text: // 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>
  #include <stdlib.h>
  #include <string.h>
  #include <limits.h>
  
  #include "nvim/api/vim.h"
  #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/api/window.h"
  #include "nvim/msgpack_rpc/channel.h"
  #include "nvim/msgpack_rpc/helpers.h"
  #include "nvim/lua/executor.h"
  #include "nvim/vim.h"
  #include "nvim/buffer.h"
  #include "nvim/context.h"
  #include "nvim/file_search.h"
  #include "nvim/highlight.h"
  #include "nvim/window.h"
  #include "nvim/types.h"
  #include "nvim/ex_docmd.h"
  #include "nvim/screen.h"
  #include "nvim/memline.h"
  #include "nvim/mark.h"
  #include "nvim/memory.h"
  #include "nvim/message.h"
  #include "nvim/popupmnu.h"
  #include "nvim/edit.h"
  #include "nvim/eval.h"
  #include "nvim/eval/typval.h"
  #include "nvim/fileio.h"
  #include "nvim/ops.h"
  #include "nvim/option.h"
  #include "nvim/state.h"
  #include "nvim/mark_extended.h"
  #include "nvim/syntax.h"
  #include "nvim/getchar.h"
  #include "nvim/os/input.h"
  #include "nvim/os/process.h"
  #include "nvim/viml/parser/expressions.h"
  #include "nvim/viml/parser/parser.h"
  #include "nvim/ui.h"
  
  #define LINE_BUFFER_SIZE 4096
  
  #ifdef INCLUDE_GENERATED_DECLARATIONS
  # include "api/vim.c.generated.h"
  #endif
  
  void api_vim_init(void)
    FUNC_API_NOEXPORT
  {
    namespace_ids = map_new(String, handle_T)();
  }
  
  void api_vim_free_all_mem(void)
    FUNC_API_NOEXPORT
  {
    String name;
    handle_T id;
    map_foreach(namespace_ids, name, id, {
      (void)id;
      xfree(name.data);
    })
    map_free(String, handle_T)(namespace_ids);
  }
  
  /// Executes an ex-command.
  ///
  /// On execution error: fails with VimL error, does not update v:errmsg.
  ///
  /// @param command  Ex-command string
  /// @param[out] err Error details (Vim error), if any
  void nvim_command(String command, Error *err)
    FUNC_API_SINCE(1)
  {
    try_start();
    do_cmdline_cmd(command.data);
    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);
  }
  
  /// Sends input-keys to Nvim, subject to various quirks controlled by `mode`
  /// flags. This is a blocking call, unlike |nvim_input()|.
  ///
  /// On execution error: does not fail, but updates v:errmsg.
  ///
  /// @param keys         to be typed
  /// @param mode         behavior flags, see |feedkeys()|
  /// @param escape_csi   If true, escape K_SPECIAL/CSI bytes in `keys`
  /// @see feedkeys()
  /// @see vim_strsave_escape_csi
  void nvim_feedkeys(String keys, String mode, Boolean escape_csi)
    FUNC_API_SINCE(1)
  {
    bool remap = true;
    bool insert = false;
    bool typed = false;
    bool execute = false;
    bool dangerous = false;
  
    for (size_t i = 0; i < mode.size; ++i) {
      switch (mode.data[i]) {
      case 'n': remap = false; break;
      case 'm': remap = true; break;
      case 't': typed = true; break;
      case 'i': insert = true; break;
      case 'x': execute = true; break;
      case '!': dangerous = true; break;
      }
    }
  
    if (keys.size == 0 && !execute) {
      return;
    }
  
    char *keys_esc;
    if (escape_csi) {
        // Need to escape K_SPECIAL and CSI before putting the string in the
        // typeahead buffer.
        keys_esc = (char *)vim_strsave_escape_csi((char_u *)keys.data);
    } else {
        keys_esc = keys.data;
    }
    ins_typebuf((char_u *)keys_esc, (remap ? REMAP_YES : REMAP_NONE),
        insert ? 0 : typebuf.tb_len, !typed, false);
  
    if (escape_csi) {
        xfree(keys_esc);
    }
  
    if (vgetc_busy) {
      typebuf_was_filled = true;
    }
    if (execute) {
      int save_msg_scroll = msg_scroll;
  
      /* Avoid a 1 second delay when the keys start Insert mode. */
      msg_scroll = false;
      if (!dangerous) {
        ex_normal_busy++;
      }
      exec_normal(true);
      if (!dangerous) {
        ex_normal_busy--;
      }
      msg_scroll |= save_msg_scroll;
    }
  }
  
  /// Queues raw user-input. Unlike |nvim_feedkeys()|, this uses a low-level
  /// input buffer and the call is non-blocking (input is processed
  /// asynchronously by the eventloop).
  ///
  /// On execution error: does not fail, but updates v:errmsg.
  ///
  /// @note |keycodes| like <CR> are translated, so "<" is special.
  ///       To input a literal "<", send <LT>.
  ///
  /// @note For mouse events use |nvim_input_mouse()|. The pseudokey form
  ///       "<LeftMouse><col,row>" is deprecated since |api-level| 6.
  ///
  /// @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_FAST
  {
    return (Integer)input_enqueue(keys);
  }
  
  /// Send mouse event from GUI.
  ///
  /// Non-blocking: does not wait on any result, but queues the event to be
  /// processed soon by the event loop.
  ///
  /// @note Currently this doesn't support "scripting" multiple mouse events
  ///       by calling it multiple times in a loop: the intermediate mouse
  ///       positions will be ignored. It should be used to implement real-time
  ///       mouse input in a GUI. The deprecated pseudokey form
  ///       ("<LeftMouse><col,row>") of |nvim_input()| has the same limitiation.
  ///
  /// @param button Mouse button: one of "left", "right", "middle", "wheel".
  /// @param action For ordinary buttons, one of "press", "drag", "release".
  ///               For the wheel, one of "up", "down", "left", "right".
  /// @param modifier String of modifiers each represented by a single char.
  ///                 The same specifiers are used as for a key press, except
  ///                 that the "-" separator is optional, so "C-A-", "c-a"
  ///                 and "CA" can all be used to specify Ctrl+Alt+click.
  /// @param grid Grid number if the client uses |ui-multigrid|, else 0.
  /// @param row Mouse row-position (zero-based, like redraw events)
  /// @param col Mouse column-position (zero-based, like redraw events)
  /// @param[out] err Error details, if any
  void nvim_input_mouse(String button, String action, String modifier,
                        Integer grid, Integer row, Integer col, Error *err)
    FUNC_API_SINCE(6) FUNC_API_FAST
  {
    if (button.data == NULL || action.data == NULL) {
      goto error;
    }
  
    int code = 0;
  
    if (strequal(button.data, "left")) {
      code = KE_LEFTMOUSE;
    } else if (strequal(button.data, "middle")) {
      code = KE_MIDDLEMOUSE;
    } else if (strequal(button.data, "right")) {
      code = KE_RIGHTMOUSE;
    } else if (strequal(button.data, "wheel")) {
      code = KE_MOUSEDOWN;
    } else {
      goto error;
    }
  
    if (code == KE_MOUSEDOWN) {
      if (strequal(action.data, "down")) {
        code = KE_MOUSEUP;
      } else if (strequal(action.data, "up")) {
        code = KE_MOUSEDOWN;
      } else if (strequal(action.data, "left")) {
        code = KE_MOUSERIGHT;
      } else if (strequal(action.data, "right")) {
        code = KE_MOUSELEFT;
      } else {
        goto error;
      }
    } else {
      if (strequal(action.data, "press")) {
        // pass
      } else if (strequal(action.data, "drag")) {
        code += KE_LEFTDRAG - KE_LEFTMOUSE;
      } else if (strequal(action.data, "release")) {
        code += KE_LEFTRELEASE - KE_LEFTMOUSE;
      } else {
        goto error;
      }
    }
  
    int modmask = 0;
    for (size_t i = 0; i < modifier.size; i++) {
      char byte = modifier.data[i];
      if (byte == '-') {
        continue;
      }
      int mod = name_to_mod_mask(byte);
      if (mod == 0) {
        api_set_error(err, kErrorTypeValidation,
                      "invalid modifier %c", byte);
        return;
      }
      modmask |= mod;
    }
  
    input_enqueue_mouse(code, (uint8_t)modmask, (int)grid, (int)row, (int)col);
    return;
  
  error:
    api_set_error(err, kErrorTypeValidation,
                  "invalid button or action");
  }
  
  /// 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)
  {
    if (str.size == 0) {
      // Empty string
      return (String) { .data = NULL, .size = 0 };
    }
  
    char *ptr = NULL;
    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);
  }
  
  /// Executes an ex-command and returns its (non-error) output.
  /// Shell |:!| output is not captured.
  ///
  /// On execution error: fails with VimL error, does not update v:errmsg.
  ///
  /// @param command  Ex-command string
  /// @param[out] err Error details (Vim error), if any
  String nvim_command_output(String command, Error *err)
    FUNC_API_SINCE(1)
  {
    const int save_msg_silent = msg_silent;
    garray_T *const save_capture_ga = capture_ga;
    garray_T capture_local;
    ga_init(&capture_local, 1, 80);
  
    try_start();
    msg_silent++;
    capture_ga = &capture_local;
    do_cmdline_cmd(command.data);
    capture_ga = save_capture_ga;
    msg_silent = save_msg_silent;
    try_end(err);
  
    if (ERROR_SET(err)) {
      goto theend;
    }
  
    if (capture_local.ga_len > 1) {
      String s = (String){
        .data = capture_local.ga_data,
        .size = (size_t)capture_local.ga_len,
      };
      // redir usually (except :echon) prepends a newline.
      if (s.data[0] == '\n') {
        memmove(s.data, s.data + 1, s.size - 1);
        s.data[s.size - 1] = '\0';
        s.size = s.size - 1;
      }
      return s;  // Caller will free the memory.
    }
  
  theend:
    ga_clear(&capture_local);
    return (String)STRING_INIT;
  }
  
  /// Evaluates a VimL expression (:help expression).
  /// Dictionaries and Lists are recursively expanded.
  ///
  /// On execution error: fails with VimL error, does not update v:errmsg.
  ///
  /// @param expr     VimL expression string
  /// @param[out] err Error details, if any
  /// @return         Evaluation result or expanded object
  Object nvim_eval(String expr, Error *err)
    FUNC_API_SINCE(1)
  {
    static int recursive = 0;  // recursion depth
    Object rv = OBJECT_INIT;
  
