From e2eb1dd1973677925edecdd91772d2e4ba4d5dc3 Mon Sep 17 00:00:00 2001
From: Julien Vincent <m@julienvincent.io>
Date: Sun, 10 Sep 2023 16:15:35 +0100
Subject: [PATCH 1/5] Add auto indentation correction on slurp/barf

---
 lua/nvim-paredit/api/barfing.lua        |  35 ++++-
 lua/nvim-paredit/api/slurping.lua       |  41 +++++-
 lua/nvim-paredit/config.lua             |   4 +-
 lua/nvim-paredit/defaults.lua           |   4 +
 lua/nvim-paredit/indentation/init.lua   |  27 ++++
 lua/nvim-paredit/indentation/native.lua | 136 +++++++++++++++++++
 lua/nvim-paredit/indentation/utils.lua  |  64 +++++++++
 lua/nvim-paredit/init.lua               |   4 +-
 lua/nvim-paredit/utils/common.lua       |  32 ++---
 tests/nvim-paredit/indentation_spec.lua | 169 ++++++++++++++++++++++++
 10 files changed, 483 insertions(+), 33 deletions(-)
 create mode 100644 lua/nvim-paredit/indentation/init.lua
 create mode 100644 lua/nvim-paredit/indentation/native.lua
 create mode 100644 lua/nvim-paredit/indentation/utils.lua
 create mode 100644 tests/nvim-paredit/indentation_spec.lua

diff --git a/lua/nvim-paredit/api/barfing.lua b/lua/nvim-paredit/api/barfing.lua
index 329987f..4d0c177 100644
--- a/lua/nvim-paredit/api/barfing.lua
+++ b/lua/nvim-paredit/api/barfing.lua
@@ -1,4 +1,5 @@
 local traversal = require("nvim-paredit.utils.traversal")
+local indentation = require("nvim-paredit.indentation")
 local common = require("nvim-paredit.utils.common")
 local ts = require("nvim-treesitter.ts_utils")
 local config = require("nvim-paredit.config")
@@ -28,11 +29,11 @@ function M.barf_forwards(opts)
   local child
   if opts.reversed then
     child = traversal.get_first_child_ignoring_comments(form, {
-      lang = lang
+      lang = lang,
     })
   else
     child = traversal.get_last_child_ignoring_comments(form, {
-      lang = lang
+      lang = lang,
     })
   end
   if not child then
@@ -42,7 +43,7 @@ function M.barf_forwards(opts)
   local edges = lang.get_form_edges(form)
 
   local sibling = traversal.get_prev_sibling_ignoring_comments(child, {
-    lang = lang
+    lang = lang,
   })
 
   local end_pos
@@ -55,6 +56,7 @@ function M.barf_forwards(opts)
   local buf = vim.api.nvim_get_current_buf()
 
   local range = edges.right.range
+  -- stylua: ignore
   vim.api.nvim_buf_set_text(
     buf,
     range[1], range[2],
@@ -63,6 +65,7 @@ function M.barf_forwards(opts)
   )
 
   local text = edges.right.text
+  -- stylua: ignore
   vim.api.nvim_buf_set_text(buf,
     end_pos[1], end_pos[2],
     end_pos[1], end_pos[2],
@@ -77,6 +80,16 @@ function M.barf_forwards(opts)
       vim.api.nvim_win_set_cursor(0, { end_pos[1] + 1, end_pos[2] })
     end
   end
+
+  local event = {
+    type = "barf-forwards",
+    -- stylua: ignore
+    parent_range = {
+      edges.left.range[1], edges.left.range[2],
+      end_pos[1], end_pos[2],
+    },
+  }
+  indentation.handle_indentation(event, opts)
 end
 
 function M.barf_backwards(opts)
@@ -99,7 +112,7 @@ function M.barf_backwards(opts)
   end
 
   local child = traversal.get_first_child_ignoring_comments(form, {
-    lang = lang
+    lang = lang,
   })
   if not child then
     return
@@ -108,7 +121,7 @@ function M.barf_backwards(opts)
   local edges = lang.get_form_edges(lang.get_node_root(form))
 
   local sibling = traversal.get_next_sibling_ignoring_comments(child, {
-    lang = lang
+    lang = lang,
   })
 
   local end_pos
@@ -121,6 +134,7 @@ function M.barf_backwards(opts)
   local buf = vim.api.nvim_get_current_buf()
 
   local text = edges.left.text
+  -- stylua: ignore
   vim.api.nvim_buf_set_text(buf,
     end_pos[1], end_pos[2],
     end_pos[1], end_pos[2],
@@ -128,6 +142,7 @@ function M.barf_backwards(opts)
   )
 
   local range = edges.left.range
+  -- stylua: ignore
   vim.api.nvim_buf_set_text(
     buf,
     range[1], range[2],
@@ -143,6 +158,16 @@ function M.barf_backwards(opts)
       vim.api.nvim_win_set_cursor(0, { end_pos[1] + 1, end_pos[2] })
     end
   end
+
+  local event = {
+    type = "barf-backwards",
+    -- stylua: ignore
+    parent_range = {
+      end_pos[1], end_pos[2],
+      edges.right.range[1], edges.right.range[2],
+    },
+  }
+  indentation.handle_indentation(event, opts)
 end
 
