Merge #39889 from ofseed/pos-util

refactor(pos,range): drop `to_cursor`, extract `vim.pos._util`

6 files changed, 407 insertions, 359 deletions

diff --git a/runtime/lua/vim/lsp/inline_completion.lua b/runtime/lua/vim/lsp/inline_completion.lua
index e759562747..7dae0c717b 100644
--- a/runtime/lua/vim/lsp/inline_completion.lua
+++ b/runtime/lua/vim/lsp/inline_completion.lua
@@ -348,7 +348,7 @@ function Completor:accept(item)
       api.nvim_buf_set_text(self.bufnr, start_row, start_col, end_row, end_col, lines)
       local win = api.nvim_get_current_win()
       win = api.nvim_win_get_buf(win) == self.bufnr and win or vim.fn.bufwinid(self.bufnr)
-      local row, col = item.range:to_cursor()
+      local row, col = item.range:to_mark()
       api.nvim_win_set_cursor(win, {
         row + #lines - 1,
         (#lines == 1 and col or 0) + #lines[#lines],
diff --git a/runtime/lua/vim/lsp/util.lua b/runtime/lua/vim/lsp/util.lua
index 7a37d5ebfa..1687037e6b 100644
--- a/runtime/lua/vim/lsp/util.lua
+++ b/runtime/lua/vim/lsp/util.lua
@@ -133,9 +133,9 @@ local function sort_by_key(fn)
   end
 end
 
-local get_lines = vim.pos._get_lines
-
-local get_line = vim.pos._get_line
+-- TODO(ofseed): remove these exported functions by replacing their usages with `vim.pos`.
+local get_lines = require('vim.pos._util').get_lines
+local get_line = require('vim.pos._util').get_line
 
 --- Applies a list of text edits to a buffer. Note: this mutates `text_edits` (sorts in-place and
 --- adds `_index` fields).
diff --git a/runtime/lua/vim/pos.lua b/runtime/lua/vim/pos.lua
index a37353f736..15cc318ddd 100644
--- a/runtime/lua/vim/pos.lua
+++ b/runtime/lua/vim/pos.lua
@@ -7,8 +7,8 @@
 --- objects.
 
 local api = vim.api
-local uv = vim.uv
 local validate = vim.validate
+local util = require('vim.pos._util')
 
 --- Represents a well-defined position.
 ---
@@ -80,134 +80,25 @@ function M.new(buf, row, col)
   return self
 end
 
----@param p1 vim.Pos First position to compare.
----@param p2 vim.Pos Second position to compare.
----@return integer
---- 1: a > b
---- 0: a == b
---- -1: a < b
-local function cmp_pos(p1, p2)
-  if p1[1] == p2[1] then
-    if p1[2] > p2[2] then
-      return 1
-    elseif p1[2] < p2[2] then
-      return -1
-    else
-      return 0
-    end
-  elseif p1[1] > p2[1] then
-    return 1
-  end
-
-  return -1
-end
-
 ---@private
-function M.__lt(...)
-  return cmp_pos(...) == -1
+---@param p1 vim.Pos
+---@param p2 vim.Pos
+function M.__lt(p1, p2)
+  return util.cmp_pos.lt(p1[1], p1[2], p2[1], p2[2])
 end
 
 ---@private
-function M.__le(...)
-  return cmp_pos(...) ~= 1
+---@param p1 vim.Pos
+---@param p2 vim.Pos
+function M.__le(p1, p2)
+  return util.cmp_pos.le(p1[1], p1[2], p2[1], p2[2])
 end
 