    TRY_WRAP({
    // Initialize `force_abort`  and `suppress_errthrow` at the top level.
    if (!recursive) {
      force_abort = false;
      suppress_errthrow = false;
      current_exception = NULL;
      // `did_emsg` is set by emsg(), which cancels execution.
      did_emsg = false;
    }
    recursive++;
    try_start();
  
    typval_T rettv;
    int ok = eval0((char_u *)expr.data, &rettv, NULL, true);
  
    if (!try_end(err)) {
      if (ok == FAIL) {
        // Should never happen, try_end() should get the error. #8371
        api_set_error(err, kErrorTypeException, "Failed to evaluate expression");
      } else {
        rv = vim_to_object(&rettv);
      }
    }
  
    tv_clear(&rettv);
    recursive--;
    });
  
    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);
  }
  
  /// Calls a VimL function.
  ///
  /// @param fn Function name
  /// @param args Function arguments
  /// @param self `self` dict, or NULL for non-dict functions
  /// @param[out] err Error details, if any
  /// @return Result of the function call
  static Object _call_function(String fn, Array args, dict_T *self, Error *err)
  {
    static int recursive = 0;  // recursion depth
    Object rv = OBJECT_INIT;
  
    if (args.size > MAX_FUNC_ARGS) {
      api_set_error(err, kErrorTypeValidation,
                    "Function called with too many arguments");
      return rv;
    }
  
    // Convert the arguments in args from Object to typval_T values
    typval_T vim_args[MAX_FUNC_ARGS + 1];
    size_t i = 0;  // also used for freeing the variables
    for (; i < args.size; i++) {
      if (!object_to_vim(args.items[i], &vim_args[i], err)) {
        goto free_vim_args;
      }
    }
  
    TRY_WRAP({
    // Initialize `force_abort`  and `suppress_errthrow` at the top level.
    if (!recursive) {
      force_abort = false;
      suppress_errthrow = false;
      current_exception = NULL;
      // `did_emsg` is set by emsg(), which cancels execution.
      did_emsg = false;
    }
    recursive++;
    try_start();
    typval_T rettv;
    int dummy;
    // call_func() retval is deceptive, ignore it.  Instead we set `msg_list`
    // (see above) to capture abort-causing non-exception errors.
    (void)call_func((char_u *)fn.data, (int)fn.size, &rettv, (int)args.size,
                    vim_args, NULL, curwin->w_cursor.lnum, curwin->w_cursor.lnum,
                    &dummy, true, NULL, self);
    if (!try_end(err)) {
      rv = vim_to_object(&rettv);
    }
    tv_clear(&rettv);
    recursive--;
    });
  
  free_vim_args:
    while (i > 0) {
      tv_clear(&vim_args[--i]);
    }
  
    return rv;
  }
  
  /// Calls a VimL function with the given arguments.
  ///
  /// On execution error: fails with VimL error, does not update v:errmsg.
  ///
  /// @param fn       Function to call
  /// @param args     Function arguments packed in an Array
  /// @param[out] err Error details, if any
  /// @return Result of the function call
  Object nvim_call_function(String fn, Array args, Error *err)
    FUNC_API_SINCE(1)
  {
    return _call_function(fn, args, NULL, err);
  }
  
  /// Calls a VimL |Dictionary-function| with the given arguments.
  ///
  /// On execution error: fails with VimL error, does not update v:errmsg.
  ///
  /// @param dict Dictionary, or String evaluating to a VimL |self| dict
  /// @param fn Name of the function defined on the VimL dict
  /// @param args Function arguments packed in an Array
  /// @param[out] err Error details, if any
  /// @return Result of the function call
  Object nvim_call_dict_function(Object dict, String fn, Array args, Error *err)
    FUNC_API_SINCE(4)
  {
    Object rv = OBJECT_INIT;
  
    typval_T rettv;
    bool mustfree = false;
    switch (dict.type) {
      case kObjectTypeString: {
        try_start();
        if (eval0((char_u *)dict.data.string.data, &rettv, NULL, true) == FAIL) {
          api_set_error(err, kErrorTypeException,
                        "Failed to evaluate dict expression");
        }
        if (try_end(err)) {
          return rv;
        }
        // Evaluation of the string arg created a new dict or increased the
        // refcount of a dict. Not necessary for a RPC dict.
        mustfree = true;
        break;
      }
      case kObjectTypeDictionary: {
        if (!object_to_vim(dict, &rettv, err)) {
          goto end;
        }
        break;
      }
      default: {
        api_set_error(err, kErrorTypeValidation,
                      "dict argument type must be String or Dictionary");
        return rv;
      }
    }
    dict_T *self_dict = rettv.vval.v_dict;
    if (rettv.v_type != VAR_DICT || !self_dict) {
      api_set_error(err, kErrorTypeValidation, "dict not found");
      goto end;
    }
  
    if (fn.data && fn.size > 0 && dict.type != kObjectTypeDictionary) {
      dictitem_T *const di = tv_dict_find(self_dict, fn.data, (ptrdiff_t)fn.size);
      if (di == NULL) {
        api_set_error(err, kErrorTypeValidation, "Not found: %s", fn.data);
        goto end;
      }
      if (di->di_tv.v_type == VAR_PARTIAL) {
        api_set_error(err, kErrorTypeValidation,
                      "partial function not supported");
        goto end;
      }
      if (di->di_tv.v_type != VAR_FUNC) {
        api_set_error(err, kErrorTypeValidation, "Not a function: %s", fn.data);
        goto end;
      }
      fn = (String) {
        .data = (char *)di->di_tv.vval.v_string,
        .size = strlen((char *)di->di_tv.vval.v_string),
      };
    }
  
    if (!fn.data || fn.size < 1) {
      api_set_error(err, kErrorTypeValidation, "Invalid (empty) function name");
      goto end;
    }
  
    rv = _call_function(fn, args, self_dict, err);
  end:
    if (mustfree) {
      tv_clear(&rettv);
    }
  
    return rv;
  }
  
  /// 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 text, Error *err)
    FUNC_API_SINCE(1)
  {
    if (text.size > INT_MAX) {
      api_set_error(err, kErrorTypeValidation, "String is too long");
      return 0;
    }
  
    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)
  {
    Array rv = ARRAY_DICT_INIT;
    char_u *rtp = p_rtp;
  
    if (*rtp == NUL) {
      // No paths
      return rv;
    }
  
    // Count the number of paths in rtp
    while (*rtp != NUL) {
      if (*rtp == ',') {
        rv.size++;
      }
      rtp++;
    }
    rv.size++;
  
    // Allocate memory for the copies
    rv.items = xmalloc(sizeof(*rv.items) * rv.size);
    // Reset the position
    rtp = p_rtp;
    // Start copying
    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]
      size_t length = copy_option_part(&rtp,
                                       (char_u *)rv.items[i].data.string.data,
                                       MAXPATHL,
                                       ",");
      rv.items[i].data.string.size = length;
    }
  
    return rv;
  }
  
  /// Changes the global working directory.
  ///
  /// @param dir      Directory path
  /// @param[out] err Error details, if any
  void nvim_set_current_dir(String dir, Error *err)
    FUNC_API_SINCE(1)
  {
    if (dir.size >= MAXPATHL) {
      api_set_error(err, kErrorTypeValidation, "Directory name is too long");
      return;
    }
  
    char string[MAXPATHL];
    memcpy(string, dir.data, dir.size);
    string[dir.size] = NUL;
  
    try_start();
  
    if (vim_chdir((char_u *)string)) {
      if (!try_end(err)) {
        api_set_error(err, kErrorTypeException, "Failed to change directory");
      }
      return;
    }
  
    post_chdir(kCdScopeGlobal, true);
    try_end(err);
  }
  
  /// Gets the current line.
  ///
  /// @param[out] err Error details, if any
  /// @return Current line string
  String nvim_get_current_line(Error *err)
    FUNC_API_SINCE(1)
  {
    return buffer_get_line(curbuf->handle, curwin->w_cursor.lnum - 1, err);
  }
  
  /// Sets the current line.
  ///
  /// @param line     Line contents
  /// @param[out] err Error details, if any
  void nvim_set_current_line(String line, Error *err)
    FUNC_API_SINCE(1)
  {
    buffer_set_line(curbuf->handle, curwin->w_cursor.lnum - 1, line, err);
  }
  
  /// Deletes the current line.
  ///
  /// @param[out] err Error details, if any
  void nvim_del_current_line(Error *err)
    FUNC_API_SINCE(1)
  {
    buffer_del_line(curbuf->handle, curwin->w_cursor.lnum - 1, err);
  }
  
  /// Gets a global (g:) variable.
  ///
  /// @param name     Variable name
  /// @param[out] err Error details, if any
  /// @return Variable value
  Object nvim_get_var(String name, Error *err)
    FUNC_API_SINCE(1)
  {
    return dict_get_value(&globvardict, name, err);
  }
  
  /// Sets a global (g:) variable.
  ///
  /// @param name     Variable name
  /// @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)
  {
    dict_set_var(&globvardict, name, value, false, false, err);
  }
  
  /// Removes a global (g:) variable.
  ///
  /// @param name     Variable name
  /// @param[out] err Error details, if any
  void nvim_del_var(String name, Error *err)
    FUNC_API_SINCE(1)
  {
    dict_set_var(&globvardict, name, NIL, true, false, err);
  }
  
  /// @deprecated
  /// @see nvim_set_var
  /// @warning May return nil if there was no previous value
  ///          OR if previous value was `v:null`.
  /// @return Old value or nil if there was no previous value.
  Object vim_set_var(String name, Object value, Error *err)
  {
    return dict_set_var(&globvardict, name, value, false, true, err);
  }
  
  /// @deprecated
  /// @see nvim_del_var
  Object vim_del_var(String name, Error *err)
  {
    return dict_set_var(&globvardict, name, NIL, true, true, err);
  }
  
