE(1)
 {
   if (str.size == 0) {
     // Empty string
-    return str;
+    return (String) { .data = NULL, .size = 0 };
   }
 
   char *ptr = NULL;
-  // Set 'cpoptions' the way we want it.
-  //    FLAG_CPO_BSLASH  set - backslashes are *not* treated specially
-  //    FLAG_CPO_KEYCODE set - keycodes are *not* reverse-engineered
-  //    FLAG_CPO_SPECI unset - <Key> sequences *are* interpreted
-  //  The third from end parameter of replace_termcodes() is true so that the
-  //  <lt> sequence is recognised - needed for a real backslash.
   replace_termcodes((char_u *)str.data, str.size, (char_u **)&ptr,
                     from_part, do_lt, special, CPO_TO_CPO_FLAGS);
   return cstr_as_string(ptr);
 }
 
 String nvim_command_output(String str, Error *err)
-    FUNC_API_SINCE(1)
+  FUNC_API_SINCE(1)
 {
   do_cmdline_cmd("redir => v:command_output");
   nvim_command(str, err);
   do_cmdline_cmd("redir END");
 
-  if (err->set) {
-    return (String) STRING_INIT;
+  if (ERROR_SET(err)) {
+    return (String)STRING_INIT;
   }
 
   return cstr_to_string((char *)get_vim_var_str(VV_COMMAND_OUTPUT));
@@ -176,28 +227,30 @@ String nvim_command_output(String str, Error *err)
 /// @param[out] err Error details, if any
 /// @return         Evaluation result or expanded object
 Object nvim_eval(String expr, Error *err)
-    FUNC_API_SINCE(1)
+  FUNC_API_SINCE(1)
 {
   Object rv = OBJECT_INIT;
   // Evaluate the expression
   try_start();
-  typval_T *expr_result = eval_expr((char_u *)expr.data, NULL);
 
-  if (!expr_result) {
-    api_set_error(err, Exception, _("Failed to evaluate expression"));
+  typval_T rettv;
+  if (eval0((char_u *)expr.data, &rettv, NULL, true) == FAIL) {
+    api_set_error(err, kErrorTypeException, "Failed to evaluate expression");
   }
 
   if (!try_end(err)) {
     // No errors, convert the result
-    rv = vim_to_object(expr_result);
+    rv = vim_to_object(&rettv);
   }
 
-  // Free the vim object
-  free_tv(expr_result);
+  // Free the Vim object
+  tv_clear(&rettv);
+
   return rv;
 }
 
-/// Calls a VimL function with the given arguments.
+/// Calls a VimL function with the given arguments
+///
 /// On VimL error: Returns a generic error; v:errmsg is not updated.
 ///
 /// @param fname    Function to call
@@ -205,12 +258,12 @@ Object nvim_eval(String expr, Error *err)
 /// @param[out] err Error details, if any
 /// @return Result of the function call
 Object nvim_call_function(String fname, Array args, Error *err)
-    FUNC_API_SINCE(1)
+  FUNC_API_SINCE(1)
 {
   Object rv = OBJECT_INIT;
   if (args.size > MAX_FUNC_ARGS) {
-    api_set_error(err, Validation,
-      _("Function called with too many arguments."));
+    api_set_error(err, kErrorTypeValidation,
+                  "Function called with too many arguments.");
     return rv;
   }
 
@@ -232,46 +285,64 @@ Object nvim_call_function(String fname, Array args, Error *err)
                     curwin->w_cursor.lnum, curwin->w_cursor.lnum, &dummy,
                     true, NULL, NULL);
   if (r == FAIL) {
-    api_set_error(err, Exception, _("Error calling function."));
+    api_set_error(err, kErrorTypeException, "Error calling function.");
   }
   if (!try_end(err)) {
     rv = vim_to_object(&rettv);
   }
-  clear_tv(&rettv);
+  tv_clear(&rettv);
 
 free_vim_args:
   while (i > 0) {
-    clear_tv(&vim_args[--i]);
+    tv_clear(&vim_args[--i]);
   }
 
