Fix for #594.

[cgranade]

This PR suggests a fix for #594, and is marked in draft to avoid duplication of code in the qsharp-compiler repo. If we want to adopt these changes, I would suggest that a corresponding PR should be made against qsharp-compiler to make the SyntaxExtensions class publicly available.

Example screenshot

[cgranade]

@xinyi-joffre: Is this something you would find useful in the portal-hosted notebook experience?

[xinyi-joffre]

Yes, this looks like a cool feature!

[cgranade]

@xinyi-joffre: Awesome!

@SamarSha: Any thoughts on where code that's currently duplicated should live longer-term? Thanks!

[cgranade]

@SamarSha: Apologies for the hassle, but wanted to ping again for your thoughts on this one. Thanks!

[bamarsha]

• ToSyntax could go in the Q# unparser in the compiler (Transformations/QsharpCodeOutput.cs).
• InputDeclarations could maybe go in Core/SyntaxTreeExtensions.fs or some other general utility file. Probably would generalize it to return string? or string option for the invalid names.
• I guess it makes sense for TryResolveXref, ToLink, and ToHtml to stay in DocumentationGenerator. But you'd need to generalize them to output either Markdown or HTML?

[cgranade]

Much obliged, really appreciate your thoughts!

• ToSyntax could go in the Q# unparser in the compiler (Transformations/QsharpCodeOutput.cs).

Sounds good, we may also want to refactor DocumentationGenerator to rely on some of that as well then. At least when DocumentationGenerator was first written, the unparser was missing a few cases and had a fair bit marked as private or internal.

• InputDeclarations could maybe go in Core/SyntaxTreeExtensions.fs or some other general utility file. Probably would generalize it to return string? or string option for the invalid names.

Makes sense! Would you prefer it in that F# project, then?

• I guess it makes sense for TryResolveXref, ToLink, and ToHtml to stay in DocumentationGenerator. But you'd need to generalize them to output either Markdown or HTML?

Sounds good, I guess then we could pull in the [Microsoft.Quantum.DocumentationGenerator package](https://www.nuget.org/packages/Microsoft.Quantum.DocumentationGenerator/0.24.203411-beta f) from here to get that extension, would just need to mark it public in that project?

[bamarsha]

Sounds good, we may also want to refactor DocumentationGenerator to rely on some of that as well then. At least when DocumentationGenerator was first written, the unparser was missing a few cases and had a fair bit marked as private or internal.

I think the unparser's API could use a lot of improvement, yeah - if you have specific examples of things the documentation generator wants, that would be helpful.

Makes sense! Would you prefer it in that F# project, then?

Core is probably the best place for it, yeah.

Sounds good, I guess then we could pull in the [Microsoft.Quantum.DocumentationGenerator package](https://www.nuget.org/packages/Microsoft.Quantum.DocumentationGenerator/0.24.203411-beta f) from here to get that extension, would just need to mark it public in that project?

Yes, there'd be a dependency here on the DocumentationGenerator package.