Merge pull request #305 from theHamsta/textobjects-submodules

Textobjects submodules

15 files changed, 513 insertions, 133 deletions

diff --git a/README.md b/README.md
index 915fcf71a..21d6df24b 100644
--- a/README.md
+++ b/README.md
@@ -147,7 +147,31 @@ require'nvim-treesitter.configs'.setup {
         ["ad"] = "@comment.outer",
         ["am"] = "@call.outer",
         ["im"] = "@call.inner"
-      }
+      },
+      -- swap parameters (keymap -> textobject query)
+      swap_next = {
+        ["<a-p>"] = "@parameter.inner",
+      },
+      swap_previous = {
+        ["<a-P>"] = "@parameter.inner",
+      },
+      -- set mappings to go to start/end of adjacent textobjects (keymap -> textobject query)
+      goto_previous_start = {
+        ["[m"] = "@function.outer",
+        ["[["] = "@class.outer",
+      },
+      goto_previous_end = {
+        ["[M"] = "@function.outer",
+        ["[]"] = "@class.outer",
+      },
+      goto_next_start = {
+        ["]m"] = "@function.outer",
+        ["]]"] = "@class.outer",
+      },
+      goto_next_end = {
+        ["]M"] = "@function.outer",
+        ["]["] = "@class.outer",
+      },
     },
     ensure_installed = "all" -- one of "all", "language", or a list of languages
 }
diff --git a/doc/nvim-treesitter.txt b/doc/nvim-treesitter.txt
index 3634418d1..096d8698c 100644
--- a/doc/nvim-treesitter.txt
+++ b/doc/nvim-treesitter.txt
@@ -94,7 +94,31 @@ By default, everything is disabled. To enable support for features, in your `ini
 	  ["ad"] = "@comment.outer",
 	  ["am"] = "@call.outer",
 	  ["im"] = "@call.inner"
-	}
+	},
+        -- swap parameters (keymap -> textobject query)
+	swap_next = {
+	  ["<a-p>"] = "@parameter.inner",
+	},
+	swap_previous = {
+	  ["<a-P>"] = "@parameter.inner",
+	},
+        -- set mappings to go to start/end of adjacent textobjects (keymap -> textobject query)
+	goto_previous_start = {
+	  ["[m"] = "@function.outer",
+	  ["[["] = "@class.outer",
+	},
+	goto_previous_end = {
+	  ["[M"] = "@function.outer",
+	  ["[]"] = "@class.outer",
+	},
+	goto_next_start = {
+	  ["]m"] = "@function.outer",
+	  ["]]"] = "@class.outer",
+	},
+	goto_next_end = {
+	  ["]M"] = "@function.outer",
+	  ["]["] = "@class.outer",
+	},
       },
       ensure_installed = "all" -- one of "all", "language", or a list of languages
   }
diff --git a/lua/nvim-treesitter/configs.lua b/lua/nvim-treesitter/configs.lua
index 02a636dff..ba4ae3f8d 100644
--- a/lua/nvim-treesitter/configs.lua
+++ b/lua/nvim-treesitter/configs.lua
@@ -7,7 +7,7 @@ local utils = require'nvim-treesitter.utils'
 local M = {}
 
 local function has_some_textobject_mapping(lang)
-  for _, v in pairs(M.get_module('textobjects').keymaps) do
+  for _, v in pairs(M.get_module('textobjects.select').keymaps) do
     if type(v) == 'table' then
       if v[lang] then
         return true
@@ -79,13 +79,33 @@ local builtin_modules = {
     }
   },
   textobjects = {
-    module_path = 'nvim-treesitter.textobjects',
-    enable = false,
-    disable = {},
-    is_supported = function(lang)
-      return has_some_textobject_mapping(lang) or queries.has_textobjects(lang)
-    end,
-    keymaps = {}
+    select = {
+      module_path = 'nvim-treesitter.textobjects.select',
+      enable = false,
+      disable = {},
+      is_supported = function(lang)
+        return has_some_textobject_mapping(lang) or queries.has_textobjects(lang)
+      end,
+      keymaps = {},
+    },
+    move = {
+      module_path = 'nvim-treesitter.textobjects.move',
+      enable = false,
+      disable = {},
+      is_supported = queries.has_textobjects,
+      goto_next_start = {},
+      goto_next_end = {},
+      goto_previous_start = {},
+      goto_previous_end = {},
+    },
+    swap = {
+      module_path = 'nvim-treesitter.textobjects.swap',
+      enable = false,
+      disable = {},
+      is_supported = queries.has_textobjects,
+      swap_next = {},
+      swap_previous = {},
+    },
   }
 }
 