 ---@private
-function M.__eq(...)
-  return cmp_pos(...) == 0
-end
-
---- Gets the zero-indexed lines from the given buffer.
---- Works on unloaded buffers by reading the file using libuv to bypass buf reading events.
---- Falls back to loading the buffer and nvim_buf_get_lines for buffers with non-file URI.
----
----@param bufnr integer bufnr to get the lines from
----@param rows integer[] zero-indexed line numbers
----@return table<integer, string> # a table mapping rows to lines
-local function get_lines(bufnr, rows)
-  --- @type integer[]
-  rows = type(rows) == 'table' and rows or { rows }
-
-  -- This is needed for bufload and bufloaded
-  bufnr = vim._resolve_bufnr(bufnr)
-
-  local function buf_lines()
-    local lines = {} --- @type table<integer,string>
-    for _, row in ipairs(rows) do
-      lines[row] = (api.nvim_buf_get_lines(bufnr, row, row + 1, false) or { '' })[1]
-    end
-    return lines
-  end
-
-  -- use loaded buffers if available
-  if vim.fn.bufloaded(bufnr) == 1 then
-    return buf_lines()
-  end
-
-  local uri = vim.uri_from_bufnr(bufnr)
-
-  -- load the buffer if this is not a file uri
-  -- Custom language server protocol extensions can result in servers sending URIs with custom schemes. Plugins are able to load these via `BufReadCmd` autocmds.
-  if uri:sub(1, 4) ~= 'file' then
-    vim.fn.bufload(bufnr)
-    return buf_lines()
-  end
-
-  local filename = api.nvim_buf_get_name(bufnr)
-  if vim.fn.isdirectory(filename) ~= 0 then
-    return {}
-  end
-
-  -- get the data from the file
-  local fd = uv.fs_open(filename, 'r', 438)
-  if not fd then
-    return {}
-  end
-  local stat = assert(uv.fs_fstat(fd))
-  local data = assert(uv.fs_read(fd, stat.size, 0))
-  uv.fs_close(fd)
-
-  local lines = {} --- @type table<integer,true|string> rows we need to retrieve
-  local need = 0 -- keep track of how many unique rows we need
-  for _, row in pairs(rows) do
-    if not lines[row] then
-      need = need + 1
-    end
-    lines[row] = true
-  end
-
-  local found = 0
-  local lnum = 0
-
-  for line in string.gmatch(data, '([^\n]*)\n?') do
-    if lines[lnum] == true then
-      lines[lnum] = line
-      found = found + 1
-      if found == need then
-        break
-      end
-    end
-    lnum = lnum + 1
-  end
-
-  -- change any lines we didn't find to the empty string
-  for i, line in pairs(lines) do
-    if line == true then
-      lines[i] = ''
-    end
-  end
-  return lines --[[@as table<integer,string>]]
-end
-
---- Gets the zero-indexed line from the given buffer.
---- Works on unloaded buffers by reading the file using libuv to bypass buf reading events.
---- Falls back to loading the buffer and nvim_buf_get_lines for buffers with non-file URI.
----
----@param bufnr integer
----@param row integer zero-indexed line number
----@return string the line at row in filename
-local function get_line(bufnr, row)
-  return get_lines(bufnr, { row })[row]
+---@param p1 vim.Pos
+---@param p2 vim.Pos
+function M.__eq(p1, p2)
+  return util.cmp_pos.eq(p1[1], p1[2], p2[1], p2[2])
 end
 
 --- Converts |vim.Pos| to `lsp.Position`.
@@ -221,25 +112,12 @@ end
 --- ```
 ---@param pos vim.Pos
 ---@param position_encoding lsp.PositionEncodingKind
+---@return lsp.Position
 function M.to_lsp(pos, position_encoding)
   validate('pos', pos, 'table')
   validate('position_encoding', position_encoding, 'string')
 
-  local buf, row, col = pos.buf, pos[1], pos[2]
-  -- When on the first character,
-  -- we can ignore the difference between byte and character.
-  if col > 0 then
-    col = vim.str_utfindex(get_line(buf, row), position_encoding, col, false)
-  elseif col == 0 and row == api.nvim_buf_line_count(buf) and not vim.bo[buf].endofline then
-    -- Some LSP servers reject ranges that end at the virtual EOF position
-    -- (i.e., `[line_count, 0]`) when the buffer has no trailing newline.
-    -- Normalize such positions to the end of the last real line instead.
-    row = row - 1
-    col = vim.str_utfindex(get_line(buf, row), position_encoding)
-  end
-
-  ---@type lsp.Position
-  return { line = row, character = col }
+  return util.to_lsp(pos.buf, pos[1], pos[2], position_encoding)
 end
 
 --- Creates a new |vim.Pos| from `lsp.Position`.
@@ -256,6 +134,7 @@ end
 ---@param buf integer
 ---@param pos lsp.Position
 ---@param position_encoding lsp.PositionEncodingKind
+---@return vim.Pos
 function M.lsp(buf, pos, position_encoding)
   validate('buf', buf, 'number')
   validate('pos', pos, 'table')
@@ -265,82 +144,125 @@ function M.lsp(buf, pos, position_encoding)
     buf = api.nvim_get_current_buf()
   end
 
-  local row, col = pos.line, pos.character
-  -- When on the first character,
-  -- we can ignore the difference between byte and character.
-  if col > 0 then
-    -- `strict_indexing` is disabled, because LSP responses are asynchronous,
-    -- and the buffer content may have changed, causing out-of-bounds errors.
-    col = vim.str_byteindex(get_line(buf, row) or '', position_encoding, col, false)
-  end
-
+  local row, col = util.from_lsp(buf, pos, position_encoding)
   return M.new(buf, row, col)
 end
 
 --- Converts |vim.Pos| to cursor position (see |api-indexing|).
+---
+--- Example:
+--- ```lua
+--- local pos = vim.pos(0, 3, 5)
+---
+--- -- Convert to cursor position, you can call it in a method style.
+--- local cursor_pos = { pos:to_cursor() }
+--- vim.api.nvim_win_set_cursor(0, cursor_pos)
+--- ```
 ---@param pos vim.Pos
----@return integer, integer
+---@return integer lnum, integer col
 function M.to_cursor(pos)
-  return pos[1] + 1, pos[2]
+  validate('pos', pos, 'table')
+  return util.to_mark(pos[1], pos[2])
 end
 