  /// Gets a v: variable.
  ///
  /// @param name     Variable name
  /// @param[out] err Error details, if any
  /// @return         Variable value
  Object nvim_get_vvar(String name, Error *err)
    FUNC_API_SINCE(1)
  {
    return dict_get_value(&vimvardict, name, err);
  }
  
  /// Sets a v: variable, if it is not readonly.
  ///
  /// @param name     Variable name
  /// @param value    Variable value
  /// @param[out] err Error details, if any
  void nvim_set_vvar(String name, Object value, Error *err)
    FUNC_API_SINCE(6)
  {
    dict_set_var(&vimvardict, name, value, false, false, err);
  }
  
  /// Gets an option value string.
  ///
  /// @param name     Option name
  /// @param[out] err Error details, if any
  /// @return         Option value (global)
  Object nvim_get_option(String name, Error *err)
    FUNC_API_SINCE(1)
  {
    return get_option_from(NULL, SREQ_GLOBAL, name, err);
  }
  
  /// Sets an option value.
  ///
  /// @param channel_id
  /// @param name     Option name
  /// @param value    New option value
  /// @param[out] err Error details, if any
  void nvim_set_option(uint64_t channel_id, String name, Object value, Error *err)
    FUNC_API_SINCE(1)
  {
    set_option_to(channel_id, NULL, SREQ_GLOBAL, name, value, err);
  }
  
  /// 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)
  {
    write_msg(str, false);
  }
  
  /// 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)
  {
    write_msg(str, true);
  }
  
  /// 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)
  {
    nvim_err_write(str);
    nvim_err_write((String) { .data = "\n", .size = 1 });
  }
  
  /// Gets the current list of buffer handles
  ///
  /// Includes unlisted (unloaded/deleted) buffers, like `:ls!`.
  /// Use |nvim_buf_is_loaded()| to check if a buffer is loaded.
  ///
  /// @return List of buffer handles
  ArrayOf(Buffer) nvim_list_bufs(void)
    FUNC_API_SINCE(1)
  {
    Array rv = ARRAY_DICT_INIT;
  
    FOR_ALL_BUFFERS(b) {
      rv.size++;
    }
  
    rv.items = xmalloc(sizeof(Object) * rv.size);
    size_t i = 0;
  
    FOR_ALL_BUFFERS(b) {
      rv.items[i++] = BUFFER_OBJ(b->handle);
    }
  
    return rv;
  }
  
  /// Gets the current buffer.
  ///
  /// @return Buffer handle
  Buffer nvim_get_current_buf(void)
    FUNC_API_SINCE(1)
  {
    return curbuf->handle;
  }
  
  /// Sets the current buffer.
  ///
  /// @param buffer   Buffer handle
  /// @param[out] err Error details, if any
  void nvim_set_current_buf(Buffer buffer, Error *err)
    FUNC_API_SINCE(1)
  {
    buf_T *buf = find_buffer_by_handle(buffer, err);
  
    if (!buf) {
      return;
    }
  
    try_start();
    int result = do_buffer(DOBUF_GOTO, DOBUF_FIRST, FORWARD, buf->b_fnum, 0);
    if (!try_end(err) && result == FAIL) {
      api_set_error(err,
                    kErrorTypeException,
                    "Failed to switch to buffer %d",
                    buffer);
    }
  }
  
  /// Gets the current list of window handles.
  ///
  /// @return List of window handles
  ArrayOf(Window) nvim_list_wins(void)
    FUNC_API_SINCE(1)
  {
    Array rv = ARRAY_DICT_INIT;
  
    FOR_ALL_TAB_WINDOWS(tp, wp) {
      rv.size++;
    }
  
    rv.items = xmalloc(sizeof(Object) * rv.size);
    size_t i = 0;
  
    FOR_ALL_TAB_WINDOWS(tp, wp) {
      rv.items[i++] = WINDOW_OBJ(wp->handle);
    }
  
    return rv;
  }
  
  /// Gets the current window.
  ///
  /// @return Window handle
  Window nvim_get_current_win(void)
    FUNC_API_SINCE(1)
  {
    return curwin->handle;
  }
  
  /// Sets the current window.
  ///
  /// @param window Window handle
  /// @param[out] err Error details, if any
  void nvim_set_current_win(Window window, Error *err)
    FUNC_API_SINCE(1)
  {
    win_T *win = find_window_by_handle(window, err);
  
    if (!win) {
      return;
    }
  
    try_start();
    goto_tabpage_win(win_find_tabpage(win), win);
    if (!try_end(err) && win != curwin) {
      api_set_error(err,
                    kErrorTypeException,
                    "Failed to switch to window %d",
                    window);
    }
  }
  
  /// Creates a new, empty, unnamed buffer.
  ///
  /// @param listed Sets 'buflisted'
  /// @param scratch Creates a "throwaway" |scratch-buffer| for temporary work
  ///                (always 'nomodified')
  /// @param[out] err Error details, if any
  /// @return Buffer handle, or 0 on error
  ///
  /// @see buf_open_scratch
  Buffer nvim_create_buf(Boolean listed, Boolean scratch, Error *err)
    FUNC_API_SINCE(6)
  {
    try_start();
    buf_T *buf = buflist_new(NULL, NULL, (linenr_T)0,
                             BLN_NOOPT | BLN_NEW | (listed ? BLN_LISTED : 0));
    try_end(err);
    if (buf == NULL) {
      goto fail;
    }
  
    // Open the memline for the buffer. This will avoid spurious autocmds when
    // a later nvim_buf_set_lines call would have needed to "open" the buffer.
    try_start();
    block_autocmds();
    int status = ml_open(buf);
    unblock_autocmds();
    try_end(err);
    if (status == FAIL) {
      goto fail;
    }
  
    if (scratch) {
      aco_save_T aco;
      aucmd_prepbuf(&aco, buf);
      set_option_value("bh", 0L, "hide", OPT_LOCAL);
      set_option_value("bt", 0L, "nofile", OPT_LOCAL);
      set_option_value("swf", 0L, NULL, OPT_LOCAL);
      aucmd_restbuf(&aco);
    }
    return buf->b_fnum;
  
  fail:
    if (!ERROR_SET(err)) {
      api_set_error(err, kErrorTypeException, "Failed to create buffer");
    }
    return 0;
  }
  
  /// Open a new window.
  ///
  /// Currently this is used to open floating and external windows.
  /// Floats are windows that are drawn above the split layout, at some anchor
  /// position in some other window. Floats can be drawn internally or by external
  /// GUI with the |ui-multigrid| extension. External windows are only supported
  /// with multigrid GUIs, and are displayed as separate top-level windows.
  ///
  /// For a general overview of floats, see |api-floatwin|.
  ///
  /// Exactly one of `external` and `relative` must be specified. The `width` and
  /// `height` of the new window must be specified.
  ///
  /// With relative=editor (row=0,col=0) refers to the top-left corner of the
  /// screen-grid and (row=Lines-1,col=Columns-1) refers to the bottom-right
  /// corner. Fractional values are allowed, but the builtin implementation
  /// (used by non-multigrid UIs) will always round down to nearest integer.
  ///
  /// Out-of-bounds values, and configurations that make the float not fit inside
  /// the main editor, are allowed. The builtin implementation truncates values
  /// so floats are fully within the main screen grid. External GUIs
  /// could let floats hover outside of the main window like a tooltip, but
  /// this should not be used to specify arbitrary WM screen positions.
  ///
  /// Example (Lua): window-relative float
  /// <pre>
  ///     vim.api.nvim_open_win(0, false,
  ///       {relative='win', row=3, col=3, width=12, height=3})
  /// </pre>
  ///
  /// Example (Lua): buffer-relative float (travels as buffer is scrolled)
  /// <pre>
  ///     vim.api.nvim_open_win(0, false,
  ///       {relative='win', width=12, height=3, bufpos={100,10}})
  /// </pre>
  ///
  /// @param buffer Buffer to display, or 0 for current buffer
  /// @param enter  Enter the window (make it the current window)
  /// @param config Map defining the window configuration. Keys:
  ///   - `relative`: Sets the window layout to "floating", placed at (row,col)
  ///                 coordinates relative to:
  ///      - "editor" The global editor grid
  ///      - "win"    Window given by the `win` field, or current window.
  ///      - "cursor" Cursor position in current window.
  ///   - `win`: |window-ID| for relative="win".
  ///   - `anchor`: Decides which corner of the float to place at (row,col):
  ///      - "NW" northwest (default)
  ///      - "NE" northeast
  ///      - "SW" southwest
  ///      - "SE" southeast
  ///   - `width`: Window width (in character cells). Minimum of 1.
  ///   - `height`: Window height (in character cells). Minimum of 1.
  ///   - `bufpos`: Places float relative to buffer text (only when
  ///               relative="win"). Takes a tuple of zero-indexed [line, column].
  ///               `row` and `col` if given are applied relative to this
  ///               position, else they default to `row=1` and `col=0`
  ///               (thus like a tooltip near the buffer text).
  ///   - `row`: Row position in units of "screen cell height", may be fractional.
  ///   - `col`: Column position in units of "screen cell width", may be
  ///            fractional.
  ///   - `focusable`: Enable focus by user actions (wincmds, mouse events).
  ///       Defaults to true. Non-focusable windows can be entered by
  ///       |nvim_set_current_win()|.
  ///   - `external`: GUI should display the window as an external
  ///       top-level window. Currently accepts no other positioning
  ///       configuration together with this.
  ///   - `style`: Configure the appearance of the window. Currently only takes
  ///       one non-empty value:
  ///       - "minimal"  Nvim will display the window with many UI options
  ///                    disabled. This is useful when displaying a temporary
  ///                    float where the text should not be edited. Disables
  ///                    'number', 'relativenumber', 'cursorline', 'cursorcolumn',
  ///                    'foldcolumn', 'spell' and 'list' options. 'signcolumn'
  ///                    is changed to `auto` and 'colorcolumn' is cleared. The
  ///                    end-of-buffer region is hidden by setting `eob` flag of
  ///                    'fillchars' to a space char, and clearing the
  ///                    |EndOfBuffer| region in 'winhighlight'.
  /// @param[out] err Error details, if any
  ///
  /// @return Window handle, or 0 on error
  Window nvim_open_win(Buffer buffer, Boolean enter, Dictionary config,
                       Error *err)
    FUNC_API_SINCE(6)
  {
    FloatConfig fconfig = FLOAT_CONFIG_INIT;
    if (!parse_float_config(config, &fconfig, false, err)) {
      return 0;
    }
    win_T *wp = win_new_float(NULL, fconfig, err);
    if (!wp) {
      return 0;
    }
    if (enter) {
      win_enter(wp, false);
    }
    if (buffer > 0) {
      nvim_win_set_buf(wp->handle, buffer, err);
    }
  
    if (fconfig.style == kWinStyleMinimal) {
      win_set_minimal_style(wp);
      didset_window_options(wp);
    }
    return wp->handle;
  }
  
