refactor(lsp): gen_lsp

- Simplify usage:
  - Instead of `nvim -l src/gen/gen_lsp.lua gen` now just
    run `./src/gen/gen_lsp.lua`

- Removed `--methods` and `--capabilities` options.

- Improved rendering code in various areas.

MAINTAIN.md

@@ -152,7 +152,7 @@ These dependencies are "vendored" (inlined), we must update the sources manually
 * `src/nvim/tui/terminfo_defs.h`: terminfo definitions
     * Run `scripts/update_terminfo.sh` to update these definitions.
 * `runtime/lua/vim/lsp/_meta/protocol.lua`: LSP specification
-    * Run `scripts/gen_lsp.lua` to update.
+    * Run `src/gen/gen_lsp.lua` to update.
 * `runtime/lua/vim/_meta/lpeg.lua`: LPeg definitions.
     * Refer to [`LuaCATS/lpeg`](https://github.com/LuaCATS/lpeg) for updates.
     * Update the git SHA revision from which the documentation was taken.

runtime/lua/vim/lsp/_meta/protocol.lua

@@ -1,11 +1,11 @@
 --[[
-THIS FILE IS GENERATED by scr/gen/gen_lsp.lua
+THIS FILE IS GENERATED by src/gen/gen_lsp.lua
 DO NOT EDIT MANUALLY
 
 Based on LSP protocol 3.18
 
 Regenerate:
-nvim -l scr/gen/gen_lsp.lua gen --version 3.18
+nvim -l src/gen/gen_lsp.lua --version 3.18
 --]]
 
 ---@meta

src/gen/gen_lsp.lua

@@ -1,29 +1,20 @@
+#!/usr/bin/env -S nvim -l
 -- Generates lua-ls annotations for lsp.
 
 local USAGE = [[
 Generates lua-ls annotations for lsp.
 
-USAGE:
-nvim -l src/gen/gen_lsp.lua gen  # by default, this will overwrite runtime/lua/vim/lsp/_meta/protocol.lua
-nvim -l src/gen/gen_lsp.lua gen --version 3.18 --out runtime/lua/vim/lsp/_meta/protocol.lua
-nvim -l src/gen/gen_lsp.lua gen --version 3.18 --methods --capabilities
+Also updates types in runtime/lua/vim/lsp/protocol.lua
+
+Usage:
+  src/gen/gen_lsp.lua [options]
+
+Options:
+  --version <version>  LSP version to use (default: 3.18)
+  --out <out>          Output file (default: runtime/lua/vim/lsp/_meta/protocol.lua)
+  --help               Print this help message
 ]]
 
-local DEFAULT_LSP_VERSION = '3.18'
-
-local M = {}
-
-local function tofile(fname, text)
-  local f = io.open(fname, 'w')
-  if not f then
-    error(('failed to write: %s'):format(f))
-  else
-    print(('Written to: %s'):format(fname))
-    f:write(text)
-    f:close()
-  end
-end
-
 --- The LSP protocol JSON data (it's partial, non-exhaustive).
 --- https://raw.githubusercontent.com/microsoft/language-server-protocol/gh-pages/_specifications/lsp/3.18/metaModel/metaModel.schema.json
 --- @class vim._gen_lsp.Protocol
@@ -51,6 +42,66 @@ end
 --- @field partialResult? any
 --- @field result any
 
