From ce62b9c8dacd10d59e6eaf38fd72a46701d81192 Mon Sep 17 00:00:00 2001
From: George Sokianos <George.Sokianos@hostelworld.com>
Date: Fri, 7 Jan 2022 11:00:50 +0000
Subject: [PATCH] Applied PR255 changes

---
 data/core/commands/doc.lua | 349 ++++++++++++++++++++-----------------
 data/core/common.lua       |  20 +++
 data/core/doc/init.lua     | 250 +++++++++++++++++---------
 data/core/docview.lua      |  72 +++++---
 data/core/keymap-macos.lua |   2 +
 data/core/keymap.lua       |   2 +
 6 files changed, 426 insertions(+), 269 deletions(-)

diff --git a/data/core/commands/doc.lua b/data/core/commands/doc.lua
index 8165b426..25dd3fa2 100755
--- a/data/core/commands/doc.lua
+++ b/data/core/commands/doc.lua
@@ -24,13 +24,16 @@ local function get_indent_string()
 end
 
 
-local function doc_multiline_selection(sort)
-  local line1, col1, line2, col2, swap = doc():get_selection(sort)
-  if line2 > line1 and col2 == 1 then
-    line2 = line2 - 1
-    col2 = #doc().lines[line2]
+local function doc_multiline_selections(sort)
+  local iter, state, idx, line1, col1, line2, col2 = doc():get_selections(sort)
+  return function() 
+    idx, line1, col1, line2, col2 = iter(state, idx)
+    if idx and line2 > line1 and col2 == 1 then
+      line2 = line2 - 1
+      col2 = #doc().lines[line2]
+    end
+    return idx, line1, col1, line2, col2
   end
-  return line1, col1, line2, col2, swap
 end
 
 local function append_line_if_last_line(line)
@@ -39,7 +42,6 @@ local function append_line_if_last_line(line)
   end
 end
 
-
 local function save(filename)
   doc():save(filename and core.normalize_to_project_dir(filename))
   local saved_filename = doc().filename
@@ -47,55 +49,31 @@ local function save(filename)
   core.log("Saved \"%s\"", saved_filename)
 end
 
--- returns the size of the original indent, and the indent
--- in your config format, rounded either up or down
-local function get_line_indent(line, rnd_up)
-  local _, e = line:find("^[ \t]+")
-  local soft_tab = string.rep(" ", config.indent_size)
-  if config.tab_type == "hard" then
-    local indent = e and line:sub(1, e):gsub(soft_tab, "\t") or ""
-    return e, indent:gsub(" +", rnd_up and "\t" or "")
-  else
-    local indent = e and line:sub(1, e):gsub("\t", soft_tab) or ""
-    local number = #indent / #soft_tab
-    return e, indent:sub(1,
-      (rnd_up and math.ceil(number) or math.floor(number))*#soft_tab)
+local function cut_or_copy(delete)
+  local full_text = ""
+  for idx, line1, col1, line2, col2 in doc():get_selections() do
+    if line1 ~= line2 or col1 ~= col2 then
+      local text = doc():get_text(line1, col1, line2, col2)
+      if delete then
+        doc():delete_to_cursor(idx, 0)
+      end
+      full_text = full_text == "" and text or (full_text .. "\n" .. text)
+      doc().cursor_clipboard[idx] = text
+    else
+      doc().cursor_clipboard[idx] = ""
+    end
   end
+  system.set_clipboard(full_text)
 end
 
--- un/indents text; behaviour varies based on selection and un/indent.
--- * if there's a selection, it will stay static around the
---   text for both indenting and unindenting.
--- * if you are in the beginning whitespace of a line, and are indenting, the
---   cursor will insert the exactly appropriate amount of spaces, and jump the
---   cursor to the beginning of first non whitespace characters
--- * if you are not in the beginning whitespace of a line, and you indent, it
---   inserts the appropriate whitespace, as if you typed them normally.
--- * if you are unindenting, the cursor will jump to the start of the line,
---   and remove the appropriate amount of spaces (or a tab).
-local function indent_text(unindent)
-  local text = get_indent_string()
-  local line1, col1, line2, col2, swap = doc_multiline_selection(true)
-  local _, se = doc().lines[line1]:find("^[ \t]+")
-  local in_beginning_whitespace = col1 == 1 or (se and col1 <= se + 1)
-  if unindent or doc():has_selection() or in_beginning_whitespace then
-    local l1d, l2d = #doc().lines[line1], #doc().lines[line2]
-    for line = line1, line2 do
-      local e, rnded = get_line_indent(doc().lines[line], unindent)
-      doc():remove(line, 1, line, (e or 0) + 1)
-      doc():insert(line, 1,
-        unindent and rnded:sub(1, #rnded - #text) or rnded .. text)
+local function split_cursor(direction)
+  local new_cursors = {}
+  for _, line1, col1 in doc():get_selections() do
+    if line1 > 1 and line1 < #doc().lines then
+      table.insert(new_cursors, { line1 + direction, col1 })
     end
-    l1d, l2d = #doc().lines[line1] - l1d, #doc().lines[line2] - l2d
-    if (unindent or in_beginning_whitespace) and not doc():has_selection() then
-      local start_cursor = (se and se + 1 or 1) + l1d or #(doc().lines[line1])
-      doc():set_selection(line1, start_cursor, line2, start_cursor, swap)
-    else
-      doc():set_selection(line1, col1 + l1d, line2, col2 + l2d, swap)
-    end
-  else
-    doc():text_input(text)
   end
+  for i,v in ipairs(new_cursors) do doc():add_selection(v[1], v[2]) end
 end
 
 local commands = {
@@ -108,65 +86,66 @@ local commands = {
   end,
 
   ["doc:cut"] = function()
-    if doc():has_selection() then
-      local text = doc():get_text(doc():get_selection())
-      system.set_clipboard(text)
-      doc():delete_to(0)
-    end
+    cut_or_copy(true)
   end,
 
