Source code for questionary.prompts.checkbox

from typing import Any
from typing import Callable
from typing import Dict
from typing import List
from typing import Optional
from typing import Sequence
from typing import Tuple
from typing import Union

from prompt_toolkit.application import Application
from prompt_toolkit.formatted_text import FormattedText
from prompt_toolkit.key_binding import KeyBindings
from prompt_toolkit.keys import Keys
from prompt_toolkit.styles import Style

from questionary import utils
from questionary.constants import DEFAULT_QUESTION_PREFIX
from questionary.constants import DEFAULT_SELECTED_POINTER
from questionary.constants import INVALID_INPUT
from questionary.prompts import common
from questionary.prompts.common import Choice
from questionary.prompts.common import InquirerControl
from questionary.prompts.common import Separator
from questionary.question import Question
from questionary.styles import merge_styles_default


[docs]def checkbox( message: str, choices: Sequence[Union[str, Choice, Dict[str, Any]]], default: Optional[str] = None, validate: Callable[[List[str]], Union[bool, str]] = lambda a: True, qmark: str = DEFAULT_QUESTION_PREFIX, pointer: Optional[str] = DEFAULT_SELECTED_POINTER, style: Optional[Style] = None, initial_choice: Optional[Union[str, Choice, Dict[str, Any]]] = None, use_arrow_keys: bool = True, use_jk_keys: bool = True, use_emacs_keys: bool = True, instruction: Optional[str] = None, **kwargs: Any, ) -> Question: """Ask the user to select from a list of items. This is a multiselect, the user can choose one, none or many of the items. Example: >>> import questionary >>> questionary.checkbox( ... 'Select toppings', ... choices=[ ... "Cheese", ... "Tomato", ... "Pineapple", ... ]).ask() ? Select toppings done (2 selections) ['Cheese', 'Pineapple'] .. image:: ../images/checkbox.gif This is just a really basic example, the prompt can be customised using the parameters. Args: message: Question text choices: Items shown in the selection, this can contain :class:`Choice` or or :class:`Separator` objects or simple items as strings. Passing :class:`Choice` objects, allows you to configure the item more (e.g. preselecting it or disabling it). default: Default return value (single value). If you want to preselect multiple items, use ``Choice("foo", checked=True)`` instead. validate: Require the entered value to pass a validation. The value can not be submitted until the validator accepts it (e.g. to check minimum password length). This should be a function accepting the input and returning a boolean. Alternatively, the return value may be a string (indicating failure), which contains the error message to be displayed. qmark: Question prefix displayed in front of the question. By default this is a ``?``. pointer: Pointer symbol in front of the currently highlighted element. By default this is a ``»``. Use ``None`` to disable it. style: A custom color and style for the question parts. You can configure colors as well as font types for different elements. initial_choice: A value corresponding to a selectable item in the choices, to initially set the pointer position to. use_arrow_keys: Allow the user to select items from the list using arrow keys. use_jk_keys: Allow the user to select items from the list using `j` (down) and `k` (up) keys. use_emacs_keys: Allow the user to select items from the list using `Ctrl+N` (down) and `Ctrl+P` (up) keys. instruction: A message describing how to navigate the menu. Returns: :class:`Question`: Question instance, ready to be prompted (using ``.ask()``). """ if not (use_arrow_keys or use_jk_keys or use_emacs_keys): raise ValueError( "Some option to move the selection is required. Arrow keys or j/k or " "Emacs keys." ) merged_style = merge_styles_default( [ # Disable the default inverted colours bottom-toolbar behaviour (for # the error message). However it can be re-enabled with a custom # style. Style([("bottom-toolbar", "noreverse")]), style, ] ) if not callable(validate): raise ValueError("validate must be callable") ic = InquirerControl( choices, default, pointer=pointer, initial_choice=initial_choice ) def get_prompt_tokens() -> List[Tuple[str, str]]: tokens = [] tokens.append(("class:qmark", qmark)) tokens.append(("class:question", " {} ".format(message))) if ic.is_answered: nbr_selected = len(ic.selected_options) if nbr_selected == 0: tokens.append(("class:answer", "done")) elif nbr_selected == 1: if isinstance(ic.get_selected_values()[0].title, list): ts = ic.get_selected_values()[0].title tokens.append( ( "class:answer", "".join([token[1] for token in ts]), # type:ignore ) ) else: tokens.append( ( "class:answer", "[{}]".format(ic.get_selected_values()[0].title), ) ) else: tokens.append( ("class:answer", "done ({} selections)".format(nbr_selected)) ) else: if instruction is not None: tokens.append(("class:instruction", instruction)) else: tokens.append( ( "class:instruction", "(Use arrow keys to move, " "<space> to select, " "<a> to toggle, " "<i> to invert)", ) ) return tokens def get_selected_values() -> List[Any]: return [c.value for c in ic.get_selected_values()] def perform_validation(selected_values: List[str]) -> bool: verdict = validate(selected_values) valid = verdict is True if not valid: if verdict is False: error_text = INVALID_INPUT else: error_text = str(verdict) error_message = FormattedText([("class:validation-toolbar", error_text)]) ic.error_message = ( error_message if not valid and ic.submission_attempted else None # type: ignore[assignment] ) return valid layout = common.create_inquirer_layout(ic, get_prompt_tokens, **kwargs) bindings = KeyBindings() @bindings.add(Keys.ControlQ, eager=True) @bindings.add(Keys.ControlC, eager=True) def _(event): event.app.exit(exception=KeyboardInterrupt, style="class:aborting") @bindings.add(" ", eager=True) def toggle(_event): pointed_choice = ic.get_pointed_at().value if pointed_choice in ic.selected_options: ic.selected_options.remove(pointed_choice) else: ic.selected_options.append(pointed_choice) perform_validation(get_selected_values()) @bindings.add("i", eager=True) def invert(_event): inverted_selection = [ c.value for c in ic.choices if not isinstance(c, Separator) and c.value not in ic.selected_options and not c.disabled ] ic.selected_options = inverted_selection perform_validation(get_selected_values()) @bindings.add("a", eager=True) def all(_event): all_selected = True # all choices have been selected for c in ic.choices: if ( not isinstance(c, Separator) and c.value not in ic.selected_options and not c.disabled ): # add missing ones ic.selected_options.append(c.value) all_selected = False if all_selected: ic.selected_options = [] perform_validation(get_selected_values()) def move_cursor_down(event): ic.select_next() while not ic.is_selection_valid(): ic.select_next() def move_cursor_up(event): ic.select_previous() while not ic.is_selection_valid(): ic.select_previous() if use_arrow_keys: bindings.add(Keys.Down, eager=True)(move_cursor_down) bindings.add(Keys.Up, eager=True)(move_cursor_up) if use_jk_keys: bindings.add("j", eager=True)(move_cursor_down) bindings.add("k", eager=True)(move_cursor_up) if use_emacs_keys: bindings.add(Keys.ControlN, eager=True)(move_cursor_down) bindings.add(Keys.ControlP, eager=True)(move_cursor_up) @bindings.add(Keys.ControlM, eager=True) def set_answer(event): selected_values = get_selected_values() ic.submission_attempted = True if perform_validation(selected_values): ic.is_answered = True event.app.exit(result=selected_values) @bindings.add(Keys.Any) def other(_event): """Disallow inserting other text.""" return Question( Application( layout=layout, key_bindings=bindings, style=merged_style, **utils.used_kwargs(kwargs, Application.__init__), ) )