 --- Creates a new |vim.Pos| from cursor position (see |api-indexing|).
+---
+--- Example:
+--- ```lua
+--- local cursor_pos = vim.api.nvim_win_get_cursor(0)
+--- local pos = vim.pos.lsp(0, cursor_pos)
+--- ```
 ---@param buf integer
----@param pos [integer, integer]
+---@param pos [integer, integer] (lnum, col) tuple
+---@return vim.Pos
 function M.cursor(buf, pos)
-  return M.new(buf, pos[1] - 1, pos[2])
+  validate('buf', buf, 'number')
+  validate('pos', pos, 'table')
+
+  if buf == 0 then
+    buf = api.nvim_get_current_buf()
+  end
+
+  return M.new(buf, util.from_mark(pos[1], pos[2]))
 end
 
 --- Converts |vim.Pos| to mark position (see |api-indexing|).
+---
+--- Example:
+--- ```lua
+--- local pos = vim.pos(0, 3, 5)
+---
+--- -- Convert to mark position, you can call it in a method style.
+--- local lnum, col = pos:to_mark()
+--- vim.api.nvim_buf_set_mark(0, 'M', lnum, col, {})
+--- ```
 ---@param pos vim.Pos
----@return integer, integer
+---@return integer lnum, integer col
 function M.to_mark(pos)
-  return pos[1] + 1, pos[2]
+  validate('pos', pos, 'table')
+  return util.to_mark(pos[1], pos[2])
 end
 
 --- Creates a new |vim.Pos| from mark position (see |api-indexing|).
+---
+--- Example:
+--- ```lua
+--- local mark_info = vim.api.nvim_get_mark('M', {})
+--- local lnum, col, buf, name = unpack(mark_info)
+---
+--- if lnum == 0 and col == 0 and buf == 0 then
+---   return -- mark 'M' is not set.
+--- end
+---
+--- local pos = vim.pos.mark(buf, lnum, col)
+--- ```
 ---@param buf integer
----@param row integer
+---@param lnum integer
 ---@param col integer
-function M.mark(buf, row, col)
+---@return vim.Pos
+function M.mark(buf, lnum, col)
+  validate('buf', buf, 'number')
+  validate('lnum', lnum, 'number')
+  validate('col', col, 'number')
+
   if buf == 0 then
     buf = api.nvim_get_current_buf()
   end
 
-  return M.new(buf, row - 1, col)
+  return M.new(buf, util.from_mark(lnum, col))
 end
 
 --- Converts |vim.Pos| to extmark position (see |api-indexing|).
+---
+--- Example:
+--- ```lua
+--- local pos = vim.pos(0, 3, 5)
+---
+--- -- Convert to extmark position, you can call it in a method style.
+--- local extmark_pos = pos:to_extmark()
+--- ```
 ---@param pos vim.Pos
----@return integer, integer
+---@return integer row, integer col
 function M.to_extmark(pos)
-  local row, col = pos[1], pos[2]
-  -- Consider a buffer like this:
-  -- ```
-  -- 0123456
-  -- abcdefg
-  -- ```
-  --
-  -- Two ways to describe the range of the first line, i.e. '0123456':
-  -- 1. `{ start_row = 0, start_col = 0, end_row = 0, end_col = 7 }`
-  -- 2. `{ start_row = 0, start_col = 0, end_row = 1, end_col = 0 }`
-  --
-  -- Both of the above methods satisfy the "end-exclusive" definition,
-  -- but `nvim_buf_set_extmark()` throws an out-of-bounds error for the second method,
-  -- so we need to convert it to the first method.
-  if col == 0 and row == api.nvim_buf_line_count(pos.buf) then
-    row = row - 1
-    col = #get_line(pos.buf, row)
-  end
-
-  return row, col
+  validate('pos', pos, 'table')
+  return pos[1], pos[2]
 end
 
 --- Creates a new |vim.Pos| from extmark position (see |api-indexing|).
+---
+--- Example:
+--- ```lua
+--- local pos = vim.pos.extmark(0, 3, 5)
+--- ```
 ---@param buf integer
 ---@param row integer
 ---@param col integer
+---@return vim.Pos
 function M.extmark(buf, row, col)
+  validate('buf', buf, 'number')
+  validate('row', row, 'number')
+  validate('col', col, 'number')
+
   if buf == 0 then
     buf = api.nvim_get_current_buf()
   end
@@ -348,18 +270,40 @@ function M.extmark(buf, row, col)
   return M.new(buf, row, col)
 end
 
