CHANGELOG

=========

3.0.41: 2023-11-14

------------------

Fixes:

- Fix regression regarding IPython input hook (%gui) integration.

3.0.40: 2023-11-10

------------------

Fixes:

- Improved Python 3.12 support (fixes event loop `DeprecationWarning`).

New features:

- Vi key bindings: `control-t` and `control-d` for indent/unindent in insert

mode.

- Insert partial suggestion when `control+right` is pressed, similar to Fish.

- Use sphinx-nefertiti theme for the docs.

3.0.39: 2023-07-04

------------------

Fixes:

- Fix `RuntimeError` when `__breakpointhook__` is called from another thread.

- Fix memory leak in filters usage.

- Ensure that key bindings are handled in the right context (when using

contextvars).

New features:

- Accept `in_thread` keyword in `prompt_toolkit.shortcuts.prompt()`.

- Support the `NO_COLOR` environment variable.

3.0.38: 2023-02-28

------------------

Fixes:

- Fix regression in filters. (Use of `WeakValueDictionary` caused filters to

not be cached).

New features:

- Use 24-bit true color now by default on Windows 10/11.

3.0.37: 2023-02-21

------------------

Bug fixes:

- Fix `currentThread()` deprecation warning.

- Fix memory leak in filters.

- Make VERSION tuple numeric.

New features:

- Add `.run()` method in `TelnetServer`. (To be used instead of

`.start()/.stop()`.

Breaking changes:

- Subclasses of `Filter` have to call `super()` in their `__init__`.

- Drop support for Python 3.6:

* This includes code cleanup for Python 3.6 compatibility.

* Use `get_running_loop()` instead of `get_event_loop()`.

* Use `asyncio.run()` instead of `asyncio.run_until_complete()`.

3.0.36: 2022-12-06

------------------

Fixes:

- Another Python 3.6 fix for a bug that was introduced in 3.0.34.

3.0.35: 2022-12-06

------------------

Fixes:

- Fix bug introduced in 3.0.34 for Python 3.6. Use asynccontextmanager

implementation from prompt_toolkit itself.

3.0.34: 2022-12-06

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Fixes:

- Improve completion performance in various places.

- Improve renderer performance.

- Handle `KeyboardInterrupt` when the stacktrace of an unhandled error is

displayed.

- Use correct event loop in `Application.create_background_task()`.

- Fix `show_cursor` attribute in `ScrollablePane`.

3.0.33: 2022-11-21

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Fixes:

- Improve termination of `Application`. Don't suppress `CancelledError`. This

fixes a race condition when an `Application` gets cancelled while we're

waiting for the background tasks to complete.

- Fixed typehint for `OneStyleAndTextTuple`.

- Small bugfix in `CombinedRegistry`. Fixed missing `@property`.

3.0.32: 2022-11-03

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Bug fixes:

- Use `DummyInput` by default in `create_input()` if `sys.stdin` does not have

a valid file descriptor. This fixes errors when `sys.stdin` is patched in

certain situations.

- Fix control-c key binding for `ProgressBar` when the progress bar was not

created from the main thread. The current code would try to kill the main

thread when control-c was pressed.

New features:

- Accept a `cancel_callback` in `ProgressBar` to specify the cancellation

behavior for when `control-c` is pressed.

- Small performance improvement in the renderer.

3.0.31: 2022-09-02

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New features:

- Pass through `name` property in `TextArea` widget to `Buffer`.

- Added a `enable_cpr` parameter to `Vt100_Output`, `TelnetServer` and

`PromptToolkitSSHServer`, to completely disable CPR support instead of

automatically detecting it.

3.0.30: 2022-06-27

------------------

New features:

- Allow zero-width-escape sequences in `print_formatted_text`.

- Add default value option for input dialog.

- Added `has_suggestion` filter.

Fixes:

- Fix rendering of control-shift-6 (or control-^). Render as '^^'

- Always wrap lines in the Label widget by default.

- Fix enter key binding in system toolbar in Vi mode.

- Improved handling of stdout objects that don't have a 'buffer' attribute. For

instance, when using `renderer_print_formatted_text` in a Jupyter Notebook.