 return M
diff --git a/lua/nvim-paredit/api/slurping.lua b/lua/nvim-paredit/api/slurping.lua
index 47fb369..794072c 100644
--- a/lua/nvim-paredit/api/slurping.lua
+++ b/lua/nvim-paredit/api/slurping.lua
@@ -1,5 +1,5 @@
 local traversal = require("nvim-paredit.utils.traversal")
-local common = require("nvim-paredit.utils.common")
+local indentation = require("nvim-paredit.indentation")
 local ts = require("nvim-treesitter.ts_utils")
 local config = require("nvim-paredit.config")
 local langs = require("nvim-paredit.lang")
@@ -40,11 +40,12 @@ local function slurp(opts)
   end
 
   local buf = vim.api.nvim_get_current_buf()
+  local form_edges = lang.get_form_edges(form)
   local left_or_right_edge
   if opts.reversed then
-    left_or_right_edge = lang.get_form_edges(form).left
+    left_or_right_edge = form_edges.left
   else
-    left_or_right_edge = lang.get_form_edges(form).right
+    left_or_right_edge = form_edges.right
   end
 
   local start_or_end
@@ -57,6 +58,7 @@ local function slurp(opts)
   local row = start_or_end[1]
   local col = start_or_end[2]
 
+  -- stylua: ignore
   vim.api.nvim_buf_set_text(buf,
     row, col,
     row, col,
@@ -65,9 +67,10 @@ local function slurp(opts)
 
   local offset = 0
   if opts.reversed and row == left_or_right_edge.range[1] then
-    offset = string.len(left_or_right_edge.text)
+    offset = #left_or_right_edge.text
   end
 
+  -- stylua: ignore
   vim.api.nvim_buf_set_text(
     buf,
     left_or_right_edge.range[1], left_or_right_edge.range[2] + offset,
@@ -77,7 +80,7 @@ local function slurp(opts)
 
   local cursor_behaviour = opts.cursor_behaviour or config.config.cursor_behaviour
   if cursor_behaviour == "follow" then
-    local offset = 0
+    offset = 0
     if not opts.reversed then
       offset = string.len(left_or_right_edge.text)
     end
@@ -88,6 +91,30 @@ local function slurp(opts)
       vim.api.nvim_win_set_cursor(0, cursor_pos)
     end
   end
+
+  local operation_type
+  local new_range
+  if not opts.reversed then
+    operation_type = "slurp-forwards"
+    -- stylua: ignore
+    new_range = {
+      form_edges.left.range[1], form_edges.left.range[2],
+      row, col,
+    }
+  else
+    operation_type = "slurp-backwards"
+    -- stylua: ignore
+    new_range = {
+      row, col,
+      form_edges.right.range[1], form_edges.right.range[2],
+    }
+  end
+
+  local event = {
+    type = operation_type,
+    parent_range = new_range,
+  }
+  indentation.handle_indentation(event, opts)
 end
 
 function M.slurp_forwards(opts)
@@ -95,8 +122,8 @@ function M.slurp_forwards(opts)
 end
 
 function M.slurp_backwards(opts)
-  slurp(common.merge(opts or {}, {
-    reversed = true
+  slurp(vim.tbl_deep_extend("force", opts or {}, {
+    reversed = true,
   }))
 end
 
diff --git a/lua/nvim-paredit/config.lua b/lua/nvim-paredit/config.lua
index 1f43cb2..c09f05a 100644
--- a/lua/nvim-paredit/config.lua
+++ b/lua/nvim-paredit/config.lua
@@ -1,11 +1,9 @@
-local common = require("nvim-paredit.utils.common")
-
 local M = {}
 
 M.config = {}
 
 function M.update_config(config)
-  M.config = common.merge(M.config, config)
+  M.config = vim.tbl_deep_extend("force", M.config, config)
 end
 
 return M
diff --git a/lua/nvim-paredit/defaults.lua b/lua/nvim-paredit/defaults.lua
index 2e40bf6..9796505 100644
--- a/lua/nvim-paredit/defaults.lua
+++ b/lua/nvim-paredit/defaults.lua
@@ -61,6 +61,10 @@ M.default_keys = {
 M.defaults = {
   use_default_keys = true,
   cursor_behaviour = "auto", -- remain, follow, auto
+  indent = {
+    enabled = true,
+    indentor = require("nvim-paredit.indentation.native").indentor,
+  },
   keys = {},
 }
 