---- Converts |vim.Pos| to buffer offset.
+--- Converts |vim.Pos| to buffer (bytes) offset.
+---
+--- Example:
+--- ```lua
+--- local p1 = vim.pos(0, 3, 5)
+--- local p2 = vim.pos(0, 4, 0)
+---
+--- -- Convert to buffer offset, you can call it in a method style.
+--- local offset1 = p1:to_offset()
+--- local offset2 = p2:to_offset()
+--- -- Can be used to calculate the distance between two locations.
+--- local distance = offset2 - offset1
+--- ```
 ---@param pos vim.Pos
 ---@return integer
 function M.to_offset(pos)
+  validate('pos', pos, 'table')
   return api.nvim_buf_get_offset(pos.buf, pos[1]) + pos[2]
 end
 
---- Creates a new |vim.Pos| from buffer offset.
+--- Creates a new |vim.Pos| from buffer (bytes) offset.
+---
+--- Example:
+--- ```lua
+--- local offset = vim.api.nvim_buf_get_offset(0, vim.api.nvim_buf_line_count(0))
+--- local pos = vim.pos.offset(0, offset)
+--- ```
 ---@param buf integer
 ---@param offset integer
 ---@return vim.Pos
 function M.offset(buf, offset)
+  validate('buf', buf, 'number')
+  validate('offset', offset, 'number')
+
   local lnum = vim.list.bisect(
     setmetatable({}, {
       __index = function(_, lnum)
@@ -375,11 +319,6 @@ function M.offset(buf, offset)
   return M.new(buf, row, col)
 end
 