+--- @class vim._gen_lsp.Structure translated to @class
+--- @field deprecated? string
+--- @field documentation? string
+--- @field extends? { kind: string, name: string }[]
+--- @field mixins? { kind: string, name: string }[]
+--- @field name string
+--- @field properties? vim._gen_lsp.Property[]  members, translated to @field
+--- @field proposed? boolean
+--- @field since? string
+
+--- @class vim._gen_lsp.StructureLiteral translated to anonymous @class.
+--- @field deprecated? string
+--- @field description? string
+--- @field properties vim._gen_lsp.Property[]
+--- @field proposed? boolean
+--- @field since? string
+
+--- @class vim._gen_lsp.Property translated to @field
+--- @field deprecated? string
+--- @field documentation? string
+--- @field name string
+--- @field optional? boolean
+--- @field proposed? boolean
+--- @field since? string
+--- @field type { kind: string, name: string }
+
+--- @class vim._gen_lsp.Enumeration translated to @enum
+--- @field deprecated string?
+--- @field documentation string?
+--- @field name string?
+--- @field proposed boolean?
+--- @field since string?
+--- @field suportsCustomValues boolean?
+--- @field values { name: string, value: string, documentation?: string, since?: string }[]
+
+--- @class vim._gen_lsp.TypeAlias translated to @alias
+--- @field deprecated? string?
+--- @field documentation? string
+--- @field name string
+--- @field proposed? boolean
+--- @field since? string
+--- @field type vim._gen_lsp.Type
+
+--- @class vim._gen_lsp.Type
+--- @field kind string a common field for all Types.
+--- @field name? string for ReferenceType, BaseType
+--- @field element? any for ArrayType
+--- @field items? vim._gen_lsp.Type[] for OrType, AndType
+--- @field key? vim._gen_lsp.Type for MapType
+--- @field value? string|vim._gen_lsp.Type for StringLiteralType, MapType, StructureLiteralType
+
+--- @param fname string
+--- @param text string
+local function tofile(fname, text)
+  local f = assert(io.open(fname, 'w'), ('failed to open: %s'):format(fname))
+  f:write(text)
+  f:close()
+  print('Written to:', fname)
+end
+
 ---@param opt vim._gen_lsp.opt
 ---@return vim._gen_lsp.Protocol
 local function read_json(opt)
@@ -68,28 +119,24 @@ local function read_json(opt)
   return vim.json.decode(res.stdout)
 end
 
--- Gets the Lua symbol for a given fully-qualified LSP method name.
+--- Gets the Lua symbol for a given fully-qualified LSP method name.
+--- @param s string
+--- @return string
 local function to_luaname(s)
   -- "$/" prefix is special: https://microsoft.github.io/language-server-protocol/specification/#dollarRequests
-  return s:gsub('^%$', 'dollar'):gsub('/', '_')
+  return (s:gsub('^%$', 'dollar'):gsub('/', '_'))
+end
+
+--- @param a vim._gen_lsp.Notification
+--- @param b vim._gen_lsp.Notification
+--- @return boolean
+local function compare_method(a, b)
+  return to_luaname(a.method) < to_luaname(b.method)
 end
 
 ---@param protocol vim._gen_lsp.Protocol
----@param gen_methods boolean
----@param gen_capabilities boolean
-local function write_to_protocol(protocol, gen_methods, gen_capabilities)
-  if not gen_methods and not gen_capabilities then
-    return
-  end
-
-  local indent = (' '):rep(2)
-
-  local function compare_method(a, b)
-    return to_luaname(a.method) < to_luaname(b.method)
-  end
-
-  ---@type (vim._gen_lsp.Request|vim._gen_lsp.Notification)[]
-  local all = {}
+local function write_to_vim_protocol(protocol)
+  local all = {} --- @type (vim._gen_lsp.Request|vim._gen_lsp.Notification)[]
   vim.list_extend(all, protocol.notifications)
   vim.list_extend(all, protocol.requests)
 
@@ -99,7 +146,7 @@ local function write_to_protocol(protocol, gen_methods, gen_capabilities)
 
   local output = { '-- Generated by gen_lsp.lua, keep at end of file.' }
 
-  if gen_methods then
+  do -- methods
     for _, dir in ipairs({ 'clientToServer', 'serverToClient' }) do
       local dir1 = dir:sub(1, 1):upper() .. dir:sub(2)
       local alias = ('vim.lsp.protocol.Method.%s'):format(dir1)
@@ -141,16 +188,16 @@ local function write_to_protocol(protocol, gen_methods, gen_capabilities)
         if item.documentation then
           local document = vim.split(item.documentation, '\n?\n', { trimempty = true })
           for _, docstring in ipairs(document) do
-            output[#output + 1] = indent .. '--- ' .. docstring
+            output[#output + 1] = '  --- ' .. docstring
           end
         end
-        output[#output + 1] = ("%s%s = '%s',"):format(indent, to_luaname(item.method), item.method)
+        output[#output + 1] = ("  %s = '%s',"):format(to_luaname(item.method), item.method)
       end
     end
     output[#output + 1] = '}'
   end
 