diff --git a/lua/nvim-paredit/indentation/init.lua b/lua/nvim-paredit/indentation/init.lua
new file mode 100644
index 0000000..881bb79
--- /dev/null
+++ b/lua/nvim-paredit/indentation/init.lua
@@ -0,0 +1,27 @@
+local config = require("nvim-paredit.config")
+
+local M = {}
+
+function M.handle_indentation(event, opts)
+  local indent = opts.indent or config.config.indent or {}
+  if not indent.enabled or not indent.indentor then
+    return
+  end
+
+  local tree = vim.treesitter.get_parser(0)
+
+  tree:parse()
+  local parent = tree:named_node_for_range(event.parent_range)
+
+  indent.indentor(
+    vim.tbl_deep_extend("force", event, {
+      tree = tree,
+      parent = parent,
+    }),
+    vim.tbl_deep_extend("force", opts, {
+      indent = indent,
+    })
+  )
+end
+
+return M
diff --git a/lua/nvim-paredit/indentation/native.lua b/lua/nvim-paredit/indentation/native.lua
new file mode 100644
index 0000000..f47da35
--- /dev/null
+++ b/lua/nvim-paredit/indentation/native.lua
@@ -0,0 +1,136 @@
+local traversal = require("nvim-paredit.utils.traversal")
+local utils = require("nvim-paredit.indentation.utils")
+local langs = require("nvim-paredit.lang")
+
+local M = {}
+
+local function dedent_lines(lines, delta, opts)
+  -- stylua: ignore
+  local line_text = vim.api.nvim_buf_get_lines(
+    opts.buf or 0,
+    lines[1], lines[#lines] + 1,
+    false
+  )
+
+  local smallest_distance = delta
+  for _, line in ipairs(line_text) do
+    local first_char_index = string.find(line, "[^%s]")
+    if first_char_index and (first_char_index - 1) < smallest_distance then
+      smallest_distance = first_char_index - 1
+    end
+  end
+
+  for index, line in ipairs(lines) do
+    local deletion_range = smallest_distance
+    local contains_chars = string.find(line_text[index], "[^%s]")
+    if not contains_chars then
+      deletion_range = #line_text[index]
+    end
+    -- stylua: ignore
+    vim.api.nvim_buf_set_text(
+      opts.buf or 0,
+      line, 0,
+      line, deletion_range,
+      {}
+    )
+  end
+end
+
+local function indent_lines(lines, delta, opts)
+  if delta == 0 then
+    return
+  end
+
+  if delta < 0 then
+    return dedent_lines(lines, delta * -1, opts)
+  end
+
+  local chars = string.rep(" ", delta)
+  for _, line in ipairs(lines) do
+    -- stylua: ignore
+    vim.api.nvim_buf_set_text(
+      opts.buf or 0,
+      line, 0,
+      line, 0,
+      {chars}
+    )
+  end
+end
+
+local function indent_barf(event)
+  local lang = langs.get_language_api()
+
+  local lhs
+  local node
+  if event.type == "barf-forwards" then
+    node = traversal.get_next_sibling_ignoring_comments(event.parent, { lang = lang })
+    lhs = event.parent
+  else
+    node = event.parent
+    lhs = traversal.get_prev_sibling_ignoring_comments(event.parent, { lang = lang })
+  end
+
+  if not node or not lhs then
+    return
+  end
+
+  local parent = node:parent()
+
+  local lhs_range = { lhs:range() }
+  local node_range = { node:range() }
+
+  if not utils.node_is_first_on_line(node, { lang = lang }) or lhs_range[1] == node_range[1] then
+    return
+  end
+
+  local lines = utils.find_affected_lines(node, utils.get_node_line_range(node_range))
+
+  local delta
+  if parent:type() == "source" then
+    delta = node_range[2]
+  else
+    local form_edges = lang.get_form_edges(parent)
+    delta = node_range[2] - form_edges.left.range[2] - 1
+  end
+
+  indent_lines(lines, delta * -1, {
+    buf = event.buf,
+  })
+end
+
+local function indent_slurp(event)
+  local parent = event.parent
+  local lang = langs.get_language_api()
+
+  local child
+  if event.type == "slurp-forwards" then
+    child = parent:named_child(parent:named_child_count() - 1)
+  else
+    child = parent:named_child(1)
+  end
+
+  local parent_range = { parent:range() }
+  local child_range = { child:range() }
+
+  if not utils.node_is_first_on_line(child, { lang = lang }) or parent_range[1] == child_range[1] then
+    return
+  end
+
+  local lines = utils.find_affected_lines(child, utils.get_node_line_range(child_range))
+  local form_edges = lang.get_form_edges(parent)
+
+  local delta = form_edges.left.range[4] - child_range[2]
+  indent_lines(lines, delta, {
+    buf = event.buf,
+  })
+end
+
+function M.indentor(event, _)
+  if event.type == "slurp-forwards" or event.type == "slurp-backwards" then
+    indent_slurp(event)
+  else
+    indent_barf(event)
+  end
+end
+
+return M
diff --git a/lua/nvim-paredit/indentation/utils.lua b/lua/nvim-paredit/indentation/utils.lua
new file mode 100644
index 0000000..0afb09c
--- /dev/null
+++ b/lua/nvim-paredit/indentation/utils.lua
@@ -0,0 +1,64 @@
+local traversal = require("nvim-paredit.utils.traversal")
+local common = require("nvim-paredit.utils.common")
+
+local M = {}
+
+function M.get_node_line_range(range)
+  local lines = {}
+  for i = range[1], range[3], 1 do
+    table.insert(lines, i)
+  end
+  return lines
+end
+
+function M.get_node_rhs_siblings(node)
+  local nodes = {}
+  local current = node
+  while current do
+    table.insert(nodes, current)
+    current = current:next_named_sibling()
+  end
+  return nodes
+end
+
+function M.find_affected_lines(node, lines)
+  local siblings = M.get_node_rhs_siblings(node)
+  for _, sibling in ipairs(siblings) do
+    local range = { sibling:range() }
+
+    local sibling_is_affected = false
+    for _, line in ipairs(lines) do
+      if line == range[1] then
+        sibling_is_affected = true
+      end
+    end
+
+    if sibling_is_affected then
+      local new_lines = M.get_node_line_range(range)
+      for _, row in ipairs(new_lines) do
+        table.insert(lines, row)
+      end
+    end
+  end
+
+  local parent = node:parent()
+  if parent then
+    return M.find_affected_lines(parent, lines)
+  end
+
+  return common.ordered_set(lines)
+end
+
+function M.node_is_first_on_line(node, opts)
+  local node_range = { node:range() }
+
+  local sibling = traversal.get_prev_sibling_ignoring_comments(node, opts)
+  if not sibling then
+    return true
+  end
+
+  local sibling_range = { sibling:range() }
+  return sibling_range[3] ~= node_range[1]
+end
+
+return M
diff --git a/lua/nvim-paredit/init.lua b/lua/nvim-paredit/init.lua
index 6b691b8..64b0895 100644
--- a/lua/nvim-paredit/init.lua
+++ b/lua/nvim-paredit/init.lua
@@ -49,11 +49,11 @@ function M.setup(opts)
   local keys = opts.keys or {}
 