3.0.29: 2022-04-04

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New features:

- Accept 'handle_sigint' parameter in PromptSession.

Fixes

- Fix 'variable referenced before assignment' error in vt100 mouse bindings.

- Pass `handle_sigint` from `Application.run` to `Application.run_async`.

- Fix detection of telnet client side changes.

- Fix `print_container` utility (handle `EOFError`).

Breaking changes:

- The following are now context managers:

`create_pipe_input`, `PosixPipeInput` and `Win32PipeInput`.

3.0.28: 2022-02-11

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New features:

- Support format specifiers for HTML and ANSI formatted text.

- Accept defaults for checkbox and radio list, and their corresponding dialogs.

Fixes:

- Fix resetting of cursor shape after the application terminates.

3.0.27: 2022-02-07

------------------

New features:

- Support for cursor shapes. The cursor shape for prompts/applications can now

be configured, either as a fixed cursor shape, or in case of Vi input mode,

according to the current input mode.

- Handle "cursor forward" command in ANSI formatted text. This makes it

possible to render many kinds of generated ANSI art.

- Accept `align` attribute in `Label` widget.

- Added `PlainTextOutput`: an output implementation that doesn't render any

ANSI escape sequences. This will be used by default when redirecting stdout

to a file.

- Added `create_app_session_from_tty`: a context manager that enforces

input/output to go to the current TTY, even if stdin/stdout are attached to

pipes.

- Added `to_plain_text` utility for converting formatted text into plain text.

Fixes:

- Don't automatically use `sys.stderr` for output when `sys.stdout` is not a

TTY, but `sys.stderr` is. The previous behavior was confusing, especially

when rendering formatted text to the output, and we expect it to follow

redirection.

3.0.26: 2022-01-27

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Fixes:

- Fixes issue introduced in 3.0.25: Don't handle SIGINT on Windows.

3.0.25: 2022-01-27

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Fixes:

- Use `DummyOutput` when `sys.stdout` is `None` and `DummyInput` when

`sys.stdin` is `None`. This fixes an issue when the code runs on windows,

using pythonw.exe and still tries to interact with the terminal.

- Correctly reset `Application._is_running` flag in case of exceptions in some

situations.

- Handle SIGINT (when sent from another process) and allow binding it to a key

binding. For prompt sessions, the behavior is now identical to pressing

control-c.

- Increase the event loop `slow_duration_callback` by default to 0.5. This

prevents printing warnings if rendering takes too long on slow systems.

3.0.24: 2021-12-09

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Fixes:

- Prevent window content overflowing when using scrollbars.

- Handle `PermissionError` when trying to attach /dev/null in vt100 input.

3.0.23: 2021-11-26

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Fixes:

- Fix multiline bracketed paste on Windows

New features:

- Add support for some CSI 27 modified variants of "Enter" for xterm in the

vt100 input parser.

3.0.22: 2021-11-04

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Fixes:

- Fix stopping of telnet server (capture cancellation exception).

3.0.21: 2021-10-21

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New features:

- Improved mouse support:

* Support for click-drag, which is useful for selecting text.

* Detect mouse movements when no button is pressed.

- Support for Python 3.10.

3.0.20: 2021-08-20

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New features:

- Add support for strikethrough text attributes.

- Set up custom breakpointhook while an application is running (if no other

breakpointhook was installed). This enhances the usage of PDB for debugging

applications.

- Strict type checking is now enabled.

Fixes:

- Ensure that `print_formatted_text` is always printed above the running

application, like `patch_stdout`. (Before, `patch_stdout` was even completely

ignored in case of `print_formatted_text, so there was no proper way to use

it in a running application.)

- Fix handling of non-bmp unicode input on Windows.

- Set minimum Python version to 3.6.2 (Some 3.6.2 features were used).

3.0.19: 2021-06-17

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Fixes:

- Make the flush method of the vt100 output implementation re-entrant (fixes an

issue when using aiogevent).

- Fix off-by-one in `FormattedTextControl` mouse logic.

- Run `print_container` always in a thread (avoid interfering with possible

event loop).

- Make sphinx autodoc generation platform agnostic (don't import Windows stuff

when generating Sphinx docs).