  /// Gets the current list of tabpage handles.
  ///
  /// @return List of tabpage handles
  ArrayOf(Tabpage) nvim_list_tabpages(void)
    FUNC_API_SINCE(1)
  {
    Array rv = ARRAY_DICT_INIT;
  
    FOR_ALL_TABS(tp) {
      rv.size++;
    }
  
    rv.items = xmalloc(sizeof(Object) * rv.size);
    size_t i = 0;
  
    FOR_ALL_TABS(tp) {
      rv.items[i++] = TABPAGE_OBJ(tp->handle);
    }
  
    return rv;
  }
  
  /// Gets the current tabpage.
  ///
  /// @return Tabpage handle
  Tabpage nvim_get_current_tabpage(void)
    FUNC_API_SINCE(1)
  {
    return curtab->handle;
  }
  
  /// Sets the current tabpage.
  ///
  /// @param tabpage  Tabpage handle
  /// @param[out] err Error details, if any
  void nvim_set_current_tabpage(Tabpage tabpage, Error *err)
    FUNC_API_SINCE(1)
  {
    tabpage_T *tp = find_tab_by_handle(tabpage, err);
  
    if (!tp) {
      return;
    }
  
    try_start();
    goto_tabpage_tp(tp, true, true);
    if (!try_end(err) && tp != curtab) {
      api_set_error(err,
                    kErrorTypeException,
                    "Failed to switch to tabpage %d",
                    tabpage);
    }
  }
  
  /// Creates a new namespace, or gets an existing one.
  ///
  /// Namespaces are used for buffer highlights and virtual text, see
  /// |nvim_buf_add_highlight()| and |nvim_buf_set_virtual_text()|.
  ///
  /// Namespaces can be named or anonymous. If `name` matches an existing
  /// namespace, the associated id is returned. If `name` is an empty string
  /// a new, anonymous namespace is created.
  ///
  /// @param name Namespace name or empty string
  /// @return Namespace id
  Integer nvim_create_namespace(String name)
    FUNC_API_SINCE(5)
  {
    handle_T id = map_get(String, handle_T)(namespace_ids, name);
    if (id > 0) {
      return id;
    }
    id = next_namespace_id++;
    if (name.size > 0) {
      String name_alloc = copy_string(name);
      map_put(String, handle_T)(namespace_ids, name_alloc, id);
    }
    return (Integer)id;
  }
  
  /// Gets existing, non-anonymous namespaces.
  ///
  /// @return dict that maps from names to namespace ids.
  Dictionary nvim_get_namespaces(void)
    FUNC_API_SINCE(5)
  {
    Dictionary retval = ARRAY_DICT_INIT;
    String name;
    handle_T id;
  
    map_foreach(namespace_ids, name, id, {
      PUT(retval, name.data, INTEGER_OBJ(id));
    })
  
    return retval;
  }
  
  /// Pastes at cursor, in any mode.
  ///
  /// Invokes the `vim.paste` handler, which handles each mode appropriately.
  /// Sets redo/undo. Faster than |nvim_input()|. Lines break at LF ("\n").
  ///
  /// Errors ('nomodifiable', `vim.paste()` failure, …) are reflected in `err`
  /// but do not affect the return value (which is strictly decided by
  /// `vim.paste()`).  On error, subsequent calls are ignored ("drained") until
  /// the next paste is initiated (phase 1 or -1).
  ///
  /// @param data  Multiline input. May be binary (containing NUL bytes).
  /// @param crlf  Also break lines at CR and CRLF.
  /// @param phase  -1: paste in a single call (i.e. without streaming).
  ///               To "stream" a paste, call `nvim_paste` sequentially with
  ///               these `phase` values:
  ///                 - 1: starts the paste (exactly once)
  ///                 - 2: continues the paste (zero or more times)
  ///                 - 3: ends the paste (exactly once)
  /// @param[out] err Error details, if any
  /// @return
  ///     - true: Client may continue pasting.
  ///     - false: Client must cancel the paste.
  Boolean nvim_paste(String data, Boolean crlf, Integer phase, Error *err)
    FUNC_API_SINCE(6)
  {
    static bool draining = false;
    bool cancel = false;
  
    if (phase < -1 || phase > 3) {
      api_set_error(err, kErrorTypeValidation, "Invalid phase: %"PRId64, phase);
      return false;
    }
    Array args = ARRAY_DICT_INIT;
    Object rv = OBJECT_INIT;
    if (phase == -1 || phase == 1) {  // Start of paste-stream.
      draining = false;
    } else if (draining) {
      // Skip remaining chunks.  Report error only once per "stream".
      goto theend;
    }
    Array lines = string_to_array(data, crlf);
    ADD(args, ARRAY_OBJ(lines));
    ADD(args, INTEGER_OBJ(phase));
    rv = nvim_execute_lua(STATIC_CSTR_AS_STRING("return vim.paste(...)"), args,
                          err);
    if (ERROR_SET(err)) {
      draining = true;
      goto theend;
    }
    if (!(State & (CMDLINE | INSERT)) && (phase == -1 || phase == 1)) {
      ResetRedobuff();
      AppendCharToRedobuff('a');  // Dot-repeat.
    }
    // vim.paste() decides if client should cancel.  Errors do NOT cancel: we
    // want to drain remaining chunks (rather than divert them to main input).
    cancel = (rv.type == kObjectTypeBoolean && !rv.data.boolean);
    if (!cancel && !(State & CMDLINE)) {  // Dot-repeat.
      for (size_t i = 0; i < lines.size; i++) {
        String s = lines.items[i].data.string;
        assert(data.size <= INT_MAX);
        AppendToRedobuffLit((char_u *)s.data, (int)s.size);
        // readfile()-style: "\n" is indicated by presence of N+1 item.
        if (i + 1 < lines.size) {
          AppendCharToRedobuff(NL);
        }
      }
    }
    if (!(State & (CMDLINE | INSERT)) && (phase == -1 || phase == 3)) {
      AppendCharToRedobuff(ESC);  // Dot-repeat.
    }
  theend:
    api_free_object(rv);
    api_free_array(args);
    if (cancel || phase == -1 || phase == 3) {  // End of paste-stream.
      draining = false;
    }
  
    return !cancel;
  }
  
  /// Puts text at cursor, in any mode.
  ///
  /// Compare |:put| and |p| which are always linewise.
  ///
  /// @param lines  |readfile()|-style list of lines. |channel-lines|
  /// @param type  Edit behavior: any |getregtype()| result, or:
  ///              - "b" |blockwise-visual| mode (may include width, e.g. "b3")
  ///              - "c" |characterwise| mode
  ///              - "l" |linewise| mode
  ///              - ""  guess by contents, see |setreg()|
  /// @param after  Insert after cursor (like |p|), or before (like |P|).
  /// @param follow  Place cursor at end of inserted text.
  /// @param[out] err Error details, if any
  void nvim_put(ArrayOf(String) lines, String type, Boolean after,
                Boolean follow, Error *err)
    FUNC_API_SINCE(6)
  {
    yankreg_T *reg = xcalloc(sizeof(yankreg_T), 1);
    if (!prepare_yankreg_from_object(reg, type, lines.size)) {
      api_set_error(err, kErrorTypeValidation, "Invalid type: '%s'", type.data);
      goto cleanup;
    }
    if (lines.size == 0) {
      goto cleanup;  // Nothing to do.
    }
  
    for (size_t i = 0; i < lines.size; i++) {
      if (lines.items[i].type != kObjectTypeString) {
        api_set_error(err, kErrorTypeValidation,
                      "Invalid lines (expected array of strings)");
        goto cleanup;
      }
      String line = lines.items[i].data.string;
      reg->y_array[i] = (char_u *)xmemdupz(line.data, line.size);
      memchrsub(reg->y_array[i], NUL, NL, line.size);
    }
  
    finish_yankreg_from_object(reg, false);
  
    TRY_WRAP({
      try_start();
      bool VIsual_was_active = VIsual_active;
      msg_silent++;  // Avoid "N more lines" message.
      do_put(0, reg, after ? FORWARD : BACKWARD, 1, follow ? PUT_CURSEND : 0);
      msg_silent--;
      VIsual_active = VIsual_was_active;
      try_end(err);
    });
  
  cleanup:
    free_register(reg);
    xfree(reg);
  }
  
  /// Subscribes to event broadcasts.
  ///
  /// @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_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;
    rpc_subscribe(channel_id, e);
  }
  
  /// Unsubscribes to event broadcasts.
  ///
  /// @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_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;
    rpc_unsubscribe(channel_id, e);
  }
  
  /// Returns the 24-bit RGB value of a |nvim_get_color_map()| color name or
  /// "#rrggbb" hexadecimal string.
  ///
  /// Example:
  /// <pre>
  ///     :echo nvim_get_color_by_name("Pink")
  ///     :echo nvim_get_color_by_name("#cbcbcb")
  /// </pre>
  ///
  /// @param name Color name or "#rrggbb" string
  /// @return 24-bit RGB value, or -1 for invalid argument.
  Integer nvim_get_color_by_name(String name)
    FUNC_API_SINCE(1)
  {
    return name_to_color((char_u *)name.data);
  }
  
  /// Returns a map of color names and RGB values.
  ///
  /// Keys are color names (e.g. "Aqua") and values are 24-bit RGB color values
  /// (e.g. 65535).
  ///
  /// @return Map of color names and RGB values.
  Dictionary nvim_get_color_map(void)
    FUNC_API_SINCE(1)
  {
    Dictionary colors = ARRAY_DICT_INIT;
  
    for (int i = 0; color_name_table[i].name != NULL; i++) {
      PUT(colors, color_name_table[i].name,
          INTEGER_OBJ(color_name_table[i].color));
    }
    return colors;
  }
  
