1 files changed, 557 insertions, 0 deletions
diff --git a/src/prompt_toolkit/key_binding/bindings/emacs.py b/src/prompt_toolkit/key_binding/bindings/emacs.py
new file mode 100644
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--- /dev/null
+++ b/src/prompt_toolkit/key_binding/bindings/emacs.py
@@ -0,0 +1,557 @@
+# pylint: disable=function-redefined
+from __future__ import annotations
+
+from prompt_toolkit.application.current import get_app
+from prompt_toolkit.buffer import Buffer, indent, unindent
+from prompt_toolkit.completion import CompleteEvent
+from prompt_toolkit.filters import (
+    Condition,
+    emacs_insert_mode,
+    emacs_mode,
+    has_arg,
+    has_selection,
+    in_paste_mode,
+    is_multiline,
+    is_read_only,
+    shift_selection_mode,
+    vi_search_direction_reversed,
+)
+from prompt_toolkit.key_binding.key_bindings import Binding
+from prompt_toolkit.key_binding.key_processor import KeyPressEvent
+from prompt_toolkit.keys import Keys
+from prompt_toolkit.selection import SelectionType
+
+from ..key_bindings import ConditionalKeyBindings, KeyBindings, KeyBindingsBase
+from .named_commands import get_by_name
+
+__all__ = [
+    "load_emacs_bindings",
+    "load_emacs_search_bindings",
+    "load_emacs_shift_selection_bindings",
+]
+
+E = KeyPressEvent
+
+
+def load_emacs_bindings() -> KeyBindingsBase:
+    """
+    Some e-macs extensions.
+    """
+    # Overview of Readline emacs commands:
+    # http://www.catonmat.net/download/readline-emacs-editing-mode-cheat-sheet.pdf
+    key_bindings = KeyBindings()
+    handle = key_bindings.add
+
+    insert_mode = emacs_insert_mode
+
+    @handle("escape")
+    def _esc(event: E) -> None:
+        """
+        By default, ignore escape key.
+
+        (If we don't put this here, and Esc is followed by a key which sequence
+        is not handled, we'll insert an Escape character in the input stream.
+        Something we don't want and happens to easily in emacs mode.
+        Further, people can always use ControlQ to do a quoted insert.)
+        """
+        pass
+
+    handle("c-a")(get_by_name("beginning-of-line"))
+    handle("c-b")(get_by_name("backward-char"))
+    handle("c-delete", filter=insert_mode)(get_by_name("kill-word"))
+    handle("c-e")(get_by_name("end-of-line"))
+    handle("c-f")(get_by_name("forward-char"))
+    handle("c-left")(get_by_name("backward-word"))
+    handle("c-right")(get_by_name("forward-word"))
+    handle("c-x", "r", "y", filter=insert_mode)(get_by_name("yank"))
+    handle("c-y", filter=insert_mode)(get_by_name("yank"))
+    handle("escape", "b")(get_by_name("backward-word"))
+    handle("escape", "c", filter=insert_mode)(get_by_name("capitalize-word"))
+    handle("escape", "d", filter=insert_mode)(get_by_name("kill-word"))
+    handle("escape", "f")(get_by_name("forward-word"))
+    handle("escape", "l", filter=insert_mode)(get_by_name("downcase-word"))
+    handle("escape", "u", filter=insert_mode)(get_by_name("uppercase-word"))
+    handle("escape", "y", filter=insert_mode)(get_by_name("yank-pop"))
+    handle("escape", "backspace", filter=insert_mode)(get_by_name("backward-kill-word"))
+    handle("escape", "\\", filter=insert_mode)(get_by_name("delete-horizontal-space"))
+
+    handle("c-home")(get_by_name("beginning-of-buffer"))
+    handle("c-end")(get_by_name("end-of-buffer"))
+
+    handle("c-_", save_before=(lambda e: False), filter=insert_mode)(
+        get_by_name("undo")
+    )
+
+    handle("c-x", "c-u", save_before=(lambda e: False), filter=insert_mode)(
+        get_by_name("undo")
+    )
+
+    handle("escape", "<", filter=~has_selection)(get_by_name("beginning-of-history"))
+    handle("escape", ">", filter=~has_selection)(get_by_name("end-of-history"))
+
+    handle("escape", ".", filter=insert_mode)(get_by_name("yank-last-arg"))
+    handle("escape", "_", filter=insert_mode)(get_by_name("yank-last-arg"))
+    handle("escape", "c-y", filter=insert_mode)(get_by_name("yank-nth-arg"))
+    handle("escape", "#", filter=insert_mode)(get_by_name("insert-comment"))
+    handle("c-o")(get_by_name("operate-and-get-next"))
+
+    # ControlQ does a quoted insert. Not that for vt100 terminals, you have to
+    # disable flow control by running ``stty -ixon``, otherwise Ctrl-Q and
+    # Ctrl-S are captured by the terminal.