-  if gen_capabilities then
+  do -- capabilities
     vim.list_extend(output, {
       '',
       '-- stylua: ignore start',
@@ -161,18 +208,9 @@ local function write_to_protocol(protocol, gen_methods, gen_capabilities)
 
     for _, item in ipairs(all) do
       if item.serverCapability then
-        output[#output + 1] = ("%s['%s'] = { %s },"):format(
-          indent,
+        output[#output + 1] = ("  ['%s'] = { %s },"):format(
           item.method,
-          table.concat(
-            vim
-              .iter(vim.split(item.serverCapability, '.', { plain = true }))
-              :map(function(segment)
-                return "'" .. segment .. "'"
-              end)
-              :totable(),
-            ', '
-          )
+          "'" .. item.serverCapability:gsub('%.', "', '") .. "'"
         )
       end
     end
@@ -197,28 +235,116 @@ local function write_to_protocol(protocol, gen_methods, gen_capabilities)
   vim.cmd.write()
 end
 
----@class vim._gen_lsp.opt
----@field output_file string
----@field version string
----@field methods boolean
----@field capabilities boolean
+--- @param doc string
+local function process_documentation(doc)
+  doc = doc:gsub('\n', '\n---')
+  -- Remove <200b> (zero-width space) unicode characters: e.g., `**/<200b>*`
+  doc = doc:gsub('\226\128\139', '')
+  -- Escape annotations that are not recognized by lua-ls
+  doc = doc:gsub('%^---@sample', '---\\@sample')
+  return '---' .. doc
+end
 
----@param opt vim._gen_lsp.opt
-function M.gen(opt)
-  --- @type vim._gen_lsp.Protocol
-  local protocol = read_json(opt)
+local simple_types = {
+  string = true,
+  boolean = true,
+  integer = true,
+  uinteger = true,
+  decimal = true,
+}
 
-  write_to_protocol(protocol, opt.methods, opt.capabilities)
+local anonymous_num = 0
 
+--- @type string[]
+local anonym_classes = {}
+
+--- @param type vim._gen_lsp.Type
+--- @param prefix? string Optional prefix associated with the this type, made of (nested) field name.
+---              Used to generate class name for structure literal types.
+--- @return string
+local function parse_type(type, prefix)
+  if type.kind == 'reference' or type.kind == 'base' then
+    if simple_types[type.name] then
+      return type.name
+    end
+    return 'lsp.' .. type.name
+  elseif type.kind == 'array' then
+    local parsed_items = parse_type(type.element, prefix)
+    if type.element.items and #type.element.items > 1 then
+      parsed_items = '(' .. parsed_items .. ')'
+    end
+    return parsed_items .. '[]'
+  elseif type.kind == 'or' then
+    local types = {} --- @type string[]
+    for _, item in ipairs(type.items) do
+      types[#types + 1] = parse_type(item, prefix)
+    end
+    return table.concat(types, '|')
+  elseif type.kind == 'stringLiteral' then
+    return '"' .. type.value .. '"'
+  elseif type.kind == 'map' then
+    local key = assert(type.key)
+    local value = type.value --[[ @as vim._gen_lsp.Type ]]
+    return ('table<%s, %s>'):format(parse_type(key, prefix), parse_type(value, prefix))
+  elseif type.kind == 'literal' then
+    -- can I use ---@param disabled? {reason: string}
+    -- use | to continue the inline class to be able to add docs
+    -- https://github.com/LuaLS/lua-language-server/issues/2128
+    anonymous_num = anonymous_num + 1
+    local anonymous_classname = 'lsp._anonym' .. anonymous_num
+    if prefix then
+      anonymous_classname = anonymous_classname .. '.' .. prefix
+    end
+
+    local anonym = { '---@class ' .. anonymous_classname }
+    if anonymous_num > 1 then
+      table.insert(anonym, 1, '')
+    end
+
+    ---@type vim._gen_lsp.StructureLiteral
+    local structural_literal = assert(type.value) --[[ @as vim._gen_lsp.StructureLiteral ]]
+    for _, field in ipairs(structural_literal.properties) do
+      anonym[#anonym + 1] = '---'
+      if field.documentation then
+        anonym[#anonym + 1] = process_documentation(field.documentation)
+      end
+      anonym[#anonym + 1] = ('---@field %s%s %s'):format(
+        field.name,
+        (field.optional and '?' or ''),
+        parse_type(field.type, prefix .. '.' .. field.name)
+      )
+    end
+    for _, line in ipairs(anonym) do
+      if line then
+        anonym_classes[#anonym_classes + 1] = line
+      end
+    end
+    return anonymous_classname
+  elseif type.kind == 'tuple' then
+    local types = {} --- @type string[]
+    for _, value in ipairs(type.items) do
+      types[#types + 1] = parse_type(value, prefix)
+    end
+    return '[' .. table.concat(types, ', ') .. ']'
+  end
+
+  vim.print('WARNING: Unknown type ', type)
+  return ''
+end
+
+--- @param protocol vim._gen_lsp.Protocol
+--- @param version string
+--- @param output_file string
+local function write_to_meta_protocol(protocol, version, output_file)
   local output = {
     '--' .. '[[',
-    'THIS FILE IS GENERATED by scr/gen/gen_lsp.lua',
+    'THIS FILE IS GENERATED by src/gen/gen_lsp.lua',
     'DO NOT EDIT MANUALLY',
     '',
-    'Based on LSP protocol ' .. opt.version,
+    'Based on LSP protocol ' .. version,
     '',
     'Regenerate:',
-    ([=[nvim -l scr/gen/gen_lsp.lua gen --version %s]=]):format(DEFAULT_LSP_VERSION),
+    ([=[nvim -l src/gen/gen_lsp.lua --version %s]=]):format(version),
     '--' .. ']]',
     '',
     '---@meta',
@@ -232,150 +358,9 @@ function M.gen(opt)
     '',
   }
 