  /// Gets a map of the current editor state.
  ///
  /// @param opts  Optional parameters.
  ///               - types:  List of |context-types| ("regs", "jumps", "bufs",
  ///                 "gvars", …) to gather, or empty for "all".
  /// @param[out]  err  Error details, if any
  ///
  /// @return map of global |context|.
  Dictionary nvim_get_context(Dictionary opts, Error *err)
    FUNC_API_SINCE(6)
  {
    Array types = ARRAY_DICT_INIT;
    for (size_t i = 0; i < opts.size; i++) {
      String k = opts.items[i].key;
      Object v = opts.items[i].value;
      if (strequal("types", k.data)) {
        if (v.type != kObjectTypeArray) {
          api_set_error(err, kErrorTypeValidation, "invalid value for key: %s",
                        k.data);
          return (Dictionary)ARRAY_DICT_INIT;
        }
        types = v.data.array;
      } else {
        api_set_error(err, kErrorTypeValidation, "unexpected key: %s", k.data);
        return (Dictionary)ARRAY_DICT_INIT;
      }
    }
  
    int int_types = types.size > 0 ? 0 : kCtxAll;
    if (types.size > 0) {
      for (size_t i = 0; i < types.size; i++) {
        if (types.items[i].type == kObjectTypeString) {
          const char *const s = types.items[i].data.string.data;
          if (strequal(s, "regs")) {
            int_types |= kCtxRegs;
          } else if (strequal(s, "jumps")) {
            int_types |= kCtxJumps;
          } else if (strequal(s, "bufs")) {
            int_types |= kCtxBufs;
          } else if (strequal(s, "gvars")) {
            int_types |= kCtxGVars;
          } else if (strequal(s, "sfuncs")) {
            int_types |= kCtxSFuncs;
          } else if (strequal(s, "funcs")) {
            int_types |= kCtxFuncs;
          } else {
            api_set_error(err, kErrorTypeValidation, "unexpected type: %s", s);
            return (Dictionary)ARRAY_DICT_INIT;
          }
        }
      }
    }
  
    Context ctx = CONTEXT_INIT;
    ctx_save(&ctx, int_types);
    Dictionary dict = ctx_to_dict(&ctx);
    ctx_free(&ctx);
    return dict;
  }
  
  /// Sets the current editor state from the given |context| map.
  ///
  /// @param  dict  |Context| map.
  Object nvim_load_context(Dictionary dict)
    FUNC_API_SINCE(6)
  {
    Context ctx = CONTEXT_INIT;
  
    int save_did_emsg = did_emsg;
    did_emsg = false;
  
    ctx_from_dict(dict, &ctx);
    if (!did_emsg) {
      ctx_restore(&ctx, kCtxAll);
    }
  
    ctx_free(&ctx);
  
    did_emsg = save_did_emsg;
    return (Object)OBJECT_INIT;
  }
  
  /// 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_FAST
  {
    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 global (non-buffer-local) |mapping| definitions.
  ///
  /// @param  mode       Mode short-name ("n", "i", "v", ...)
  /// @returns Array of maparg()-like dictionaries describing mappings.
  ///          The "buffer" key is always zero.
  ArrayOf(Dictionary) nvim_get_keymap(String mode)
    FUNC_API_SINCE(3)
  {
    return keymap_array(mode, NULL);
  }
  
  /// Sets a global |mapping| for the given mode.
  ///
  /// To set a buffer-local mapping, use |nvim_buf_set_keymap()|.
  ///
  /// Unlike |:map|, leading/trailing whitespace is accepted as part of the {lhs}
  /// or {rhs}. Empty {rhs} is |<Nop>|. |keycodes| are replaced as usual.
  ///
  /// Example:
  /// <pre>
  ///     call nvim_set_keymap('n', ' <NL>', '', {'nowait': v:true})
  /// </pre>
  ///
  /// is equivalent to:
  /// <pre>
  ///     nmap <nowait> <Space><NL> <Nop>
  /// </pre>
  ///
  /// @param  mode  Mode short-name (map command prefix: "n", "i", "v", "x", …)
  ///               or "!" for |:map!|, or empty string for |:map|.
  /// @param  lhs   Left-hand-side |{lhs}| of the mapping.
  /// @param  rhs   Right-hand-side |{rhs}| of the mapping.
  /// @param  opts  Optional parameters map. Accepts all |:map-arguments|
  ///               as keys excluding |<buffer>| but including |noremap|.
  ///               Values are Booleans. Unknown key is an error.
  /// @param[out]   err   Error details, if any.
  void nvim_set_keymap(String mode, String lhs, String rhs,
                       Dictionary opts, Error *err)
    FUNC_API_SINCE(6)
  {
    modify_keymap(-1, false, mode, lhs, rhs, opts, err);
  }
  
  /// Unmaps a global |mapping| for the given mode.
  ///
  /// To unmap a buffer-local mapping, use |nvim_buf_del_keymap()|.
  ///
  /// @see |nvim_set_keymap()|
  void nvim_del_keymap(String mode, String lhs, Error *err)
    FUNC_API_SINCE(6)
  {
    nvim_buf_del_keymap(-1, mode, lhs, err);
  }
  
  /// Gets a map of global (non-buffer-local) Ex commands.
  ///
  /// Currently only |user-commands| are supported, not builtin Ex commands.
  ///
  /// @param  opts  Optional parameters. Currently only supports
  ///               {"builtin":false}
  /// @param[out]  err   Error details, if any.
  ///
  /// @returns Map of maps describing commands.
  Dictionary nvim_get_commands(Dictionary opts, Error *err)
    FUNC_API_SINCE(4)
  {
    return nvim_buf_get_commands(-1, opts, err);
  }
  
  /// Returns a 2-tuple (Array), where item 0 is the current channel id and item
  /// 1 is the |api-metadata| map (Dictionary).
  ///
  /// @returns 2-tuple [{channel-id}, {api-metadata}]
  Array nvim_get_api_info(uint64_t channel_id)
    FUNC_API_SINCE(1) FUNC_API_FAST FUNC_API_REMOTE_ONLY
  {
    Array rv = ARRAY_DICT_INIT;
  
    assert(channel_id <= INT64_MAX);
    ADD(rv, INTEGER_OBJ((int64_t)channel_id));
    ADD(rv, DICTIONARY_OBJ(api_metadata()));
  
    return rv;
  }
  
  /// Self-identifies the client.
  ///
  /// The client/plugin/application should call this after connecting, to provide
  /// hints about its identity and purpose, for debugging and orchestration.
  ///
  /// Can be called more than once; the caller should merge old info if
  /// appropriate. Example: library first identifies the channel, then a plugin
  /// using that library later identifies itself.
  ///
  /// @note "Something is better than nothing". You don't need to include all the
  ///       fields.
  ///
  /// @param channel_id
  /// @param name Short name for the connected client
  /// @param version  Dictionary describing the version, with these
  ///                 (optional) keys:
  ///     - "major" major version (defaults to 0 if not set, for no release yet)
  ///     - "minor" minor version
  ///     - "patch" patch number
  ///     - "prerelease" string describing a prerelease, like "dev" or "beta1"
  ///     - "commit" hash or similar identifier of commit
  /// @param type Must be one of the following values. Client libraries should
  ///             default to "remote" unless overridden by the user.
  ///     - "remote" remote client connected to Nvim.
  ///     - "ui" gui frontend
  ///     - "embedder" application using Nvim as a component (for example,
  ///                  IDE/editor implementing a vim mode).
  ///     - "host" plugin host, typically started by nvim
  ///     - "plugin" single plugin, started by nvim
  /// @param methods Builtin methods in the client. For a host, this does not
  ///                include plugin methods which will be discovered later.
  ///                The key should be the method name, the values are dicts with
  ///                these (optional) keys (more keys may be added in future
  ///                versions of Nvim, thus unknown keys are ignored. Clients
  ///                must only use keys defined in this or later versions of
  ///                Nvim):
  ///     - "async"  if true, send as a notification. If false or unspecified,
  ///                use a blocking request
  ///     - "nargs" Number of arguments. Could be a single integer or an array
  ///                of two integers, minimum and maximum inclusive.
  ///
  /// @param attributes Arbitrary string:string map of informal client properties.
  ///     Suggested keys:
  ///     - "website": Client homepage URL (e.g. GitHub repository)
  ///     - "license": License description ("Apache 2", "GPLv3", "MIT", …)
  ///     - "logo":    URI or path to image, preferably small logo or icon.
  ///                  .png or .svg format is preferred.
  ///
  /// @param[out] err Error details, if any
  void nvim_set_client_info(uint64_t channel_id, String name,
                            Dictionary version, String type,
                            Dictionary methods, Dictionary attributes,
                            Error *err)
    FUNC_API_SINCE(4) FUNC_API_REMOTE_ONLY
  {
    Dictionary info = ARRAY_DICT_INIT;
    PUT(info, "name", copy_object(STRING_OBJ(name)));
  
    version = copy_dictionary(version);
    bool has_major = false;
    for (size_t i = 0; i < version.size; i++) {
      if (strequal(version.items[i].key.data, "major")) {
        has_major = true;
        break;
      }
    }
    if (!has_major) {
      PUT(version, "major", INTEGER_OBJ(0));
    }
    PUT(info, "version", DICTIONARY_OBJ(version));
  