diff --git a/lua/nvim-treesitter/query.lua b/lua/nvim-treesitter/query.lua
index ec93d5bbb..4a2ce57d1 100644
--- a/lua/nvim-treesitter/query.lua
+++ b/lua/nvim-treesitter/query.lua
@@ -213,6 +213,36 @@ function M.get_capture_matches(bufnr, capture_string, query_group)
     return matches
 end
 
+function M.find_best_match(bufnr, capture_string, query_group, filter_predicate, scoring_function)
+    if not string.sub(capture_string, 1,2) == '@' then
+      api.nvim_err_writeln('capture_string must start with "@"')
+      return
+    end
+
+    --remove leading "@"
+    capture_string = string.sub(capture_string, 2)
+
+    local best
+    local best_score
+
+    for maybe_match in M.iter_group_results(bufnr, query_group) do
+      local match = utils.get_at_path(maybe_match, capture_string)
+
+      if match and filter_predicate(match) then
+        local current_score = scoring_function(match)
+        if not best then
+          best = match
+          best_score = current_score
+        end
+        if current_score > best_score then
+          best = match
+          best_score = current_score
+        end
+      end
+    end
+    return best
+end
+
 -- Iterates matches from a query file.
 -- @param bufnr the buffer
 -- @param query_group the query file to use
diff --git a/lua/nvim-treesitter/refactor/navigation.lua b/lua/nvim-treesitter/refactor/navigation.lua
index a3fee20e8..5f5eebd53 100644
--- a/lua/nvim-treesitter/refactor/navigation.lua
+++ b/lua/nvim-treesitter/refactor/navigation.lua
@@ -1,6 +1,7 @@
 -- Definition based navigation module
 
 local ts_utils = require'nvim-treesitter.ts_utils'
+local utils = require'nvim-treesitter.utils'
 local locals = require'nvim-treesitter.locals'
 local configs = require'nvim-treesitter.configs'
 local api = vim.api
@@ -11,8 +12,7 @@ function M.goto_definition(bufnr)
   local bufnr = bufnr or api.nvim_get_current_buf()
   local node_at_point = ts_utils.get_node_at_cursor()
 
-  -- Set the item in jump list
-  vim.cmd "normal! m'"
+  utils.set_jump()
 
