feat: add search functionality to select and checkbox prompt, based on #42

examples/checkbox_search.py

@@ -0,0 +1,75 @@
+import questionary
+from examples import custom_style_dope
+
+zoo_animals = [
+    "Lion",
+    "Tiger",
+    "Elephant",
+    "Giraffe",
+    "Zebra",
+    "Panda",
+    "Kangaroo",
+    "Gorilla",
+    "Chimpanzee",
+    "Orangutan",
+    "Hippopotamus",
+    "Rhinoceros",
+    "Leopard",
+    "Cheetah",
+    "Polar Bear",
+    "Grizzly Bear",
+    "Penguin",
+    "Flamingo",
+    "Peacock",
+    "Ostrich",
+    "Emu",
+    "Koala",
+    "Sloth",
+    "Armadillo",
+    "Meerkat",
+    "Lemur",
+    "Red Panda",
+    "Wolf",
+    "Fox",
+    "Otter",
+    "Sea Lion",
+    "Walrus",
+    "Seal",
+    "Crocodile",
+    "Alligator",
+    "Python",
+    "Boa Constrictor",
+    "Iguana",
+    "Komodo Dragon",
+    "Tortoise",
+    "Turtle",
+    "Parrot",
+    "Toucan",
+    "Macaw",
+    "Hyena",
+    "Jaguar",
+    "Anteater",
+    "Capybara",
+    "Bison",
+    "Moose",
+]
+
+
+if __name__ == "__main__":
+    toppings = (
+        questionary.checkbox(
+            "Select animals for your zoo",
+            choices=zoo_animals,
+            validate=lambda a: (
+                True if len(a) > 0 else "You must select at least one zoo animal"
+            ),
+            style=custom_style_dope,
+            use_jk_keys=False,
+            use_search_filter=True,
+        ).ask()
+        or []
+    )
+
+    print(
+        f"Alright let's create our zoo with following animals: {', '.join(toppings)}."
+    )

examples/select_search.py

@@ -0,0 +1,62 @@
+# -*- coding: utf-8 -*-
+"""Example for a select question type with search enabled.
+
+Run example by typing `python -m examples.select_search` in your console."""
+from pprint import pprint
+
+import questionary
+from examples import custom_style_dope
+from questionary import Choice
+from questionary import Separator
+from questionary import prompt
+
+
+def ask_pystyle(**kwargs):
+    # create the question object
+    question = questionary.select(
+        "What do you want to do?",
+        qmark="😃",
+        choices=[
+            "Order a pizza",
+            "Make a reservation",
+            "Cancel a reservation",
+            "Modify your order",
+            Separator(),
+            "Ask for opening hours",
+            Choice("Contact support", disabled="Unavailable at this time"),
+            "Talk to the receptionist",
+        ],
+        style=custom_style_dope,
+        use_jk_keys=False,
+        use_search_filter=True,
+        **kwargs,
+    )
+
+    # prompt the user for an answer
+    return question.ask()
+
+
+def ask_dictstyle(**kwargs):
+    questions = [
+        {
+            "type": "select",
+            "name": "theme",
+            "message": "What do you want to do?",
+            "choices": [
+                "Order a pizza",
+                "Make a reservation",
+                "Cancel a reservation",
+                "Modify your order",
+                Separator(),
+                "Ask for opening hours",
+                {"name": "Contact support", "disabled": "Unavailable at this time"},
+                "Talk to the receptionist",
+            ],
+        }
+    ]
+
+    return prompt(questions, style=custom_style_dope, **kwargs)
+
+
+if __name__ == "__main__":
+    pprint(ask_pystyle())

questionary/constants.py

@@ -39,6 +39,14 @@
         ("qmark", "fg:#5f819d"),  # token in front of the question
         ("question", "bold"),  # question text
         ("answer", "fg:#FF9D00 bold"),  # submitted answer text behind the question
+        (
+            "search_success",
+            "noinherit fg:#00FF00 bold",
+        ),  # submitted answer text behind the question
+        (
+            "search_none",
+            "noinherit fg:#FF0000 bold",
+        ),  # submitted answer text behind the question
         ("pointer", ""),  # pointer used in select and checkbox prompts
         ("selected", ""),  # style for a selected item of a checkbox
         ("separator", ""),  # separator in lists