+    handle("c-q", filter=~has_selection)(get_by_name("quoted-insert"))
+
+    handle("c-x", "(")(get_by_name("start-kbd-macro"))
+    handle("c-x", ")")(get_by_name("end-kbd-macro"))
+    handle("c-x", "e")(get_by_name("call-last-kbd-macro"))
+
+    @handle("c-n")
+    def _next(event: E) -> None:
+        "Next line."
+        event.current_buffer.auto_down()
+
+    @handle("c-p")
+    def _prev(event: E) -> None:
+        "Previous line."
+        event.current_buffer.auto_up(count=event.arg)
+
+    def handle_digit(c: str) -> None:
+        """
+        Handle input of arguments.
+        The first number needs to be preceded by escape.
+        """
+
+        @handle(c, filter=has_arg)
+        @handle("escape", c)
+        def _(event: E) -> None:
+            event.append_to_arg_count(c)
+
+    for c in "0123456789":
+        handle_digit(c)
+
+    @handle("escape", "-", filter=~has_arg)
+    def _meta_dash(event: E) -> None:
+        """"""
+        if event._arg is None:
+            event.append_to_arg_count("-")
+
+    @handle("-", filter=Condition(lambda: get_app().key_processor.arg == "-"))
+    def _dash(event: E) -> None:
+        """
+        When '-' is typed again, after exactly '-' has been given as an
+        argument, ignore this.
+        """
+        event.app.key_processor.arg = "-"
+
+    @Condition
+    def is_returnable() -> bool:
+        return get_app().current_buffer.is_returnable
+
+    # Meta + Enter: always accept input.
+    handle("escape", "enter", filter=insert_mode & is_returnable)(
+        get_by_name("accept-line")
+    )
+
+    # Enter: accept input in single line mode.
+    handle("enter", filter=insert_mode & is_returnable & ~is_multiline)(
+        get_by_name("accept-line")
+    )
+
+    def character_search(buff: Buffer, char: str, count: int) -> None:
+        if count < 0:
+            match = buff.document.find_backwards(
+                char, in_current_line=True, count=-count
+            )
+        else:
+            match = buff.document.find(char, in_current_line=True, count=count)
+
+        if match is not None:
+            buff.cursor_position += match
+
+    @handle("c-]", Keys.Any)
+    def _goto_char(event: E) -> None:
+        "When Ctl-] + a character is pressed. go to that character."
+        # Also named 'character-search'
+        character_search(event.current_buffer, event.data, event.arg)
+
+    @handle("escape", "c-]", Keys.Any)
+    def _goto_char_backwards(event: E) -> None:
+        "Like Ctl-], but backwards."
+        # Also named 'character-search-backward'
+        character_search(event.current_buffer, event.data, -event.arg)
+
+    @handle("escape", "a")
+    def _prev_sentence(event: E) -> None:
+        "Previous sentence."
+        # TODO:
+
+    @handle("escape", "e")
+    def _end_of_sentence(event: E) -> None:
+        "Move to end of sentence."
+        # TODO:
+
+    @handle("escape", "t", filter=insert_mode)
+    def _swap_characters(event: E) -> None:
+        """
+        Swap the last two words before the cursor.
+        """
+        # TODO
+
+    @handle("escape", "*", filter=insert_mode)
+    def _insert_all_completions(event: E) -> None:
+        """
+        `meta-*`: Insert all possible completions of the preceding text.
