PowerToys/doc/devdocs/modules/launcher/plugins/calculator.md

Calculator Plugin

The Calculator plugin as the name suggests is used to perform calculations on the user entered query.

Optional plugin settings

• We have the following settings that the user can configure to change the behavior of the plugin:

  Key	Default value	Name	Description
  InputUseEnglishFormat	false	Use English (United States) number format for input	Ignores your system setting and expects numbers in the format '1,000.50'
  OutputUseEnglishFormat	false	Use English (United States) number format for output	Ignores your system setting and returns numbers in the format '1000.50'

• The optional plugin settings are implemented via the ISettingProvider interface from Wox.Plugin project. All available settings for the plugin are defined in the Main class of the plugin.

Technical details

BracketHelper

• This helper validates the bracket usage in the input string.

CalculateHelper

• The CalculateHelper.cs class checks to see if the user entered query is a valid input to the calculator and only if the input is valid does it perform the operation.
  • It does so by matching the user query to a valid regex.
• This class also handles some human multiplication expression like 2(1+2) and (2+3)(3+4) in order to be computed by Mages lib.
  • It does so by matching some regex and inserting '*' where appropriate, e.g: 2(1+2) -> 2 * (1+2)
  • It takes into account the combination of numbers (num), constants (const), functions (func) and expressions in parentheses ((exp)).
  • The blank spaces between them are also considered.
  • Some combinations were not handled as they are not common such as 'const num' or 'func const'

CalculateEngine

• The main computation is done in the CalculateEngine.cs file using the Mages library.

var result = CalculateEngine.Interpret(query.Search, CultureInfo.CurrentUICulture);

CalculateResult

• The class which encapsulates the result of the computation.
• It comprises of the Result and RoundedResult properties.

ErrorHandler

• The class which encapsulates the code to log errors and format the user message.
• It returns an error result if the user searches with the activation command. This error result is shown to the user.

Score

The score of each result from the calculator plugin is 300.

Unit Tests

We have a Unit Test project that executes various test to ensure that the plugin works as expected.

BracketHelperTests

• The BracketHelperTests.cs class contains tests to validate that brackets are handled correctly.

ExtendedCalculatorParserTests

• The ExtendedCalculatorParserTests.cs class contains tests to validate that the input is parsed correctly and the result is correct.

NumberTranslatorTests

• The NumberTranslatorTests.cs class contains tests to validate that each number is converted correctly based on the defined locals.

QueryTests

• The QueryTests.cs class contains tests to validate that the user gets the correct results when searching.