Still need to add tests

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Still need to have WriteVerbose, etc... use the $PSStyle settings before taking this out of draft

I really like this PR! It will be super useful to me!

So

PS>"$($PSStyle.Formatting.Error)custom error message"`

will output red colored string.

In time of evaluating the string we already know values of all constants - SupportsVirtualTerminal, isHost, Console.IsOutputRedirected. If so why do we need the filtering at all if we can return $null at the evaluating time if we do not need the ANSI value?

Ilya (@iSazonov) Error is currently a special case due to the custom formatting that happens. After this gets merged, I'll update the error formatting to use $PSStyle.Formatting.Error.

Steve Lee (@SteveL-MSFT) I say that $PSStyle could not be a const and be evaluated - as result we have no need to filter out escapes because $PSStyle would return $null if user turns off coloring or terminal does not support escapes and so on.

In time of evaluating the string we already know values of all constants - SupportsVirtualTerminal, isHost, Console.IsOutputRedirected.

Ilya (@iSazonov) The PowerShell engine doesn't know if the output/error is being reidrected. It cannot depedn on Console.IsOutputRedirected because it may be hosted in a Windows GUI applicatioin which doesn't have a console at all.
The information about whether the output/error is redirected or whether ANSI sequences should be stripped off because the process's output/error is redirected should be decided only by the host implementation.

Take the host implementation of the PowerShell sub kernel (jupyter kernel) in .NET Interactive as an instance, it's a console application, and the process's output/error streams are always redirected to send to the frontend -- jupyter notebook, which is capable of handling ANSI sequences. So, in this case, even thought Console.IsOutputRedirected and Console.IsErrorRedirected return true, the ANSI sequences shouldn't be stripped off.

To summarize, the host implementation has the final call on whether ANSI sequences should be stripped off or not, and that's why I opened #14387.

To summarize, the host implementation has the final call on whether ANSI sequences should be stripped off or not

Why can't PowerShell engine get this information from the host implementation?

because it may be hosted in a Windows GUI applicatioin which doesn't have a console at all.

So PowerShell engine can get get this information from the host implementation?

I don't know how that would work and how well that would work if it works.

• From a design point of view, I like to decouple engine and host instead of more coupling.
• From an implementation point of view, a host may dynamically change how it want the ANSI sequences to be handled.

Ilya (@iSazonov) I will merge this PR to make the cut of 7.2.0-preview.2 release build. Feel free to comment in #14387 about how you think this feature can be improved.

🎉v7.2.0-preview.2 has been released which incorporates this pull request.:tada:

Handy links:

• Release Notes

These changes don't seem to work in the Integrated Console: #14435