+        """
+        buff = event.current_buffer
+
+        # List all completions.
+        complete_event = CompleteEvent(text_inserted=False, completion_requested=True)
+        completions = list(
+            buff.completer.get_completions(buff.document, complete_event)
+        )
+
+        # Insert them.
+        text_to_insert = " ".join(c.text for c in completions)
+        buff.insert_text(text_to_insert)
+
+    @handle("c-x", "c-x")
+    def _toggle_start_end(event: E) -> None:
+        """
+        Move cursor back and forth between the start and end of the current
+        line.
+        """
+        buffer = event.current_buffer
+
+        if buffer.document.is_cursor_at_the_end_of_line:
+            buffer.cursor_position += buffer.document.get_start_of_line_position(
+                after_whitespace=False
+            )
+        else:
+            buffer.cursor_position += buffer.document.get_end_of_line_position()
+
+    @handle("c-@")  # Control-space or Control-@
+    def _start_selection(event: E) -> None:
+        """
+        Start of the selection (if the current buffer is not empty).
+        """
+        # Take the current cursor position as the start of this selection.
+        buff = event.current_buffer
+        if buff.text:
+            buff.start_selection(selection_type=SelectionType.CHARACTERS)
+
+    @handle("c-g", filter=~has_selection)
+    def _cancel(event: E) -> None:
+        """
+        Control + G: Cancel completion menu and validation state.
+        """
+        event.current_buffer.complete_state = None
+        event.current_buffer.validation_error = None
+
+    @handle("c-g", filter=has_selection)
+    def _cancel_selection(event: E) -> None:
+        """
+        Cancel selection.
+        """
+        event.current_buffer.exit_selection()
+
+    @handle("c-w", filter=has_selection)
+    @handle("c-x", "r", "k", filter=has_selection)
+    def _cut(event: E) -> None:
+        """
+        Cut selected text.
+        """
+        data = event.current_buffer.cut_selection()
+        event.app.clipboard.set_data(data)
+
+    @handle("escape", "w", filter=has_selection)
+    def _copy(event: E) -> None:
+        """
+        Copy selected text.
+        """
+        data = event.current_buffer.copy_selection()
+        event.app.clipboard.set_data(data)
+
+    @handle("escape", "left")
+    def _start_of_word(event: E) -> None:
+        """
+        Cursor to start of previous word.
+        """
+        buffer = event.current_buffer
+        buffer.cursor_position += (
+            buffer.document.find_previous_word_beginning(count=event.arg) or 0
+        )
+
+    @handle("escape", "right")
+    def _start_next_word(event: E) -> None:
+        """
+        Cursor to start of next word.
+        """
+        buffer = event.current_buffer
+        buffer.cursor_position += (
+            buffer.document.find_next_word_beginning(count=event.arg)
+            or buffer.document.get_end_of_document_position()
+        )
+
+    @handle("escape", "/", filter=insert_mode)
+    def _complete(event: E) -> None:
+        """
+        M-/: Complete.
+        """
+        b = event.current_buffer
+        if b.complete_state:
+            b.complete_next()
+        else:
+            b.start_completion(select_first=True)
+
+    @handle("c-c", ">", filter=has_selection)
+    def _indent(event: E) -> None:
+        """
+        Indent selected text.
+        """
+        buffer = event.current_buffer
+
+        buffer.cursor_position += buffer.document.get_start_of_line_position(
+            after_whitespace=True
+        )
+
+        from_, to = buffer.document.selection_range()
+        from_, _ = buffer.document.translate_index_to_position(from_)
+        to, _ = buffer.document.translate_index_to_position(to)
+
+        indent(buffer, from_, to + 1, count=event.arg)
+
+    @handle("c-c", "<", filter=has_selection)
+    def _unindent(event: E) -> None:
+        """
+        Unindent selected text.
+        """
+        buffer = event.current_buffer
+
+        from_, to = buffer.document.selection_range()
+        from_, _ = buffer.document.translate_index_to_position(from_)
+        to, _ = buffer.document.translate_index_to_position(to)
+
+        unindent(buffer, from_, to + 1, count=event.arg)
+
+    return ConditionalKeyBindings(key_bindings, emacs_mode)
+
+
+def load_emacs_search_bindings() -> KeyBindingsBase:
+    key_bindings = KeyBindings()
+    handle = key_bindings.add
+    from . import search
+
+    # NOTE: We don't bind 'Escape' to 'abort_search'. The reason is that we
+    #       want Alt+Enter to accept input directly in incremental search mode.
