CmdPal: Make Calculator Great Again

[jiripolasek]

Summary of the Pull Request

This PR continues the tradition of alphabetical progress. After MBGA, we move on to MCBA — Make Calculator Better Again!

• Introduces limited automatic correction and completion of expressions.
  • The goal is to allow uninterrupted typing and avoid disruptions when a partially entered expression is temporarily invalid (which previously caused the result to be replaced by an error message or hidden by the fallback).
  • The implementation intentionally aims for a sweet spot:
    • Ignores trailing binary operators.
    • Automatically closes all opened parentheses.
    • It is not exhaustive; for example, incomplete constants or functions may still result in an invalid query.
• Copy current result to the search bar.
  • Adds an option to copy the current result to the search bar when the user types = at the end of the expression.
  • Adds a new menu item for the same action.
  • Fixes the Save command to also copy the result to the query.
• Adds support for the factorial(x) function and the x! expression.
  • Factorial calculations are supported up to 170! (limited by double), but display is constrained by decimal conversion and allows direct display of results up to 20!.
• Adds support for the sign(x) function.
• Adds support for the π symbol as an alternative to the pi constant.
• Adds a context menu item to the result list item and fallback that displays the octal representation of the result.
• Implements beautification of the query:
  • Converts technical symbols such as * or / to × or ÷, respectively.
  • Not enabled for fallbacks for now, since the item text should match the query to keep the score intact.
• Implements additional normalization of symbols in the query:
  • Percent: ％, %, ﹪
  • Minus: −, -, –, —
  • Factorial: ！, !
  • Multiplication: *, ×, ∗, ·, ⋅, ✕, ✖, \u2062 (invisible times)
  • Division: /, ÷, ➗, :
• Allows use of ² and ³ as alternatives to ^2 and ^3.
• Updates the unit test that was culture sensitive to force en-US output (not an actual fix, but at least it clears false positive for now)
• Fixes pre-parsing of scientific notation to prevent capturing minus sign as part of it.
• Fixes normalization/rounding of the result, so it can display small values (the current solution turned it into a string with scientific notation and couldn't parse it back).
• Updates test with new cases

Pictures? Moving!

Previous behavior:

Screen.Recording.2026-01-07.195332.mp4

New behavior:

Screen.Recording.2026-01-07.195614.mp4

PR Checklist

• Closes: Command palette - display other number systems for expressions #43481
• Closes: Command Palette Calculator extension: Replace input if query ends with '=' #43460
• Closes: Factorials for the Command Palette calculator #42078
• Closes: Command Palette math module is not equal to PowerToys Run, missing ! operator #41839
• Closes: Operations involving Scientific Notation #39659
• Closes: [cmpal] calculator - scientific notation not working as expected #40502
• Related to: CmdPal: Calc extension unit test fails in non-English culture #41715

• Communication: I've discussed this with core contributors already. If the work hasn't been agreed, this work might be rejected
• Tests: Added/updated and all pass
• Localization: All end-user-facing strings can be localized
• Dev docs: Added/updated
• New binaries: Added on the required places
  • JSON for signing for new binaries
  • WXS for installer for new binaries and localization folder
  • YML for CI pipeline for new test projects
  • YML for signed pipeline
• Documentation updated: If checked, please file a pull request on our docs repo and link it here: #xxx

Detailed Description of the Pull Request / Additional comments

Validation Steps Performed

[jiripolasek]

Build fail; unrelated to changes in this PR:

   157>RunVSTest:
            Assert.AreEqual failed. Expected:<1>. Actual:<0>. 
           Stack Trace:
              at Microsoft.CmdPal.Ext.Shell.UnitTests.QueryTests.QueryWithoutHistoryCommand(String command, String exeName) in C:\a\_work\1\s\src\modules\cmdpal\Tests\Microsoft.CmdPal.Ext.Shell.UnitTests\QueryTests.cs:line 97

/azp run

[jiripolasek]

/azp run

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[michaeljolley]

Love this @jiripolasek