   ["doc:copy"] = function()
-    if doc():has_selection() then
-      local text = doc():get_text(doc():get_selection())
-      system.set_clipboard(text)
-    end
+    cut_or_copy(false)
   end,
 
   ["doc:paste"] = function()
-    doc():text_input(system.get_clipboard():gsub("\r", ""))
+    for idx, line1, col1, line2, col2 in doc():get_selections() do
+      local value = doc().cursor_clipboard[idx] or system.get_clipboard()
+      doc():text_input(value:gsub("\r", ""), idx)
+    end
   end,
 
   ["doc:newline"] = function()
-    local line, col = doc():get_selection()
-    local indent = doc().lines[line]:match("^[\t ]*")
-    if col <= #indent then
-      indent = indent:sub(#indent + 2 - col)
+    for idx, line, col in doc():get_selections(false, true) do
+      local indent = doc().lines[line]:match("^[\t ]*")
+      if col <= #indent then
+        indent = indent:sub(#indent + 2 - col)
+      end
+      doc():text_input("\n" .. indent, idx)
     end
-    doc():text_input("\n" .. indent)
   end,
 
   ["doc:newline-below"] = function()
-    local line = doc():get_selection()
-    local indent = doc().lines[line]:match("^[\t ]*")
-    doc():insert(line, math.huge, "\n" .. indent)
-    doc():set_selection(line + 1, math.huge)
+    for idx, line in doc():get_selections(false, true) do
+      local indent = doc().lines[line]:match("^[\t ]*")
+      doc():insert(line, math.huge, "\n" .. indent)
+      doc():set_selections(idx, line + 1, math.huge)
+    end
   end,
 
   ["doc:newline-above"] = function()
-    local line = doc():get_selection()
-    local indent = doc().lines[line]:match("^[\t ]*")
-    doc():insert(line, 1, indent .. "\n")
-    doc():set_selection(line, math.huge)
+    for idx, line in doc():get_selections(false, true) do
+      local indent = doc().lines[line]:match("^[\t ]*")
+      doc():insert(line, 1, indent .. "\n")
+      doc():set_selections(idx, line, math.huge)
+    end
   end,
 
   ["doc:delete"] = function()
-    local line, col = doc():get_selection()
-    if not doc():has_selection() and doc().lines[line]:find("^%s*$", col) then
-      doc():remove(line, col, line, math.huge)
+    for idx, line1, col1, line2, col2 in doc():get_selections() do
+      if line1 == line2 and col1 == col2 and doc().lines[line1]:find("^%s*$", col1) then
+        doc():remove(line1, col1, line1, math.huge)
+      end
+      doc():delete_to_cursor(idx, translate.next_char)
     end
-    doc():delete_to(translate.next_char)
   end,
 
   ["doc:backspace"] = function()
-    local line, col = doc():get_selection()
-    if not doc():has_selection() then
-      local text = doc():get_text(line, 1, line, col)
-      if #text >= config.indent_size and text:find("^ *$") then
-        doc():delete_to(0, -config.indent_size)
-        return
+    for idx, line1, col1, line2, col2 in doc():get_selections() do
+      if line1 == line2 and col1 == col2 then
+        local text = doc():get_text(line1, 1, line1, col1)
+        if #text >= config.indent_size and text:find("^ *$") then
+          doc():delete_to_cursor(idx, 0, -config.indent_size)
+          return
+        end
       end
+      doc():delete_to_cursor(idx, translate.previous_char)
     end
-    doc():delete_to(translate.previous_char)
   end,
 
   ["doc:select-all"] = function()
@@ -177,77 +156,104 @@ local commands = {
     local line, col = doc():get_selection()
     doc():set_selection(line, col)
   end,
+  
+  
+  ["doc:indent"] = function()
+    for idx, line1, col1, line2, col2 in doc_multiline_selections(true) do
+      local l1, c1, l2, c2 = doc():indent_text(false, line1, col1, line2, col2)
+      if l1 then
+        doc():set_selections(idx, l1, c1, l2, c2)
+      end
+    end
+  end,
 
   ["doc:select-lines"] = function()
-    local line1, _, line2, _, swap = doc():get_selection(true)
-    append_line_if_last_line(line2)
-    doc():set_selection(line1, 1, line2 + 1, 1, swap)
+    for idx, line1, _, line2 in doc():get_selections(true) do
+      append_line_if_last_line(line2)
+      doc():set_selections(idx, line1, 1, line2 + 1, 1, swap)
+    end
   end,
 