+    #       Instead, we have double escape.
+
+    handle("c-r")(search.start_reverse_incremental_search)
+    handle("c-s")(search.start_forward_incremental_search)
+
+    handle("c-c")(search.abort_search)
+    handle("c-g")(search.abort_search)
+    handle("c-r")(search.reverse_incremental_search)
+    handle("c-s")(search.forward_incremental_search)
+    handle("up")(search.reverse_incremental_search)
+    handle("down")(search.forward_incremental_search)
+    handle("enter")(search.accept_search)
+
+    # Handling of escape.
+    handle("escape", eager=True)(search.accept_search)
+
+    # Like Readline, it's more natural to accept the search when escape has
+    # been pressed, however instead the following two bindings could be used
+    # instead.
+    # #handle('escape', 'escape', eager=True)(search.abort_search)
+    # #handle('escape', 'enter', eager=True)(search.accept_search_and_accept_input)
+
+    # If Read-only: also include the following key bindings:
+
+    # '/' and '?' key bindings for searching, just like Vi mode.
+    handle("?", filter=is_read_only & ~vi_search_direction_reversed)(
+        search.start_reverse_incremental_search
+    )
+    handle("/", filter=is_read_only & ~vi_search_direction_reversed)(
+        search.start_forward_incremental_search
+    )
+    handle("?", filter=is_read_only & vi_search_direction_reversed)(
+        search.start_forward_incremental_search
+    )
+    handle("/", filter=is_read_only & vi_search_direction_reversed)(
+        search.start_reverse_incremental_search
+    )
+
+    @handle("n", filter=is_read_only)
+    def _jump_next(event: E) -> None:
+        "Jump to next match."
+        event.current_buffer.apply_search(
+            event.app.current_search_state,
+            include_current_position=False,
+            count=event.arg,
+        )
+
+    @handle("N", filter=is_read_only)
+    def _jump_prev(event: E) -> None:
+        "Jump to previous match."
+        event.current_buffer.apply_search(
+            ~event.app.current_search_state,
+            include_current_position=False,
+            count=event.arg,
+        )
+
+    return ConditionalKeyBindings(key_bindings, emacs_mode)
+
+
+def load_emacs_shift_selection_bindings() -> KeyBindingsBase:
+    """
+    Bindings to select text with shift + cursor movements
+    """
+
+    key_bindings = KeyBindings()
+    handle = key_bindings.add
+
+    def unshift_move(event: E) -> None:
+        """
+        Used for the shift selection mode. When called with
+        a shift + movement key press event, moves the cursor
+        as if shift is not pressed.
+        """
+        key = event.key_sequence[0].key
+
+        if key == Keys.ShiftUp:
+            event.current_buffer.auto_up(count=event.arg)
+            return
+        if key == Keys.ShiftDown:
+            event.current_buffer.auto_down(count=event.arg)
+            return
+
+        # the other keys are handled through their readline command
+        key_to_command: dict[Keys | str, str] = {
+            Keys.ShiftLeft: "backward-char",
+            Keys.ShiftRight: "forward-char",
+            Keys.ShiftHome: "beginning-of-line",
+            Keys.ShiftEnd: "end-of-line",
+            Keys.ControlShiftLeft: "backward-word",
+            Keys.ControlShiftRight: "forward-word",
+            Keys.ControlShiftHome: "beginning-of-buffer",
+            Keys.ControlShiftEnd: "end-of-buffer",
+        }
+
+        try:
+            # Both the dict lookup and `get_by_name` can raise KeyError.
+            binding = get_by_name(key_to_command[key])
+        except KeyError:
+            pass
+        else:  # (`else` is not really needed here.)