   if not node_at_point then return end
 
diff --git a/lua/nvim-treesitter/textobjects.lua b/lua/nvim-treesitter/textobjects.lua
deleted file mode 100644
index 7227b9e0e..000000000
--- a/lua/nvim-treesitter/textobjects.lua
+++ /dev/null
@@ -1,113 +0,0 @@
-local api = vim.api
-local ts = vim.treesitter
-
-local configs = require "nvim-treesitter.configs"
-local parsers = require "nvim-treesitter.parsers"
-local queries = require'nvim-treesitter.query'
-local ts_utils = require'nvim-treesitter.ts_utils'
-
-local M = {}
-
-function M.select_textobject(query_string)
-  local bufnr = vim.api.nvim_get_current_buf()
-  local lang = parsers.get_buf_lang(bufnr)
-  if not lang then return end
-
-  local row, col = unpack(vim.api.nvim_win_get_cursor(0))
-  row = row - 1
-
-  local matches = {}
-
-  if string.match(query_string, '^@.*') then
-    matches = queries.get_capture_matches(bufnr, query_string, 'textobjects')
-  else
-    local parser = parsers.get_parser(bufnr, lang)
-    local root = parser:parse():root()
-
-    local start_row, _, end_row, _ = root:range()
-
-    local query = ts.parse_query(lang, query_string)
-    for m in queries.iter_prepared_matches(query, root, bufnr, start_row, end_row) do
-      for _, n in pairs(m) do
-        if n.node then
-          table.insert(matches, n)
-        end
-      end
-    end
-  end
-
-  local match_length
-  local smallest_range
-  local earliest_start
-
-  for _, m in pairs(matches) do
-    if m.node and ts_utils.is_in_node_range(m.node, row, col) then
-      local length = ts_utils.node_length(m.node)
-      if not match_length or length < match_length then
-        smallest_range = m
-        match_length = length
-      end
-      -- for nodes with same length take the one with earliest start
-      if match_length and length == smallest_range then
-        local start = m.start
-        if start then
-          local _, _, start_byte = m.start.node:start()
-          if not earliest_start or start_byte < earliest_start then
-            smallest_range = m
-            match_length = length
-            earliest_start = start_byte
-          end
-        end
-      end
-    end
-  end
-
-  if smallest_range then
-    if smallest_range.start then
-      local start_range = {smallest_range.start.node:range()}
-      local node_range = {smallest_range.node:range()}
-      ts_utils.update_selection(bufnr, {start_range[1], start_range[2], node_range[3], node_range[4]})
-    else
-      ts_utils.update_selection(bufnr, smallest_range.node)
-    end
-  end
-end
-
-function M.attach(bufnr, lang)
-  local buf = bufnr or api.nvim_get_current_buf()
-  local config = configs.get_module("textobjects")
-  local lang = lang or parsers.get_buf_lang(buf)
-
-  for mapping, query in pairs(config.keymaps) do
-    if type(query) == 'table' then
-      query = query[lang]
-    elseif not queries.get_query(lang, 'textobjects') then
-      query = nil
-    end
-    if query then
-      local cmd = ":lua require'nvim-treesitter.textobjects'.select_textobject('"..query.."')<CR>"
-      api.nvim_buf_set_keymap(buf, "o", mapping, cmd, {silent = true, noremap = true })
-      api.nvim_buf_set_keymap(buf, "v", mapping, cmd, {silent = true, noremap = true })
-    end
-  end
-end
-
-function M.detach(bufnr)
-  local buf = bufnr or api.nvim_get_current_buf()
-  local config = configs.get_module("textobjects")
-  local lang = parsers.get_buf_lang(bufnr)
-
-  for mapping, query in pairs(config.keymaps) do
-    if type(query) == 'table' then
-      query = query[lang]
-    elseif not queries.get_query(lang, 'textobjects') then
-      query = nil
-    end
-    if query then
-      api.nvim_buf_del_keymap(buf, "o", mapping)
-      api.nvim_buf_del_keymap(buf, "v", mapping)
-    end
-  end
-end
-
-return M
diff --git a/lua/nvim-treesitter/textobjects/attach.lua b/lua/nvim-treesitter/textobjects/attach.lua
new file mode 100644
index 000000000..22d6b650d
--- /dev/null
+++ b/lua/nvim-treesitter/textobjects/attach.lua
@@ -0,0 +1,61 @@
+local configs = require'nvim-treesitter.configs'
+local parsers = require'nvim-treesitter.parsers'