   if type(opts.use_default_keys) ~= "boolean" or opts.use_default_keys then
-    keys = common.merge(defaults.default_keys, opts.keys or {})
+    keys = vim.tbl_deep_extend("force", defaults.default_keys, opts.keys or {})
   end
 
   config.update_config(defaults.defaults)
-  config.update_config(common.merge(opts, {
+  config.update_config(vim.tbl_deep_extend("force", opts, {
     keys = keys,
   }))
 
diff --git a/lua/nvim-paredit/utils/common.lua b/lua/nvim-paredit/utils/common.lua
index ea297e3..c4c7fbd 100644
--- a/lua/nvim-paredit/utils/common.lua
+++ b/lua/nvim-paredit/utils/common.lua
@@ -9,17 +9,6 @@ function M.included_in_table(table, item)
   return false
 end
 
-function M.merge(a, b)
-  local result = {}
-  for k, v in pairs(a) do
-    result[k] = v
-  end
-  for k, v in pairs(b) do
-    result[k] = v
-  end
-  return result
-end
-
 -- Compares the two given { col, row } position tuples and returns -1/0/1 depending
 -- on whether `a` is less than, equal to or greater than `b`
 --
@@ -59,6 +48,20 @@ function M.intersection(tbl, original)
   return result
 end
 
+function M.ordered_set(lines)
+  local seen = {}
+  local result = {}
+  for _, value in ipairs(lines) do
+    if not seen[value] then
+      table.insert(result, value)
+      seen[value] = true
+    end
+  end
+
+  table.sort(result)
+  return result
+end
+
 function M.ensure_visual_mode()
   if vim.api.nvim_get_mode().mode ~= "v" then
     vim.api.nvim_command("normal! v")
@@ -72,11 +75,8 @@ function M.is_whitespace_under_cursor(lang)
   cursor = { cursor[1] - 1, cursor[2] }
 
   local char_under_cursor = vim.api.nvim_buf_get_text(0, cursor[1], cursor[2], cursor[1], cursor[2] + 1, {})
-  return M.included_in_table(
-    lang.whitespace_chars or M.default_whitespace_chars,
-    char_under_cursor[1]
-  ) or char_under_cursor[1] == ""
+  return M.included_in_table(lang.whitespace_chars or M.default_whitespace_chars, char_under_cursor[1])
+    or char_under_cursor[1] == ""
 end
 