+            if isinstance(binding, Binding):
+                # (It should always be a binding here)
+                binding.call(event)
+
+    @handle("s-left", filter=~has_selection)
+    @handle("s-right", filter=~has_selection)
+    @handle("s-up", filter=~has_selection)
+    @handle("s-down", filter=~has_selection)
+    @handle("s-home", filter=~has_selection)
+    @handle("s-end", filter=~has_selection)
+    @handle("c-s-left", filter=~has_selection)
+    @handle("c-s-right", filter=~has_selection)
+    @handle("c-s-home", filter=~has_selection)
+    @handle("c-s-end", filter=~has_selection)
+    def _start_selection(event: E) -> None:
+        """
+        Start selection with shift + movement.
+        """
+        # Take the current cursor position as the start of this selection.
+        buff = event.current_buffer
+        if buff.text:
+            buff.start_selection(selection_type=SelectionType.CHARACTERS)
+
+            if buff.selection_state is not None:
+                # (`selection_state` should never be `None`, it is created by
+                # `start_selection`.)
+                buff.selection_state.enter_shift_mode()
+
+            # Then move the cursor
+            original_position = buff.cursor_position
+            unshift_move(event)
+            if buff.cursor_position == original_position:
+                # Cursor didn't actually move - so cancel selection
+                # to avoid having an empty selection
+                buff.exit_selection()
+
+    @handle("s-left", filter=shift_selection_mode)
+    @handle("s-right", filter=shift_selection_mode)
+    @handle("s-up", filter=shift_selection_mode)
+    @handle("s-down", filter=shift_selection_mode)
+    @handle("s-home", filter=shift_selection_mode)
+    @handle("s-end", filter=shift_selection_mode)
+    @handle("c-s-left", filter=shift_selection_mode)
+    @handle("c-s-right", filter=shift_selection_mode)
+    @handle("c-s-home", filter=shift_selection_mode)
+    @handle("c-s-end", filter=shift_selection_mode)
+    def _extend_selection(event: E) -> None:
+        """
+        Extend the selection
+        """
+        # Just move the cursor, like shift was not pressed
+        unshift_move(event)
+        buff = event.current_buffer
+
+        if buff.selection_state is not None:
+            if buff.cursor_position == buff.selection_state.original_cursor_position:
+                # selection is now empty, so cancel selection
+                buff.exit_selection()
+
+    @handle(Keys.Any, filter=shift_selection_mode)
+    def _replace_selection(event: E) -> None:
+        """
+        Replace selection by what is typed
+        """
+        event.current_buffer.cut_selection()
+        get_by_name("self-insert").call(event)
+
+    @handle("enter", filter=shift_selection_mode & is_multiline)
+    def _newline(event: E) -> None:
+        """
+        A newline replaces the selection
+        """
+        event.current_buffer.cut_selection()
+        event.current_buffer.newline(copy_margin=not in_paste_mode())
+
+    @handle("backspace", filter=shift_selection_mode)
+    def _delete(event: E) -> None:
+        """
+        Delete selection.
+        """
+        event.current_buffer.cut_selection()
+
+    @handle("c-y", filter=shift_selection_mode)
+    def _yank(event: E) -> None:
+        """
+        In shift selection mode, yanking (pasting) replace the selection.
+        """
+        buff = event.current_buffer
+        if buff.selection_state:
+            buff.cut_selection()
+        get_by_name("yank").call(event)
+
+    # moving the cursor in shift selection mode cancels the selection
+    @handle("left", filter=shift_selection_mode)
+    @handle("right", filter=shift_selection_mode)
+    @handle("up", filter=shift_selection_mode)
+    @handle("down", filter=shift_selection_mode)
+    @handle("home", filter=shift_selection_mode)
+    @handle("end", filter=shift_selection_mode)
+    @handle("c-left", filter=shift_selection_mode)
+    @handle("c-right", filter=shift_selection_mode)
+    @handle("c-home", filter=shift_selection_mode)
+    @handle("c-end", filter=shift_selection_mode)
+    def _cancel(event: E) -> None:
+        """
+        Cancel selection.
+        """
+        event.current_buffer.exit_selection()
+        # we then process the cursor movement
+        key_press = event.key_sequence[0]
+        event.key_processor.feed(key_press, first=True)
+
+    return ConditionalKeyBindings(key_bindings, emacs_mode)