Indent Enhancements (#202)

* Indent enhancements.

* Fixed to match style guidelines.

* Added in useful explanatory comment.

* Changed which selection we're using, as we don't want this kind of wrapping to happen.

* Fixed bug involving lines full of whitespace.

* Removed unecessary commit.

* Actually reverted function, so that we don't screw up commenting.

* Fixed hard tab issue.

data/core/commands/doc.lua

@@ -46,21 +46,14 @@ local function insert_at_start_of_selected_lines(text, skip_empty)
 end
 
 
-
-local function remove_from_start_of_selected_lines(text, skip_empty, remove_partial)
+local function remove_from_start_of_selected_lines(text, skip_empty)
   local line1, col1, line2, col2, swap = doc_multiline_selection(true)
   for line = line1, line2 do
     local line_text = doc().lines[line]
-    for i = #text, 1, -1 do
-      if line_text:sub(1, i) == text:sub(1, i)
-        and (not skip_empty or line_text:find("%S"))
-      then
-        doc():remove(line, 1, line, i + 1)
-        break
-      end
-      if not remove_partial then
-        break
-      end
+    if  line_text:sub(1, #text) == text
+    and (not skip_empty or line_text:find("%S"))
+    then
+      doc():remove(line, 1, line, #text + 1)
     end
   end
   doc():set_selection(line1, col1 - #text, line2, col2 - #text, swap)
@@ -81,6 +74,56 @@ 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)
+  end
+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():get_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)
+    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
+end
 
 local commands = {
   ["doc:undo"] = function()
@@ -190,17 +233,11 @@ local commands = {
   end,
 
   ["doc:indent"] = function()
-    local text = get_indent_string()
-    if doc():has_selection() then
-      insert_at_start_of_selected_lines(text)
-    else
-      doc():text_input(text)
-    end
+    indent_text()
   end,
 
   ["doc:unindent"] = function()
-    local text = get_indent_string()
-    remove_from_start_of_selected_lines(text, false, true)
+    indent_text(true)
   end,
 
   ["doc:duplicate-lines"] = function()