   return rv;
 }
 
+/// Execute lua code. Parameters (if any) are available as `...` inside the
+/// chunk. The chunk can return a value.
+///
+/// Only statements are executed. To evaluate an expression, prefix it
+/// with `return`: return my_function(...)
+///
+/// @param code       lua code to execute
+/// @param args       Arguments to the code
+/// @param[out] err   Details of an error encountered while parsing
+///                   or executing the lua code.
+///
+/// @return           Return value of lua code if present or NIL.
+Object nvim_execute_lua(String code, Array args, Error *err)
+  FUNC_API_SINCE(3) FUNC_API_REMOTE_ONLY
+{
+  return executor_exec_lua_api(code, args, err);
+}
+
 /// Calculates the number of display cells occupied by `text`.
 /// <Tab> counts as one cell.
 ///
 /// @param text       Some text
 /// @param[out] err   Error details, if any
 /// @return Number of cells
-Integer nvim_strwidth(String str, Error *err)
-    FUNC_API_SINCE(1)
+Integer nvim_strwidth(String text, Error *err)
+  FUNC_API_SINCE(1)
 {
-  if (str.size > INT_MAX) {
-    api_set_error(err, Validation, _("String length is too high"));
+  if (text.size > INT_MAX) {
+    api_set_error(err, kErrorTypeValidation, "String length is too high");
     return 0;
   }
 
-  return (Integer) mb_string2cells((char_u *) str.data);
+  return (Integer)mb_string2cells((char_u *)text.data);
 }
 
 /// Gets the paths contained in 'runtimepath'.
 ///
 /// @return List of paths
 ArrayOf(String) nvim_list_runtime_paths(void)
-    FUNC_API_SINCE(1)
+  FUNC_API_SINCE(1)
 {
   Array rv = ARRAY_DICT_INIT;
-  uint8_t *rtp = p_rtp;
+  char_u *rtp = p_rtp;
 
   if (*rtp == NUL) {
     // No paths
@@ -285,13 +356,14 @@ ArrayOf(String) nvim_list_runtime_paths(void)
     }
     rtp++;
   }
+  rv.size++;
 
   // Allocate memory for the copies
-  rv.items = xmalloc(sizeof(Object) * rv.size);
+  rv.items = xmalloc(sizeof(*rv.items) * rv.size);
   // Reset the position
   rtp = p_rtp;
   // Start copying
-  for (size_t i = 0; i < rv.size && *rtp != NUL; i++) {
+  for (size_t i = 0; i < rv.size; i++) {
     rv.items[i].type = kObjectTypeString;
     rv.items[i].data.string.data = xmalloc(MAXPATHL);
     // Copy the path from 'runtimepath' to rv.items[i]
@@ -310,10 +382,10 @@ ArrayOf(String) nvim_list_runtime_paths(void)
 /// @param dir      Directory path
 /// @param[out] err Error details, if any
 void nvim_set_current_dir(String dir, Error *err)
-    FUNC_API_SINCE(1)
+  FUNC_API_SINCE(1)
 {
   if (dir.size >= MAXPATHL) {
-    api_set_error(err, Validation, _("Directory string is too long"));
+    api_set_error(err, kErrorTypeValidation, "Directory string is too long");
     return;
   }
 
@@ -325,7 +397,7 @@ void nvim_set_current_dir(String dir, Error *err)
 
   if (vim_chdir((char_u *)string, kCdScopeGlobal)) {
     if (!try_end(err)) {
-      api_set_error(err, Exception, _("Failed to change directory"));
+      api_set_error(err, kErrorTypeException, "Failed to change directory");
     }
     return;
   }
@@ -339,7 +411,7 @@ void nvim_set_current_dir(String dir, Error *err)
 /// @param[out] err Error details, if any
 /// @return Current line string
 String nvim_get_current_line(Error *err)
-    FUNC_API_SINCE(1)
+  FUNC_API_SINCE(1)
 {
   return buffer_get_line(curbuf->handle, curwin->w_cursor.lnum - 1, err);
 }
@@ -349,7 +421,7 @@ String nvim_get_current_line(Error *err)
 /// @param line     Line contents
 /// @param[out] err Error details, if any
 void nvim_set_current_line(String line, Error *err)
-    FUNC_API_SINCE(1)
+  FUNC_API_SINCE(1)
 {
   buffer_set_line(curbuf->handle, curwin->w_cursor.lnum - 1, line, err);
 }
@@ -358,7 +430,7 @@ void nvim_set_current_line(String line, Error *err)
 ///
 /// @param[out] err Error details, if any
 void nvim_del_current_line(Error *err)
-    FUNC_API_SINCE(1)
+  FUNC_API_SINCE(1)
 {
   buffer_del_line(curbuf->handle, curwin->w_cursor.lnum - 1, err);
 }
@@ -369,7 +441,7 @@ void nvim_del_current_line(Error *err)
 /// @param[out] err Error details, if any
 /// @return Variable value
 Object nvim_get_var(String name, Error *err)
-    FUNC_API_SINCE(1)
+  FUNC_API_SINCE(1)
 {
   return dict_get_value(&globvardict, name, err);
 }
@@ -380,7 +452,7 @@ Object nvim_get_var(String name, Error *err)
 /// @param value    Variable value
 /// @param[out] err Error details, if any
 void nvim_set_var(String name, Object value, Error *err)
-    FUNC_API_SINCE(1)
+  FUNC_API_SINCE(1)
 {
   dict_set_var(&globvardict, name, value, false, false, err);
 }
@@ -390,34 +462,23 @@ void nvim_set_var(String name, Object value, Error *err)
 /// @param name     Variable name
 /// @param[out] err Error details, if any
 void nvim_del_var(String name, Error *err)
-    FUNC_API_SINCE(1)
+  FUNC_API_SINCE(1)
 {
   dict_set_var(&globvardict, name, NIL, true, false, err);
 }
 