questionary/prompts/checkbox.py

@@ -1,3 +1,4 @@
+import string
 from typing import Any
 from typing import Callable
 from typing import Dict
@@ -37,6 +38,7 @@ def checkbox(
     use_arrow_keys: bool = True,
     use_jk_keys: bool = True,
     use_emacs_keys: bool = True,
+    use_search_filter: Union[str, bool, None] = False,
     instruction: Optional[str] = None,
     show_description: bool = True,
     **kwargs: Any,
@@ -105,6 +107,14 @@ def checkbox(
 
         use_emacs_keys: Allow the user to select items from the list using
                         `Ctrl+N` (down) and `Ctrl+P` (up) keys.
+
+        use_search_filter: Flag to enable search filtering. Typing some string will
+                           filter the choices to keep only the ones that contain the
+                           search string.
+                           Note that activating this option disables "vi-like"
+                           navigation as "j" and "k" can be part of a prefix and
+                           therefore cannot be used for navigation
+
         instruction: A message describing how to navigate the menu.
 
         show_description: Display description of current selection if available.
@@ -119,6 +129,11 @@ def checkbox(
             "Emacs keys."
         )
 
+    if use_jk_keys and use_search_filter:
+        raise ValueError(
+            "Cannot use j/k keys with prefix filter search, since j/k can be part of the prefix."
+        )
+
     merged_style = merge_styles_default(
         [
             # Disable the default inverted colours bottom-toolbar behaviour (for
@@ -179,8 +194,9 @@ def get_prompt_tokens() -> List[Tuple[str, str]]:
                         "class:instruction",
                         "(Use arrow keys to move, "
                         "<space> to select, "
-                        "<a> to toggle, "
-                        "<i> to invert)",
+                        f"<{'ctrl-a' if use_search_filter else 'a'}> to toggle, "
+                        f"<{'ctrl-a' if use_search_filter else 'i'}> to invert"
+                        f"{', type to filter' if use_search_filter else ''})",
                     )
                 )
         return tokens
@@ -225,7 +241,7 @@ def toggle(_event):
 
         perform_validation(get_selected_values())
 
-    @bindings.add("i", eager=True)
+    @bindings.add(Keys.ControlI if use_search_filter else "i", eager=True)
     def invert(_event):
         inverted_selection = [
             c.value
@@ -238,7 +254,7 @@ def invert(_event):
 
         perform_validation(get_selected_values())
 
-    @bindings.add("a", eager=True)
+    @bindings.add(Keys.ControlA if use_search_filter else "a", eager=True)
     def all(_event):
         all_selected = True  # all choices have been selected
         for c in ic.choices:
@@ -265,6 +281,17 @@ def move_cursor_up(event):
         while not ic.is_selection_valid():
             ic.select_previous()
 
+    if use_search_filter:
+
+        def search_filter(event):
+            ic.add_search_character(event.key_sequence[0].key)
+
+        for character in string.printable:
+            if character in string.whitespace:
+                continue
+            bindings.add(character, eager=True)(search_filter)
+        bindings.add(Keys.Backspace, eager=True)(search_filter)
+
     if use_arrow_keys:
         bindings.add(Keys.Down, eager=True)(move_cursor_down)
         bindings.add(Keys.Up, eager=True)(move_cursor_up)

