Mid Term Calculator Project

Overview

This Mid Term Calculator Project is a command-line calculator that uses a Read-Evaluate-Print Loop (REPL) for user interaction. It supports basic arithmetic operations and manages calculation history efficiently.

Table of Contents

• Features
• Setup Instructions
• Usage Examples
• Architectural Decisions
• Design Patterns
• Logging Strategy

Features

• Arithmetic Operations: Perform addition, subtraction, multiplication, and division on two numeric values.
• Calculation History: -- Load: Retrieve past calculations from a CSV file using Pandas. -- Save: Store current calculation history to a CSV file. -- Clear: Remove all entries from the current history.
• Plugin System: Dynamically load commands for enhanced functionality.
• User-Friendly Interface: Access a menu of commands for easy navigation.

Setup Instructions

1. Clone the Repository: git clone https://github.com/yourusername/Midterm_Calc.git cd Midterm_Calc

2. Create a Virtual Environment (optional but recommended): python3 -m venv my_env source my_env/bin/activate # On Windows use my_env\Scripts\activate

3. Install Required Packages: pip install -r requirements.txt

4. Configure Environment Variables: Create a .env file in the root directory: ENVIRONMENT=DEVELOPMENT DATABASE_USERNAME=root HISTORY_FILE_PATH=history.csv

5. Run the Application: python main.py

Usage Examples

• Accessing Commands:

• View available commands: menu

• Basic Operations:

• To add two numbers: add 1 2

• To subtract: subtract 5 3

• To multiply: multiply 4 2

• To divide: divide 8 4

• Managing History:

• Save history: save

• Load history: load

• Clear history: clear

Architectural Decisions

Design Patterns and Concepts

• Facade Pattern: Provides a simplified interface for complex data operations involving Pandas. For implementation details, see Facade Pattern in Code.

• Command Pattern: Encapsulates each command (add, subtract, etc.) as an object for easier management and extension. See Command Pattern in Code.

• Factory Method: Used for creating command instances dynamically. Details can be found in Factory Method Code.

• Singleton Pattern: Ensures the history manager is instantiated only once. See Singleton Pattern Code.

• Strategy Pattern: Allows swapping different calculation strategies with the use of plugins and class instantiation. Refer to Strategy Pattern Code.

• REPL (Read-Eval-Print Loop): Facilitates direct interaction with the calculator, allowing users to enter commands and receive immediate feedback. Refer to REPL Code.

• LBYL (Look Before You Leap): Checks user input for validity before executing commands to prevent errors. This ensures that only valid commands are processed. Refer to LBYL Code.

• EAFP (Easier to Ask for Forgiveness than Permission): Attempts calculations and handles exceptions as they arise, allowing for cleaner and more efficient code. This approach is particularly useful for managing invalid inputs and division errors. Refer to EAFP Code.

• Environment Variables: Utilizes environment variables to manage sensitive information and configuration settings, such as file paths and database credentials. This is achieved through a .env file and the dotenv library. Refer to Environment Variables Code.

Logging Strategy

The logging system captures user actions and errors at various severity levels (INFO, WARNING, ERROR).

• Configuration: Configured through logging.conf for flexible management. See Logging Configuration Code.

• Usage in Code: Logger methods record events such as command execution and errors. Example usage can be seen in Logging Usage Code.