-/// Sets a global variable
-///
 /// @deprecated
-///
-/// @param name     Variable name
-/// @param value    Variable value
-/// @param[out] err Error details, if any
+/// @see nvim_set_var
 /// @return Old value or nil if there was no previous value.
-///
-///         @warning It may return nil if there was no previous value
-///                  or if previous value was `v:null`.
+/// @warning May return nil if there was no previous value
+///          OR if previous value was `v:null`.
 Object vim_set_var(String name, Object value, Error *err)
 {
   return dict_set_var(&globvardict, name, value, false, true, err);
 }
 
-/// Removes a global variable
-///
 /// @deprecated
-///
-/// @param name     Variable name
-/// @param[out] err Error details, if any
-/// @return Old value
+/// @see nvim_del_var
 Object vim_del_var(String name, Error *err)
 {
   return dict_set_var(&globvardict, name, NIL, true, true, err);
@@ -429,7 +490,7 @@ Object vim_del_var(String name, Error *err)
 /// @param[out] err Error details, if any
 /// @return         Variable value
 Object nvim_get_vvar(String name, Error *err)
-    FUNC_API_SINCE(1)
+  FUNC_API_SINCE(1)
 {
   return dict_get_value(&vimvardict, name, err);
 }
@@ -438,9 +499,9 @@ Object nvim_get_vvar(String name, Error *err)
 ///
 /// @param name     Option name
 /// @param[out] err Error details, if any
-/// @return         Option value
+/// @return         Option value (global)
 Object nvim_get_option(String name, Error *err)
-    FUNC_API_SINCE(1)
+  FUNC_API_SINCE(1)
 {
   return get_option_from(NULL, SREQ_GLOBAL, name, err);
 }
@@ -451,36 +512,38 @@ Object nvim_get_option(String name, Error *err)
 /// @param value    New option value
 /// @param[out] err Error details, if any
 void nvim_set_option(String name, Object value, Error *err)
-    FUNC_API_SINCE(1)
+  FUNC_API_SINCE(1)
 {
   set_option_to(NULL, SREQ_GLOBAL, name, value, err);
 }
 
-/// Writes a message to vim output buffer
+/// Writes a message to the Vim output buffer. Does not append "\n", the
+/// message is buffered (won't display) until a linefeed is written.
 ///
 /// @param str Message
 void nvim_out_write(String str)
-    FUNC_API_SINCE(1)
+  FUNC_API_SINCE(1)
 {
   write_msg(str, false);
 }
 
-/// Writes a message to vim error buffer
+/// Writes a message to the Vim error buffer. Does not append "\n", the
+/// message is buffered (won't display) until a linefeed is written.
 ///
 /// @param str Message
 void nvim_err_write(String str)
-    FUNC_API_SINCE(1)
+  FUNC_API_SINCE(1)
 {
   write_msg(str, true);
 }
 
-/// Writes a message to vim error buffer. Appends a linefeed to ensure all
-/// contents are written.
+/// Writes a message to the Vim error buffer. Appends "\n", so the buffer is
+/// flushed (and displayed).
 ///
 /// @param str Message
 /// @see nvim_err_write()
 void nvim_err_writeln(String str)
-    FUNC_API_SINCE(1)
+  FUNC_API_SINCE(1)
 {
   nvim_err_write(str);
   nvim_err_write((String) { .data = "\n", .size = 1 });
@@ -490,7 +553,7 @@ void nvim_err_writeln(String str)
 ///
 /// @return List of buffer handles
 ArrayOf(Buffer) nvim_list_bufs(void)
-    FUNC_API_SINCE(1)
+  FUNC_API_SINCE(1)
 {
   Array rv = ARRAY_DICT_INIT;
 