    PUT(info, "type", copy_object(STRING_OBJ(type)));
    PUT(info, "methods", DICTIONARY_OBJ(copy_dictionary(methods)));
    PUT(info, "attributes", DICTIONARY_OBJ(copy_dictionary(attributes)));
  
    rpc_set_client_info(channel_id, info);
  }
  
  /// Get information about a channel.
  ///
  /// @returns Dictionary describing a channel, with these keys:
  ///    - "stream"  the stream underlying the channel
  ///         - "stdio"      stdin and stdout of this Nvim instance
  ///         - "stderr"     stderr of this Nvim instance
  ///         - "socket"     TCP/IP socket or named pipe
  ///         - "job"        job with communication over its stdio
  ///    -  "mode"    how data received on the channel is interpreted
  ///         - "bytes"      send and receive raw bytes
  ///         - "terminal"   a |terminal| instance interprets ASCII sequences
  ///         - "rpc"        |RPC| communication on the channel is active
  ///    -  "pty"     Name of pseudoterminal, if one is used (optional).
  ///                 On a POSIX system, this will be a device path like
  ///                 /dev/pts/1. Even if the name is unknown, the key will
  ///                 still be present to indicate a pty is used. This is
  ///                 currently the case when using winpty on windows.
  ///    -  "buffer"  buffer with connected |terminal| instance (optional)
  ///    -  "client"  information about the client on the other end of the
  ///                 RPC channel, if it has added it using
  ///                 |nvim_set_client_info()|. (optional)
  ///
  Dictionary nvim_get_chan_info(Integer chan, Error *err)
    FUNC_API_SINCE(4)
  {
    if (chan < 0) {
      return (Dictionary)ARRAY_DICT_INIT;
    }
    return channel_info((uint64_t)chan);
  }
  
  /// Get information about all open channels.
  ///
  /// @returns Array of Dictionaries, each describing a channel with
  ///          the format specified at |nvim_get_chan_info()|.
  Array nvim_list_chans(void)
    FUNC_API_SINCE(4)
  {
    return channel_all_info();
  }
  
  /// Calls many API methods atomically.
  ///
  /// This has two main usages:
  /// 1. To perform several requests from an async context atomically, i.e.
  ///    without interleaving redraws, RPC requests from other clients, or user
  ///    interactions (however API methods may trigger autocommands or event
  ///    processing which have such side-effects, e.g. |:sleep| may wake timers).
  /// 2. To minimize RPC overhead (roundtrips) of a sequence of many requests.
  ///
  /// @param channel_id
  /// @param calls an array of calls, where each call is described by an array
  ///              with two elements: the request name, and an array of arguments.
  /// @param[out] err Validation error details (malformed `calls` parameter),
  ///             if any. Errors from batched calls are given in the return value.
  ///
  /// @return Array of two elements. The first is an array of return
  /// values. The second is NIL if all calls succeeded. If a call resulted in
  /// an error, it is a three-element array with the zero-based index of the call
  /// which resulted in an error, the error type and the error message. If an
  /// error occurred, 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_REMOTE_ONLY
  {
    Array rv = ARRAY_DICT_INIT;
    Array results = ARRAY_DICT_INIT;
    Error nested_error = ERROR_INIT;
  
    size_t i;  // also used for freeing the variables
    for (i = 0; i < calls.size; i++) {
      if (calls.items[i].type != kObjectTypeArray) {
        api_set_error(err,
                      kErrorTypeValidation,
                      "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,
                      kErrorTypeValidation,
                      "Items in calls array must be arrays of size 2");
        goto validation_error;
      }
  
      if (call.items[0].type != kObjectTypeString) {
        api_set_error(err,
                      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,
                      kErrorTypeValidation,
                      "Args must be Array");
        goto validation_error;
      }
      Array args = call.items[1].data.array;
  
      MsgpackRpcRequestHandler handler =
          msgpack_rpc_get_handler_for(name.data,
                                      name.size,
                                      &nested_error);
  
      if (ERROR_SET(&nested_error)) {
        break;
      }
      Object result = handler.fn(channel_id, args, &nested_error);
      if (ERROR_SET(&nested_error)) {
        // error handled after loop
        break;
      }
  
      ADD(results, result);
    }
  
    ADD(rv, ARRAY_OBJ(results));
    if (ERROR_SET(&nested_error)) {
      Array errval = ARRAY_DICT_INIT;
      ADD(errval, INTEGER_OBJ((Integer)i));
      ADD(errval, INTEGER_OBJ(nested_error.type));
      ADD(errval, STRING_OBJ(cstr_to_string(nested_error.msg)));
      ADD(rv, ARRAY_OBJ(errval));
    } else {
      ADD(rv, NIL);
    }
    goto theend;
  
  validation_error:
    api_free_array(results);
  theend:
    api_clear_error(&nested_error);
    return rv;
  }
  
  typedef struct {
    ExprASTNode **node_p;
    Object *ret_node_p;
  } ExprASTConvStackItem;
  
  /// @cond DOXYGEN_NOT_A_FUNCTION
  typedef kvec_withinit_t(ExprASTConvStackItem, 16) ExprASTConvStack;
  /// @endcond
  
  /// Parse a VimL expression.
  ///
  /// @param[in]  expr  Expression to parse. Always treated as a single line.
  /// @param[in]  flags Flags:
  ///                    - "m" if multiple expressions in a row are allowed (only
  ///                      the first one will be parsed),
  ///                    - "E" if EOC tokens are not allowed (determines whether
  ///                      they will stop parsing process or be recognized as an
  ///                      operator/space, though also yielding an error).
  ///                    - "l" when needing to start parsing with lvalues for
  ///                      ":let" or ":for".
  ///                    Common flag sets:
  ///                    - "m" to parse like for ":echo".
  ///                    - "E" to parse like for "<C-r>=".
  ///                    - empty string for ":call".
  ///                    - "lm" to parse for ":let".
  /// @param[in]  highlight  If true, return value will also include "highlight"
  ///                        key containing array of 4-tuples (arrays) (Integer,
  ///                        Integer, Integer, String), where first three numbers
  ///                        define the highlighted region and represent line,
  ///                        starting column and ending column (latter exclusive:
  ///                        one should highlight region [start_col, end_col)).
  ///
  /// @return
  ///      - AST: top-level dictionary with these keys:
  ///        - "error": Dictionary with error, present only if parser saw some
  ///                 error. Contains the following keys:
  ///          - "message": String, error message in printf format, translated.
  ///                       Must contain exactly one "%.*s".
  ///          - "arg": String, error message argument.
  ///        - "len": Amount of bytes successfully parsed. With flags equal to ""
  ///                 that should be equal to the length of expr string.
  ///                 (“Sucessfully parsed” here means “participated in AST
  ///                  creation”, not “till the first error”.)
  ///        - "ast": AST, either nil or a dictionary with these keys:
  ///          - "type": node type, one of the value names from ExprASTNodeType
  ///                    stringified without "kExprNode" prefix.
  ///          - "start": a pair [line, column] describing where node is "started"
  ///                     where "line" is always 0 (will not be 0 if you will be
  ///                     using nvim_parse_viml() on e.g. ":let", but that is not
  ///                     present yet). Both elements are Integers.
  ///          - "len": “length” of the node. This and "start" are there for
  ///                   debugging purposes primary (debugging parser and providing
  ///                   debug information).
  ///          - "children": a list of nodes described in top/"ast". There always
  ///                        is zero, one or two children, key will not be present
  ///                        if node has no children. Maximum number of children
  ///                        may be found in node_maxchildren array.
  ///      - Local values (present only for certain nodes):
  ///        - "scope": a single Integer, specifies scope for "Option" and
  ///                   "PlainIdentifier" nodes. For "Option" it is one of
  ///                   ExprOptScope values, for "PlainIdentifier" it is one of
  ///                   ExprVarScope values.
  ///        - "ident": identifier (without scope, if any), present for "Option",
  ///                   "PlainIdentifier", "PlainKey" and "Environment" nodes.
  ///        - "name": Integer, register name (one character) or -1. Only present
  ///                for "Register" nodes.
  ///        - "cmp_type": String, comparison type, one of the value names from
  ///                      ExprComparisonType, stringified without "kExprCmp"
  ///                      prefix. Only present for "Comparison" nodes.
  ///        - "ccs_strategy": String, case comparison strategy, one of the
  ///                          value names from ExprCaseCompareStrategy,
  ///                          stringified without "kCCStrategy" prefix. Only
  ///                          present for "Comparison" nodes.
  ///        - "augmentation": String, augmentation type for "Assignment" nodes.
  ///                          Is either an empty string, "Add", "Subtract" or
  ///                          "Concat" for "=", "+=", "-=" or ".=" respectively.
  ///        - "invert": Boolean, true if result of comparison needs to be
  ///                    inverted. Only present for "Comparison" nodes.
  ///        - "ivalue": Integer, integer value for "Integer" nodes.
  ///        - "fvalue": Float, floating-point value for "Float" nodes.
  ///        - "svalue": String, value for "SingleQuotedString" and
  ///                    "DoubleQuotedString" nodes.
  /// @param[out] err Error details, if any
  Dictionary nvim_parse_expression(String expr, String flags, Boolean highlight,
                                   Error *err)
    FUNC_API_SINCE(4) FUNC_API_FAST
  {
    int pflags = 0;
    for (size_t i = 0 ; i < flags.size ; i++) {
      switch (flags.data[i]) {
        case 'm': { pflags |= kExprFlagsMulti; break; }
        case 'E': { pflags |= kExprFlagsDisallowEOC; break; }
        case 'l': { pflags |= kExprFlagsParseLet; break; }
        case NUL: {
          api_set_error(err, kErrorTypeValidation, "Invalid flag: '\\0' (%u)",
                        (unsigned)flags.data[i]);
          return (Dictionary)ARRAY_DICT_INIT;
        }
        default: {
          api_set_error(err, kErrorTypeValidation, "Invalid flag: '%c' (%u)",
                        flags.data[i], (unsigned)flags.data[i]);
          return (Dictionary)ARRAY_DICT_INIT;
        }
      }
    }
    ParserLine plines[] = {
      {
        .data = expr.data,
        .size = expr.size,
        .allocated = false,
      },
      { NULL, 0, false },
    };
    ParserLine *plines_p = plines;
    ParserHighlight colors;
    kvi_init(colors);
    ParserHighlight *const colors_p = (highlight ? &colors : NULL);
    ParserState pstate;
    viml_parser_init(
        &pstate, parser_simple_get_line, &plines_p, colors_p);
    ExprAST east = viml_pexpr_parse(&pstate, pflags);
  
