initial commit

main.py

@@ -0,0 +1,207 @@
+"""SymPy Math App — desktop calculator / REPL powered by SymPy and PyQt5."""
+
+from __future__ import annotations
+
+import re
+import sys
+from typing import Any
+
+import sympy
+from PyQt5.QtCore import Qt
+from PyQt5.QtWidgets import (
+    QApplication,
+    QHBoxLayout,
+    QLabel,
+    QLineEdit,
+    QMainWindow,
+    QPushButton,
+    QTextEdit,
+    QVBoxLayout,
+    QWidget,
+)
+
+_SEPARATOR = "-" * 50
+_ASSIGNMENT_RE = re.compile(r"^\s*\w+\s*=(?!=)")
+
+
+class HistoryLineEdit(QLineEdit):
+    """QLineEdit with Up / Down arrow command-history navigation."""
+
+    def __init__(self, parent: QWidget | None = None) -> None:
+        super().__init__(parent)
+        self._entries: list[str] = []
+        self._cursor: int = 0
+
+    @property
+    def entries(self) -> list[str]:
+        return list(self._entries)
+
+    def append(self, command: str) -> None:
+        """Record *command*, skipping consecutive duplicates."""
+        if command and (not self._entries or self._entries[-1] != command):
+            self._entries.append(command)
+        self._cursor = len(self._entries)
+
+    def reset_cursor(self) -> None:
+        self._cursor = len(self._entries)
+
+    def keyPressEvent(self, event) -> None:  # noqa: N802 – Qt naming
+        if event.key() == Qt.Key_Up:
+            self._navigate(-1)
+            event.accept()
+        elif event.key() == Qt.Key_Down:
+            self._navigate(1)
+            event.accept()
+        else:
+            super().keyPressEvent(event)
+
+    def _navigate(self, direction: int) -> None:
+        if not self._entries:
+            return
+        new_index = self._cursor + direction
+        if 0 <= new_index < len(self._entries):
+            self._cursor = new_index
+            self.setText(self._entries[new_index])
+        elif new_index >= len(self._entries):
+            self._cursor = len(self._entries)
+            self.clear()
+
+
+class MathWindow(QMainWindow):
+    """Main application window for the SymPy calculator."""
+
+    _BUTTONS = ("Evaluate", "Clear", "Show Variables", "Show History")
+
+    def __init__(self) -> None:
+        super().__init__()
+        self._namespace: dict[str, Any] = sympy.__dict__.copy()
+        self._build_ui()
+
+    # -- UI construction -------------------------------------------------------
+
+    def _build_ui(self) -> None:
+        self.setWindowTitle("SymPy Math App")
+        self.setGeometry(100, 100, 600, 500)
+
+        root = QWidget()
+        self.setCentralWidget(root)
+        layout = QVBoxLayout(root)
+
+        layout.addWidget(QLabel("Enter SymPy command:"))
+
+        self._command_input = HistoryLineEdit(self)
+        self._command_input.setPlaceholderText(
+            'e.g., x = Symbol("x"), or x**2 + 2*x + 1, or diff(x**2, x)'
+        )
+        self._command_input.returnPressed.connect(self._evaluate)
+        layout.addWidget(self._command_input)
+
+        button_row = QHBoxLayout()
+        handlers = (self._evaluate, self._clear, self._show_variables, self._show_history)
+        for label, handler in zip(self._BUTTONS, handlers):
+            btn = QPushButton(label)
+            btn.clicked.connect(handler)
+            button_row.addWidget(btn)
+        layout.addLayout(button_row)
+
+        layout.addWidget(QLabel("Results:"))
+
+        self._results_display = QTextEdit()
+        self._results_display.setReadOnly(True)
+        self._results_display.setPlaceholderText("Results will appear here...")
+        layout.addWidget(self._results_display)
+
+    # -- helpers ---------------------------------------------------------------
+
+    def _append_result(self, *lines: str) -> None:
+        for line in lines:
+            self._results_display.append(line)
+
+    @staticmethod
+    def _format_value(value: Any) -> str:
+        if isinstance(value, sympy.Basic):
+            return sympy.pretty(value)
+        return str(value)
+
+    # -- slots -----------------------------------------------------------------
+
+    def _evaluate(self) -> None:
+        command = self._command_input.text().strip()
+        if not command:
+            self._append_result("Error: Please enter a command.")
+            return
+
+        self._command_input.append(command)
+
+        try:
+            if _ASSIGNMENT_RE.match(command):
+                self._execute_assignment(command)
+            else:
+                self._evaluate_expression(command)
+            self._command_input.clear()
+        except Exception as exc:
+            self._append_result(f"Command: {command}", f"Error: {exc}", _SEPARATOR)
+
+    def _execute_assignment(self, command: str) -> None:
+        exec(command, {"__builtins__": {}}, self._namespace)  # noqa: S102
+        self._append_result(f"Command: {command}", "Variable set successfully.", _SEPARATOR)
+
+    def _evaluate_expression(self, command: str) -> None:
+        try:
+            result = sympy.sympify(command, locals=self._namespace)
+        except (sympy.SympifyError, SyntaxError, TypeError):
+            result = eval(command, {"__builtins__": {}}, self._namespace)  # noqa: S307
+
+        self._append_result(
+            f"Command: {command}",
+            f"Result:\n{self._format_value(result)}",
+            _SEPARATOR,
+        )
+
+    def _clear(self) -> None:
+        self._command_input.clear()
+        self._results_display.clear()
+        self._command_input.reset_cursor()
+
+    def _show_variables(self) -> None:
+        builtin_keys = set(sympy.__dict__)
+        user_vars = {
+            name: val
+            for name, val in self._namespace.items()
+            if name not in builtin_keys and not name.startswith("_")
+        }
+
+        if not user_vars:
+            self._append_result("No variables defined.", _SEPARATOR)
+            return
+
+        self._append_result("Current Variables:")
+        for name, value in user_vars.items():
+            self._append_result(f"  {name} = {self._format_value(value)}")
+        self._append_result(_SEPARATOR)
+
+    def _show_history(self) -> None:
+        entries = self._command_input.entries
+        if not entries:
+            self._append_result("No command history yet.", _SEPARATOR)
+            return
+
+        self._append_result("Command History:")
+        for index, cmd in enumerate(entries, 1):
+            self._append_result(f"  {index}. {cmd}")
+        self._append_result(
+            _SEPARATOR,
+            "Tip: Use Up/Down arrow keys to navigate through history.",
+            _SEPARATOR,
+        )
+
+
+def main() -> None:
+    app = QApplication(sys.argv)
+    window = MathWindow()
+    window.show()
+    sys.exit(app.exec_())
+
+
+if __name__ == "__main__":
+    main()