-  local anonymous_num = 0
-
-  ---@type string[]
-  local anonym_classes = {}
-
-  local simple_types = {
-    'string',
-    'boolean',
-    'integer',
-    'uinteger',
-    'decimal',
-  }
-
-  ---@param documentation string
-  local _process_documentation = function(documentation)
-    documentation = documentation:gsub('\n', '\n---')
-    -- Remove <200b> (zero-width space) unicode characters: e.g., `**/<200b>*`
-    documentation = documentation:gsub('\226\128\139', '')
-    -- Escape annotations that are not recognized by lua-ls
-    documentation = documentation:gsub('%^---@sample', '---\\@sample')
-    return '---' .. documentation
-  end
-
-  --- @class vim._gen_lsp.Type
-  --- @field kind string a common field for all Types.
-  --- @field name? string for ReferenceType, BaseType
-  --- @field element? any for ArrayType
-  --- @field items? vim._gen_lsp.Type[] for OrType, AndType
-  --- @field key? vim._gen_lsp.Type for MapType
-  --- @field value? string|vim._gen_lsp.Type for StringLiteralType, MapType, StructureLiteralType
-
-  ---@param type vim._gen_lsp.Type
-  ---@param prefix? string Optional prefix associated with the this type, made of (nested) field name.
-  ---             Used to generate class name for structure literal types.
-  ---@return string
-  local function parse_type(type, prefix)
-    -- ReferenceType | BaseType
-    if type.kind == 'reference' or type.kind == 'base' then
-      if vim.tbl_contains(simple_types, type.name) then
-        return type.name
-      end
-      return 'lsp.' .. type.name
-
-    -- ArrayType
-    elseif type.kind == 'array' then
-      local parsed_items = parse_type(type.element, prefix)
-      if type.element.items and #type.element.items > 1 then
-        parsed_items = '(' .. parsed_items .. ')'
-      end
-      return parsed_items .. '[]'
-
-    -- OrType
-    elseif type.kind == 'or' then
-      local val = ''
-      for _, item in ipairs(type.items) do
-        val = val .. parse_type(item, prefix) .. '|' --[[ @as string ]]
-      end
-      val = val:sub(0, -2)
-      return val
-
-    -- StringLiteralType
-    elseif type.kind == 'stringLiteral' then
-      return '"' .. type.value .. '"'
-
-    -- MapType
-    elseif type.kind == 'map' then
-      local key = assert(type.key)
-      local value = type.value --[[ @as vim._gen_lsp.Type ]]
-      return 'table<' .. parse_type(key, prefix) .. ', ' .. parse_type(value, prefix) .. '>'
-
-    -- StructureLiteralType
-    elseif type.kind == 'literal' then
-      -- can I use ---@param disabled? {reason: string}
-      -- use | to continue the inline class to be able to add docs
-      -- https://github.com/LuaLS/lua-language-server/issues/2128
-      anonymous_num = anonymous_num + 1
-      local anonymous_classname = 'lsp._anonym' .. anonymous_num
-      if prefix then
-        anonymous_classname = anonymous_classname .. '.' .. prefix
-      end
-      local anonym = vim
-        .iter({
-          (anonymous_num > 1 and { '' } or {}),
-          { '---@class ' .. anonymous_classname },
-        })
-        :flatten()
-        :totable()
-
-      --- @class vim._gen_lsp.StructureLiteral translated to anonymous @class.
-      --- @field deprecated? string
-      --- @field description? string
-      --- @field properties vim._gen_lsp.Property[]
-      --- @field proposed? boolean
-      --- @field since? string
-
-      ---@type vim._gen_lsp.StructureLiteral
-      local structural_literal = assert(type.value) --[[ @as vim._gen_lsp.StructureLiteral ]]
-      for _, field in ipairs(structural_literal.properties) do
-        anonym[#anonym + 1] = '---'
-        if field.documentation then
-          anonym[#anonym + 1] = _process_documentation(field.documentation)
-        end
-        anonym[#anonym + 1] = '---@field '
-          .. field.name
-          .. (field.optional and '?' or '')
-          .. ' '
-          .. parse_type(field.type, prefix .. '.' .. field.name)
-      end
-      -- anonym[#anonym + 1] = ''
-      for _, line in ipairs(anonym) do
-        if line then
-          anonym_classes[#anonym_classes + 1] = line
-        end
-      end
-      return anonymous_classname
-
-    -- TupleType
-    elseif type.kind == 'tuple' then
-      local tuple = '['
-      for _, value in ipairs(type.items) do
-        tuple = tuple .. parse_type(value, prefix) .. ', '
-      end
-      -- remove , at the end
-      tuple = tuple:sub(0, -3)
-      return tuple .. ']'
-    end
-
-    vim.print('WARNING: Unknown type ', type)
-    return ''
-  end
-
-  --- @class vim._gen_lsp.Structure translated to @class
-  --- @field deprecated? string
-  --- @field documentation? string
-  --- @field extends? { kind: string, name: string }[]
-  --- @field mixins? { kind: string, name: string }[]
-  --- @field name string
-  --- @field properties? vim._gen_lsp.Property[]  members, translated to @field
-  --- @field proposed? boolean
-  --- @field since? string
   for _, structure in ipairs(protocol.structures) do
-    -- output[#output + 1] = ''
     if structure.documentation then
-      output[#output + 1] = _process_documentation(structure.documentation)
+      output[#output + 1] = process_documentation(structure.documentation)
     end
     local class_string = ('---@class lsp.%s'):format(structure.name)
     if structure.extends or structure.mixins then
@@ -390,126 +375,97 @@ function M.gen(opt)
     end
     output[#output + 1] = class_string
 