@@ -512,17 +575,17 @@ ArrayOf(Buffer) nvim_list_bufs(void)
 ///
 /// @return Buffer handle
 Buffer nvim_get_current_buf(void)
-    FUNC_API_SINCE(1)
+  FUNC_API_SINCE(1)
 {
   return curbuf->handle;
 }
 
 /// Sets the current buffer
 ///
-/// @param id       Buffer handle
+/// @param buffer   Buffer handle
 /// @param[out] err Error details, if any
 void nvim_set_current_buf(Buffer buffer, Error *err)
-    FUNC_API_SINCE(1)
+  FUNC_API_SINCE(1)
 {
   buf_T *buf = find_buffer_by_handle(buffer, err);
 
@@ -534,8 +597,8 @@ void nvim_set_current_buf(Buffer buffer, Error *err)
   int result = do_buffer(DOBUF_GOTO, DOBUF_FIRST, FORWARD, buf->b_fnum, 0);
   if (!try_end(err) && result == FAIL) {
     api_set_error(err,
-                  Exception,
-                  _("Failed to switch to buffer %d"),
+                  kErrorTypeException,
+                  "Failed to switch to buffer %d",
                   buffer);
   }
 }
@@ -544,7 +607,7 @@ void nvim_set_current_buf(Buffer buffer, Error *err)
 ///
 /// @return List of window handles
 ArrayOf(Window) nvim_list_wins(void)
-    FUNC_API_SINCE(1)
+  FUNC_API_SINCE(1)
 {
   Array rv = ARRAY_DICT_INIT;
 
@@ -566,16 +629,16 @@ ArrayOf(Window) nvim_list_wins(void)
 ///
 /// @return Window handle
 Window nvim_get_current_win(void)
-    FUNC_API_SINCE(1)
+  FUNC_API_SINCE(1)
 {
   return curwin->handle;
 }
 
 /// Sets the current window
 ///
-/// @param handle Window handle
+/// @param window Window handle
 void nvim_set_current_win(Window window, Error *err)
-    FUNC_API_SINCE(1)
+  FUNC_API_SINCE(1)
 {
   win_T *win = find_window_by_handle(window, err);
 
@@ -587,8 +650,8 @@ void nvim_set_current_win(Window window, Error *err)
   goto_tabpage_win(win_find_tabpage(win), win);
   if (!try_end(err) && win != curwin) {
     api_set_error(err,
-                  Exception,
-                  _("Failed to switch to window %d"),
+                  kErrorTypeException,
+                  "Failed to switch to window %d",
                   window);
   }
 }
@@ -597,7 +660,7 @@ void nvim_set_current_win(Window window, Error *err)
 ///
 /// @return List of tabpage handles
 ArrayOf(Tabpage) nvim_list_tabpages(void)
-    FUNC_API_SINCE(1)
+  FUNC_API_SINCE(1)
 {
   Array rv = ARRAY_DICT_INIT;
 
@@ -619,17 +682,17 @@ ArrayOf(Tabpage) nvim_list_tabpages(void)
 ///
 /// @return Tabpage handle
 Tabpage nvim_get_current_tabpage(void)
-    FUNC_API_SINCE(1)
+  FUNC_API_SINCE(1)
 {
   return curtab->handle;
 }
 
 /// Sets the current tabpage
 ///
-/// @param handle   Tabpage handle
+/// @param tabpage  Tabpage handle
 /// @param[out] err Error details, if any
 void nvim_set_current_tabpage(Tabpage tabpage, Error *err)
-    FUNC_API_SINCE(1)
+  FUNC_API_SINCE(1)
 {
   tabpage_T *tp = find_tab_by_handle(tabpage, err);
 