--- TODO(ofseed): remove these exported functions by replacing their usages with `vim.pos`.
-M._get_lines = get_lines
-
-M._get_line = get_line
-
 -- Overload `Range.new` to allow calling this module as a function.
 setmetatable(M, {
   __call = function(_, ...)
diff --git a/runtime/lua/vim/pos/_util.lua b/runtime/lua/vim/pos/_util.lua
new file mode 100644
index 0000000000..cd82a649fd
--- /dev/null
+++ b/runtime/lua/vim/pos/_util.lua
@@ -0,0 +1,205 @@
+---@brief
+--- Unlike `vim.pos`, this module is used to provide utility functions
+--- for unpacked `row`, `col`.
+---
+--- The variable names have some implications:
+---
+--- - `row`  is used to represent a 0-based index of a line.
+--- - `lnum` is used to represent a 1-based index of a line, short for "line number".
+
+local api = vim.api
+local uv = vim.uv
+
+local M = {}
+
+---@param a_row integer
+---@param a_col integer
+---@param b_row integer
+---@param b_col integer
+---@return integer
+--- 1: a > b
+--- 0: a == b
+--- -1: a < b
+local function cmp_pos(a_row, a_col, b_row, b_col)
+  if a_row == b_row then
+    if a_col > b_col then
+      return 1
+    elseif a_col < b_col then
+      return -1
+    else
+      return 0
+    end
+  elseif a_row > b_row then
+    return 1
+  end
+
+  return -1
+end
+
+---@type table<'lt'|'le'|'gt'|'ge'|'eq'|'ne', fun(a_row: integer, a_col: integer, b_row: integer, b_col: integer): boolean>
+M.cmp_pos = {
+  lt = function(...)
+    return cmp_pos(...) == -1
+  end,
+  le = function(...)
+    return cmp_pos(...) ~= 1
+  end,
+  gt = function(...)
+    return cmp_pos(...) == 1
+  end,
+  ge = function(...)
+    return cmp_pos(...) ~= -1
+  end,
+  eq = function(...)
+    return cmp_pos(...) == 0
+  end,
+  ne = function(...)
+    return cmp_pos(...) ~= 0
+  end,
+}
+
+setmetatable(M.cmp_pos, { __call = cmp_pos })
+
+--- Gets the zero-indexed lines from the given buffer.
+--- Works on unloaded buffers by reading the file using libuv to bypass buf reading events.
+--- Falls back to loading the buffer and nvim_buf_get_lines for buffers with non-file URI.
+---
+---@param bufnr integer bufnr to get the lines from
+---@param rows integer[] zero-indexed line numbers
+---@return table<integer, string> # a table mapping rows to lines
+function M.get_lines(bufnr, rows)
+  --- @type integer[]
+  rows = type(rows) == 'table' and rows or { rows }
+
+  -- This is needed for bufload and bufloaded
+  bufnr = vim._resolve_bufnr(bufnr)
+
+  local function buf_lines()
+    local lines = {} --- @type table<integer,string>
+    for _, row in ipairs(rows) do
+      lines[row] = (api.nvim_buf_get_lines(bufnr, row, row + 1, false) or { '' })[1]
+    end
+    return lines
+  end
+
+  -- use loaded buffers if available
+  if vim.fn.bufloaded(bufnr) == 1 then
+    return buf_lines()
+  end
+
+  local uri = vim.uri_from_bufnr(bufnr)
+
+  -- load the buffer if this is not a file uri
+  -- Custom language server protocol extensions can result in servers sending URIs with custom schemes. Plugins are able to load these via `BufReadCmd` autocmds.
+  if uri:sub(1, 4) ~= 'file' then
+    vim.fn.bufload(bufnr)
+    return buf_lines()
+  end
+
+  local filename = api.nvim_buf_get_name(bufnr)
+  if vim.fn.isdirectory(filename) ~= 0 then
+    return {}
+  end
+
+  -- get the data from the file
+  local fd = uv.fs_open(filename, 'r', 438)
+  if not fd then
+    return {}
+  end
+  local stat = assert(uv.fs_fstat(fd))
+  local data = assert(uv.fs_read(fd, stat.size, 0))
+  uv.fs_close(fd)
+
+  local lines = {} --- @type table<integer,true|string> rows we need to retrieve
+  local need = 0 -- keep track of how many unique rows we need
+  for _, row in pairs(rows) do
+    if not lines[row] then
+      need = need + 1
+    end
+    lines[row] = true
+  end
+
+  local found = 0
+  local lnum = 0
+
+  for line in string.gmatch(data, '([^\n]*)\n?') do
+    if lines[lnum] == true then
+      lines[lnum] = line
+      found = found + 1
+      if found == need then
+        break
+      end
+    end
+    lnum = lnum + 1
+  end
+
+  -- change any lines we didn't find to the empty string
+  for i, line in pairs(lines) do
+    if line == true then
+      lines[i] = ''
+    end
+  end
+  return lines --[[@as table<integer,string>]]
+end
+
+--- Gets the zero-indexed line from the given buffer.
+--- Works on unloaded buffers by reading the file using libuv to bypass buf reading events.
+--- Falls back to loading the buffer and nvim_buf_get_lines for buffers with non-file URI.
+---
+---@param bufnr integer
+---@param row integer zero-indexed line number
+---@return string the line at row in filename
+function M.get_line(bufnr, row)
+  return M.get_lines(bufnr, { row })[row]
+end
+
+---@param buf integer
+---@param row integer
+---@param col integer
+---@param position_encoding lsp.PositionEncodingKind
+function M.to_lsp(buf, row, col, position_encoding)
+  -- When on the first character,
+  -- we can ignore the difference between byte and character.
+  if col > 0 then
+    col = vim.str_utfindex(M.get_line(buf, row), position_encoding, col, false)
+  elseif col == 0 and row == api.nvim_buf_line_count(buf) and not vim.bo[buf].endofline then
+    -- Some LSP servers reject ranges that end at the virtual EOF position
+    -- (i.e., `[line_count, 0]`) when the buffer has no trailing newline.
+    -- Normalize such positions to the end of the last real line instead.
+    row = row - 1
+    col = vim.str_utfindex(M.get_line(buf, row), position_encoding)
+  end
+  ---@type lsp.Position
+  return { line = row, character = col }
+end
+
+---@param buf integer
+---@param position lsp.Position
+---@param position_encoding lsp.PositionEncodingKind
+function M.from_lsp(buf, position, position_encoding)
+  local row, col = position.line, position.character
+  -- When on the first character,
+  -- we can ignore the difference between byte and character.
+  if col > 0 then
+    -- `strict_indexing` is disabled, because LSP responses are asynchronous,
+    -- and the buffer content may have changed, causing out-of-bounds errors.
+    col = vim.str_byteindex(M.get_line(buf, row) or '', position_encoding, col, false)
+  end
+  return row, col
+end
+
+---@param row integer
+---@param col integer
+---@return integer lnum, integer col
+function M.to_mark(row, col)
+  return row + 1, col
+end
+
+---@param lnum integer
+---@param col integer
+---@return integer row, integer col
+function M.from_mark(lnum, col)
+  return lnum - 1, col
+end
+
+return M
diff --git a/runtime/lua/vim/range.lua b/runtime/lua/vim/range.lua
index e069df4a3a..489b41e2b3 100644
--- a/runtime/lua/vim/range.lua
+++ b/runtime/lua/vim/range.lua
@@ -8,6 +8,7 @@
 
 local validate = vim.validate
 local api = vim.api
+local util = require('vim.pos._util')
 
 --- Represents a range. Call `vim.range()` to create a new range.
 ---
@@ -114,43 +115,12 @@ function M.new(...)
   return self
 end
 