    const size_t ret_size = (
        2  // "ast", "len"
        + (size_t)(east.err.msg != NULL)  // "error"
        + (size_t)highlight  // "highlight"
        + 0);
    Dictionary ret = {
      .items = xmalloc(ret_size * sizeof(ret.items[0])),
      .size = 0,
      .capacity = ret_size,
    };
    ret.items[ret.size++] = (KeyValuePair) {
      .key = STATIC_CSTR_TO_STRING("ast"),
      .value = NIL,
    };
    ret.items[ret.size++] = (KeyValuePair) {
      .key = STATIC_CSTR_TO_STRING("len"),
      .value = INTEGER_OBJ((Integer)(pstate.pos.line == 1
                                     ? plines[0].size
                                     : pstate.pos.col)),
    };
    if (east.err.msg != NULL) {
      Dictionary err_dict = {
        .items = xmalloc(2 * sizeof(err_dict.items[0])),
        .size = 2,
        .capacity = 2,
      };
      err_dict.items[0] = (KeyValuePair) {
        .key = STATIC_CSTR_TO_STRING("message"),
        .value = STRING_OBJ(cstr_to_string(east.err.msg)),
      };
      if (east.err.arg == NULL) {
        err_dict.items[1] = (KeyValuePair) {
          .key = STATIC_CSTR_TO_STRING("arg"),
          .value = STRING_OBJ(STRING_INIT),
        };
      } else {
        err_dict.items[1] = (KeyValuePair) {
          .key = STATIC_CSTR_TO_STRING("arg"),
          .value = STRING_OBJ(((String) {
            .data = xmemdupz(east.err.arg, (size_t)east.err.arg_len),
            .size = (size_t)east.err.arg_len,
          })),
        };
      }
      ret.items[ret.size++] = (KeyValuePair) {
        .key = STATIC_CSTR_TO_STRING("error"),
        .value = DICTIONARY_OBJ(err_dict),
      };
    }
    if (highlight) {
      Array hl = (Array) {
        .items = xmalloc(kv_size(colors) * sizeof(hl.items[0])),
        .capacity = kv_size(colors),
        .size = kv_size(colors),
      };
      for (size_t i = 0 ; i < kv_size(colors) ; i++) {
        const ParserHighlightChunk chunk = kv_A(colors, i);
        Array chunk_arr = (Array) {
          .items = xmalloc(4 * sizeof(chunk_arr.items[0])),
          .capacity = 4,
          .size = 4,
        };
        chunk_arr.items[0] = INTEGER_OBJ((Integer)chunk.start.line);
        chunk_arr.items[1] = INTEGER_OBJ((Integer)chunk.start.col);
        chunk_arr.items[2] = INTEGER_OBJ((Integer)chunk.end_col);
        chunk_arr.items[3] = STRING_OBJ(cstr_to_string(chunk.group));
        hl.items[i] = ARRAY_OBJ(chunk_arr);
      }
      ret.items[ret.size++] = (KeyValuePair) {
        .key = STATIC_CSTR_TO_STRING("highlight"),
        .value = ARRAY_OBJ(hl),
      };
    }
    kvi_destroy(colors);
  
    // Walk over the AST, freeing nodes in process.
    ExprASTConvStack ast_conv_stack;
    kvi_init(ast_conv_stack);
    kvi_push(ast_conv_stack, ((ExprASTConvStackItem) {
      .node_p = &east.root,
      .ret_node_p = &ret.items[0].value,
    }));
    while (kv_size(ast_conv_stack)) {
      ExprASTConvStackItem cur_item = kv_last(ast_conv_stack);
      ExprASTNode *const node = *cur_item.node_p;
      if (node == NULL) {
        assert(kv_size(ast_conv_stack) == 1);
        kv_drop(ast_conv_stack, 1);
      } else {
        if (cur_item.ret_node_p->type == kObjectTypeNil) {
          const size_t ret_node_items_size = (size_t)(
              3  // "type", "start" and "len"
              + (node->children != NULL)  // "children"
              + (node->type == kExprNodeOption
                 || node->type == kExprNodePlainIdentifier)  // "scope"
              + (node->type == kExprNodeOption
                 || node->type == kExprNodePlainIdentifier
                 || node->type == kExprNodePlainKey
                 || node->type == kExprNodeEnvironment)  // "ident"
              + (node->type == kExprNodeRegister)  // "name"
              + (3  // "cmp_type", "ccs_strategy", "invert"
                 * (node->type == kExprNodeComparison))
              + (node->type == kExprNodeInteger)  // "ivalue"
              + (node->type == kExprNodeFloat)  // "fvalue"
              + (node->type == kExprNodeDoubleQuotedString
                 || node->type == kExprNodeSingleQuotedString)  // "svalue"
              + (node->type == kExprNodeAssignment)  // "augmentation"
              + 0);
          Dictionary ret_node = {
            .items = xmalloc(ret_node_items_size * sizeof(ret_node.items[0])),
            .capacity = ret_node_items_size,
            .size = 0,
          };
          *cur_item.ret_node_p = DICTIONARY_OBJ(ret_node);
        }
        Dictionary *ret_node = &cur_item.ret_node_p->data.dictionary;
        if (node->children != NULL) {
          const size_t num_children = 1 + (node->children->next != NULL);
          Array children_array = {
            .items = xmalloc(num_children * sizeof(children_array.items[0])),
            .capacity = num_children,
            .size = num_children,
          };
          for (size_t i = 0; i < num_children; i++) {
            children_array.items[i] = NIL;
          }
          ret_node->items[ret_node->size++] = (KeyValuePair) {
            .key = STATIC_CSTR_TO_STRING("children"),
            .value = ARRAY_OBJ(children_array),
          };
          kvi_push(ast_conv_stack, ((ExprASTConvStackItem) {
            .node_p = &node->children,
            .ret_node_p = &children_array.items[0],
          }));
        } else if (node->next != NULL) {
          kvi_push(ast_conv_stack, ((ExprASTConvStackItem) {
            .node_p = &node->next,
            .ret_node_p = cur_item.ret_node_p + 1,
          }));
        } else {
          kv_drop(ast_conv_stack, 1);
          ret_node->items[ret_node->size++] = (KeyValuePair) {
            .key = STATIC_CSTR_TO_STRING("type"),
            .value = STRING_OBJ(cstr_to_string(east_node_type_tab[node->type])),
          };
          Array start_array = {
            .items = xmalloc(2 * sizeof(start_array.items[0])),
            .capacity = 2,
            .size = 2,
          };
          start_array.items[0] = INTEGER_OBJ((Integer)node->start.line);
          start_array.items[1] = INTEGER_OBJ((Integer)node->start.col);
          ret_node->items[ret_node->size++] = (KeyValuePair) {
            .key = STATIC_CSTR_TO_STRING("start"),
            .value = ARRAY_OBJ(start_array),
          };
          ret_node->items[ret_node->size++] = (KeyValuePair) {
            .key = STATIC_CSTR_TO_STRING("len"),
            .value = INTEGER_OBJ((Integer)node->len),
          };
          switch (node->type) {
            case kExprNodeDoubleQuotedString:
            case kExprNodeSingleQuotedString: {
              ret_node->items[ret_node->size++] = (KeyValuePair) {
                .key = STATIC_CSTR_TO_STRING("svalue"),
                .value = STRING_OBJ(((String) {
                  .data = node->data.str.value,
                  .size = node->data.str.size,
                })),
              };
              break;
            }
            case kExprNodeOption: {
              ret_node->items[ret_node->size++] = (KeyValuePair) {
                .key = STATIC_CSTR_TO_STRING("scope"),
                .value = INTEGER_OBJ(node->data.opt.scope),
              };
              ret_node->items[ret_node->size++] = (KeyValuePair) {
                .key = STATIC_CSTR_TO_STRING("ident"),
                .value = STRING_OBJ(((String) {
                  .data = xmemdupz(node->data.opt.ident,
                                   node->data.opt.ident_len),
                  .size = node->data.opt.ident_len,
                })),
              };
              break;
            }
            case kExprNodePlainIdentifier: {
              ret_node->items[ret_node->size++] = (KeyValuePair) {
                .key = STATIC_CSTR_TO_STRING("scope"),
                .value = INTEGER_OBJ(node->data.var.scope),
              };
              ret_node->items[ret_node->size++] = (KeyValuePair) {
                .key = STATIC_CSTR_TO_STRING("ident"),
                .value = STRING_OBJ(((String) {
                  .data = xmemdupz(node->data.var.ident,
                                   node->data.var.ident_len),
                  .size = node->data.var.ident_len,
                })),
              };
              break;
            }
            case kExprNodePlainKey: {
              ret_node->items[ret_node->size++] = (KeyValuePair) {
                .key = STATIC_CSTR_TO_STRING("ident"),
                .value = STRING_OBJ(((String) {
                  .data = xmemdupz(node->data.var.ident,
                                   node->data.var.ident_len),
                  .size = node->data.var.ident_len,
                })),
              };
              break;
            }
            case kExprNodeEnvironment: {
              ret_node->items[ret_node->size++] = (KeyValuePair) {
                .key = STATIC_CSTR_TO_STRING("ident"),
                .value = STRING_OBJ(((String) {
                  .data = xmemdupz(node->data.env.ident,
                                   node->data.env.ident_len),
                  .size = node->data.env.ident_len,
                })),
              };
              break;
            }
            case kExprNodeRegister: {
              ret_node->items[ret_node->size++] = (KeyValuePair) {
                .key = STATIC_CSTR_TO_STRING("name"),
                .value = INTEGER_OBJ(node->data.reg.name),
              };
              break;
            }
            case kExprNodeComparison: {
              ret_node->items[ret_node->size++] = (KeyValuePair) {
                .key = STATIC_CSTR_TO_STRING("cmp_type"),
                .value = STRING_OBJ(cstr_to_string(
                    eltkn_cmp_type_tab[node->data.cmp.type])),
              };
              ret_node->items[ret_node->size++] = (KeyValuePair) {
                .key = STATIC_CSTR_TO_STRING("ccs_strategy"),
                .value = STRING_OBJ(cstr_to_string(
                    ccs_tab[node->data.cmp.ccs])),
              };
              ret_node->items[ret_node->size++] = (KeyValuePair) {
                .key = STATIC_CSTR_TO_STRING("invert"),
                .value = BOOLEAN_OBJ(node->data.cmp.inv),
              };
              break;
            }
            case kExprNodeFloat: {
              ret_node->items[ret_node->size++] = (KeyValuePair) {
                .key = STATIC_CSTR_TO_STRING("fvalue"),
                .value = FLOAT_OBJ(node->data.flt.value),
              };
              break;
            }
            case kExprNodeInteger: {
              ret_node->items[ret_node->size++] = (KeyValuePair) {
                .key = STATIC_CSTR_TO_STRING("ivalue"),
                .value = INTEGER_OBJ((Integer)(
                    node->data.num.value > API_INTEGER_MAX
                    ? API_INTEGER_MAX
                    : (Integer)node->data.num.value)),
              };
              break;
            }
            case kExprNodeAssignment: {
              const ExprAssignmentType asgn_type = node->data.ass.type;
              ret_node->items[ret_node->size++] = (KeyValuePair) {
                .key = STATIC_CSTR_TO_STRING("augmentation"),
                .value = STRING_OBJ(
                    asgn_type == kExprAsgnPlain
                    ? (String)STRING_INIT
                    : cstr_to_string(expr_asgn_type_tab[asgn_type])),
              };
              break;
            }
            case kExprNodeMissing:
            case kExprNodeOpMissing:
            case kExprNodeTernary:
            case kExprNodeTernaryValue:
            case kExprNodeSubscript:
            case kExprNodeListLiteral:
            case kExprNodeUnaryPlus:
            case kExprNodeBinaryPlus:
            case kExprNodeNested:
            case kExprNodeCall:
            case kExprNodeComplexIdentifier:
            case kExprNodeUnknownFigure:
            case kExprNodeLambda:
            case kExprNodeDictLiteral:
            case kExprNodeCurlyBracesIdentifier:
            case kExprNodeComma:
            case kExprNodeColon:
            case kExprNodeArrow:
            case kExprNodeConcat:
            case kExprNodeConcatOrSubscript:
            case kExprNodeOr:
            case kExprNodeAnd:
            case kExprNodeUnaryMinus:
            case kExprNodeBinaryMinus:
            case kExprNodeNot:
            case kExprNodeMultiplication:
            case kExprNodeDivision:
            case kExprNodeMod: {
              break;
            }
          }
          assert(cur_item.ret_node_p->data.dictionary.size
                 == cur_item.ret_node_p->data.dictionary.capacity);
          xfree(*cur_item.node_p);
          *cur_item.node_p = NULL;
        }
      }
    }
    kvi_destroy(ast_conv_stack);
  