@@ -641,8 +704,8 @@ void nvim_set_current_tabpage(Tabpage tabpage, Error *err)
   goto_tabpage_tp(tp, true, true);
   if (!try_end(err) && tp != curtab) {
     api_set_error(err,
-                  Exception,
-                  _("Failed to switch to tabpage %d"),
+                  kErrorTypeException,
+                  "Failed to switch to tabpage %d",
                   tabpage);
   }
 }
@@ -652,13 +715,13 @@ void nvim_set_current_tabpage(Tabpage tabpage, Error *err)
 /// @param channel_id Channel id (passed automatically by the dispatcher)
 /// @param event      Event type string
 void nvim_subscribe(uint64_t channel_id, String event)
-    FUNC_API_SINCE(1) FUNC_API_NOEVAL
+  FUNC_API_SINCE(1) FUNC_API_REMOTE_ONLY
 {
   size_t length = (event.size < METHOD_MAXLEN ? event.size : METHOD_MAXLEN);
   char e[METHOD_MAXLEN + 1];
   memcpy(e, event.data, length);
   e[length] = NUL;
-  channel_subscribe(channel_id, e);
+  rpc_subscribe(channel_id, e);
 }
 
 /// Unsubscribes to event broadcasts
@@ -666,7 +729,7 @@ void nvim_subscribe(uint64_t channel_id, String event)
 /// @param channel_id Channel id (passed automatically by the dispatcher)
 /// @param event      Event type string
 void nvim_unsubscribe(uint64_t channel_id, String event)
-    FUNC_API_SINCE(1) FUNC_API_NOEVAL
+  FUNC_API_SINCE(1) FUNC_API_REMOTE_ONLY
 {
   size_t length = (event.size < METHOD_MAXLEN ?
                    event.size :
@@ -674,17 +737,17 @@ void nvim_unsubscribe(uint64_t channel_id, String event)
   char e[METHOD_MAXLEN + 1];
   memcpy(e, event.data, length);
   e[length] = NUL;
-  channel_unsubscribe(channel_id, e);
+  rpc_unsubscribe(channel_id, e);
 }
 
 Integer nvim_get_color_by_name(String name)
-    FUNC_API_SINCE(1)
+  FUNC_API_SINCE(1)
 {
-  return name_to_color((uint8_t *)name.data);
+  return name_to_color((char_u *)name.data);
 }
 
 Dictionary nvim_get_color_map(void)
-    FUNC_API_SINCE(1)
+  FUNC_API_SINCE(1)
 {
   Dictionary colors = ARRAY_DICT_INIT;
 
@@ -696,8 +759,36 @@ Dictionary nvim_get_color_map(void)
 }
 
 
+/// Gets the current mode. |mode()|
+/// "blocking" is true if Nvim is waiting for input.
+///
+/// @returns Dictionary { "mode": String, "blocking": Boolean }
+Dictionary nvim_get_mode(void)
+  FUNC_API_SINCE(2) FUNC_API_ASYNC
+{
+  Dictionary rv = ARRAY_DICT_INIT;
+  char *modestr = get_mode();
+  bool blocked = input_blocking();
+
+  PUT(rv, "mode", STRING_OBJ(cstr_as_string(modestr)));
+  PUT(rv, "blocking", BOOLEAN_OBJ(blocked));
+
+  return rv;
+}
+
+/// Gets a list of dictionaries describing global (non-buffer) mappings.
+/// The "buffer" key in the returned dictionary is always zero.
+///
+/// @param  mode       Mode short-name ("n", "i", "v", ...)
+/// @returns Array of maparg()-like dictionaries describing mappings
+ArrayOf(Dictionary) nvim_get_keymap(String mode)
+    FUNC_API_SINCE(3)
+{
+  return keymap_array(mode, NULL);
+}
+
 Array nvim_get_api_info(uint64_t channel_id)
-    FUNC_API_SINCE(1) FUNC_API_ASYNC FUNC_API_NOEVAL
+  FUNC_API_SINCE(1) FUNC_API_ASYNC FUNC_API_REMOTE_ONLY
 {
   Array rv = ARRAY_DICT_INIT;
 
@@ -730,7 +821,7 @@ Array nvim_get_api_info(uint64_t channel_id)
 /// which resulted in an error, the error type and the error message. If an
 /// error ocurred, the values from all preceding calls will still be returned.
 Array nvim_call_atomic(uint64_t channel_id, Array calls, Error *err)
-    FUNC_API_SINCE(1) FUNC_API_NOEVAL
+  FUNC_API_SINCE(1) FUNC_API_REMOTE_ONLY
 {
   Array rv = ARRAY_DICT_INIT;
   Array results = ARRAY_DICT_INIT;
@@ -740,30 +831,30 @@ Array nvim_call_atomic(uint64_t channel_id, Array calls, Error *err)
   for (i = 0; i < calls.size; i++) {
     if (calls.items[i].type != kObjectTypeArray) {
       api_set_error(err,
-                    Validation,
-                    _("All items in calls array must be arrays"));
+                    kErrorTypeValidation,
+                    "All items in calls array must be arrays");
       goto validation_error;
     }
     Array call = calls.items[i].data.array;
     if (call.size != 2) {
       api_set_error(err,
-                    Validation,
-                    _("All items in calls array must be arrays of size 2"));
+                    kErrorTypeValidation,
+                    "All items in calls array must be arrays of size 2");
       goto validation_error;
     }
 