+local queries = require'nvim-treesitter.query'
+local api = vim.api
+local M = {}
+
+function M.make_attach(normal_mode_functions, submodule)
+  return function(bufnr, lang)
+    local buf = bufnr or api.nvim_get_current_buf()
+    local config = configs.get_module("textobjects."..submodule)
+    local lang = lang or parsers.get_buf_lang(buf)
+
+    for _, function_call in pairs(normal_mode_functions) do
+      for mapping, query in pairs(config[function_call] or {}) do
+        if type(query) == 'table' then
+          query = query[lang]
+        elseif not queries.get_query(lang, 'textobjects') then
+          query = nil
+        end
+        if query then
+          local cmd = ":lua require'nvim-treesitter.textobjects."..submodule.."'."..function_call.."('"..query.."')<CR>"
+          api.nvim_buf_set_keymap(buf, "n", mapping, cmd, {silent = true, noremap = true })
+        end
+      end
+    end
+  end
+end
+
+function M.make_detach(normal_mode_functions, submodule)
+  return function(bufnr)
+    local buf = bufnr or api.nvim_get_current_buf()
+    local config = configs.get_module("textobjects."..submodule)
+    local lang = parsers.get_buf_lang(bufnr)
+
+    for mapping, query in pairs(config.keymaps) do
+      if type(query) == 'table' then
+        query = query[lang]
+      elseif not queries.get_query(lang, 'textobjects') then
+        query = nil
+      end
+      if query then
+        api.nvim_buf_del_keymap(buf, "o", mapping)
+        api.nvim_buf_del_keymap(buf, "v", mapping)
+      end
+    end
+    for _, function_call in pairs(normal_mode_functions) do
+      for mapping, query in pairs(config[function_call] or {}) do
+        if type(query) == 'table' then
+          query = query[lang]
+        elseif not queries.get_query(lang, 'textobjects') then
+          query = nil
+        end
+        if query then
+          api.nvim_buf_del_keymap(buf, "n", mapping)
+        end
+      end
+    end
+  end
+end
+
+return M
diff --git a/lua/nvim-treesitter/textobjects/move.lua b/lua/nvim-treesitter/textobjects/move.lua
new file mode 100644
index 000000000..8cfb71188
--- /dev/null
+++ b/lua/nvim-treesitter/textobjects/move.lua
@@ -0,0 +1,41 @@
+local utils = require'nvim-treesitter.utils'
+local shared = require'nvim-treesitter.textobjects.shared'
+local attach = require'nvim-treesitter.textobjects.attach'
+local api = vim.api
+
+local M = {}
+
+function M.goto_adjacent(query_string, forward, start, same_parent, overlapping_range_ok)
+  local bufnr, _, node = shared.textobject_at_point(query_string)
+  local adjacent = shared.get_adjacent(forward, node,  query_string, same_parent, overlapping_range_ok, bufnr)
+
+  if adjacent then
+    utils.set_jump()
+
+    local adjacent_textobject_range = {adjacent:range()}
+    local position
+    if start then
+      position = { adjacent_textobject_range[1] + 1, adjacent_textobject_range[2] }
+    else
+      position = { adjacent_textobject_range[3] + 1, adjacent_textobject_range[4] }
+    end
+    api.nvim_win_set_cursor(api.nvim_get_current_win(), position)
+  end
+end
+
+-- luacheck: push ignore 631
+M.goto_next_start = function(query_string) M.goto_adjacent(query_string, 'forward', 'start', not 'same_parent', 'overlap ok') end
+M.goto_next_end = function(query_string) M.goto_adjacent(query_string, 'forward', not 'start', not 'same_parent', 'overlap ok') end
+M.goto_previous_start = function(query_string) M.goto_adjacent(query_string, not 'forward', 'start', not 'same_parent', 'overlap ok') end
+M.goto_previous_end = function(query_string) M.goto_adjacent(query_string, not 'forward', not 'start', not 'same_parent', 'overlap ok') end
+-- luacheck: pop
+
+local normal_mode_functions = {"goto_next_start",
+                               "goto_next_end",
+                               "goto_previous_start",
+                               "goto_previous_end"}
+
+M.attach = attach.make_attach(normal_mode_functions, "move")
+M.deattach = attach.make_detach(normal_mode_functions, "move")
+
+return M
diff --git a/lua/nvim-treesitter/textobjects/select.lua b/lua/nvim-treesitter/textobjects/select.lua
new file mode 100644