---- TODO(ofseed): Make it work for unloaded buffers. Check get_line() in vim.lsp.util.
----@param buf integer
----@param row integer
-local function get_line(buf, row)
-  return api.nvim_buf_get_lines(buf, row, row + 1, true)[1]
-end
-
----@param p1_row integer Row of first position to compare.
----@param p1_col integer Col of first position to compare.
----@param p2_row integer Row of second position to compare.
----@param p2_col integer Col of second position to compare.
----@return integer
---- 1: a > b
---- 0: a == b
---- -1: a < b
-local function cmp_pos(p1_row, p1_col, p2_row, p2_col)
-  if p1_row == p2_row then
-    if p1_col > p2_col then
-      return 1
-    elseif p1_col < p2_col then
-      return -1
-    else
-      return 0
-    end
-  elseif p1_row > p2_row then
-    return 1
-  end
-
-  return -1
-end
-
 ---@param row integer
 ---@param col integer
 ---@param buf integer
 ---@return integer, integer
 local function to_inclusive_pos(buf, row, col)
-  local line = get_line(buf, row)
+  local line = util.get_line(buf, row)
   if col > 0 then
     col = col + vim.str_utf_start(line, col) - 1
   elseif col == 0 and row > 0 then
@@ -166,7 +136,7 @@ end
 ---@param buf integer
 ---@return integer, integer
 local function to_exclusive_pos(buf, row, col)
-  local line = get_line(buf, row)
+  local line = util.get_line(buf, row)
   if col >= #line then
     row = row + 1
     col = 0
@@ -182,11 +152,11 @@ end
 ---@param r2 vim.Range
 function M.__lt(r1, r2)
   if r1:is_empty() or r2:is_empty() then
-    return cmp_pos(r1[3], r1[4], r2[1], r2[2]) ~= 1
+    return util.cmp_pos.le(r1[3], r1[4], r2[1], r2[2])
   end
 
   local r1_inclusive_end_row, r1_inclusive_end_col = to_inclusive_pos(r1.buf, r1[3], r1[4])
-  return cmp_pos(r1_inclusive_end_row, r1_inclusive_end_col, r2[1], r2[2]) == -1
+  return util.cmp_pos.lt(r1_inclusive_end_row, r1_inclusive_end_col, r2[1], r2[2])
 end
 
 ---@private
@@ -194,18 +164,18 @@ end
 ---@param r2 vim.Range
 function M.__le(r1, r2)
   if r1:is_empty() or r2:is_empty() then
-    return cmp_pos(r1[3], r1[4], r2[1], r2[2]) ~= 1
+    return util.cmp_pos.le(r1[3], r1[4], r2[1], r2[2])
   end
 
   local r1_inclusive_end_row, r1_inclusive_end_col = to_inclusive_pos(r1.buf, r1[3], r1[4])
-  return cmp_pos(r1_inclusive_end_row, r1_inclusive_end_col, r2[1], r2[2]) ~= 1
+  return util.cmp_pos.le(r1_inclusive_end_row, r1_inclusive_end_col, r2[1], r2[2])
 end
 
 ---@private
 ---@param r1 vim.Range
 ---@param r2 vim.Range
 function M.__eq(r1, r2)
-  return cmp_pos(r1[1], r1[2], r2[1], r2[2]) == 0 and cmp_pos(r1[3], r1[4], r2[3], r2[4]) == 0
+  return util.cmp_pos.eq(r1[1], r1[2], r2[1], r2[2]) and util.cmp_pos.eq(r1[3], r1[4], r2[3], r2[4])
 end
 
 --- Checks whether the given range is empty; i.e., start >= end.
@@ -213,7 +183,8 @@ end
 ---@param range vim.Range
 ---@return boolean `true` if the given range is empty.
 function M.is_empty(range)
-  return cmp_pos(range[1], range[2], range[3], range[4]) ~= -1
+  validate('range', range, 'table')
+  return util.cmp_pos.ge(range[1], range[2], range[3], range[4])
 end
 
 --- Checks whether {outer} range contains {inner} range or position.
@@ -222,10 +193,13 @@ end
 ---@param inner vim.Range|vim.Pos
 ---@return boolean `true` if {outer} range fully contains {inner} range or position.
 function M.has(outer, inner)
+  validate('outer', outer, 'table')
+  validate('inner', inner, 'table')
+
   if getmetatable(inner) == vim.pos then
     ---@cast inner -vim.Range
-    return cmp_pos(outer[1], outer[2], inner[1], inner[2]) ~= 1
-      and cmp_pos(outer[3], outer[4], inner[1], inner[2]) ~= -1
+    return util.cmp_pos.le(outer[1], outer[2], inner[1], inner[2])
+      and util.cmp_pos.ge(outer[3], outer[4], inner[1], inner[2])
   end
   ---@cast inner -vim.Pos
 
@@ -237,15 +211,15 @@ function M.has(outer, inner)
   -- the text outside `outer`
   if
     (
-      cmp_pos(outer[1], outer[2], inner[3], inner[4]) ~= -1
-      or cmp_pos(outer[3], outer[4], inner[1], inner[2]) ~= 1
+      util.cmp_pos.ge(outer[1], outer[2], inner[3], inner[4])
+      or util.cmp_pos.le(outer[3], outer[4], inner[1], inner[2])
     ) and inner:is_empty()
   then
     return false
   end
 