   ["doc:select-word"] = function()
-    local line1, col1 = doc():get_selection(true)
-    local line1, col1 = translate.start_of_word(doc(), line1, col1)
-    local line2, col2 = translate.end_of_word(doc(), line1, col1)
-    doc():set_selection(line2, col2, line1, col1)
+    for idx, line1, col1 in doc():get_selections(true) do
+      local line1, col1 = translate.start_of_word(doc(), line1, col1)
+      local line2, col2 = translate.end_of_word(doc(), line1, col1)
+      doc():set_selections(idx, line2, col2, line1, col1)
+    end
   end,
 
   ["doc:join-lines"] = function()
-    local line1, _, line2 = doc():get_selection(true)
-    if line1 == line2 then line2 = line2 + 1 end
-    local text = doc():get_text(line1, 1, line2, math.huge)
-    text = text:gsub("(.-)\n[\t ]*", function(x)
-      return x:find("^%s*$") and x or x .. " "
-    end)
-    doc():insert(line1, 1, text)
-    doc():remove(line1, #text + 1, line2, math.huge)
-    if doc():has_selection() then
-      doc():set_selection(line1, math.huge)
+    for idx, line1, col1, line2, col2 in doc():get_selections(true) do
+      if line1 == line2 then line2 = line2 + 1 end
+      local text = doc():get_text(line1, 1, line2, math.huge)
+      text = text:gsub("(.-)\n[\t ]*", function(x)
+        return x:find("^%s*$") and x or x .. " "
+      end)
+      doc():insert(line1, 1, text)
+      doc():remove(line1, #text + 1, line2, math.huge)
+      if line1 ~= line2 or col1 ~= col2 then
+        doc():set_selections(idx, line1, math.huge)
+      end
     end
   end,
 
   ["doc:indent"] = function()
-    indent_text()
+    for idx, line1, col1, line2, col2 in doc_multiline_selections(true) do
+      local l1, c1, l2, c2 = doc():indent_text(false, line1, col1, line2, col2)
+      if l1 then
+        doc():set_selections(idx, l1, c1, l2, c2)
+      end
+    end
   end,
 
   ["doc:unindent"] = function()
-    indent_text(true)
+    for idx, line1, col1, line2, col2 in doc_multiline_selections(true) do
+      local l1, c1, l2, c2 = doc():indent_text(true, line1, col1, line2, col2)
+      if l1 then
+        doc():set_selections(idx, l1, c1, l2, c2)
+      end
+    end
   end,
 
   ["doc:duplicate-lines"] = function()
-    local line1, col1, line2, col2, swap = doc_multiline_selection(true)
-    append_line_if_last_line(line2)
-    local text = doc():get_text(line1, 1, line2 + 1, 1)
-    doc():insert(line2 + 1, 1, text)
-    local n = line2 - line1 + 1
-    doc():set_selection(line1 + n, col1, line2 + n, col2, swap)
+    for idx, line1, col1, line2, col2 in doc_multiline_selections(true) do
+      append_line_if_last_line(line2)
+      local text = doc():get_text(line1, 1, line2 + 1, 1)
+      doc():insert(line2 + 1, 1, text)
+      local n = line2 - line1 + 1
+      doc():set_selections(idx, line1 + n, col1, line2 + n, col2, swap)
+    end
   end,
 
   ["doc:delete-lines"] = function()
-    local line1, col1, line2 = doc_multiline_selection(true)
-    append_line_if_last_line(line2)
-    doc():remove(line1, 1, line2 + 1, 1)
-    doc():set_selection(line1, col1)
+    for idx, line1, col1, line2, col2 in doc_multiline_selections(true) do
+      append_line_if_last_line(line2)
+      doc():remove(line1, 1, line2 + 1, 1)
+      doc():set_selections(idx, line1, col1)
+    end
   end,
 
   ["doc:move-lines-up"] = function()
-    local line1, col1, line2, col2, swap = doc_multiline_selection(true)
-    append_line_if_last_line(line2)
-    if line1 > 1 then
-      local text = doc().lines[line1 - 1]
-      doc():insert(line2 + 1, 1, text)
-      doc():remove(line1 - 1, 1, line1, 1)
-      doc():set_selection(line1 - 1, col1, line2 - 1, col2, swap)
+    for idx, line1, col1, line2, col2 in doc_multiline_selections(true) do
+      append_line_if_last_line(line2)
+      if line1 > 1 then
+        local text = doc().lines[line1 - 1]
+        doc():insert(line2 + 1, 1, text)
+        doc():remove(line1 - 1, 1, line1, 1)
+        doc():set_selections(idx, line1 - 1, col1, line2 - 1, col2)
+      end
     end
   end,
 