3.0.18: 2021-03-22

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New features:

- Added `in_thread` parameter to `Application.run`.

This is useful for running an application in a background thread, while the

main thread blocks. This way, we are sure not to interfere with an event loop

in the current thread. (This simplifies some code in ptpython and fixes an

issue regarding leaking file descriptors due to not closing the event loop

that was created in this background thread.)

3.0.17: 2021-03-11

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New features:

- Accept `style` parameter in `print_container` utility.

- On Windows, handle Control-Delete.

Fixes:

- Avoid leaking file descriptors in SSH server.

3.0.16: 2021-02-11

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New features:

- Added `ScrollablePane`: a scrollable layout container.

This allows applications to build a layout, larger than the terminal, with a

vertical scroll bar. The vertical scrolling will be done automatically when

certain widgets receive the focus.

- Added `DeduplicateCompleter and `ConditionalCompleter`.

- Added `deduplicate` argument to `merge_completers`.

3.0.15: 2021-02-10

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Fixes:

- Set stdout blocking when writing in vt100 output. Fixes an issue when uvloop

is used and big amounts of text are written.

- Guarantee height of at least 1 for both labels and text areas.

- In the `Window` rendering, take `dont_extend_width`/`dont_extend_height` into

account. This fixes issues where one window is enlarged unexpectedly because

it's bundled with another window in a `HSplit`/`VSplit`, but with different

width/height.

- Don't handle `SIGWINCH` in progress bar anymore. (The UI runs in another

thread, and we have terminal size polling now).

- Fix several thread safety issues and a race condition in the progress bar.

- Fix thread safety issues in `Application.invalidate()`. (Fixes a

`RuntimeError` in some situations when using progress bars.)

- Fix handling of mouse events on Windows if we have a Windows 10 console with

ANSI support.

- Disable `QUICK_EDIT_MODE` on Windows 10 when mouse support is requested.

3.0.14: 2021-01-24

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New features:

- Disable bell when `PROMPT_TOOLKIT_BELL=false` environment variable has been

set.

Fixes:

- Improve cancellation of history loading.

3.0.13: 2021-01-21

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Fixes:

- Again, fixed the race condition in `ThreadedHistory`. Previous fix was not

correct.

3.0.12: 2021-01-21

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Fixes:

- Fixed a race condition in `ThreadedHistory` that happens when continuously

pasting input text (which would continuously repopulate the history).

- Move cursor key mode resetting (for vt100 terminals) to the renderer. (Mostly

cleanup).

3.0.11: 2021-01-20

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New features:

- Poll terminal size: better handle resize events when the application runs in

a thread other than the main thread (where handling SIGWINCH doesn't work) or

in the Windows console.

Fixes:

- Fix bug in system toolbar. The execution of system commands was broken.

- A refactoring of patch_stdout that includes several fixes.

* We know look at the `AppSession` in order to see which application is

running, rather then looking at the event loop which is installed when

`StdoutProxy` is created. This way, `patch_stdout` will work when

prompt_toolkit applications with a different event loop run.

* Fix printing when no application/event loop is running.

* Fixed the `raw` argument of `PatchStdout`.

- A refactoring of the `ThreadedHistory`, which includes several fixes, in

particular a race condition (see issue #1158) that happened when editing

input while a big history was still being loaded in the background.

3.0.10: 2021-01-08

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New features:

- Improved `WordCompleter`: accept `display_dict`. Also accept formatted text

for both `display_dict` and `meta_dict`.

- Allow customization of button arrows.

Fixes:

- Correctly recognize backtab on Windows.

- Show original display text in fuzzy completer if no filtering was done.

3.0.9: 2021-01-05

-----------------

New features:

- Handle c-tab for TERM=linux.

Fixes:

- Improve rendering speed of `print_formatted_text`. (Don't render styling

attributes to output between fragments that have identical styling.)

- Gracefully handle `FileHistory` decoding errors.

- Prevent asyncio deprecation warnings.

3.0.8: 2020-10-12

-----------------

New features:

- Added `validator` parameter to `input_dialog`.

Fixes:

- Cope with stdout not having a working `fileno`.

- Handle situation when /dev/null is piped into stdin, or when stdin is closed

somehow.

