1 files changed, 154 insertions, 0 deletions
diff --git a/lua/clever_f/capabilities.lua b/lua/clever_f/capabilities.lua
new file mode 100644
index 0000000..77ce130
--- /dev/null
+++ b/lua/clever_f/capabilities.lua
@@ -0,0 +1,154 @@
+local M = {}
+
+M.read_methods = {
+  text = { "read_text" },
+  cursor = { "read_cursor" },
+  mode = { "read_mode", "read_pending_operator" },
+  selection = { "read_selection" },
+  count = { "read_count" },
+  configuration = { "read_configuration", "configuration_present" },
+  encoding = { "read_encoding" },
+  macro_state = { "read_macro_state" },
+  fold_state = { "read_fold_state" },
+  time = { "read_time_ms" },
+}
+
+M.effect_methods = {
+  movement = { "apply_cursor", "apply_selection", "set_operator_inclusive" },
+  input = { "read_input" },
+  folds = { "open_fold" },
+  prompt = { "show_prompt" },
+  redraw = { "redraw" },
+  diagnostics = { "emit_diagnostic" },
+  highlights = { "create_highlight", "remove_highlight" },
+  cursor_presentation = {
+    "suppress_cursor_presentation",
+    "restore_cursor_presentation",
+  },
+  timers = { "supports_timers", "start_timer", "stop_timer" },
+  events = {
+    "register_events",
+    "remove_event_registration",
+    "deliver_event",
+    "begin_action_transition",
+    "commit_action_transition",
+  },
+  mappings = { "register_action", "register_mapping" },
+  dot_repeat = { "register_dot_repeat" },
+}
+
+local function collect_methods(groups)
+  local result = {}
+  local group_names = {}
+  for group_name in pairs(groups) do
+    group_names[#group_names + 1] = group_name
+  end
+  table.sort(group_names)
+  for _, group_name in ipairs(group_names) do
+    for _, method_name in ipairs(groups[group_name]) do
+      result[#result + 1] = method_name
+    end
+  end
+  return result
+end
+
+local all_methods = collect_methods(M.read_methods)
+for _, method_name in ipairs(collect_methods(M.effect_methods)) do
+  all_methods[#all_methods + 1] = method_name
+end
+table.sort(all_methods)
+
+function M.required_methods()
+  local result = {}
+  for index = 1, #all_methods do
+    result[index] = all_methods[index]
+  end
+  return result
+end
+
+function M.missing_methods(host)
+  local missing = {}
+  for _, method_name in ipairs(all_methods) do
+    if type(host) ~= "table" or type(host[method_name]) ~= "function" then
+      missing[#missing + 1] = method_name
+    end
+  end
+  return missing
+end
+
+function M.assert_implements(host)
+  local missing = M.missing_methods(host)
+  if #missing > 0 then
+    error("host is missing semantic capabilities: " .. table.concat(missing, ", "), 2)
+  end
+  return host
+end
+
+local EventQueue = {}
+EventQueue.__index = EventQueue
+M.EventQueue = EventQueue
+
+function EventQueue.new(deliver)
+  if type(deliver) ~= "function" then
+    error("event delivery must be a function", 2)
+  end
+  return setmetatable({
+    _deliver = deliver,
+    _active_token = nil,
+    _pending = {},
+    _next_token = 1,
+  }, EventQueue)
+end
+
+function EventQueue:begin_transition()
+  if self._active_token ~= nil then
+    error("an action transition is already active", 2)
+  end
+  local token = "action-transition-" .. tostring(self._next_token)
+  self._next_token = self._next_token + 1
+  self._active_token = token
+  self._pending = {}
+  return token
+end
+
+function EventQueue:is_transition_active()
+  return self._active_token ~= nil
+end
+
+function EventQueue:pending_count()
+  return #self._pending
+end
+
+function EventQueue:emit(name, payload)
+  if type(name) ~= "string" or name == "" then
+    error("event name must be a nonempty string", 2)
+  end
+  if self._active_token ~= nil then
+    self._pending[#self._pending + 1] = {
+      name = name,
+      payload = payload,
+    }
+    return false
+  end
+  self._deliver(name, payload)
+  return true
+end
+
+function EventQueue:commit_transition(token)
+  if self._active_token == nil then
+    error("no action transition is active", 2)
+  end
+  if token ~= self._active_token then
+    error("action transition token does not match", 2)
+  end
+
+  local pending = self._pending
+  self._active_token = nil
+  self._pending = {}
+  for index = 1, #pending do
+    local event = pending[index]
+    self._deliver(event.name, event.payload)
+  end
+end
+
+return M