   ["doc:move-lines-down"] = function()
-    local line1, col1, line2, col2, swap = doc_multiline_selection(true)
-    append_line_if_last_line(line2 + 1)
-    if line2 < #doc().lines then
-      local text = doc().lines[line2 + 1]
-      doc():remove(line2 + 1, 1, line2 + 2, 1)
-      doc():insert(line1, 1, text)
-      doc():set_selection(line1 + 1, col1, line2 + 1, col2, swap)
+    for idx, line1, col1, line2, col2 in doc_multiline_selections(true) do
+      append_line_if_last_line(line2 + 1)
+      if line2 < #doc().lines then
+        local text = doc().lines[line2 + 1]
+        doc():remove(line2 + 1, 1, line2 + 2, 1)
+        doc():insert(line1, 1, text)
+        doc():set_selections(idx, line1 + 1, col1, line2 + 1, col2)
+      end
     end
   end,
 
@@ -256,28 +262,29 @@ local commands = {
     if not comment then return end
     local indentation = get_indent_string()
     local comment_text = comment .. " "
-    local line1, _, line2 = doc_multiline_selection(true)
-    local uncomment = true
-    local start_offset = math.huge
-    for line = line1, line2 do
-      local text = doc().lines[line]
-      local s = text:find("%S")
-      local cs, ce = text:find(comment_text, s, true)
-      if s and cs ~= s then
-        uncomment = false
-        start_offset = math.min(start_offset, s)
-      end
-    end
-    for line = line1, line2 do
-      local text = doc().lines[line]
-      local s = text:find("%S")
-      if uncomment then
+    for idx, line1, _, line2 in doc_multiline_selections(true) do
+      local uncomment = true
+      local start_offset = math.huge
+      for line = line1, line2 do
+        local text = doc().lines[line]
+        local s = text:find("%S")
         local cs, ce = text:find(comment_text, s, true)
-        if ce then
-          doc():remove(line, cs, line, ce + 1)
+        if s and cs ~= s then
+          uncomment = false
+          start_offset = math.min(start_offset, s)
+        end
+      end
+      for line = line1, line2 do
+        local text = doc().lines[line]
+        local s = text:find("%S")
+        if uncomment then
+          local cs, ce = text:find(comment_text, s, true)
+          if ce then
+            doc():remove(line, cs, line, ce + 1)
+          end
+        elseif s then
+          doc():insert(line, start_offset, comment_text)
         end
-      elseif s then
-        doc():insert(line, start_offset, comment_text)
       end
     end
   end,
@@ -363,6 +370,32 @@ local commands = {
       end
     end, common.path_suggest)
   end,
+  
+
+  ["file:delete"] = function()
+    local filename = doc().abs_filename
+    if not filename then
+      core.error("Cannot remove unsaved doc")
+      return
+    end
+    for i,docview in ipairs(core.get_views_referencing_doc(doc())) do
+      local node = core.root_view.root_node:get_node_for_view(docview)
+      node:close_view(core.root_view, docview)
+    end
+    os.remove(filename)
+    core.log("Removed \"%s\"", filename)
+  end,
+
+  ["doc:create-cursor-previous-line"] = function()
+    split_cursor(-1)
+    doc():merge_cursors()
+  end,
+  
+  ["doc:create-cursor-next-line"] = function()
+    split_cursor(1)
+    doc():merge_cursors()
+  end
+
 }
 
 
@@ -392,21 +425,21 @@ for name, fn in pairs(translations) do
 end
 
 commands["doc:move-to-previous-char"] = function()
-  if doc():has_selection() then
-    local line, col = doc():get_selection(true)
-    doc():set_selection(line, col)
-  else
-    doc():move_to(translate.previous_char)
+  for idx, line1, col1, line2, col2 in doc():get_selections(true) do
+    if line1 ~= line2 or col1 ~= col2 then
+      doc():set_selections(idx, line1, col1)
+    end
   end
+  doc():move_to(translate.previous_char)
 end
 
 commands["doc:move-to-next-char"] = function()
-  if doc():has_selection() then
-    local _, _, line, col = doc():get_selection(true)
-    doc():set_selection(line, col)
-  else
-    doc():move_to(translate.next_char)
+  for idx, line1, col1, line2, col2 in doc():get_selections(true) do
+    if line1 ~= line2 or col1 ~= col2 then
+      doc():set_selections(idx, line2, col2)
+    end
   end
+  doc():move_to(translate.next_char)
 end
 
 command.add("core.docview", commands)
diff --git a/data/core/common.lua b/data/core/common.lua
index e8a989df..c1fd2498 100755
--- a/data/core/common.lua
+++ b/data/core/common.lua
@@ -54,6 +54,26 @@ function common.color(str)
 end
 
 
+function common.splice(t, at, remove, insert)
+  insert = insert or {}
+  local offset = #insert - remove
+  local old_len = #t
+  if offset < 0 then
+    for i = at - offset, old_len - offset do
+      t[i + offset] = t[i]
+    end
+  elseif offset > 0 then
+    for i = old_len, at, -1 do
+      t[i + offset] = t[i]
+    end
+  end
+  for i, item in ipairs(insert) do
+    t[at + i - 1] = item
+  end
+end
+
+
+
 local function compare_score(a, b)
   return a.score > b.score
 end
diff --git a/data/core/doc/init.lua b/data/core/doc/init.lua
index 39fae9ca..0c5ba8fb 100755
--- a/data/core/doc/init.lua
+++ b/data/core/doc/init.lua
@@ -16,26 +16,6 @@ local function split_lines(text)
   return res
 end
 