-    --- @class vim._gen_lsp.Property translated to @field
-    --- @field deprecated? string
-    --- @field documentation? string
-    --- @field name string
-    --- @field optional? boolean
-    --- @field proposed? boolean
-    --- @field since? string
-    --- @field type { kind: string, name: string }
     for _, field in ipairs(structure.properties or {}) do
       output[#output + 1] = '---' -- Insert a single newline between @fields (and after @class)
       if field.documentation then
-        output[#output + 1] = _process_documentation(field.documentation)
+        output[#output + 1] = process_documentation(field.documentation)
       end
-      output[#output + 1] = '---@field '
-        .. field.name
-        .. (field.optional and '?' or '')
-        .. ' '
-        .. parse_type(field.type, field.name)
+      output[#output + 1] = ('---@field %s%s %s'):format(
+        field.name,
+        (field.optional and '?' or ''),
+        parse_type(field.type, field.name)
+      )
     end
     output[#output + 1] = ''
   end
 
-  --- @class vim._gen_lsp.Enumeration translated to @enum
-  --- @field deprecated string?
-  --- @field documentation string?
-  --- @field name string?
-  --- @field proposed boolean?
-  --- @field since string?
-  --- @field suportsCustomValues boolean?
-  --- @field values { name: string, value: string, documentation?: string, since?: string }[]
   for _, enum in ipairs(protocol.enumerations) do
     if enum.documentation then
-      output[#output + 1] = _process_documentation(enum.documentation)
+      output[#output + 1] = process_documentation(enum.documentation)
     end
-    local enum_type = '---@alias lsp.' .. enum.name
+    output[#output + 1] = '---@alias lsp.' .. enum.name
     for _, value in ipairs(enum.values) do
-      enum_type = enum_type
-        .. '\n---| '
-        .. (type(value.value) == 'string' and '"' .. value.value .. '"' or value.value)
-        .. ' # '
-        .. value.name
+      local value1 = (type(value.value) == 'string' and ('"%s"'):format(value.value) or value.value)
+      output[#output + 1] = ('---| %s # %s'):format(value1, value.name)
     end
-    output[#output + 1] = enum_type
     output[#output + 1] = ''
   end
 