 return M
-
diff --git a/tests/nvim-paredit/indentation_spec.lua b/tests/nvim-paredit/indentation_spec.lua
new file mode 100644
index 0000000..674ab6f
--- /dev/null
+++ b/tests/nvim-paredit/indentation_spec.lua
@@ -0,0 +1,169 @@
+local defaults = require("nvim-paredit.defaults")
+local paredit = require("nvim-paredit.api")
+
+local expect_all = require("tests.nvim-paredit.utils").expect_all
+
+local opts = vim.tbl_deep_extend("force", defaults.defaults, {
+  indent = {
+    enabled = true,
+  },
+})
+
+describe("forward slurping indentation", function()
+  vim.api.nvim_buf_set_option(0, "filetype", "clojure")
+  local function slurp_forwards()
+    paredit.slurp_forwards(opts)
+  end
+
+  expect_all(slurp_forwards, {
+    {
+      "should indent a nested child",
+      before_content = { "()", "a" },
+      before_cursor = { 1, 1 },
+      after_content = { "(", " a)" },
+      after_cursor = { 1, 0 },
+    },
+    {
+      "should indent a multi-line child",
+      before_content = { "()", "(a", " b c)" },
+      before_cursor = { 1, 1 },
+      after_content = { "(", " (a", "  b c))" },
+      after_cursor = { 1, 0 },
+    },
+    {
+      "should indent a multi-line child that pushes other nodes",
+      before_content = { "()", "(a", " b) (c", "d) (e", "f)" },
+      before_cursor = { 1, 1 },
+      after_content = { "(", " (a", "  b)) (c", " d) (e", " f)" },
+      after_cursor = { 1, 0 },
+    },
+    {
+      "should not indent if node is not first on line",
+      before_content = { "(", "a) (a", "b)" },
+      before_cursor = { 1, 1 },
+      after_content = { "(", "a (a", "b))" },
+      after_cursor = { 1, 0 },
+    },
+    {
+      "should not indent when on same line",
+      before_content = "() 1",
+      before_cursor = { 1, 1 },
+      after_content = "( 1)",
+      after_cursor = { 1, 1 },
+    },
+    {
+      "should dedent when node is too far indented",
+      before_content = { "()", "  a" },
+      before_cursor = { 1, 1 },
+      after_content = { "(", " a)" },
+      after_cursor = { 1, 0 },
+    },
+    {
+      "should dedent without deleting characters",
+      before_content = { "()", "   (a", " b)" },
+      before_cursor = { 1, 1 },
+      after_content = { "(", "  (a", "b))" },
+      after_cursor = { 1, 0 },
+    },
+    {
+      "should indent the correct node ignoring comments",
+      before_content = { "()", ";; comment", "a" },
+      before_cursor = { 1, 1 },
+      after_content = { "(", ";; comment", " a)" },
+      after_cursor = { 1, 0 },
+    },
+  })
+end)
+
+describe("backward slurping indentation", function()
+  vim.api.nvim_buf_set_option(0, "filetype", "clojure")
+  local function slurp_backwards()
+    paredit.slurp_backwards(opts)
+  end
+
+  expect_all(slurp_backwards, {
+    {
+      "should indent a nested child",
+      before_content = { "a", "(b)" },
+      before_cursor = { 2, 1 },
+      after_content = { "(a", " b)" },
+      after_cursor = { 2, 2 },
+    },
+    {
+      "should not indent when on same line",
+      before_content = { "a (b)" },
+      before_cursor = { 1, 3 },
+      after_content = { "(a b)" },
+      after_cursor = { 1, 3 },
+    },
+  })
+end)
+
+describe("forward barfing indentation", function()
+  vim.api.nvim_buf_set_option(0, "filetype", "clojure")
+  local function barf_forwards()
+    paredit.barf_forwards(opts)
+  end
+
+  expect_all(barf_forwards, {
+    {
+      "should dedent the barfed child",
+      before_content = { "(", " a)" },
+      before_cursor = { 1, 0 },
+      after_content = { "()", "a" },
+      after_cursor = { 1, 0 },
+    },
+    {
+      "should dedent a multi-line child and affected siblings",
+      before_content = { "(", " (a", "  b c)) (a", " d)" },
+      before_cursor = { 1, 0 },
+      after_content = { "()", "(a", " b c) (a", "d)" },
+      after_cursor = { 1, 0 },
+    },
+    {
+      "should not dedent if node is on the same line",
+      before_content = { "(a", "b c)" },
+      before_cursor = { 1, 1 },
+      after_content = { "(a", "b) c" },
+      after_cursor = { 1, 1 },
+    },
+    {
+      "should not dedent when there is no indentation",
+      before_content = { "(", "a)" },
+      before_cursor = { 1, 0 },
+      after_content = { "()", "a" },
+      after_cursor = { 1, 0 },
+    },
+    {
+      "should dedent the minimum amount without deleting chars",
+      before_content = { "(", "  a) (b", " c)" },
+      before_cursor = { 1, 0 },
+      after_content = { "()", " a (b", "c)" },
+      after_cursor = { 1, 0 },
+    },
+    {
+      "should dedent the correct node ignoring comments",
+      before_content = { "(", ";; comment", " a)" },
+      before_cursor = { 1, 1 },
+      after_content = { "()", ";; comment", "a" },
+      after_cursor = { 1, 0 },
+    },
+  })
+end)
+
+describe("backward barfing indentation", function()
+  vim.api.nvim_buf_set_option(0, "filetype", "clojure")
+  local function barf_backwards()
+    paredit.barf_backwards(opts)
+  end
+
+  expect_all(barf_backwards, {
+    {
+      "should dedent a nested child",
+      before_content = { "(a", " b)" },
+      before_cursor = { 1, 0 },
+      after_content = { "a", "(b)" },
+      after_cursor = { 2, 1 },
+    },
+  })
+end)

From 603dc8a2dda6ab0cfde875b247a969bde6d17732 Mon Sep 17 00:00:00 2001
From: Julien Vincent <m@julienvincent.io>
Date: Sun, 10 Sep 2023 12:25:38 +0100
Subject: [PATCH 2/5] Save and restore cursor pos after indentation fix

---
 lua/nvim-paredit/indentation/native.lua | 30 ++++++++++++++++---------
 tests/nvim-paredit/indentation_spec.lua |  9 +++++++-
 2 files changed, 28 insertions(+), 11 deletions(-)

diff --git a/lua/nvim-paredit/indentation/native.lua b/lua/nvim-paredit/indentation/native.lua
index f47da35..83e2dc8 100644
--- a/lua/nvim-paredit/indentation/native.lua
+++ b/lua/nvim-paredit/indentation/native.lua
@@ -1,5 +1,6 @@
 local traversal = require("nvim-paredit.utils.traversal")
 local utils = require("nvim-paredit.indentation.utils")
+local common = require("nvim-paredit.utils.common")
 local langs = require("nvim-paredit.lang")
 
 local M = {}
@@ -34,6 +35,8 @@ local function dedent_lines(lines, delta, opts)
       {}
     )
   end
+
+  return smallest_distance
 end
 
 local function indent_lines(lines, delta, opts)
@@ -41,19 +44,26 @@ local function indent_lines(lines, delta, opts)
     return
   end
 
