notepad-based-calculator

This is a unfinished project, but it is in a state where you can easily reuse it.

The concept

Making an app similar to numi.app, soulver.app and parsify.app, cross-platform using C#.

Current state

The calculator engine is about 100% done. But it remains a few features I wanted to add that I didn't finish.

Feature	Example	Support
Basic algebra using digits	2 + 3	✅
Basic algebra using plain words	two plus three	✅
Implicit algebra operations	20 (50)	✅
Nested grouped operation	(12)3+(1 +2)(3(2))(1 +2)-3	✅
Binary operations	0.2 >= a fifth	✅
Percentage calculation	10 + 25%	✅
Comments	12 + 3 // anything after "//" is ignored	✅
Headers	# Title	✅
Variables	my income tax = 25%	✅
Conditions	if my income tax > 30% then $123 else $456	✅
Unit calculation	2km + 25% // should result 2.5 km 2 USD + 2 CAD // should result something like 3.05 USD 3 MB - 2 KB // should result 2.998 MB Supports length, mass, currencies, area, angle, volume, speed, temperature, date and time, percentage, computer data	✅
Function grammars (see detail below)	PERCENTAGE of what is NUMERIC i.e: 25% of what is 50 // should result 200	✅
Multilanguage	deux plus trois	✅ (partial)
Unit conversion	What is 1 USD in EUR 1km in meters Shouldn't be too complicated to implement using function grammar	❌

Please check the unit tests for a complete list of supported scenarios.

Technical details

Overall architecture

• NotepadBasedCalculator.Api
  This is the public API.

• NotepadBasedCalculator.Core
  This is core engine. It contains the lexer, parser and generic interpreter.

• NotepadBasedCalculator.BuiltInPlugins
  Contains all the basic extensions, which includes the components for parsing and interpreting units, basic algebra and binary operation and built-in functions grammars.

• NotepadBasedCalculator.StandaloneConsoleTestApp This is a console app you can use for testing the calculator manually. Check out how this project is made to understand how to use the calculator.

Extensiblity & Dependency injection

This project uses MEF as primary dependency injection & extensibility framework.

Function grammars

The calculation engine supports various kind of input data: percentage, length, numbers, etc. While this app/library tries to be smart enough to understand input like 25% of what is 50, it isn't smart enough to understand such an input without the help of a pre-defined grammar.

The full grammar for English language can be found here: FunctionDefinition.json

Each function is associated to a MEF extension. The C# implementation automatically binds the class with the function name from the grammar. Here is an example:

1. Grammar for 25% of what is 50
2. Implementation in C#

Main third-party dependencies for the calculator engine

• Community Toolkit
• Microsoft.Recognizers.Text
• UnitsNet
• Newtonsoft.Json

How to build and run?

Set up development environment

• Visual Studio 2022 with Desktop Development workload (Windows)
• Rider (Windows or MacOS)
• VS Code with C# extension (MacOS)
• (Optional) Avalonia UI

Set up repository

1. Clone the repository
2. Run init.ps1 (or .sh) to download all the required dependencies.

Build & Debug

1. Open src/NotepadBasedCalculator.App.sln in Visual Studio or Rider.
2. Set NotepadBasedCalculator.StandaloneConsoleTestApp as startup project.
3. F5 😉