     if (call.items[0].type != kObjectTypeString) {
       api_set_error(err,
-                    Validation,
-                    _("name must be String"));
+                    kErrorTypeValidation,
+                    "Name must be String");
       goto validation_error;
     }
     String name = call.items[0].data.string;
 
     if (call.items[1].type != kObjectTypeArray) {
       api_set_error(err,
-                    Validation,
-                    _("args must be Array"));
+                    kErrorTypeValidation,
+                    "Args must be Array");
       goto validation_error;
     }
     Array args = call.items[1].data.array;
@@ -771,7 +862,7 @@ Array nvim_call_atomic(uint64_t channel_id, Array calls, Error *err)
     MsgpackRpcRequestHandler handler = msgpack_rpc_get_handler_for(name.data,
                                                                    name.size);
     Object result = handler.fn(channel_id, args, &nested_error);
-    if (nested_error.set) {
+    if (ERROR_SET(&nested_error)) {
       // error handled after loop
       break;
     }
@@ -780,7 +871,7 @@ Array nvim_call_atomic(uint64_t channel_id, Array calls, Error *err)
   }
 
   ADD(rv, ARRAY_OBJ(results));
-  if (nested_error.set) {
+  if (ERROR_SET(&nested_error)) {
     Array errval = ARRAY_DICT_INIT;
     ADD(errval, INTEGER_OBJ((Integer)i));
     ADD(errval, INTEGER_OBJ(nested_error.type));
@@ -789,10 +880,12 @@ Array nvim_call_atomic(uint64_t channel_id, Array calls, Error *err)
   } else {
     ADD(rv, NIL);
   }
-  return rv;
+  goto theend;
 
 validation_error:
   api_free_array(results);
+theend:
+  api_clear_error(&nested_error);
   return rv;
 }
 
@@ -811,7 +904,7 @@ static void write_msg(String message, bool to_err)
 #define PUSH_CHAR(i, pos, line_buf, msg) \
   if (message.data[i] == NL || pos == LINE_BUFFER_SIZE - 1) { \
     line_buf[pos] = NUL; \
-    msg((uint8_t *)line_buf); \
+    msg((char_u *)line_buf); \
     pos = 0; \
     continue; \
   } \
@@ -829,3 +922,57 @@ static void write_msg(String message, bool to_err)
   --no_wait_return;
   msg_end();
 }
+
+// Functions used for testing purposes
+
+/// Returns object given as argument
+///
+/// This API function is used for testing. One should not rely on its presence
+/// in plugins.
+///
+/// @param[in]  obj  Object to return.
+///
+/// @return its argument.
+Object nvim__id(Object obj)
+{
+  return copy_object(obj);
+}
+
+/// Returns array given as argument
+///
+/// This API function is used for testing. One should not rely on its presence
+/// in plugins.
+///
+/// @param[in]  arr  Array to return.
+///
+/// @return its argument.
+Array nvim__id_array(Array arr)
+{
+  return copy_object(ARRAY_OBJ(arr)).data.array;
+}
+
+/// Returns dictionary given as argument
+///
+/// This API function is used for testing. One should not rely on its presence
+/// in plugins.
+///
+/// @param[in]  dct  Dictionary to return.
+///
+/// @return its argument.
+Dictionary nvim__id_dictionary(Dictionary dct)
+{
+  return copy_object(DICTIONARY_OBJ(dct)).data.dictionary;
+}
+
+/// Returns floating-point value given as argument
+///
+/// This API function is used for testing. One should not rely on its presence
+/// in plugins.
+///
+/// @param[in]  flt  Value to return.
+///
+/// @return its argument.
+Float nvim__id_float(Float flt)
+{
+  return flt;
+}
diff --git a/src/nvim/api/window.c b/src/nvim/api/window.c
index 3c564ada99..9bc91ef8fb 100644
--- a/src/nvim/api/window.c
+++ b/src/nvim/api/window.c
@@ -1,3 +1,6 @@
+// This is an open source non-commercial project. Dear PVS-Studio, please check
+// it. PVS-Studio Static Code Analyzer for C, C++ and C#: http://www.viva64.com
+
 #include <stdbool.h>
 #include <stdint.h>
 #include <stdlib.h>
@@ -19,7 +22,7 @@
 /// @param[out] err Error details, if any
 /// @return Buffer handle
 Buffer nvim_win_get_buf(Window window, Error *err)
-    FUNC_API_SINCE(1)
+  FUNC_API_SINCE(1)
 {
   win_T *win = find_window_by_handle(window, err);
 