+  local cursor_pos = vim.api.nvim_win_get_cursor(opts.buf or 0)
+  local cursor_delta = delta
+
   if delta < 0 then
-    return dedent_lines(lines, delta * -1, opts)
+    cursor_delta = dedent_lines(lines, delta * -1, opts) * -1
+  else
+    local chars = string.rep(" ", delta)
+    for _, line in ipairs(lines) do
+      -- stylua: ignore
+      vim.api.nvim_buf_set_text(
+        opts.buf or 0,
+        line, 0,
+        line, 0,
+        {chars}
+      )
+    end
   end
 
-  local chars = string.rep(" ", delta)
-  for _, line in ipairs(lines) do
-    -- stylua: ignore
-    vim.api.nvim_buf_set_text(
-      opts.buf or 0,
-      line, 0,
-      line, 0,
-      {chars}
-    )
+  if common.included_in_table(lines, cursor_pos[1] - 1) then
+    vim.api.nvim_win_set_cursor(opts.buf or 0, { cursor_pos[1], cursor_pos[2] + cursor_delta })
   end
 end
 
diff --git a/tests/nvim-paredit/indentation_spec.lua b/tests/nvim-paredit/indentation_spec.lua
index 674ab6f..aad9b9e 100644
--- a/tests/nvim-paredit/indentation_spec.lua
+++ b/tests/nvim-paredit/indentation_spec.lua
@@ -163,7 +163,14 @@ describe("backward barfing indentation", function()
       before_content = { "(a", " b)" },
       before_cursor = { 1, 0 },
       after_content = { "a", "(b)" },
-      after_cursor = { 2, 1 },
+      after_cursor = { 2, 0 },
+    },
+    {
+      "should keep the cursor in the same place",
+      before_content = { "((a", "  bc", "  de))" },
+      before_cursor = { 2, 3 },
+      after_content = { "(a", " (bc", " de))" },
+      after_cursor = { 2, 3 },
     },
   })
 end)

From 1f7b0924acd5e482a4c9c6222cceb0ad66876c79 Mon Sep 17 00:00:00 2001
From: Julien Vincent <m@julienvincent.io>
Date: Sun, 10 Sep 2023 13:02:39 +0100
Subject: [PATCH 3/5] Use lhs sibling as indentation ref point

---
 lua/nvim-paredit/indentation/native.lua | 26 +++++++++++++++++----
 lua/nvim-paredit/indentation/utils.lua  | 31 +++++++++++++++++++++++++
 tests/nvim-paredit/indentation_spec.lua | 24 +++++++++++++++++++
 3 files changed, 77 insertions(+), 4 deletions(-)

diff --git a/lua/nvim-paredit/indentation/native.lua b/lua/nvim-paredit/indentation/native.lua
index 83e2dc8..53fd815 100644
--- a/lua/nvim-paredit/indentation/native.lua
+++ b/lua/nvim-paredit/indentation/native.lua
@@ -99,8 +99,17 @@ local function indent_barf(event)
   if parent:type() == "source" then
     delta = node_range[2]
   else
-    local form_edges = lang.get_form_edges(parent)
-    delta = node_range[2] - form_edges.left.range[2] - 1
+    local row
+    local ref_node = utils.get_first_sibling_on_upper_line(node, { lang = lang })
+    if ref_node then
+      local range = { ref_node:range() }
+      row = range[2]
+    else
+      local form_edges = lang.get_form_edges(parent)
+      row = form_edges.left.range[2] - 1
+    end
+
+    delta = node_range[2] - row
   end
 
   indent_lines(lines, delta * -1, {
@@ -127,9 +136,18 @@ local function indent_slurp(event)
   end
 
   local lines = utils.find_affected_lines(child, utils.get_node_line_range(child_range))
-  local form_edges = lang.get_form_edges(parent)
 
-  local delta = form_edges.left.range[4] - child_range[2]
+  local row
+  local ref_node = utils.get_first_sibling_on_upper_line(child, { lang = lang })
+  if ref_node then
+    local range = { ref_node:range() }
+    row = range[2]
+  else
+    local form_edges = lang.get_form_edges(parent)
+    row = form_edges.left.range[4]
+  end
+
+  local delta = row - child_range[2]
   indent_lines(lines, delta, {
     buf = event.buf,
   })
diff --git a/lua/nvim-paredit/indentation/utils.lua b/lua/nvim-paredit/indentation/utils.lua
index 0afb09c..1c83cc9 100644
--- a/lua/nvim-paredit/indentation/utils.lua
+++ b/lua/nvim-paredit/indentation/utils.lua
@@ -61,4 +61,35 @@ function M.node_is_first_on_line(node, opts)
   return sibling_range[3] ~= node_range[1]
 end
 
