put fixup, esp. ". register close #5709 #5781

Note some bugs were judged to have too ugly a fix to solve, tests to
demonstrate these problems, and the explanation behind not fixing them
are below.

describe('register . problems', function()
  before_each(reset)

  -- The difficulty here is: The basic requirement is that the text
  -- inserted is treated as if it were typed in insert mode. This is why
  -- the paste method is to enter insert mode and enter the ". register
  -- into readbuf1.
  -- We can't add a count into the readbuf here because the insert mode
  -- count is implemented with readbuf2 which is checked for characters
  -- after readbuf1.
  -- Hence, the ".gp command (which adds extra characters into readbuf1
  -- to emulate leaving the cursor after the text by moving the cursor
  -- after inserting the text) would insert the motion characters into
  -- the buffer instead of using them to move after the insert has been
  -- done.
  -- I could probably get this working properly with a special flag put
  -- into start_redo_ins() and set in do_put(), but I think this adds
  -- much more complexity than fixing this bug justifies.
  pending('should not change the ". register with ".2p', function()
    local orig_register = funcs.getreg('.')
    feed('2".p')
    eq(orig_register, funcs.getreg('.'))
  end)

  describe("cursor positioning after undo and redo with '.'", function()
    before_each(reset)
    local function make_cursor_test(macro_string)
      return function()
        feed(macro_string)
        local afterpos = funcs.getcurpos()
        local orig_string = curbuf_contents()
        feed('u.')
        eq(afterpos, funcs.getcurpos())
        expect(orig_string)
      end
    end
    -- The difficulty here is: setting the cursor after the end of the
    -- pasted text is done by adding a motion command to the
    -- stuffbuffer after the insert.
    -- Modifying 'redobuff' is done in the code that handles inserting
    -- text and moving around.
    -- I could add a special case in ins_esc() that checks for a flag
    -- set in do_put() to add the motion character to the redo buffer,
    -- but I think that is starting to get way too convoluted for the
    -- benefit.
    pending('should be the same after ".gp and ".gpu.',
            make_cursor_test('".gp'))
    -- The difficulty here is: putting forwards is implemented by using
    -- 'a' instead of 'i' to start insert.
    -- Undoing with 'u' an insert that began with 'a' leaves the cursor
    -- where the first character was inserted, not where the cursor was
    -- when the 'a' was pressed.
    -- We account for this the first time by saving the cursor position
    -- in do_put(), but this isn't stored in redobuff for a second time
    -- around.
    -- We can't change how such a fundamental action as undo after
    -- inserting with 'a' behaves, we could add in a special case
    -- whereby we set a flag in do_put() and read it when entering
    -- insert mode but this seems like way too much to fix such a minor
    -- bug.
    pending('should be the same after ".pu. and ".pu.u.',
            make_cursor_test('".pu.'))
  end)
end)

test/helpers.lua

@@ -90,6 +90,24 @@ local function tmpname()
   end
 end
 
+local function map(func, tab)
+  local rettab = {}
+  for k, v in pairs(tab) do
+    rettab[k] = func(v)
+  end
+  return rettab
+end
+
+local function filter(filter_func, tab)
+  local rettab = {}
+  for _, entry in pairs(tab) do
+    if filter_func(entry) then
+      table.insert(rettab, entry)
+    end
+  end
+  return rettab
+end
+
 return {
   eq = eq,
   neq = neq,
@@ -97,4 +115,6 @@ return {
   check_logs = check_logs,
   uname = uname,
   tmpname = tmpname,
+  map = map,
+  filter = filter,
 }