@@ -36,7 +39,7 @@ Buffer nvim_win_get_buf(Window window, Error *err)
 /// @param[out] err Error details, if any
 /// @return (row, col) tuple
 ArrayOf(Integer, 2) nvim_win_get_cursor(Window window, Error *err)
-    FUNC_API_SINCE(1)
+  FUNC_API_SINCE(1)
 {
   Array rv = ARRAY_DICT_INIT;
   win_T *win = find_window_by_handle(window, err);
@@ -55,19 +58,19 @@ ArrayOf(Integer, 2) nvim_win_get_cursor(Window window, Error *err)
 /// @param pos      (row, col) tuple representing the new position
 /// @param[out] err Error details, if any
 void nvim_win_set_cursor(Window window, ArrayOf(Integer, 2) pos, Error *err)
-    FUNC_API_SINCE(1)
+  FUNC_API_SINCE(1)
 {
   win_T *win = find_window_by_handle(window, err);
 
-  if (pos.size != 2 || pos.items[0].type != kObjectTypeInteger
-      || pos.items[1].type != kObjectTypeInteger) {
-    api_set_error(err,
-                  Validation,
-                  _("Argument \"pos\" must be a [row, col] array"));
+  if (!win) {
     return;
   }
 
-  if (!win) {
+  if (pos.size != 2 || pos.items[0].type != kObjectTypeInteger
+      || pos.items[1].type != kObjectTypeInteger) {
+    api_set_error(err,
+                  kErrorTypeValidation,
+                  "Argument \"pos\" must be a [row, col] array");
     return;
   }
 
@@ -75,12 +78,12 @@ void nvim_win_set_cursor(Window window, ArrayOf(Integer, 2) pos, Error *err)
   int64_t col = pos.items[1].data.integer;
 
   if (row <= 0 || row > win->w_buffer->b_ml.ml_line_count) {
-    api_set_error(err, Validation, _("Cursor position outside buffer"));
+    api_set_error(err, kErrorTypeValidation, "Cursor position outside buffer");
     return;
   }
 
   if (col > MAXCOL || col < 0) {
-    api_set_error(err, Validation, _("Column value outside range"));
+    api_set_error(err, kErrorTypeValidation, "Column value outside range");
     return;
   }
 
@@ -102,7 +105,7 @@ void nvim_win_set_cursor(Window window, ArrayOf(Integer, 2) pos, Error *err)
 /// @param[out] err Error details, if any
 /// @return Height as a count of rows
 Integer nvim_win_get_height(Window window, Error *err)
-    FUNC_API_SINCE(1)
+  FUNC_API_SINCE(1)
 {
   win_T *win = find_window_by_handle(window, err);
 
@@ -120,7 +123,7 @@ Integer nvim_win_get_height(Window window, Error *err)
 /// @param height   Height as a count of rows
 /// @param[out] err Error details, if any
 void nvim_win_set_height(Window window, Integer height, Error *err)
-    FUNC_API_SINCE(1)
+  FUNC_API_SINCE(1)
 {
   win_T *win = find_window_by_handle(window, err);
 
@@ -129,7 +132,7 @@ void nvim_win_set_height(Window window, Integer height, Error *err)
   }
 
   if (height > INT_MAX || height < INT_MIN) {
-    api_set_error(err, Validation, _("Height value outside range"));
+    api_set_error(err, kErrorTypeValidation, "Height value outside range");
     return;
   }
 
@@ -147,7 +150,7 @@ void nvim_win_set_height(Window window, Integer height, Error *err)
 /// @param[out] err Error details, if any
 /// @return Width as a count of columns
 Integer nvim_win_get_width(Window window, Error *err)
-    FUNC_API_SINCE(1)
+  FUNC_API_SINCE(1)
 {
   win_T *win = find_window_by_handle(window, err);
 