- Fix for telnet/ssh server: `isatty` method was not implemented.

- Display correct error when a tuple is passed into `to_formatted_text`.

- Pass along WORD parameter in `Document._is_word_before_cursor_complete`.

Fixes some key bindings.

- Expose `ProgressBarCounter` in shortcuts module.

3.0.7: 2020-08-29

-----------------

New features:

- New "placeholder" parameter added to `PromptSession`.

Other changes:

- The "respond to CPR" logic has been moved from the `Input` to `Output`

classes (this does clean up some code).

Fixes:

- Bugfix in shift-selection key bindings.

- Fix height calculation of `FormattedTextControl` when line wrapping is turned

on.

- Fixes for SSH server:

* Missing encoding property.

* Fix failure in "set_line_mode" call.

* Handle `BrokenPipeError`.

3.0.6: 2020-08-10

-----------------

New features:

- The SSH/Telnet adaptors have been refactored and improved in several ways.

See issues #876 and PR #1150 and #1184 on GitHub.

* Handle terminal types for both telnet and SSH sessions.

* Added pipe input abstraction. (base class for `PosixPipeInput` and

`Win32PipeInput`).

* The color depth logic has been refactored and moved to the `Output`

implementations. Added `get_default_color_depth` method to `Output`

objects.

* All line feet are now preceded by a carriage return in the telnet

connection stdout.

- Introduce `REPLACE_SINGLE` input mode for Vi key bindings.

- Improvements to the checkbox implementation:

* Hide the scrollbar for a single checkbox.

* Added a "checked" setter to the checkbox.

- Expose `KeyPressEvent` in key_binding/__init__.py (often used in type

annotations).

- The renderer has been optimized so that no trailing spaces are generated

(this improves copying in some terminals).

Fixes:

- Ignore F21..F24 key bindings by default.

- Fix auto_suggest key bindings when suggestion text is empty.

- Bugfix in SIGWINCH handling.

- Handle bug in HSplit/VSplit when the number of children is zero.

- Bugfix in CPR handling in renderer. Proper cancellation of pending tasks.

- Ensure rprompt aligns with input.

- Use `sys.stdin.encoding` for decoding stdin stream.

3.0.5: 2020-03-26

-----------------

Fixes:

- Bugfix in mouse handling on Windows.

3.0.4: 2020-03-06

-----------------

New features:

- Added many more vt100 ANSI sequences and keys.

- Improved control/shift key support in Windows.

- No Mypy errors in prompt_toolkit anymore.

- Added `set_exception_handler` optional argument to `PromptSession.prompt()`.

Fixes:

- Bugfix in invalidate code. `PromptSession` was invalidating the UI

continuously.

- Add uvloop support (was broken due to an issue in our `call_soon_threadsafe`).

- Forwarded `set_exception_handler` in `Application.run` to the `run_async` call.

- Bugfix in `NestedCompleter` when there is a leading space.

Breaking changes:

- `ShiftControl` has been replaced with `ControlShift` and `s-c` with `c-s` in

key bindings. Aliases for backwards-compatibility have been added.

3.0.3: 2020-01-26

-----------------

New features:

- Improved support for "dumb" terminals.

- Added support for new keys (vt100 ANSI sequences): Alt +

home/end/page-up/page-down/insert.

- Better performance for the "regular languages compiler". Generate fewer and

better regular expressions. This should improve the start-up time for

applications using this feature.

- Better detection of default color depth.

- Improved the progress bar:

* Set "time left" to 0 when done or stopped.

* Added `ProgressBarCounter.stopped`.

- Accept callables for `scroll_offset`, `min_brightness` and `max_brightness`.

- Added `always_prefer_tty` parameters to `create_input()` and `create_output()`.

- Create a new event loop in `Application.run()` if `get_event_loop()` raises

`Runtimeerror`.

Fixes:

- Correct cancellation of flush timers for input. (Fixes resource leak where

too many useless coroutines were created.)

- Improved the Win32 input event loop. This fixes a bug where the

prompt_toolkit application is stopped by something other than user input. (In

that case, the application would hang, waiting for input.) This also fixes a

`RuntimeError` in the progress bar code.