index 000000000..1f3698bc4
--- /dev/null
+++ b/lua/nvim-treesitter/textobjects/select.lua
@@ -0,0 +1,55 @@
+local api = vim.api
+local configs = require'nvim-treesitter.configs'
+local parsers = require'nvim-treesitter.parsers'
+local queries = require'nvim-treesitter.query'
+
+local shared = require'nvim-treesitter.textobjects.shared'
+local ts_utils = require'nvim-treesitter.ts_utils'
+
+local M = {}
+
+function M.select_textobject(query_string)
+  local bufnr, textobject = shared.textobject_at_point(query_string)
+  if textobject then
+    ts_utils.update_selection(bufnr, textobject)
+  end
+end
+
+function M.attach(bufnr, lang)
+  local buf = bufnr or api.nvim_get_current_buf()
+  local config = configs.get_module("textobjects.select")
+  local lang = lang or parsers.get_buf_lang(buf)
+
+  for mapping, query in pairs(config.keymaps) do
+    if type(query) == 'table' then
+      query = query[lang]
+    elseif not queries.get_query(lang, 'textobjects') then
+      query = nil
+    end
+    if query then
+      local cmd = ":lua require'nvim-treesitter.textobjects.select'.select_textobject('"..query.."')<CR>"
+      api.nvim_buf_set_keymap(buf, "o", mapping, cmd, {silent = true, noremap = true })
+      api.nvim_buf_set_keymap(buf, "v", mapping, cmd, {silent = true, noremap = true })
+    end
+  end
+end
+
+function M.detach(bufnr)
+  local buf = bufnr or api.nvim_get_current_buf()
+  local config = configs.get_module("textobjects.select")
+  local lang = parsers.get_buf_lang(bufnr)
+
+  for mapping, query in pairs(config.keymaps) do
+    if type(query) == 'table' then
+      query = query[lang]
+    elseif not queries.get_query(lang, 'textobjects') then
+      query = nil
+    end
+    if query then
+      api.nvim_buf_del_keymap(buf, "o", mapping)
+      api.nvim_buf_del_keymap(buf, "v", mapping)
+    end
+  end
+end
+
+return M
diff --git a/lua/nvim-treesitter/textobjects/shared.lua b/lua/nvim-treesitter/textobjects/shared.lua
new file mode 100644
index 000000000..3a00da427
--- /dev/null
+++ b/lua/nvim-treesitter/textobjects/shared.lua
@@ -0,0 +1,142 @@
+local api = vim.api
+local ts = vim.treesitter
+
+local parsers = require "nvim-treesitter.parsers"
+local queries = require'nvim-treesitter.query'
+local ts_utils = require'nvim-treesitter.ts_utils'
+
+local M = {}
+
+function M.textobject_at_point(query_string)
+  local bufnr = vim.api.nvim_get_current_buf()
+  local lang = parsers.get_buf_lang(bufnr)
+  if not lang then return end
+
+  local row, col = unpack(vim.api.nvim_win_get_cursor(0))
+  row = row - 1
+
+  local matches = {}
+
+  if string.match(query_string, '^@.*') then
+    matches = queries.get_capture_matches(bufnr, query_string, 'textobjects')
+  else
+    local parser = parsers.get_parser(bufnr, lang)
+    local root = parser:parse():root()
+
+    local start_row, _, end_row, _ = root:range()
+
+    local query = ts.parse_query(lang, query_string)
+    for m in queries.iter_prepared_matches(query, root, bufnr, start_row, end_row) do
+      for _, n in pairs(m) do
+        if n.node then
+          table.insert(matches, n)
+        end
+      end
+    end
+  end
+
+  local match_length
+  local smallest_range
+  local earliest_start
+
+  for _, m in pairs(matches) do
+    if m.node and ts_utils.is_in_node_range(m.node, row, col) then
+      local length = ts_utils.node_length(m.node)
+      if not match_length or length < match_length then
+        smallest_range = m
+        match_length = length
+      end
+      -- for nodes with same length take the one with earliest start
+      if match_length and length == smallest_range then
+        local start = m.start
+        if start then
+          local _, _, start_byte = m.start.node:start()
+          if not earliest_start or start_byte < earliest_start then
+            smallest_range = m
+            match_length = length
+            earliest_start = start_byte
+          end
+        end
+      end
+    end
+  end
+
+  if smallest_range then
+    if smallest_range.start then
+      local start_range = {smallest_range.start.node:range()}
+      local node_range = {smallest_range.node:range()}
