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this has been replaced by the concept of class names, somewhat similar to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`.
- Other renames:
* `IncrementalSearchDirection` was renamed to `SearchDirection`.
* The `use_alternate_screen` parameter has been renamed to `full_screen`.
* `Buffer.initial_document` was renamed to `Buffer.document`.
* `TokenListControl` has been renamed to `FormattedTextControl`.
* `Application.set_return_value` has been renamed to `Application.set_result`.
- Other new features:
* `DummyAutoSuggest` and `DynamicAutoSuggest` were added.
* `DummyClipboard` and `DynamicClipboard` were added.
* `DummyCompleter` and `DynamicCompleter` were added.
* `DummyHistory` and `DynamicHistory` was added.
* `to_container` and `to_window` utilities were added.