- Fixed `line-number.current` style. (was `current-line-number`.)

- Handle situation where stdout is no longer a tty (fix bug in `get_size`).

- Fix parsing of true color in ANSI strings.

- Ignore `invalidate()` if the application is not running.

3.0.2: 2019-11-30

-----------------

Fixes:

- Bugfix in the UI invalidation. Fixes an issue when the application runs again

on another event loop.

See: https://github.com/ipython/ipython/pull/11973

3.0.1: 2019-11-28

-----------------

New features:

- Added `new_eventloop_with_inputhook` function.

- Set exception handler from within `Application.run_async`.

- Applied Black code style.

Fixes:

- No longer expect a working event loop in the `History` classes.

(Fix for special situations when a `ThreadedHistory` is created before the

event loop has been set up.)

- Accept an empty prompt continuation.

- A few fixes to the `Buffer` tempfile code.

3.0.0: 2019-11-24

-----------------

New features:

- (almost) 100% type annotated.

- Native asyncio instead of custom event loops.

- Added shift-based text selection (use shift+arrows to start selecting text).

Breaking changes:

- Python 2 support has been dropped. Minimal Python version is now 3.6,

although 3.7 is preferred (because of ContextVars).

- Native asyncio, so some async code becomes slightly different.

- The active `Application` became a contextvar. Which means that it should be

propagated correctly to the code that requires it. However, random other

threads or coroutines won't be able to know what the current application is.

- The dialog shortcuts API changed. All dialog functions now return an

`Application`. You still have to call either `run()` or `run_async` on the

`Application` object.

- The way inputhooks work is changed.

- `patch_stdout` now requires an `Application` as input.

2.0.9: 2019-02-19

-----------------

Bug fixes:

- Fixed `Application.run_system_command` on Windows.

- Fixed bug in ANSI text formatting: correctly handle 256/true color sequences.

- Fixed bug in WordCompleter. Provide completions when there's a space before

the cursor.

2.0.8: 2019-01-27

-----------------

Bug fixes:

- Fixes the issue where changes made to the buffer in the accept handler were

not reflected in the history.

- Fix in the application invalidate handler. This prevents a significant slow

down in some applications after some time (especially if there is a refresh

interval).

- Make `print_container` utility work if the input is not a pty.

New features:

- Underline non breaking spaces instead of rendering as '&'.

- Added mouse support for radio list.

- Support completion styles for `READLINE_LIKE` display method.

- Accept formatted text in the display text of completions.

- Added a `FuzzyCompleter` and `FuzzyWordCompleter`.

- Improved error handling in Application (avoid displaying a meaningless

AssertionError in many cases).

2.0.7: 2018-10-30

-----------------

Bug fixes:

- Fixed assertion in PromptSession: the style_transformation check was wrong.

- Removed 'default' attribute in PromptSession. Only ask for it in the

`prompt()` method. This fixes the issue that passing `default` once, will

store it for all consequent calls in the `PromptSession`.

- Ensure that `__pt_formatted_text__` always returns a `FormattedText`

instance. This fixes an issue with `print_formatted_text`.

New features:

- Improved handling of situations where stdin or stdout are not a terminal.

(Print warning instead of failing with an assertion.)

- Added `print_container` utility.

- Sound bell when attempting to edit read-only buffer.

- Handle page-down and page-up keys in RadioList.

- Accept any `collections.abc.Sequence` for HSplit/VSplit children (instead of

lists only).

- Improved Vi key bindings: return to navigation mode when Insert is pressed.

2.0.6: 2018-10-12

-----------------

Bug fixes:

- Don't use the predefined ANSI colors for colors that are defined as RGB.

(Terminals can assign different color schemes for ansi colors, and we don't

want use any of those for colors that are defined like #aabbcc for instance.)

- Fix in handling of CPRs when patch_stdout is used.

Backwards incompatible changes:

- Change to the `Buffer` class. Reset the buffer unless the `accept_handler`

returns `True` (which means: "keep_text"). This doesn't affect applications

that use `PromptSession`.

New features:

- Added `AdjustBrightnessStyleTransformation`. This is a simple style

transformation that improves the rendering on terminals with light or dark

background.

