add DigitDisplay for digits and basic arithmetic operators

Makefile

@@ -10,7 +10,7 @@ unit-test:
 
 .PHONY: test-snapshot-update
 test-snapshot-update:
-	$(run) pytest --cov-report term-missing --cov=textual tests/ -vv --snapshot-update
+	$(run) pytest --cov-report term-missing --cov=textual tests/ -vv --snapshot-update $(PYTEST_ARGS)
 
 .PHONY: typecheck
 typecheck:

docs/examples/widgets/digit_display.py

@@ -0,0 +1,24 @@
+from textual.app import App, ComposeResult
+from textual.widgets import Static
+from textual.widgets import DigitDisplay
+
+
+class MyApp(App):
+    BINDINGS = []
+
+    def compose(self) -> ComposeResult:
+        yield Static("Digits: 0123456789")
+        yield DigitDisplay("0123456789")
+
+        punctuation=" .+,XYZ^*/-="
+        yield Static("Punctuation: " + punctuation)
+        yield DigitDisplay(punctuation)
+
+        equation = "x = y^2 + 3.14159*y + 10"
+        yield Static("Equation: " + equation)
+        yield DigitDisplay(equation)
+
+
+if __name__ == "__main__":
+    app = MyApp()
+    app.run()

src/textual/widgets/__init__.py

@@ -40,6 +40,7 @@
     from ._tooltip import Tooltip
     from ._tree import Tree
     from ._welcome import Welcome
+    from ._digit_display import DigitDisplay
 
 
 __all__ = [
@@ -76,6 +77,7 @@
     "Tooltip",
     "Tree",
     "Welcome",
+    "DigitDisplay",
 ]
 
 _WIDGETS_LAZY_LOADING_CACHE: dict[str, type[Widget]] = {}

src/textual/widgets/_digit_display.py

@@ -0,0 +1,269 @@
+from textual.app import ComposeResult
+from textual.reactive import reactive
+from textual.widget import Widget
+from textual.widgets import Static
+
+
+_character_map: dict[str, str] = {}
+
+# in the mappings below, we use underscores to make spaces more visible,
+# we will strip them out later
+_character_map[
+    "0"
+] = """
+┏━┓
+┃╱┃
+┗━┛
+"""
+
+_character_map[
+    "1"
+] = """
+·┓·
+ ┃·
+╺┻╸
+"""
+
+_character_map[
+    "2"
+] = """
+╺━┓
+┏━┛
+┗━╸
+"""
+
+_character_map[
+    "3"
+] = """
+╺━┓
+ ━┫
+╺━┛
+"""
+
+_character_map[
+    "4"
+] = """
+╻ ╻
+┗━┫
+  ╹
+"""
+
+_character_map[
+    "5"
+] = """
+┏━╸
+┗━┓
+╺━┛
+"""
+
+_character_map[
+    "6"
+] = """
+┏━╸
+┣━┓
+┗━┛
+"""
+
+_character_map[
+    "7"
+] = """
+╺━┓
+  ╹
+ ╹·
+"""
+
+_character_map[
+    "8"
+] = """
+┏━┓
+┣━┫
+┗━┛
+"""
+
+_character_map[
+    "9"
+] = """
+┏━┓
+┗━┫
+╺━┛
+"""
+
+_character_map[
+    " "
+] = """
+···
+···
+···
+"""
+
+
+_character_map[
+    "X"
+] = """
+╻ ╻
+·╋·
+╹ ╹
+"""
+
+_character_map[
+    "Y"
+] = """
+╻ ╻
+·┳·
+·╹·
+"""
+
+_character_map[
+    "Z"
+] = """
+╺━┓
+·▞·
+┗━╸
+"""
+
+
+_character_map[
+    "."
+] = """
+··
+··
+·•
+"""
+
+
+_character_map[
+    ","
+] = """
+··
+··
+·▞
+"""
+
+_character_map[
+    "+"
+] = """
+···
+╺╋╸
+···
+"""
+
+_character_map[
+    "-"
+] = """
+···
+╺━╸
+···
+"""
+
+_character_map[
+    "="
+] = """
+···
+╺━·
+╺━·
+"""
+
+_character_map[
+    "*"
+] = """
+···
+·✱·
+···
+"""
+
+
+_character_map[
+    "/"
+] = """
+··╻
+·▞·
+╹··
+"""
+
+_character_map[
+    "^"
+] = """
+·╻·
+▝·▘
+···
+"""
+
+
+_VIRTUAL_SPACE = "·"
+
+# here we strip spaces and replace virtual spaces with spaces
+_character_map = {
+    k: v.strip().replace(_VIRTUAL_SPACE, " ") for k, v in _character_map.items()
+}
+
+
+class SingleDigitDisplay(Static):
+    digit = reactive(" ", layout=True)
+
+    DEFAULT_CSS = """
+        SingleDigitDisplay {
+          height: 3;
+          min-width: 2;
+          max-width: 3;
+        }
+    """
+
+    def __init__(self, initial_value=" ", **kwargs):
+        super().__init__(**kwargs)
+        self.digit = initial_value
+
+    def watch_digit(self, digit: str) -> None:
+        """Called when the digit attribute changes."""
+        if len(digit) > 1:
+            raise ValueError(f"Expected a single character, got {len(digit)}")
+        self.update(_character_map[digit.upper()])
+
+
+class DigitDisplay(Widget):
+    """A widget to display digits and basic arithmetic operators using Unicode blocks."""
+
+    digits = reactive("", layout=True)
+
+    DEFAULT_CSS = """
+    DigitDisplay {
+        layout: horizontal;
+        height: 3;
+    }
+    """
+
+    def __init__(self, initial_value="", **kwargs):
+        super().__init__(**kwargs)
+        self._displays = [SingleDigitDisplay(d) for d in initial_value]
+        self.digits = initial_value
+
+    def compose(self) -> ComposeResult:
+        for widget in self._displays:
+            yield widget
+
+    def _add_digit_widget(self, digit: str) -> None:
+        new_widget = SingleDigitDisplay(digit)
+        self._displays.append(new_widget)
+        self.mount(new_widget)
+
+    def watch_digits(self, digits: str) -> None:
+        """
+        Called when the digits attribute changes.
+        Here we update the display widgets to match the input digits.
+        """
+        diff_digits_len = len(digits) - len(self._displays)
+
+        # Here we add or remove widgets to match the number of digits
+        if diff_digits_len > 0:
+            start = len(self._displays)
+            for i in range(diff_digits_len):
+                self._add_digit_widget(digits[start + i])
+        elif diff_digits_len < 0:
+            for display in self._displays[diff_digits_len:]:
+                self._displays.remove(display)
+                display.remove()
+
+        # At this point, the number of widgets matches the number of digits, and we can
+        # update the contents of the widgets that might need it
+        for i, d in enumerate(self.digits):
+            if self._displays[i].digit != d:
+                self._displays[i].digit = d