+-- This functions finds the closest sibling to a given `node` which is:
+-- 1) Not on the same line (one line higher)
+-- 2) Is the first node on the line
+--
+-- This node can be used as an indentation reference point.
+function M.get_first_sibling_on_upper_line(node, opts)
+  local node_range = { node:range() }
+
+  local reference
+  local prev = node
+
+  while prev do
+    prev = traversal.get_prev_sibling_ignoring_comments(prev, opts)
+    if not prev then
+      return reference
+    end
+
+    local sibling_range = { prev:range() }
+
+    if reference and reference:range() ~= sibling_range[1] then
+      return reference
+    end
+
+    if sibling_range[1] ~= node_range[1] then
+      reference = prev
+    end
+  end
+
+  return reference
+end
+
 return M
diff --git a/tests/nvim-paredit/indentation_spec.lua b/tests/nvim-paredit/indentation_spec.lua
index aad9b9e..33fb180 100644
--- a/tests/nvim-paredit/indentation_spec.lua
+++ b/tests/nvim-paredit/indentation_spec.lua
@@ -72,6 +72,14 @@ describe("forward slurping indentation", function()
       after_content = { "(", ";; comment", " a)" },
       after_cursor = { 1, 0 },
     },
+
+    {
+      "should indent to the first relevant siblings indentation",
+      before_content = { "(def a []", "  target sibling)", "child" },
+      before_cursor = { 1, 1 },
+      after_content = { "(def a []", "  target sibling", "  child)" },
+      after_cursor = { 1, 1 },
+    },
   })
 end)
 
@@ -148,6 +156,14 @@ describe("forward barfing indentation", function()
       after_content = { "()", ";; comment", "a" },
       after_cursor = { 1, 0 },
     },
+
+    {
+      "should indent to the first relevant siblings indentation",
+      before_content = { "(def a []", "  target (sibling", "          child))" },
+      before_cursor = { 2, 10 },
+      after_content = { "(def a []", "  target (sibling)", "  child)" },
+      after_cursor = { 2, 10 },
+    },
   })
 end)
 
@@ -172,5 +188,13 @@ describe("backward barfing indentation", function()
       after_content = { "(a", " (bc", " de))" },
       after_cursor = { 2, 3 },
     },
+
+    {
+      "should indent to the first relevant siblings indentation",
+      before_content = { "(def a []", "  target (sibling", "          child))" },
+      before_cursor = { 3, 1 },
+      after_content = { "(def a []", "  target sibling", "  (child))" },
+      after_cursor = { 3, 2 },
+    },
   })
 end)

From f1169317335b967dffc889c04701325e941e87a3 Mon Sep 17 00:00:00 2001
From: Julien Vincent <m@julienvincent.io>
Date: Mon, 11 Sep 2023 14:25:40 +0100
Subject: [PATCH 4/5] Ensure indentation works on wrapped parents

---
 lua/nvim-paredit/indentation/native.lua | 12 +++++++-----
 tests/nvim-paredit/indentation_spec.lua | 14 ++++++++++++++
 2 files changed, 21 insertions(+), 5 deletions(-)

diff --git a/lua/nvim-paredit/indentation/native.lua b/lua/nvim-paredit/indentation/native.lua
index 53fd815..2aaec7b 100644
--- a/lua/nvim-paredit/indentation/native.lua
+++ b/lua/nvim-paredit/indentation/native.lua
@@ -70,14 +70,16 @@ end
 local function indent_barf(event)
   local lang = langs.get_language_api()
 
+  local form = lang.get_node_root(event.parent)
+
   local lhs
   local node
   if event.type == "barf-forwards" then
-    node = traversal.get_next_sibling_ignoring_comments(event.parent, { lang = lang })
-    lhs = event.parent
+    node = traversal.get_next_sibling_ignoring_comments(form, { lang = lang })
+    lhs = form
   else
-    node = event.parent
-    lhs = traversal.get_prev_sibling_ignoring_comments(event.parent, { lang = lang })
+    node = form
+    lhs = traversal.get_prev_sibling_ignoring_comments(form, { lang = lang })
   end
 
   if not node or not lhs then
@@ -118,8 +120,8 @@ local function indent_barf(event)
 end
 
 local function indent_slurp(event)
-  local parent = event.parent
   local lang = langs.get_language_api()
+  local parent = lang.unwrap_form(event.parent)
 
   local child
   if event.type == "slurp-forwards" then
diff --git a/tests/nvim-paredit/indentation_spec.lua b/tests/nvim-paredit/indentation_spec.lua
index 33fb180..53ab897 100644
--- a/tests/nvim-paredit/indentation_spec.lua
+++ b/tests/nvim-paredit/indentation_spec.lua
@@ -23,6 +23,13 @@ describe("forward slurping indentation", function()
       after_content = { "(", " a)" },
       after_cursor = { 1, 0 },
     },
+    {
+      "should indent a nested child from a wrapped parent",
+      before_content = { "@()", "a" },
+      before_cursor = { 1, 2 },
+      after_content = { "@(", "  a)" },
+      after_cursor = { 1, 1 },
+    },
     {
       "should indent a multi-line child",
       before_content = { "()", "(a", " b c)" },
@@ -121,6 +128,13 @@ describe("forward barfing indentation", function()
       after_content = { "()", "a" },
       after_cursor = { 1, 0 },
     },
+    {
+      "should dedent the barfed child from a wrapped parent",
+      before_content = { "@(", "  a)" },
+      before_cursor = { 1, 1 },
+      after_content = { "@()", "a" },
+      after_cursor = { 1, 1 },
+    },
     {
       "should dedent a multi-line child and affected siblings",
       before_content = { "(", " (a", "  b c)) (a", " d)" },

From f40b42c21edd5790ce7642bd887c6af5f3530769 Mon Sep 17 00:00:00 2001
From: Julien Vincent <m@julienvincent.io>
Date: Sun, 10 Sep 2023 16:15:44 +0100
Subject: [PATCH 5/5] Add README section on auto-indentation