-
-local function splice(t, at, remove, insert)
-  insert = insert or {}
-  local offset = #insert - remove
-  local old_len = #t
-  if offset < 0 then
-    for i = at - offset, old_len - offset do
-      t[i + offset] = t[i]
-    end
-  elseif offset > 0 then
-    for i = old_len, at, -1 do
-      t[i + offset] = t[i]
-    end
-  end
-  for i, item in ipairs(insert) do
-    t[at + i - 1] = item
-  end
-end
-
-
 function Doc:new(filename)
   self:reset()
   if filename then
@@ -46,7 +26,8 @@ end
 
 function Doc:reset()
   self.lines = { "\n" }
-  self.selection = { a = { line=1, col=1 }, b = { line=1, col=1 } }
+  self.selections = { 1, 1, 1, 1 }
+  self.cursor_clipboard = {}
   self.undo_stack = { idx = 1 }
   self.redo_stack = { idx = 1 }
   self.clean_change_id = 1
@@ -126,45 +107,87 @@ function Doc:get_change_id()
   return self.undo_stack.idx
 end
 
+-- Cursor section. Cursor indices are *only* valid during a get_selections() call.
+-- Cursors will always be iterated in order from top to bottom. Through normal operation
+-- curors can never swap positions; only merge or split, or change their position in cursor
+-- order.
+function Doc:get_selection(sort)
+  local idx, line1, col1, line2, col2 = self:get_selections(sort)({ self.selections, sort }, 0)
+  return line1, col1, line2, col2, sort
+end
 
-function Doc:set_selection(line1, col1, line2, col2, swap)
-  assert(not line2 == not col2, "expected 2 or 4 arguments")
+function Doc:has_selection()
+  local line1, col1, line2, col2 = self:get_selection(false)
+  return line1 ~= line2 or col1 ~= col2
+end
+
+function Doc:sanitize_selection()
+  for idx, line1, col1, line2, col2 in self:get_selections() do
+    self:set_selections(idx, line1, col1, line2, col2)
+  end
+end
+
+local function sort_positions(line1, col1, line2, col2)
+  if line1 > line2 or line1 == line2 and col1 > col2 then
+    return line2, col2, line1, col1
+  end
+  return line1, col1, line2, col2
+end
+
+function Doc:set_selections(idx, line1, col1, line2, col2, swap, rm)
+  assert(not line2 == not col2, "expected 3 or 5 arguments")
   if swap then line1, col1, line2, col2 = line2, col2, line1, col1 end
   line1, col1 = self:sanitize_position(line1, col1)
   line2, col2 = self:sanitize_position(line2 or line1, col2 or col1)
-  self.selection.a.line, self.selection.a.col = line1, col1
-  self.selection.b.line, self.selection.b.col = line2, col2
+  common.splice(self.selections, (idx - 1)*4 + 1, rm == nil and 4 or rm, { line1, col1, line2, col2 })
 end
 
-
-local function sort_positions(line1, col1, line2, col2)
-  if line1 > line2
-  or line1 == line2 and col1 > col2 then
-    return line2, col2, line1, col1, true
+function Doc:add_selection(line1, col1, line2, col2, swap)
+  local l1, c1 = sort_positions(line1, col1, line2 or line1, col2 or col1)
+  local target = #self.selections / 4 + 1
+  for idx, tl1, tc1 in self:get_selections(true) do
+    if l1 < tl1 or l1 == tl1 and c1 < tc1 then
+      target = idx
+      break
+    end
   end
-  return line1, col1, line2, col2, false
+  self:set_selections(target, line1, col1, line2, col2, swap, 0)
 end
 
+function Doc:set_selection(line1, col1, line2, col2, swap)
+  self.selections, self.cursor_clipboard = {}, {}
+  self:set_selections(1, line1, col1, line2, col2, swap)
+end
 
-function Doc:get_selection(sort)
-  local a, b = self.selection.a, self.selection.b
-  if sort then
-    return sort_positions(a.line, a.col, b.line, b.col)
+function Doc:merge_cursors(idx)
+  for i = (idx or (#self.selections - 3)), (idx or 5), -4 do
+    for j = 1, i - 4, 4 do
+      if self.selections[i] == self.selections[j] and
+        self.selections[i+1] == self.selections[j+1] then
+          common.splice(self.selections, i, 4)
+          break
+      end
+    end
   end
-  return a.line, a.col, b.line, b.col
 end
 
-
-function Doc:has_selection()
-  local a, b = self.selection.a, self.selection.b
-  return not (a.line == b.line and a.col == b.col)
+local function selection_iterator(invariant, idx)
+  local target = invariant[3] and (idx*4 - 7) or (idx*4 + 1)
+  if target > #invariant[1] or target <= 0 or (type(invariant[3]) == "number" and invariant[3] ~= idx - 1) then return end
+  if invariant[2] then
+    return idx+(invariant[3] and -1 or 1), sort_positions(unpack(invariant[1], target, target+4))
+  else
+    return idx+(invariant[3] and -1 or 1), unpack(invariant[1], target, target+4)
+  end
 end
 
