Calculator

A simple calculator tool with command-line options, a user interface with preference settings, and server support.

Overview

This is a very basic demo of a PySide widget, originally completed in two weeks for a coding test.

Requirements

• Python 3
• Docker
• PySide6
• sympy (for testing)

Package Files

• calculate: main executable script to launch tool
• calculator.py: module containing the implementation
• calculator_ui.py: module containing the user interface
• calculator_log.txt: default file where logging output is written
• client.py: module containing client implementation
• server.py: module containing server implementation
• tests.py: module containing test cases to check calculator implementation
• /themes: folder containing css stylesheets for different ui themes

Notes

• Assumes the input is a correctly formatted arithmetic string
  • No unmatched or empty parentheses
  • Numbers on both sides of an operator (+-1 or --1 assumes negative 1)
  • Invalid inputs may still compute, but no guarantee that it's correct
• Does not support parentheses multiplication
  • (1+2)(3-4) computes incorrectly
• Does not support exponents
  • 6 ** 7 fails
• Allows parentheses around negatives
  • 6-(-7)*9 is valid
  • 6--7*9 is also valid
• Spaces with negatives may throw errors
  • 6 --7 * 9 computes
  • 6 - -7 * 9 does not
• When server is used with CLI, connection closes after one input
• When server is used with GUI, connection closes when GUI is closed

Areas of Improvement

• More robust and descriptive error handling for invalid string inputs
  • Be stricter about what is allowed vs. not allowed, e.g. spaces in input
  • Catch "list index out of range" errors and replace with something more useful
• Could use clearer separation of view and controller in the calculator GUI
  • Separate the connection functions into their own class
• Debug and improve input validator on the calculator GUI to only accept digits and math operators
  • Sometimes breaks after certain buttons are pressed, allowing letters to be inserted
• Set dynamic buffer size on server based on size of input from client
• Keep CLI server connection open for multiple inputs without reinitializing each time
  • Could use some sort of escape/exit command
• Add option for user to choose implemention mode, e.g. mine or sympy

Usage

All commands are run from inside the top-level calculator directory.

Server initialization

docker compose up --build

Must have Docker set up and logged in already.

Command-line with local implementation

./calculate -i {input string}
./calculate -i "(6+7*9)/-2+4+(-10)"

This runs the command-line calculator without connecting to the server.

Command-line with server

./calculate -ip {optional ip address}
./calculate -ip "10.8.9.174"

This runs the command-line calculator and attempts to connect to the server.
If no host is provided, will use ip address "0.0.0.0".

If connection is established, accepts user input like this:

-> {input}
-> (6+7*9)/-2+4+(-10)

Note: Do not put input in quotes, will already be sent to server as string

User interface

./calculate

This runs the calculator GUI and attempts to connect to the server.
If the connection fails, will fall back to the local built-in implementation.

Preferences

• Right align: Aligns the numpad to the right and operators to the left
• Reverse order: Sets numpad to start with 0 in top row; default is 0 in bottom row

Themes

• Fun colors for the calculator!