Rui Carmo
146 lines
5.0 KiB
Python
146 lines
5.0 KiB
Python
from contextlib import suppress
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from decimal import Decimal
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from typing import ClassVar
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from textual import events
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from textual.app import App, ComposeResult
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from textual.containers import Container
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from textual.css.query import NoMatches
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from textual.reactive import var
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from textual.widgets import Button, Static
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class CalculatorApp(App):
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"""A working 'desktop' calculator."""
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CSS_PATH = "calculator.css"
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numbers = var("0")
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show_ac = var(True)
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left = var(Decimal("0"))
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right = var(Decimal("0"))
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value = var("")
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operator = var("plus")
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NAME_MAP: ClassVar = {
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"asterisk": "multiply",
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"slash": "divide",
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"underscore": "plus-minus",
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"full_stop": "point",
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"plus_minus_sign": "plus-minus",
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"percent_sign": "percent",
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"equals_sign": "equals",
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"minus": "minus",
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"plus": "plus",
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}
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def watch_numbers(self, value: str) -> None:
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"""Called when numbers is updated."""
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# Update the Numbers widget
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self.query_one("#numbers", Static).update(value)
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def compute_show_ac(self) -> bool:
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"""Compute switch to show AC or C button"""
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return self.value in ("", "0") and self.numbers == "0"
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def watch_show_ac(self, show_ac: bool) -> None:
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"""Called when show_ac changes."""
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self.query_one("#c").display = not show_ac
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self.query_one("#ac").display = show_ac
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def compose(self) -> ComposeResult:
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"""Add our buttons."""
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with Container(id="calculator"):
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yield Static(id="numbers")
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yield Button("AC", id="ac", variant="primary")
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yield Button("C", id="c", variant="primary")
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yield Button("+/-", id="plus-minus", variant="primary")
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yield Button("%", id="percent", variant="primary")
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yield Button("÷", id="divide", variant="warning")
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yield Button("7", id="number-7")
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yield Button("8", id="number-8")
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yield Button("9", id="number-9")
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yield Button("x", id="multiply", variant="warning")
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yield Button("4", id="number-4")
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yield Button("5", id="number-5")
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yield Button("6", id="number-6")
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yield Button("-", id="minus", variant="warning")
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yield Button("1", id="number-1")
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yield Button("2", id="number-2")
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yield Button("3", id="number-3")
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yield Button("+", id="plus", variant="warning")
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yield Button("0", id="number-0")
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yield Button(".", id="point")
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yield Button("=", id="equals", variant="warning")
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def on_key(self, event: events.Key) -> None:
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"""Called when the user presses a key."""
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def press(button_id: str) -> None:
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with suppress(NoMatches):
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self.query_one(f"#{button_id}", Button).press()
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key = event.key
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if key.isdecimal():
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press(f"number-{key}")
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elif key == "c":
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press("c")
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press("ac")
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else:
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button_id = self.NAME_MAP.get(key)
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if button_id is not None:
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press(self.NAME_MAP.get(key, key))
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def on_button_pressed(self, event: Button.Pressed) -> None:
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"""Called when a button is pressed."""
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button_id = event.button.id
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assert button_id is not None
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def do_math() -> None:
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"""Does the math: LEFT OPERATOR RIGHT"""
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try:
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if self.operator == "plus":
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self.left += self.right
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elif self.operator == "minus":
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self.left -= self.right
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elif self.operator == "divide":
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self.left /= self.right
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elif self.operator == "multiply":
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self.left *= self.right
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self.numbers = str(self.left)
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self.value = ""
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except Exception:
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self.numbers = "Error"
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if button_id.startswith("number-"):
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number = button_id.partition("-")[-1]
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self.numbers = self.value = self.value.lstrip("0") + number
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elif button_id == "plus-minus":
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self.numbers = self.value = str(Decimal(self.value or "0") * -1)
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elif button_id == "percent":
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self.numbers = self.value = str(Decimal(self.value or "0") / Decimal(100))
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elif button_id == "point":
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if "." not in self.value:
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self.numbers = self.value = (self.value or "0") + "."
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elif button_id == "ac":
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self.value = ""
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self.left = self.right = Decimal(0)
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self.operator = "plus"
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self.numbers = "0"
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elif button_id == "c":
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self.value = ""
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self.numbers = "0"
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elif button_id in ("plus", "minus", "divide", "multiply"):
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self.right = Decimal(self.value or "0")
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do_math()
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self.operator = button_id
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elif button_id == "equals":
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if self.value:
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self.right = Decimal(self.value)
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do_math()
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if __name__ == "__main__":
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CalculatorApp().run()
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