-  return cmp_pos(outer[1], outer[2], inner[1], inner[2]) ~= 1
-    and cmp_pos(outer[3], outer[4], inner[3], inner[4]) ~= -1
+  return util.cmp_pos.le(outer[1], outer[2], inner[1], inner[2])
+    and util.cmp_pos.ge(outer[3], outer[4], inner[3], inner[4])
 end
 
 --- Computes the common range shared by the given ranges.
@@ -255,6 +229,9 @@ end
 ---@return vim.Range? range that is present inside both `r1` and `r2`.
 ---                   `nil` if such range does not exist.
 function M.intersect(r1, r2)
+  validate('r1', r1, 'table')
+  validate('r2', r2, 'table')
+
   if r1.buf ~= r2.buf then
     return nil
   end
@@ -266,14 +243,14 @@ function M.intersect(r1, r2)
   local r2_inclusive_end_row, r2_inclusive_end_col = to_inclusive_pos(r2.buf, r2[3], r2[4])
 
   if
-    cmp_pos(r1_inclusive_end_row, r1_inclusive_end_col, r2[1], r2[2]) ~= 1
-    or cmp_pos(r1[1], r1[2], r2_inclusive_end_row, r2_inclusive_end_col) ~= -1
+    util.cmp_pos.le(r1_inclusive_end_row, r1_inclusive_end_col, r2[1], r2[2])
+    or util.cmp_pos.ge(r1[1], r1[2], r2_inclusive_end_row, r2_inclusive_end_col)
   then
     return nil
   end
 
-  local rs = cmp_pos(r1[1], r1[2], r2[1], r2[2]) ~= 1 and r2 or r1
-  local re = cmp_pos(r1[3], r1[4], r2[3], r2[4]) ~= -1 and r2 or r1
+  local rs = util.cmp_pos.le(r1[1], r1[2], r2[1], r2[2]) and r2 or r1
+  local re = util.cmp_pos.ge(r1[3], r1[4], r2[3], r2[4]) and r2 or r1
   return M.new(r1.buf, rs[1], rs[2], re[3], re[4])
 end
 
@@ -293,10 +270,11 @@ function M.to_lsp(range, position_encoding)
   validate('range', range, 'table')
   validate('position_encoding', position_encoding, 'string', true)
 
+  local buf = range.buf
   ---@type lsp.Range
   return {
-    ['start'] = vim.pos(range.buf, range[1], range[2]):to_lsp(position_encoding),
-    ['end'] = vim.pos(range.buf, range[3], range[4]):to_lsp(position_encoding),
+    ['start'] = util.to_lsp(buf, range[1], range[2], position_encoding),
+    ['end'] = util.to_lsp(buf, range[3], range[4], position_encoding),
   }
 end
 
@@ -314,6 +292,7 @@ end
 ---@param buf integer
 ---@param range lsp.Range
 ---@param position_encoding lsp.PositionEncodingKind
+---@return vim.Range
 function M.lsp(buf, range, position_encoding)
   validate('buf', buf, 'number')
   validate('range', range, 'table')
@@ -323,12 +302,9 @@ function M.lsp(buf, range, position_encoding)
     buf = api.nvim_get_current_buf()
   end
 
-  -- TODO(ofseed): avoid using `Pos:lsp()` here,
-  -- as they need reading files separately if buffer is unloaded.
-  local start = vim.pos.lsp(buf, range['start'], position_encoding)
-  local end_ = vim.pos.lsp(buf, range['end'], position_encoding)
-
-  return M.new(start, end_)
+  local start_row, start_col = util.from_lsp(buf, range['start'], position_encoding)
+  local end_row, end_col = util.from_lsp(buf, range['end'], position_encoding)
+  return M.new(buf, start_row, start_col, end_row, end_col)
 end
 
 --- Converts |vim.Range| to extmark range (see |api-indexing|).
@@ -338,10 +314,10 @@ end
 --- local range = vim.range(0, 3, 5, 4, 0)
 ---
 --- -- Convert to mark range, you can call it in a method style.
---- local start_row, start_col, end_row, end_col = range:to_mark()
+--- local start_lnum, start_col, end_lnum, end_col = range:to_mark()
 --- ```
 ---@param range vim.Range
----@return integer, integer, integer, integer
+---@return integer start_lnum, integer start_col, integer end_lnum, integer end_col
 function M.to_mark(range)
   validate('range', range, 'table')
 
@@ -351,8 +327,8 @@ function M.to_mark(range)
     end_row, end_col = to_inclusive_pos(buf, end_row, end_col)
   end
 