questionary/prompts/common.py

@@ -12,11 +12,13 @@
 from prompt_toolkit.filters import Always
 from prompt_toolkit.filters import Condition
 from prompt_toolkit.filters import IsDone
+from prompt_toolkit.keys import Keys
 from prompt_toolkit.layout import ConditionalContainer
 from prompt_toolkit.layout import FormattedTextControl
 from prompt_toolkit.layout import HSplit
 from prompt_toolkit.layout import Layout
 from prompt_toolkit.layout import Window
+from prompt_toolkit.layout.dimension import LayoutDimension
 from prompt_toolkit.styles import Style
 from prompt_toolkit.validation import ValidationError
 from prompt_toolkit.validation import Validator
@@ -204,6 +206,7 @@ class InquirerControl(FormattedTextControl):
     choices: List[Choice]
     default: Optional[Union[str, Choice, Dict[str, Any]]]
     selected_options: List[Any]
+    search_filter: Union[str, None] = None
     use_indicator: bool
     use_shortcuts: bool
     use_arrow_keys: bool
@@ -275,6 +278,7 @@ def __init__(
         self.submission_attempted = False
         self.error_message = None
         self.selected_options = []
+        self.found_in_search = False
 
         self._init_choices(choices, pointed_at)
         self._assign_shortcut_keys()
@@ -343,9 +347,19 @@ def _init_choices(
 
             self.choices.append(choice)
 
+    @property
+    def filtered_choices(self):
+        if not self.search_filter:
+            return self.choices
+        filtered = [
+            c for c in self.choices if self.search_filter.lower() in c.title.lower()
+        ]
+        self.found_in_search = len(filtered) > 0
+        return filtered if self.found_in_search else self.choices
+
     @property
     def choice_count(self) -> int:
-        return len(self.choices)
+        return len(self.filtered_choices)
 
     def _get_choice_tokens(self):
         tokens = []
@@ -425,7 +439,7 @@ def append(index: int, choice: Choice):
             tokens.append(("", "\n"))
 
         # prepare the select choices
-        for i, c in enumerate(self.choices):
+        for i, c in enumerate(self.filtered_choices):
             append(i, c)
 
         current = self.get_pointed_at()
@@ -467,7 +481,7 @@ def select_next(self) -> None:
         self.pointed_at = (self.pointed_at + 1) % self.choice_count
 
     def get_pointed_at(self) -> Choice:
-        return self.choices[self.pointed_at]
+        return self.filtered_choices[self.pointed_at]
 
     def get_selected_values(self) -> List[Choice]:
         # get values not labels
@@ -477,6 +491,39 @@ def get_selected_values(self) -> List[Choice]:
             if (not isinstance(c, Separator) and c.value in self.selected_options)
         ]
 
+    def add_search_character(self, char: Keys) -> None:
+        """Adds a character to the search filter"""
+        if char == Keys.Backspace:
+            self.remove_search_character()
+        else:
+            if self.search_filter is None:
+                self.search_filter = str(char)
+            else:
+                self.search_filter += str(char)
+
+        # Make sure that the selection is in the bounds of the filtered list
+        self.pointed_at = 0
+
+    def remove_search_character(self) -> None:
+        if self.search_filter and len(self.search_filter) > 1:
+            self.search_filter = self.search_filter[:-1]
+        else:
+            self.search_filter = None
+
+    def get_search_string_tokens(self):
+        if self.search_filter is None:
+            return None
+
+        return [
+            ("", "\n"),
+            ("class:question-mark", "/ "),
+            (
+                "class:search_success" if self.found_in_search else "class:search_none",
+                self.search_filter,
+            ),
+            ("class:question-mark", "..."),
+        ]
+
 
 def build_validator(validate: Any) -> Optional[Validator]:
     if validate:
@@ -531,6 +578,10 @@ def create_inquirer_layout(
     )
     _fix_unecessary_blank_lines(ps)
 
+    @Condition
+    def has_search_string():
+        return ic.get_search_string_tokens() is not None
+
     validation_prompt: PromptSession = PromptSession(
         bottom_toolbar=lambda: ic.error_message, **kwargs
     )
@@ -540,6 +591,13 @@ def create_inquirer_layout(
             [
                 ps.layout.container,
                 ConditionalContainer(Window(ic), filter=~IsDone()),
+                ConditionalContainer(
+                    Window(
+                        height=LayoutDimension.exact(2),
+                        content=FormattedTextControl(ic.get_search_string_tokens),
+                    ),
+                    filter=has_search_string & ~IsDone(),
+                ),
                 ConditionalContainer(
                     validation_prompt.layout.container,
                     filter=Condition(lambda: ic.error_message is not None),