-  --- @class vim._gen_lsp.TypeAlias translated to @alias
-  --- @field deprecated? string?
-  --- @field documentation? string
-  --- @field name string
-  --- @field proposed? boolean
-  --- @field since? string
-  --- @field type vim._gen_lsp.Type
   for _, alias in ipairs(protocol.typeAliases) do
     if alias.documentation then
-      output[#output + 1] = _process_documentation(alias.documentation)
+      output[#output + 1] = process_documentation(alias.documentation)
     end
+
+    local alias_type --- @type string
+
     if alias.type.kind == 'or' then
-      local alias_type = '---@alias lsp.' .. alias.name .. ' '
+      local alias_types = {} --- @type string[]
       for _, item in ipairs(alias.type.items) do
-        alias_type = alias_type .. parse_type(item, alias.name) .. '|'
+        alias_types[#alias_types + 1] = parse_type(item, alias.name)
       end
-      alias_type = alias_type:sub(0, -2)
-      output[#output + 1] = alias_type
+      alias_type = table.concat(alias_types, '|')
     else
-      output[#output + 1] = '---@alias lsp.'
-        .. alias.name
-        .. ' '
-        .. parse_type(alias.type, alias.name)
+      alias_type = parse_type(alias.type, alias.name)
     end
+    output[#output + 1] = ('---@alias lsp.%s %s'):format(alias.name, alias_type)
     output[#output + 1] = ''
   end
 
   -- anonymous classes
-  for _, line in ipairs(anonym_classes) do
-    output[#output + 1] = line
-  end
+  vim.list_extend(output, anonym_classes)
 
-  tofile(opt.output_file, table.concat(output, '\n') .. '\n')
+  tofile(output_file, table.concat(output, '\n') .. '\n')
 end
 
----@type vim._gen_lsp.opt
-local opt = {
-  output_file = 'runtime/lua/vim/lsp/_meta/protocol.lua',
-  version = DEFAULT_LSP_VERSION,
-  methods = false,
-  capabilities = false,
-}
+---@class vim._gen_lsp.opt
+---@field output_file string
+---@field version string
 
-local command = nil
-local i = 1
-while i <= #_G.arg do
-  if _G.arg[i] == '--out' then
-    opt.output_file = assert(_G.arg[i + 1], '--out <outfile> needed')
-    i = i + 1
-  elseif _G.arg[i] == '--version' then
-    opt.version = assert(_G.arg[i + 1], '--version <version> needed')
-    i = i + 1
-  elseif _G.arg[i] == '--methods' then
-    opt.methods = true
-  elseif _G.arg[i] == '--capabilities' then
-    opt.capabilities = true
-  elseif vim.startswith(_G.arg[i], '-') then
-    error('Unrecognized args: ' .. _G.arg[i])
-  else
-    if command then
-      error('More than one command was given: ' .. _G.arg[i])
-    else
-      command = _G.arg[i]
+--- @return vim._gen_lsp.opt
+local function parse_args()
+  ---@type vim._gen_lsp.opt
+  local opt = {
+    output_file = 'runtime/lua/vim/lsp/_meta/protocol.lua',
+    version = '3.18',
+  }
+
+  local i = 1
+  while i <= #_G.arg do
+    local cur_arg = _G.arg[i]
+    if cur_arg == '--out' then
+      opt.output_file = assert(_G.arg[i + 1], '--out <outfile> needed')
+      i = i + 1
+    elseif cur_arg == '--version' then
+      opt.version = assert(_G.arg[i + 1], '--version <version> needed')
+      i = i + 1
+    elseif cur_arg == '--help' or cur_arg == '-h' then
+      print(USAGE)
+      os.exit(0)
+    elseif vim.startswith(cur_arg, '-') then
+      print('Unrecognized option:', cur_arg, '\n')
+      os.exit(1)
     end
+    i = i + 1
   end
-  i = i + 1
+
+  return opt
 end
 
-if not command then
-  print(USAGE)
-elseif M[command] then
-  M[command](opt) -- see M.gen()
-else
-  error('Unknown command: ' .. command)
+local function main()
+  local opt = parse_args()
+  local protocol = read_json(opt)
+  write_to_vim_protocol(protocol)
+  write_to_meta_protocol(protocol, opt.version, opt.output_file)
 end
 
-return M
+main()