---
 README.md                     | 80 +++++++++++++++++++++++++++++++++++
 lua/nvim-paredit/defaults.lua |  2 +-
 2 files changed, 81 insertions(+), 1 deletion(-)

diff --git a/README.md b/README.md
index 926c5a4..c7cd957 100644
--- a/README.md
+++ b/README.md
@@ -51,7 +51,27 @@ require("nvim-paredit").setup({
   -- defaults to all supported file types including custom lang
   -- extensions (see next section)
   filetypes = { "clojure" },
+
+  -- This controls where the cursor is placed when performing slurp/barf operations
+  --
+  -- - "remain" - It will never change the cursor position, keeping it in the same place
+  -- - "follow" - It will always place the cursor on the form edge that was moved
+  -- - "auto"   - A combination of remain and follow, it will try keep the cursor in the original position
+  --              unless doing so would result in the cursor no longer being within the original form. In
+  --              this case it will place the cursor on the moved edge
   cursor_behaviour = "auto", -- remain, follow, auto
+
+  indent = {
+    -- This controls how nvim-paredit handles indentation when performing operations which
+    -- should change the indentation of the form (such as when slurping or barfing).
+    --
+    -- When set to true then it will attempt to fix the indentation of nodes operated on.
+    enabled = false,
+    -- A function that will be called after a slurp/barf if you want to provide a custom indentation
+    -- implementation.
+    indentor = require("nvim-paredit.indentation.native").indentor,
+  },
+
   -- list of default keybindings
   keys = {
     [">)"] = { paredit.api.slurp_forwards, "Slurp forwards" },
@@ -112,6 +132,65 @@ require("nvim-paredit").setup({
 })
 ```
 
+## Auto Indentation
+
+Nvim-paredit comes with built-in support for fixing form indentation when performing slurp and barf operations. By default this behaviour is disabled and can be enabled by setting `indent.enabled = true` in the [configuration](#configuration)
+
+The main goal of this implementation is to provide a visual aid to the user, allowing them to confirm they are operating on the correct node and to know when to stop when performing recursive slurp/barf operations. This implementation is fast and does not result in any UI lag or jitter.
+
+The goal is _not_ to be 100% correct. The implementation follows a simple set of rules which account for most scenarios but not all. If a more correct implementation is needed then the native implementation can be replaced by setting the configuration property `intent.indentor`. For example an implementation using `vim.lsp.buf.format` could be built if the user doesn't mind sacrificing performance for correctness.
+
+### Recipes
+
+<details>
+  <summary><code>vim.lsp.buf.format</code></summary>
+
+  Below is a reference implementation for using `vim.lsp.buf.format` to replace the native implementation. This implementation won't be nearly as performant but it will be more correct.
+
+  ```lua
+  local function lsp_indent(event, opts)
+    local traversal = require("nvim-paredit.utils.traversal")
+    local utils = require("nvim-paredit.indentation.utils")
+    local langs = require("nvim-paredit.lang")
+
+    local lang = langs.get_language_api()
+
+    local parent = event.parent
+
+    local child
+    if event.type == "slurp-forwards" then
+      child = parent:named_child(parent:named_child_count() - 1)
+    elseif event.type == "slurp-backwards" then
+      child = parent:named_child(1)
+    elseif event.type == "barf-forwards" then
+      child = traversal.get_next_sibling_ignoring_comments(event.parent, { lang = lang })
+    elseif event.type == "barf-backwards" then
+      child = event.parent
+    else
+      return
+    end
+
+    local child_range = { child:range() }
+    local lines = utils.find_affected_lines(child, utils.get_node_line_range(child_range))
+
+    vim.lsp.buf.format({
+      bufnr = opts.buf or 0,
+      range = {
+        ["start"] = { lines[1] + 1, 0 },
+        ["end"] = { lines[#lines] + 1, 0 },
+      },
+    })
+  end
+
+  require("nvim-paredit").setup({
+    indent = {
+      enabled = true,
+      indentor = lsp_indent
+    }
+  })
+  ```
+</details>
+
 ## Language Support
 
 As this is built using Treesitter it requires that you have the relevant Treesitter grammar installed for your language of choice. Additionally `nvim-paredit` will need explicit support for the treesitter grammar as the node names and metadata of nodes vary between languages.
@@ -270,6 +349,7 @@ The main reasons you might want to consider `nvim-paredit` instead are:
 - Easier configuration and an exposed lua API
 - Control over how the cursor is moved during slurp/barf. (For example if you don't want the cursor to always be moved)
 - Recursive slurp/barf operations. If your cursor is in a nested form you can still slurp from the forms parent(s)
+- Automatic form/element indentations on slurp/barf
 - Subjectively better out-of-the-box keybindings
 
 ### [vim-sexp-mappings-for-regular-people](https://github.com/tpope/vim-sexp-mappings-for-regular-people)
diff --git a/lua/nvim-paredit/defaults.lua b/lua/nvim-paredit/defaults.lua
index 9796505..1a5e4ae 100644
--- a/lua/nvim-paredit/defaults.lua
+++ b/lua/nvim-paredit/defaults.lua
@@ -62,7 +62,7 @@ M.defaults = {
   use_default_keys = true,
   cursor_behaviour = "auto", -- remain, follow, auto
   indent = {
-    enabled = true,
+    enabled = false,
     indentor = require("nvim-paredit.indentation.native").indentor,
   },
   keys = {},