    assert(ret.size == ret.capacity);
    // Should be a no-op actually, leaving it in case non-nodes will need to be
    // freed later.
    viml_pexpr_free_ast(east);
    viml_parser_destroy(&pstate);
    return ret;
  }
  
  
  /// Writes a message to vim output or error buffer. The string is split
  /// and flushed after each newline. Incomplete lines are kept for writing
  /// later.
  ///
  /// @param message  Message to write
  /// @param to_err   true: message is an error (uses `emsg` instead of `msg`)
  static void write_msg(String message, bool to_err)
  {
    static size_t out_pos = 0, err_pos = 0;
    static char out_line_buf[LINE_BUFFER_SIZE], err_line_buf[LINE_BUFFER_SIZE];
  
  #define PUSH_CHAR(i, pos, line_buf, msg) \
    if (message.data[i] == NL || pos == LINE_BUFFER_SIZE - 1) { \
      line_buf[pos] = NUL; \
      msg((char_u *)line_buf); \
      pos = 0; \
      continue; \
    } \
    \
    line_buf[pos++] = message.data[i];
  
    ++no_wait_return;
    for (uint32_t i = 0; i < message.size; i++) {
      if (to_err) {
        PUSH_CHAR(i, err_pos, err_line_buf, emsg);
      } else {
        PUSH_CHAR(i, out_pos, out_line_buf, msg);
      }
    }
    --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;
  }
  
  /// Gets internal stats.
  ///
  /// @return Map of various internal stats.
  Dictionary nvim__stats(void)
  {
    Dictionary rv = ARRAY_DICT_INIT;
    PUT(rv, "fsync", INTEGER_OBJ(g_stats.fsync));
    PUT(rv, "redraw", INTEGER_OBJ(g_stats.redraw));
    return rv;
  }
  
  /// Gets a list of dictionaries representing attached UIs.
  ///
  /// @return Array of UI dictionaries, each with these keys:
  ///   - "height"  Requested height of the UI
  ///   - "width"   Requested width of the UI
  ///   - "rgb"     true if the UI uses RGB colors (false implies |cterm-colors|)
  ///   - "ext_..." Requested UI extensions, see |ui-option|
  ///   - "chan"    Channel id of remote UI (not present for TUI)
  Array nvim_list_uis(void)
    FUNC_API_SINCE(4)
  {
    return ui_array();
  }
  
  /// Gets the immediate children of process `pid`.
  ///
  /// @return Array of child process ids, empty if process not found.
  Array nvim_get_proc_children(Integer pid, Error *err)
    FUNC_API_SINCE(4)
  {
    Array rvobj = ARRAY_DICT_INIT;
    int *proc_list = NULL;
  
    if (pid <= 0 || pid > INT_MAX) {
      api_set_error(err, kErrorTypeException, "Invalid pid: %" PRId64, pid);
      goto end;
    }
  
    size_t proc_count;
    int rv = os_proc_children((int)pid, &proc_list, &proc_count);
    if (rv != 0) {
      // syscall failed (possibly because of kernel options), try shelling out.
      DLOG("fallback to vim._os_proc_children()");
      Array a = ARRAY_DICT_INIT;
      ADD(a, INTEGER_OBJ(pid));
      String s = cstr_to_string("return vim._os_proc_children(select(1, ...))");
      Object o = nvim_execute_lua(s, a, err);
      api_free_string(s);
      api_free_array(a);
      if (o.type == kObjectTypeArray) {
        rvobj = o.data.array;
      } else if (!ERROR_SET(err)) {
        api_set_error(err, kErrorTypeException,
                      "Failed to get process children. pid=%" PRId64 " error=%d",
                      pid, rv);
      }
      goto end;
    }
  
    for (size_t i = 0; i < proc_count; i++) {
      ADD(rvobj, INTEGER_OBJ(proc_list[i]));
    }
  
  end:
    xfree(proc_list);
    return rvobj;
  }
  
  /// Gets info describing process `pid`.
  ///
  /// @return Map of process properties, or NIL if process not found.
  Object nvim_get_proc(Integer pid, Error *err)
    FUNC_API_SINCE(4)
  {
    Object rvobj = OBJECT_INIT;
    rvobj.data.dictionary = (Dictionary)ARRAY_DICT_INIT;
    rvobj.type = kObjectTypeDictionary;
  
    if (pid <= 0 || pid > INT_MAX) {
      api_set_error(err, kErrorTypeException, "Invalid pid: %" PRId64, pid);
      return NIL;
    }
  #ifdef WIN32
    rvobj.data.dictionary = os_proc_info((int)pid);
    if (rvobj.data.dictionary.size == 0) {  // Process not found.
      return NIL;
    }
  #else
    // Cross-platform process info APIs are miserable, so use `ps` instead.
    Array a = ARRAY_DICT_INIT;
    ADD(a, INTEGER_OBJ(pid));
    String s = cstr_to_string("return vim._os_proc_info(select(1, ...))");
    Object o = nvim_execute_lua(s, a, err);
    api_free_string(s);
    api_free_array(a);
    if (o.type == kObjectTypeArray && o.data.array.size == 0) {
      return NIL;  // Process not found.
    } else if (o.type == kObjectTypeDictionary) {
      rvobj.data.dictionary = o.data.dictionary;
    } else if (!ERROR_SET(err)) {
      api_set_error(err, kErrorTypeException,
                    "Failed to get process info. pid=%" PRId64, pid);
    }
  #endif
    return rvobj;
  }
  
  /// Selects an item in the completion popupmenu.
  ///
  /// If |ins-completion| is not active this API call is silently ignored.
  /// Useful for an external UI using |ui-popupmenu| to control the popupmenu
  /// with the mouse. Can also be used in a mapping; use <cmd> |:map-cmd| to
  /// ensure the mapping doesn't end completion mode.
  ///
  /// @param item   Index (zero-based) of the item to select. Value of -1 selects
  ///               nothing and restores the original text.
  /// @param insert Whether the selection should be inserted in the buffer.
  /// @param finish Finish the completion and dismiss the popupmenu. Implies
  ///               `insert`.
  /// @param  opts  Optional parameters. Reserved for future use.
  /// @param[out] err Error details, if any
  void nvim_select_popupmenu_item(Integer item, Boolean insert, Boolean finish,
                                  Dictionary opts, Error *err)
    FUNC_API_SINCE(6)
  {
    if (opts.size > 0) {
      api_set_error(err, kErrorTypeValidation, "opts dict isn't empty");
      return;
    }
  
    if (finish) {
      insert = true;
    }
  
    pum_ext_select_item((int)item, insert, finish);
  }
  
  /// NB: if your UI doesn't use hlstate, this will not return hlstate first time
  Array nvim__inspect_cell(Integer grid, Integer row, Integer col, Error *err)
  {
    Array ret = ARRAY_DICT_INIT;
  
    // TODO(bfredl): if grid == 0 we should read from the compositor's buffer.
    // The only problem is that it does not yet exist.
    ScreenGrid *g = &default_grid;
    if (grid == pum_grid.handle) {
      g = &pum_grid;
    } else if (grid > 1) {
      win_T *wp = get_win_by_grid_handle((handle_T)grid);
      if (wp != NULL && wp->w_grid.chars != NULL) {
        g = &wp->w_grid;
      } else {
        api_set_error(err, kErrorTypeValidation,
                      "No grid with the given handle");
        return ret;
      }
    }
  
    if (row < 0 || row >= g->Rows
        || col < 0 || col >= g->Columns) {
      return ret;
    }
    size_t off = g->line_offset[(size_t)row] + (size_t)col;
    ADD(ret, STRING_OBJ(cstr_to_string((char *)g->chars[off])));
    int attr = g->attrs[off];
    ADD(ret, DICTIONARY_OBJ(hl_get_attr_by_id(attr, true, err)));
    // will not work first time
    if (!highlight_use_hlstate()) {
      ADD(ret, ARRAY_OBJ(hl_inspect(attr)));
    }
    return ret;
  }
  