- Improved performance (string width caching and line height calculation).

- Improved `TextArea`:

* Exposed `focus_on_click`.

* Added attributes: `auto_suggest`, `complete_while_typing`, `history`,

`get_line_prefix`, `input_processors`.

* Made attributes writable: `lexer`, `completer`, `complete_while_typing`,

`accept_handler`, `read_only`, `wrap_lines`.

2.0.5: 2018-09-30

-----------------

Bug fixes:

- Fix in `DynamicContainer`. Return correct result for `get_children`. This

fixes a bug related to focusing.

- Properly compute length of `start`, `end` and `sym_b` characters of

progress bar.

- CPR (cursor position request) fix.

Backwards incompatible changes:

- Stop restoring `PromptSession` attributes when exiting prompt.

New features:

- Added `get_line_prefix` attribute to window. This opens many

possibilities:

* Line wrapping (soft and hard) can insert whitespace in front

of the line, or insert some symbols in front. Like the Vim "breakindent"

option.

* Single line prompts also support line continuations now.

* Line continuations can have a variable width.

- For VI mode: implemented temporary normal mode (control-O in insert mode).

- Added style transformations API. Useful for swapping between light and

dark color schemes. Added `swap_light_and_dark_colors` parameter to

`prompt()` function.

- Added `format()` method to ANSI formatted text.

- Set cursor position for Button widgets.

- Added `pre_run` argument to `PromptSession.prompt()` method.

2.0.4: 2018-07-22

-----------------

Bug fixes:

- Fix render height for rendering full screen applications in Windows.

- Fix in `TextArea`. Set `accept_handler` to `None` if not given.

- Go to the beginning of the next line when enter is pressed in Vi navigation

mode, and the buffer doesn't have an accept handler.

- Fix the `default` argument of the `prompt` function when called multiple

times.

- Display decomposed multiwidth characters correctly.

- Accept `history` in `prompt()` function again.

Backwards incompatible changes:

- Renamed `PipeInput` to `PosixPipeInput`. Added `Win32PipeInput` and

`create_input_pipe`.

- Pass `buffer` argument to the `accept_handler` of `TextArea`.

New features:

- Added `accept_default` argument to `prompt()`.

- Make it easier to change the body/title of a Frame/Dialog.

- Added `DynamicContainer`.

- Added `merge_completers` for merging multiple completers together.

- Add vt100 data to key presses in Windows.

- Handle left/right key bindings in Vi block insert mode.

2.0.3: 2018-06-08

-----------------

Bug fixes:

- Fix in 'x' and 'X' Vi key bindings. Correctly handle line endings and args.

- Fixed off by one error in Vi line selection.

- Fixed bugs in Vi block selection. Correctly handle lines that the selection

doesn't cross.

- Python 2 bugfix. Handle str/unicode correctly.

- Handle option+left/right in iTerm.

2.0.2: 2018-06-03

-----------------

Bug fixes:

- Python 3.7 support: correctly handle StopIteration in asynchronous generator.

- Fixed off-by-one bug in Vi visual block mode.

- Bugfix in TabsProcessor: handle situations when the cursor is at the end of

the line.

2.0.1: 2018-06-02

-----------------

Version 2.0 includes a big refactoring of the internal architecture. This

includes the merge of the CommandLineInterface and the Application object, a

rewrite of how user controls are focused, a rewrite of how event loops work

and the removal of the buffers dictionary. This introduces many backwards

incompatible changes, but the result is a very nice and powerful architecture.

Most architectural changes effect full screen applications. For applications

that use `prompt_toolkit.shortcuts` for simple prompts, there are fewer

incompatibilities.

Changes:

- No automatic translation from \r into \n during the input processing. These

are two different keys that can be handled independently. This is a big

backward-incompatibility, because the `Enter` key is `ControlM`, not

`ControlJ`. So, now that we stopped translating \r into \n, it could be that

custom key bindings for `Enter` don't work anymore. Make sure to bind

`Keys.Enter` instead of `Keys.ControlJ` for handling the `Enter` key.