+      return bufnr, {start_range[1], start_range[2], node_range[3], node_range[4]}, smallest_range.node
+    else
+      return bufnr, {smallest_range.node:range()}, smallest_range.node
+    end
+  end
+end
+
+function M.get_adjacent(forward, node, query_string, same_parent, overlapping_range_ok, bufnr)
+  local fn = forward and M.next_textobject or M.previous_textobject
+  return fn(node,  query_string, same_parent, overlapping_range_ok, bufnr)
+end
+
+function M.next_textobject(node, query_string, same_parent, overlapping_range_ok, bufnr)
+  local node = node or ts_utils.get_node_at_cursor()
+  local bufnr = bufnr or api.nvim_get_current_buf()
+  if not node then return end
+
+  local _, _, node_end = node:end_()
+  local search_start, _
+  if overlapping_range_ok then
+    _, _, search_start = node:start()
+  else
+    _, _, search_start = node:end_()
+  end
+  local function scoring_function(match)
+    if match.node == node then return end
+    if not same_parent or node:parent() == match.node:parent() then
+      local _, _, start = match.node:start()
+      local _, _, end_ = match.node:end_()
+      return start > search_start and end_ >= node_end
+    end
+  end
+  local function filter_function(match)
+    local _, _, node_start = match.node:start()
+    return -node_start
+  end
+
+  local next_node = queries.find_best_match(bufnr, query_string, 'textobjects', scoring_function, filter_function)
+
+  return next_node and next_node.node
+end
+
+function M.previous_textobject(node, query_string, same_parent, overlapping_range_ok, bufnr)
+  local node = node or ts_utils.get_node_at_cursor()
+  local bufnr = bufnr or api.nvim_get_current_buf()
+  if not node then return end
+
+  local _, _, node_start = node:start()
+  local search_end, _
+  if overlapping_range_ok then
+    _, _, search_end = node:end_()
+    search_end = search_end + 1
+  else
+    _, _, search_end = node:start()
+  end
+
+  local function scoring_function(match)
+    if not same_parent or node:parent() == match.node:parent() then
+      local _, _, end_ = match.node:end_()
+      local _, _, start = match.node:start()
+      return end_ < search_end and start < node_start
+    end
+  end
+
+  local function filter_function(match)
+    local _, _, node_end = match.node:end_()
+    return node_end
+  end
+
+  local previous_node = queries.find_best_match(bufnr, query_string, 'textobjects', scoring_function, filter_function)
+
+  return previous_node and previous_node.node
+end
+
+return M
diff --git a/lua/nvim-treesitter/textobjects/swap.lua b/lua/nvim-treesitter/textobjects/swap.lua
new file mode 100644
index 000000000..bb681fdd0
--- /dev/null
+++ b/lua/nvim-treesitter/textobjects/swap.lua
@@ -0,0 +1,35 @@
+local ts_utils = require'nvim-treesitter.ts_utils'
+local shared = require'nvim-treesitter.textobjects.shared'
+local attach = require'nvim-treesitter.textobjects.attach'
+
+local M = {}
+
+local function swap_textobject(query_string, direction)
+  local bufnr, textobject_range, node = shared.textobject_at_point(query_string)
+  if not node then return end
+
+  local step = direction > 0 and 1 or -1
+  local overlapping_range_ok = false
+  local same_parent = true
+  for _ = 1, math.abs(direction), step do
+    local forward = direction > 0
+    local adjacent = shared.get_adjacent(forward, node, query_string, same_parent, overlapping_range_ok, bufnr)
+    ts_utils.swap_nodes(textobject_range, adjacent, bufnr, "yes, set cursor!")
+  end
+end
+
+function M.swap_next(query_string)
+  swap_textobject(query_string, 1)
+end
+
+function M.swap_previous(query_string)
+  swap_textobject(query_string, -1)
+end
+
+local normal_mode_functions = {"swap_next",
+                               "swap_previous"}
+
+M.attach = attach.make_attach(normal_mode_functions, "swap")
+M.deattach = attach.make_detach(normal_mode_functions, "swap")
+
+return M
diff --git a/lua/nvim-treesitter/ts_utils.lua b/lua/nvim-treesitter/ts_utils.lua
index 0a5cbc608..52fdd0fc8 100644
--- a/lua/nvim-treesitter/ts_utils.lua
+++ b/lua/nvim-treesitter/ts_utils.lua
@@ -1,6 +1,7 @@
 local api = vim.api
 