-
-function Doc:sanitize_selection()
-  self:set_selection(self:get_selection())
+-- If idx_reverse is true, it'll reverse iterate. If nil, or false, regular iterate. 
+-- If a number, runs for exactly that iteration.
+function Doc:get_selections(sort_intra, idx_reverse)
+  return selection_iterator, { self.selections, sort_intra, idx_reverse }, 
+    idx_reverse == true and ((#self.selections / 4) + 1) or ((idx_reverse or -1)+1)
 end
-
+-- End of cursor seciton.
 
 function Doc:sanitize_position(line, col)
   line = common.clamp(line, 1, #self.lines)
@@ -251,14 +274,11 @@ local function pop_undo(self, undo_stack, redo_stack, modified)
   if cmd.type == "insert" then
     local line, col, text = table.unpack(cmd)
     self:raw_insert(line, col, text, redo_stack, cmd.time)
-
   elseif cmd.type == "remove" then
     local line1, col1, line2, col2 = table.unpack(cmd)
     self:raw_remove(line1, col1, line2, col2, redo_stack, cmd.time)
-
   elseif cmd.type == "selection" then
-    self.selection.a.line, self.selection.a.col = cmd[1], cmd[2]
-    self.selection.b.line, self.selection.b.col = cmd[3], cmd[4]
+    self.selections = { unpack(cmd) }
   end
 
   modified = modified or (cmd.type ~= "selection")
@@ -288,11 +308,11 @@ function Doc:raw_insert(line, col, text, undo_stack, time)
   lines[#lines] = lines[#lines] .. after
 
   -- splice lines into line array
-  splice(self.lines, line, 1, lines)
+  common.splice(self.lines, line, 1, lines)
 
   -- push undo
   local line2, col2 = self:position_offset(line, col, #text)
-  push_undo(undo_stack, time, "selection", self:get_selection())
+  push_undo(undo_stack, time, "selection", unpack(self.selections))
   push_undo(undo_stack, time, "remove", line, col, line2, col2)
 
   -- update highlighter and assure selection is in bounds
@@ -304,7 +324,7 @@ end
 function Doc:raw_remove(line1, col1, line2, col2, undo_stack, time)
   -- push undo
   local text = self:get_text(line1, col1, line2, col2)
-  push_undo(undo_stack, time, "selection", self:get_selection())
+  push_undo(undo_stack, time, "selection", unpack(self.selections))
   push_undo(undo_stack, time, "insert", line1, col1, text)
 
   -- get line content before/after removed text
@@ -312,7 +332,7 @@ function Doc:raw_remove(line1, col1, line2, col2, undo_stack, time)
   local after = self.lines[line2]:sub(col2)
 
   -- splice line into line array
-  splice(self.lines, line1, line2 - line1 + 1, { before .. after })
+  common.splice(self.lines, line1, line2 - line1 + 1, { before .. after })
 
   -- update highlighter and assure selection is in bounds
   self.highlighter:invalidate(line1)
@@ -348,22 +368,20 @@ function Doc:redo()
 end
 
 
-function Doc:text_input(text)
-  if self:has_selection() then
-    self:delete_to()
+function Doc:text_input(text, idx)
+  for sidx, line1, col1, line2, col2 in self:get_selections(true, idx) do
+    if line1 ~= line2 or col1 ~= col2 then
+      self:delete_to_cursor(sidx)
+    end
+    self:insert(line1, col1, text)
+    self:move_to_cursor(sidx, #text)
   end
-  local line, col = self:get_selection()
-  self:insert(line, col, text)
-  self:move_to(#text)
 end
 
 
 function Doc:replace(fn)
-  local line1, col1, line2, col2, swap
-  local had_selection = self:has_selection()
-  if had_selection then
-    line1, col1, line2, col2, swap = self:get_selection(true)
-  else
+  local line1, col1, line2, col2 = self:get_selection(true)
+  if line1 == line2 and col1 == col2 then
     line1, col1, line2, col2 = 1, 1, #self.lines, #self.lines[#self.lines]
   end
   local old_text = self:get_text(line1, col1, line2, col2)
@@ -371,38 +389,104 @@ function Doc:replace(fn)
   if old_text ~= new_text then
     self:insert(line2, col2, new_text)
     self:remove(line1, col1, line2, col2)
-    if had_selection then
+    if line1 == line2 and col1 == col2 then
       line2, col2 = self:position_offset(line1, col1, #new_text)
-      self:set_selection(line1, col1, line2, col2, swap)
+      self:set_selection(line1, col1, line2, col2)
     end
   end
   return n
 end
 