-  start_row, start_col = vim.pos(buf, start_row, start_col):to_mark()
-  end_row, end_col = vim.pos(buf, end_row, end_col):to_mark()
+  start_row, start_col = util.to_mark(start_row, start_col)
+  end_row, end_col = util.to_mark(end_row, end_col)
   return start_row, start_col, end_row, end_col
 end
 
@@ -361,35 +337,36 @@ end
 --- Example:
 --- ```lua
 --- -- A range represented by marks may be end-inclusive (decided by 'selection' option).
---- local start_row, start_col = unpack(api.nvim_buf_get_mark(bufnr, '<'))
---- local end_row, end_col = unpack(api.nvim_buf_get_mark(bufnr, '>'))
+--- local start_lnum, start_col = unpack(api.nvim_buf_get_mark(bufnr, '<'))
+--- local end_lnum, end_col = unpack(api.nvim_buf_get_mark(bufnr, '>'))
 ---
 --- -- Create an end-exclusive range.
---- local range = vim.range.mark(0, start_row, start_col, end_row, end_col)
+--- local range = vim.range.mark(0, start_lnum, start_col, end_lnum, end_col)
 --- ```
 ---@param buf integer
----@param start_row integer
+---@param start_lnum integer
 ---@param start_col integer
----@param end_row integer
+---@param end_lnum integer
 ---@param end_col integer
-function M.mark(buf, start_row, start_col, end_row, end_col)
+---@return vim.Range
+function M.mark(buf, start_lnum, start_col, end_lnum, end_col)
   validate('buf', buf, 'number')
-  validate('start_row', start_row, 'number')
+  validate('start_lnum', start_lnum, 'number')
   validate('start_col', start_col, 'number')
-  validate('end_row', end_row, 'number')
+  validate('end_lnum', end_lnum, 'number')
   validate('end_col', end_col, 'number')
 
   if buf == 0 then
     buf = api.nvim_get_current_buf()
   end
 
-  local start = vim.pos.mark(buf, start_row, start_col)
-  local end_ = vim.pos.mark(buf, end_row, end_col)
+  start_lnum, start_col = util.from_mark(start_lnum, start_col)
+  end_lnum, end_col = util.from_mark(end_lnum, end_col)
 
   if vim.o.selection ~= 'exclusive' then
-    end_[1], end_[2] = to_exclusive_pos(buf, end_[1], end_[2])
+    end_lnum, end_col = to_exclusive_pos(buf, end_lnum, end_col)
   end
-  return M.new(start, end_)
+  return M.new(buf, start_lnum, start_col, end_lnum, end_col)
 end
 
 --- Converts |vim.Range| to extmark range (see |api-indexing|).
@@ -402,12 +379,30 @@ end
 --- local extmark_range = range:to_extmark()
 --- ```
 ---@param range vim.Range
+---@return integer start_row, integer start_col, integer end_row, integer end_col
 function M.to_extmark(range)
   validate('range', range, 'table')
 
-  local srow, scol = vim.pos(range.buf, range[1], range[2]):to_extmark()
-  local erow, ecol = vim.pos(range.buf, range[3], range[4]):to_extmark()
-  return srow, scol, erow, ecol
+  local buf = range.buf
+  local start_row, start_col, end_row, end_col = range[1], range[2], range[3], range[4]
+  -- Consider a buffer like this:
+  -- ```
+  -- 0123456
+  -- abcdefg
+  -- ```
+  --
+  -- Two ways to describe the range of the first line, i.e. '0123456':
+  -- 1. `{ start_row = 0, start_col = 0, end_row = 0, end_col = 7 }`
+  -- 2. `{ start_row = 0, start_col = 0, end_row = 1, end_col = 0 }`
+  --
+  -- Both of the above methods satisfy the "end-exclusive" definition,
+  -- but `nvim_buf_set_extmark()` throws an out-of-bounds error for the second method,
+  -- so we need to convert it to the first method.
+  if end_col == 0 and end_row == api.nvim_buf_line_count(buf) then
+    end_row = end_row - 1
+    end_col = #util.get_line(buf, end_row)
+  end
+  return start_row, start_col, end_row, end_col
 end
 
 --- Creates a new |vim.Range| from extmark range (see |api-indexing|).
@@ -421,6 +416,7 @@ end
 ---@param start_col integer
 ---@param end_row integer
 ---@param end_col integer
+---@return vim.Range
 function M.extmark(buf, start_row, start_col, end_row, end_col)
   validate('buf', buf, 'number')
   validate('start_row', start_row, 'number')
@@ -432,56 +428,7 @@ function M.extmark(buf, start_row, start_col, end_row, end_col)
     buf = api.nvim_get_current_buf()
   end
 
-  local start = vim.pos.extmark(buf, start_row, start_col)
-  local end_ = vim.pos.extmark(buf, end_ro