@@ -165,7 +168,7 @@ Integer nvim_win_get_width(Window window, Error *err)
 /// @param width    Width as a count of columns
 /// @param[out] err Error details, if any
 void nvim_win_set_width(Window window, Integer width, Error *err)
-    FUNC_API_SINCE(1)
+  FUNC_API_SINCE(1)
 {
   win_T *win = find_window_by_handle(window, err);
 
@@ -174,7 +177,7 @@ void nvim_win_set_width(Window window, Integer width, Error *err)
   }
 
   if (width > INT_MAX || width < INT_MIN) {
-    api_set_error(err, Validation, _("Width value outside range"));
+    api_set_error(err, kErrorTypeValidation, "Width value outside range");
     return;
   }
 
@@ -193,7 +196,7 @@ void nvim_win_set_width(Window window, Integer width, Error *err)
 /// @param[out] err Error details, if any
 /// @return Variable value
 Object nvim_win_get_var(Window window, String name, Error *err)
-    FUNC_API_SINCE(1)
+  FUNC_API_SINCE(1)
 {
   win_T *win = find_window_by_handle(window, err);
 
@@ -211,7 +214,7 @@ Object nvim_win_get_var(Window window, String name, Error *err)
 /// @param value    Variable value
 /// @param[out] err Error details, if any
 void nvim_win_set_var(Window window, String name, Object value, Error *err)
-    FUNC_API_SINCE(1)
+  FUNC_API_SINCE(1)
 {
   win_T *win = find_window_by_handle(window, err);
 
@@ -228,7 +231,7 @@ void nvim_win_set_var(Window window, String name, Object value, Error *err)
 /// @param name     Variable name
 /// @param[out] err Error details, if any
 void nvim_win_del_var(Window window, String name, Error *err)
-    FUNC_API_SINCE(1)
+  FUNC_API_SINCE(1)
 {
   win_T *win = find_window_by_handle(window, err);
 
@@ -288,7 +291,7 @@ Object window_del_var(Window window, String name, Error *err)
 /// @param[out] err Error details, if any
 /// @return Option value
 Object nvim_win_get_option(Window window, String name, Error *err)
-    FUNC_API_SINCE(1)
+  FUNC_API_SINCE(1)
 {
   win_T *win = find_window_by_handle(window, err);
 
@@ -307,7 +310,7 @@ Object nvim_win_get_option(Window window, String name, Error *err)
 /// @param value    Option value
 /// @param[out] err Error details, if any
 void nvim_win_set_option(Window window, String name, Object value, Error *err)
-    FUNC_API_SINCE(1)
+  FUNC_API_SINCE(1)
 {
   win_T *win = find_window_by_handle(window, err);
 
@@ -324,7 +327,7 @@ void nvim_win_set_option(Window window, String name, Object value, Error *err)
 /// @param[out] err Error details, if any
 /// @return (row, col) tuple with the window position
 ArrayOf(Integer, 2) nvim_win_get_position(Window window, Error *err)
-    FUNC_API_SINCE(1)
+  FUNC_API_SINCE(1)
 {
   Array rv = ARRAY_DICT_INIT;
   win_T *win = find_window_by_handle(window, err);
@@ -343,7 +346,7 @@ ArrayOf(Integer, 2) nvim_win_get_position(Window window, Error *err)
 /// @param[out] err Error details, if any
 /// @return Tabpage that contains the window
 Tabpage nvim_win_get_tabpage(Window window, Error *err)
-    FUNC_API_SINCE(1)
+  FUNC_API_SINCE(1)
 {
   Tabpage rv = 0;
   win_T *win = find_window_by_handle(window, err);
@@ -361,7 +364,7 @@ Tabpage nvim_win_get_tabpage(Window window, Error *err)
 /// @param[out] err Error details, if any
 /// @return Window number
 Integer nvim_win_get_number(Window window, Error *err)
-    FUNC_API_SINCE(1)
+  FUNC_API_SINCE(1)
 {
   int rv = 0;
   win_T *win = find_window_by_handle(window, err);
@@ -381,9 +384,11 @@ Integer nvim_win_get_number(Window window, Error *err)
 /// @param window Window handle
 /// @return true if the window is valid, false otherwise
 Boolean nvim_win_is_valid(Window window)
-    FUNC_API_SINCE(1)
+  FUNC_API_SINCE(1)
 {
   Error stub = ERROR_INIT;
-  return find_window_by_handle(window, &stub) != NULL;
+  Boolean ret = find_window_by_handle(window, &stub) != NULL;
+  api_clear_error(&stub);
+  return ret;
 }