 
-function Doc:delete_to(...)
-  local line, col = self:get_selection(true)
-  if self:has_selection() then
-    self:remove(self:get_selection())
-  else
-    local line2, col2 = self:position_offset(line, col, ...)
-    self:remove(line, col, line2, col2)
-    line, col = sort_positions(line, col, line2, col2)
+function Doc:delete_to_cursor(idx, ...)
+  for sidx, line1, col1, line2, col2 in self:get_selections(true, idx) do
+    if line1 ~= line2 or col1 ~= col2 then
+      self:remove(line1, col1, line2, col2)
+    else
+      local l2, c2 = self:position_offset(line1, col1, ...)
+      self:remove(line1, col1, l2, c2)
+      line1, col1 = sort_positions(line1, col1, l2, c2)
+    end
+    self:set_selections(sidx, line1, col1)
   end
-  self:set_selection(line, col)
+  self:merge_cursors(idx)
+end
+function Doc:delete_to(...) return self:delete_to_cursor(nil, ...) end
+
+function Doc:move_to_cursor(idx, ...)
+  for sidx, line, col in self:get_selections(false, idx) do
+    self:set_selections(sidx, self:position_offset(line, col, ...))
+  end
+  self:merge_cursors(idx)
+end
+function Doc:move_to(...) return self:move_to_cursor(nil, ...) end
+
+
+function Doc:select_to_cursor(idx, ...)
+  for sidx, line, col, line2, col2 in self:get_selections(false, idx) do
+    line, col = self:position_offset(line, col, ...)
+    self:set_selections(sidx, line, col, line2, col2)
+  end
+  self:merge_cursors(idx)
+end
+function Doc:select_to(...) return self:select_to_cursor(nil, ...) end
+
+
+local function get_indent_string()
+  if config.tab_type == "hard" then
+    return "\t"
+  end
+  return string.rep(" ", config.indent_size)
 end
 
-
-function Doc:move_to(...)
-  local line, col = self:get_selection()
-  self:set_selection(self:position_offset(line, col, ...))
+-- returns the size of the original indent, and the indent
+-- in your config format, rounded either up or down
+local function get_line_indent(line, rnd_up)
+  local _, e = line:find("^[ \t]+")
+  local soft_tab = string.rep(" ", config.indent_size)
+  if config.tab_type == "hard" then
+    local indent = e and line:sub(1, e):gsub(soft_tab, "\t") or ""
+    return e, indent:gsub(" +", rnd_up and "\t" or "")
+  else
+    local indent = e and line:sub(1, e):gsub("\t", soft_tab) or ""
+    local number = #indent / #soft_tab
+    return e, indent:sub(1,
+      (rnd_up and math.ceil(number) or math.floor(number))*#soft_tab)
+  end
 end
 
-
-function Doc:select_to(...)
-  local line, col, line2, col2 = self:get_selection()
-  line, col = self:position_offset(line, col, ...)
-  self:set_selection(line, col, line2, col2)
+-- un/indents text; behaviour varies based on selection and un/indent.
+-- * if there's a selection, it will stay static around the
+--   text for both indenting and unindenting.
+-- * if you are in the beginning whitespace of a line, and are indenting, the
+--   cursor will insert the exactly appropriate amount of spaces, and jump the
+--   cursor to the beginning of first non whitespace characters
+-- * if you are not in the beginning whitespace of a line, and you indent, it
+--   inserts the appropriate whitespace, as if you typed them normally.
+-- * if you are unindenting, the cursor will jump to the start of the line,
+--   and remove the appropriate amount of spaces (or a tab).
+function Doc:indent_text(unindent, line1, col1, line2, col2)
+  local text = get_indent_string()
+  local _, se = self.lines[line1]:find("^[ \t]+")
+  local in_beginning_whitespace = col1 == 1 or (se and col1 <= se + 1)
+  local has_selection = line1 ~= line2 or col1 ~= col2
+  if unindent or has_selection or in_beginning_whitespace then
+    local l1d, l2d = #self.lines[line1], #self.lines[line2]
+    for line = line1, line2 do
+      local e, rnded = get_line_indent(self.lines[line], unindent)
+      self:remove(line, 1, line, (e or 0) + 1)
+      self:insert(line, 1,
+        unindent and rnded:sub(1, #rnded - #text) or rnded .. text)
+    end
+    l1d, l2d = #self.lines[line1] - l1d, #self.lines[line2] - l2d
+    if (unindent or in_beginning_whitespace) and not has_selection then
+      local start_cursor = (se and se + 1 or 1) + l1d or #(self.lines[line1])
+      return line1, start_cursor, line2, start_cursor
+    end
+    return line1, col1 + l1d, line2, col2 + l2d
+  end
+  self:insert(line1, col1, text)
+  return line1, col1 + #text, line1, col1 + #text
 end
 
 -- For plugins to add custom actions of document change
diff --git a/data/core/docview.lua b/data/core/docview.lua
index 2375a499..0db548e3 100644
--- a/data/core/docview.lua
+++ b/data/core/docview.lua
@@ -259,7 +259,11 @@ function DocView:on_mouse_pressed(button, x, y, clicks)
     end
   else
     local line, col = self:resolve_screen_position(x, y)
-    self.doc:set_selection(mouse_selection(self.doc, clicks, line, col, line, col))
+    if keymap.modkeys["ctrl"] then
+      self.doc:add_selection(mouse_selection(self.doc, clicks, line, col, line, col))
+    else
+      self.doc:set_selection(mouse_selection(self.doc, clicks, line, col, line, col))
+    end
     self.mouse_selecting = { line, col, clicks = clicks }
   end
   core.blink_reset()
@@ -279,7 +283,15 @@ function DocView:on_mouse_moved(x, y, ...)
     local l1, c1 = self:resolve_screen_position(x, y)
     local l2, c2 = table.unpack(self.mouse_selecting)
     local clicks = self.mouse_selecting.clicks
-    self.doc:set_selection(mouse_selection(self.doc, clicks, l1, c1, l2, c2))
+    if keymap.modkeys["ctrl"] then
+      if l1 > l2 then l1, l2 = l2, l1 end
+      self.doc.selections = { }
+      for i = l1, l2 do
+        self.doc:set_selections(i - l1 + 1, i, math.min(c1, #self.doc.lines[i]), i, math.min(c2, #self.doc.lines[i]))
+      end
+    else
+      self.doc:set_selection(mouse_selection(self.doc, clicks, l1, c1, l2, c2))
+    end
   end
 end
 