 local parsers = require'nvim-treesitter.parsers'
+local utils = require'nvim-treesitter.utils'
 
 local M = {}
 
@@ -13,7 +14,7 @@ function M.get_node_text(node, bufnr)
   if not node then return {} end
 
   -- We have to remember that end_col is end-exclusive
-  local start_row, start_col, end_row, end_col = node:range()
+  local start_row, start_col, end_row, end_col = M.get_node_range(node)
 
   if start_row ~= end_row then
     local lines = api.nvim_buf_get_lines(bufnr, start_row, end_row+1, false)
@@ -131,12 +132,7 @@ end
 
 -- Set visual selection to node
 function M.update_selection(buf, node)
-  local start_row, start_col, end_row, end_col
-  if type(node) == 'table' then
-    start_row, start_col, end_row, end_col = unpack(node)
-  else
-    start_row, start_col, end_row, end_col = node:range()
-  end
+  local start_row, start_col, end_row, end_col = M.get_node_range(node)
 
   if end_row == vim.fn.line('$') then
     end_col = #vim.fn.getline('$')
@@ -187,8 +183,16 @@ function M.is_in_node_range(node, line, col)
   end
 end
 
+function M.get_node_range(node_or_range)
+  if type(node_or_range) == 'table' then
+    return unpack(node_or_range)
+  else
+    return node_or_range:range()
+  end
+end
+
 function M.node_to_lsp_range(node)
-  local start_line, start_col, end_line, end_col = node:range()
+  local start_line, start_col, end_line, end_col = M.get_node_range(node)
   local rtn = {}
   rtn.start = { line = start_line, character = start_col }
   rtn['end'] = { line = end_line, character = end_col }
@@ -225,4 +229,51 @@ function M.memoize_by_buf_tick(fn, bufnr_fn)
   end
 end
 
+function M.swap_nodes(node_or_range1, node_or_range2, bufnr, cursor_to_second)
+  if not node_or_range1 or not node_or_range2 then return end
+  local range1 = M.node_to_lsp_range(node_or_range1)
+  local range2 = M.node_to_lsp_range(node_or_range2)
+
+  local text1 = M.get_node_text(node_or_range1)
+  local text2 = M.get_node_text(node_or_range2)
+
+  local edit1 = { range = range1, newText = table.concat(text2, '\n') }
+  local edit2 = { range = range2, newText = table.concat(text1, '\n') }
+  vim.lsp.util.apply_text_edits({edit1, edit2}, bufnr)
+
+  if cursor_to_second then
+    utils.set_jump()
+
+    local char_delta = 0
+    local line_delta = 0
+    if range1["end"].line < range2.start.line
+       or (range1["end"].line == range2.start.line and range1["end"].character < range2.start.character) then
+      line_delta = #text2 - #text1
+    end
+
+    if range1["end"].line == range2.start.line and range1["end"].character < range2.start.character then
+      if line_delta ~= 0 then
+        --- why?
+        --correction_after_line_change =  -range2.start.character
+        --text_now_before_range2 = #(text2[#text2])
+        --space_between_ranges = range2.start.character - range1["end"].character
+        --char_delta = correction_after_line_change + text_now_before_range2 + space_between_ranges
+        --- Equivalent to:
+        char_delta = #(text2[#text2]) - range1["end"].character
+
+        -- add range1.start.character if last line of range1 (now text2) does not start at 0
+        if range1.start.line == range2.start.line + line_delta then
+            char_delta = char_delta + range1.start.character
+        end
+      else
+        char_delta = #(text2[#text2]) - #(text1[#text1])
+      end
+    end
+
+    api.nvim_win_set_cursor(api.nvim_get_current_win(),
+                            {range2.start.line + 1 + line_delta,
+                             range2.start.character + char_delta})
+  end
+end
+
 return M
diff --git a/lua/nvim-treesitter/utils.lua b/lua/nvim-treesitter/utils.lua
index 416326e48..d3d183395 100644
--- a/lua/nvim-treesitter/utils.lua
+++ b/lua/nvim-treesitter/utils.lua
@@ -67,4 +67,8 @@ function M.print_warning(text)
   api.nvim_command(string.format([[echohl WarningMsg | echo "%s" | echohl None]], text))
 end
 
+function M.set_jump()
+  vim.cmd "normal! m'"
+end
+
 return M
diff --git a/queries/c/textobjects.scm b/queries/c/textobjects.scm
index 839169164..9151bc532 100644
--- a/queries/c/textobjects.scm
+++ b/queries/c/textobjects.scm
@@ -53,3 +53,6 @@
 
 (preproc_else
   (_) @statement.outer)
+
+(parameter_list
+  (parameter_declaration) @parameter.inner)
diff --git a/queries/cpp/textobjects.scm b/queries/cpp/textobjects.scm
index ed26fcf31..ae9879551 100644
--- a/queries/cpp/textobjects.scm
+++ b/queries/cpp/textobjects.scm
@@ -13,3 +13,6 @@
 
 (template_declaration
   (class_specifier) @class.outer) @class.outer.start
+
+(parameter_list
+  (optional_parameter_declaration) @parameter.inner)