- The `CommandLineInterface` and the `Application` classes are merged. First,

`CommandLineInterface` contained all the I/O objects (like the input, output

and event loop), while the `Application` contained everything else. There was

no practical reason to keep this separation. (`CommandLineInterface` was

mostly a proxy to `Application`.)

A consequence is that almost all code which used to receive a

`CommandLineInterface`, will now use an `Application`. Usually, where we

had an attribute `cli`, we'll now have an attribute `app`.

Secondly, the `Application` object is no longer passed around. The `get_app`

function can be used at any time to acquire the active application.

(For backwards-compatibility, we have aliases to the old names, whenever

possible.)

- prompt_toolkit no longer depends on Pygments, but it can still use Pygments

for its color schemes and lexers. In many places we used Pygments "Tokens",

this has been replaced by the concept of class names, somewhat similar to

HTML and CSS.

* `PygmentsStyle` and `PygmentsLexer` adaptors are available for

plugging in Pygments styles and lexers.

* Wherever we had a list of `(Token, text)` tuples, we now have lists of

`(style_string, text)` tuples. The style string can contain both inline

styling as well as refer to a class from the style sheet. `PygmentsTokens`

is an adaptor that converts a list of Pygments tokens into a list of

`(style_string, text)` tuples.

- Changes in the `Style` classes.

* `style.from_dict` does not exist anymore. Instantiate the ``Style`` class

directory to create a new style. ``Style.from_dict`` can be used to create

a style from a dictionary, where the dictionary keys are a space separated

list of class names, and the values, style strings (like before).

* `print_tokens` was renamed to `print_formatted_text`.

* In many places in the layout, we accept a parameter named `style`. All the

styles from the layout hierarchy are combined to decide what style to be

used.

* The ANSI color names were confusing and inconsistent with common naming

conventions. This has been fixed, but aliases for the original names were

kept.

- The way focusing works is different. Before it was always a `Buffer` that

was focused, and because of that, any visible `BufferControl` that contained

this `Buffer` would be focused. Now, any user control can be focused. All

of this is handled in the `Application.layout` object.

- The `buffers` dictionary (`CommandLineInterface.buffers`) does not exist

anymore. Further, `buffers` was a `BufferMapping` that keeps track of which

buffer has the focus. This significantly reduces the freedom for creating

complex applications. We wanted to move toward a layout that can be defined

as a (hierarchical) collection of user widgets. A user widget does not need

to have a `Buffer` underneath and any widget should be focusable.

* `layout.Layout` was introduced to contain the root layout widget and keep

track of the focus.

- The key bindings were refactored. It became much more flexible to combine

sets of key bindings.

* `Registry` has been renamed to `KeyBindings`.

* The `add_binding` function has been renamed to simply `add`.

* Every `load_*` function returns one `KeyBindings` objects, instead of

populating an existing one, like before.

* `ConditionalKeyBindings` was added. This can be used to enable/disable

all the key bindings from a given `Registry`.

* A function named `merge_key_bindings` was added. This takes a list of

`KeyBindings` and merges them into one.

* `key_binding.defaults.load_key_bindings` was added to load all the key

bindings.

* `KeyBindingManager` has been removed completely.

* `input_processor` was renamed to `key_processor`.

Further:

* The `Key` class does not exist anymore. Every key is a string and it's

considered fine to use string literals in the key bindings. This is more

readable, but we still have run-time validation. The `Keys` enum still

exist (for backwards-compatibility, but also to have an overview of which

keys are supported.)

* 'enter' and 'tab' are key aliases for 'c-m' and 'c-i'.

- User controls can define key bindings, which are active when the user control

is focused.

* `UIControl` got a `get_key_bindings` (abstract) method.

- Changes in the layout engine:

* `LayoutDimension` was renamed to `Dimension`.

* `VSplit` and `HSplit` now take a `padding` argument.

* `VSplit` and `HSplit` now take an `align` argument.

(TOP/CENTER/BOTTOM/JUSTIFY) or (LEFT/CENTER/RIGHT/JUSTIFY).

* `Float` now takes `allow_cover_cursor` and `attach_to_window` arguments.

* `Window` got an `WindowAlign` argument. This can be used for the alignment

of the content. `TokenListControl` (renamed to `FormattedTextControl`) does

not have an alignment argument anymore.

