Ali

Dehghanpour

Professional Calculator is built entirely in Python 3.9+, using CustomTkinter for a modern, native-feeling desktop UI on Windows. It's event-driven with no polling loops or background threads, so idle CPU usage stays near zero while calculations remain instant. Instead of Python's unsafe eval(), it uses a custom expression engine built on the ast module — parsing expressions into a syntax tree and evaluating only a strict whitelist of operators, functions, and constants. This safely supports operator precedence, nested parentheses, and complex expressions like sin(45)+sqrt(144). Features include a full scientific mode (trig, inverse trig, hyperbolic, logs, factorial, nCr/nPr, degrees/radians toggle), memory functions (MC/MR/M+/M-/MS), searchable and reusable calculation history, undo/redo, keyboard shortcuts, clipboard copy/paste, and Dark/Light/System themes — all persisted locally via JSON, with no telemetry or network use after setup. Error handling is graceful throughout, so inva