@@ -343,46 +355,50 @@ end
 
 
 function DocView:draw_line_body(idx, x, y)
-  local line, col = self.doc:get_selection()
-
   -- draw selection if it overlaps this line
-  local line1, col1, line2, col2 = self.doc:get_selection(true)
-  if idx >= line1 and idx <= line2 then
-    local text = self.doc.lines[idx]
-    if line1 ~= idx then col1 = 1 end
-    if line2 ~= idx then col2 = #text + 1 end
-    local x1 = x + self:get_col_x_offset(idx, col1)
-    local x2 = x + self:get_col_x_offset(idx, col2)
-    local lh = self:get_line_height()
-    renderer.draw_rect(x1, y, x2 - x1, lh, style.selection)
+  for lidx, line1, col1, line2, col2 in self.doc:get_selections(true) do 
+    if idx >= line1 and idx <= line2 then
+      local text = self.doc.lines[idx]
+      if line1 ~= idx then col1 = 1 end
+      if line2 ~= idx then col2 = #text + 1 end
+      local x1 = x + self:get_col_x_offset(idx, col1)
+      local x2 = x + self:get_col_x_offset(idx, col2)
+      local lh = self:get_line_height()
+      renderer.draw_rect(x1, y, x2 - x1, lh, style.selection)
+    end
   end
-
-  -- draw line highlight if caret is on this line
-  if config.highlight_current_line and not self.doc:has_selection()
-  and line == idx and core.active_view == self then
-    self:draw_line_highlight(x + self.scroll.x, y)
+  for lidx, line1, col1, line2, col2 in self.doc:get_selections(true) do 
+    -- draw line highlight if caret is on this line
+    if config.highlight_current_line and (line1 == line2 and col1 == col2)
+    and line1 == idx and core.active_view == self then
+      self:draw_line_highlight(x + self.scroll.x, y)
+    end
   end
-
+  
   -- draw line's text
   self:draw_line_text(idx, x, y)
 
   -- draw caret if it overlaps this line
   local T = config.blink_period
-  if line == idx and core.active_view == self
-  and (core.blink_timer - core.blink_start) % T < T / 2
-  and system.window_has_focus() then
-    local lh = self:get_line_height()
-    local x1 = x + self:get_col_x_offset(line, col)
-    renderer.draw_rect(x1, y, style.caret_width, lh, style.caret)
+  for _, line, col in self.doc:get_selections() do 
+    if line == idx and core.active_view == self
+    and (core.blink_timer - core.blink_start) % T < T / 2
+    and system.window_has_focus() then
+      local lh = self:get_line_height()
+      local x1 = x + self:get_col_x_offset(line, col)
+      renderer.draw_rect(x1, y, style.caret_width, lh, style.caret)
+    end
   end
 end
 
 
 function DocView:draw_line_gutter(idx, x, y)
   local color = style.line_number
-  local line1, _, line2, _ = self.doc:get_selection(true)
-  if idx >= line1 and idx <= line2 then
-    color = style.line_number2
+  for _, line1, _, line2 in self.doc:get_selections(true) do 
+    if idx >= line1 and idx <= line2 then
+      color = style.line_number2
+      break
+    end
   end
   local yoffset = self:get_line_text_y_offset()
   x = x + style.padding.x
diff --git a/data/core/keymap-macos.lua b/data/core/keymap-macos.lua
index ccbb102a..3db4d4f7 100755
--- a/data/core/keymap-macos.lua
+++ b/data/core/keymap-macos.lua
@@ -101,6 +101,8 @@ local function keymap_macos(keymap)
     ["cmd+shift+end"] = "doc:select-to-end-of-doc",
     ["shift+pageup"] = "doc:select-to-previous-page",
     ["shift+pagedown"] = "doc:select-to-next-page",
+    ["cmd+shift+up"] = "doc:create-cursor-previous-line",
+    ["cmd+shift+down"] = "doc:create-cursor-next-line"
   }
 end
 
diff --git a/data/core/keymap.lua b/data/core/keymap.lua
index 2e1372fb..c916892f 100644
--- a/data/core/keymap.lua
+++ b/data/core/keymap.lua
@@ -205,6 +205,8 @@ keymap.add_direct {
   ["ctrl+shift+end"] = "doc:select-to-end-of-doc",
   ["shift+pageup"] = "doc:select-to-previous-page",
   ["shift+pagedown"] = "doc:select-to-next-page",
+  ["ctrl+shift+up"] = "doc:create-cursor-previous-line",
+  ["ctrl+shift+down"] = "doc:create-cursor-next-line"
 }
 
 return keymap