v4.0.0 (includes a breaking change)

Breaking change

v4.0.0 marks a breaking change to the tab completion function.

Earlier versions expected multiple parameters to be returned however from
v4.0.0 onwards, a pointer to a structure is instead expected:

type TabCompleterReturnT struct {
	Prefix       string
	Suggestions  []string
	Descriptions map[string]string
	DisplayType  TabDisplayType
	HintCache    HintCacheFuncT
	Preview      PreviewFuncT
}

This allows for more configurability and without the cost of copying multiple
different pieces of data nor future breaking changes whenever additional new
features are added.

Improvements

• support for wide and zero width unicode characters
  (inherited from Murex)

• preview modes
  (inherited from Murex)

• API improvements

• rewritten event system
  (discussion)

• vastly improved buffered rendering -- this leads to few rendering glitches
  and particularly on slower machines and/or terminals

• added missing vim and emacs keybindings
  (full list of keybindings)

• additional tests

• fixed glitches on Windows terminals
  (discussion)

• readline command mode
  (discussion)

bug fixes

This is a bug fix release:

• Nil map panic fixed when using dtx.AppendSuggestions()

• Hint text line proper blanked (this is a fix to a regression bug introduced in version 3.0.0)

• Example 01 updated to reflect API changes in 3.0.0

asynchronous updates / improved line wrapping

This release brings a considerable number of new features and bug fixes
inherited from readline's use in murex (https://github.com/lmorg/murex)

• Wrapped lines finally working (where the input line is longer than the
  terminal width)

• Delayed tab completion - allows asynchronous updates to the tab completion so
  slower suggestions do not halt the user experience

• Delayed syntax timer - allows syntax highlighting to run asynchronously for
  slower parsers (eg spell checkers)

• Support for GetCursorPos ANSI escape sequence (though I don't have a terminal
  which supports this to test the code on)

• Better support for wrapped hint text lines

• Fixed bug with $EDITOR error handling in Windows and Plan 9

• Code clean up - fewer writes to the terminal