* All container objects, like `Window`, got a `style` argument. The style for

parent containers propagate to child containers, but can be overridden.

This is in particular useful for setting a background color.

* `FillControl` does not exist anymore. Use the `style` and `char` arguments

of the `Window` class instead.

* `DummyControl` was added.

* The continuation function of `PromptMargin` now takes `line_number` and

`is_soft_wrap` as input.

- Changes to `BufferControl`:

* The `InputProcessor` class has been refactored. The `apply_transformation`

method should now takes a `TransformationInput` object as input.

* The text `(reverse-i-search)` is now displayed through a processor. (See

the `shortcuts` module for an example of its usage.)

- `widgets` and `dialogs` modules:

* A small collection of widgets was added. These are more complex collections

of user controls that are ready to embed in a layout. A `shortcuts.dialogs`

module was added as a high level API for displaying input, confirmation and

message dialogs.

* Every class that exposes a ``__pt_container__`` method (which is supposed

to return a ``Container`` instance) is considered a widget. The

``to_container`` shortcut will call this method in situations where a

``Container`` object is expected. This avoids inheritance from other

``Container`` types, but also having to unpack the container object from

the widget, in case we would have used composition.

* Warning: The API of the widgets module is not considered stable yet, and

can change is the future, if needed.

- Changes to `Buffer`:

* A `Buffer` no longer takes an `accept_action`. Both `AcceptAction` and

`AbortAction` have been removed. Instead it takes an `accept_handler`.

- Changes regarding auto completion:

* The left and right arrows now work in the multi-column auto completion

menu.

* By default, autocompletion is synchronous. The completer needs to be

wrapped in `ThreadedCompleter` in order to get asynchronous autocompletion.

* When the completer runs in a background thread, completions will be

displayed as soon as they are generated. This means that we don't have to

wait for all the completions to be generated, before displaying the first

one. The completion menus are updated as soon as new completions arrive.

- Changes regarding input validation:

* Added the `Validator.from_callable` class method for easy creation of

new validators.

- Changes regarding the `History` classes:

* The `History` base class has a different interface. This was needed for

asynchronous loading of the history. `ThreadedHistory` was added for this.

- Changes related to `shortcuts.prompt`:

* There is now a class `PromptSession` which also has a method `prompt`. Both

the class and the method take about the same arguments. This can be used to

create a session. Every `prompt` call of the same instance will reuse all

the arguments given to the class itself.

The input history is always shared during the entire session.

Of course, it's still possible to call the global `prompt` function. This

will create a new `PromptSession` every time when it's called.

* The `prompt` function now takes a `key_bindings` argument instead of

`key_bindings_registry`. This should only contain the additional bindings.

(The default bindings are always included.)

- Changes to the event loops:

* The event loop API is now closer to how asyncio works. A prompt_toolkit

`Application` now has a `Future` object. Calling the `.run_async()` method

creates and returns that `Future`. An event loop has a `run_until_complete`

method that takes a future and runs the event loop until the Future is set.

The idea is to be able to transition easily to asyncio when Python 2

support can be dropped in the future.

* `Application` still has a method `run()` that underneath still runs the

event loop until the `Future` is set and returns that result.

* The asyncio adaptors (like the asyncio event loop integration) now require

Python 3.5. (We use the async/await syntax internally.)

* The `Input` and `Output` classes have some changes. (Not really important.)

* `Application.run_sub_applications` has been removed. The alternative is to

call `run_coroutine_in_terminal` which returns a `Future`.

- Changes to the `filters` module:

* The `Application` is no longer passed around, so both `CLIFilter` and

`SimpleFilter` were merged into `Filter`. `to_cli_filter` and

`to_simple_filter` became `to_filter`.

* All filters have been turned into functions. For instance, `IsDone`

became `is_done` and `HasCompletions` became `has_completions`.

This was done because almost all classes were called without any arguments

in the `__init__` causing additional braces everywhere. This means that

`HasCompletions()` has to be replaced by `has_completions` (without

parenthesis).

The few filters that took arguments as input, became functions, but still

have to be called with the given arguments.

For new filters, it is recommended to use the `@Condition` decorator,

rather then inheriting from `Filter`.