Handle aliased usings in RazorEditHelper

[ryzngard]

Actually ended up being easier than I thought. I didn't move AddUsings to the same functionality but definitely could? It doesn't seem like it would need it as much.

[davidwengier]

Random code written without a compiler, but rather than realising the string here and trimming twice, is it more efficient to do something like this:

// .Span ignores trivia, so by the rules of Roslyn it won't contain whitespace, right??
var span = usingDirectiveSyntax.Span;
if (!usingDirectiveSyntax.SemicolonToken.IsMissing)
{
	span = new TextSpan(span.Start, span.Length -1);
}

if (!usingDirectiveSyntax.UsingKeyword.IsMissing)
{
	span = ....
}

return sourceText.GetSubTextString(span);

[DustinCampbell]

💯

[ryzngard]

Honestly I got so in the habit of how the razor syntax tree looks I forgot about sensible things like the span not including trivia. This can be simplified even more by making some assumptions (like explicitly only handling things where the Name is not null,)

private static string GetNamespaceFromDirective(UsingDirectiveSyntax usingDirectiveSyntax, SourceText sourceText)
{
    var nameSyntax = usingDirectiveSyntax.Name.AssumeNotNull();

    if (usingDirectiveSyntax.Alias is null)
    {
        return sourceText.GetSubTextString(nameSyntax.Span);
    }

    return sourceText.GetSubTextString(TextSpan.FromBounds(usingDirectiveSyntax.Alias.Span.Start, nameSyntax.Span.End));
}

[davidwengier]

using static?

No idea if it's possible in a razor file, but worth adding a test for, either to validate or prove it's not supported?

[ryzngard]

I'm guessing since it's just a csharp block that it is supported. I'll add a test and I think I can just find the leftmost ChildNode since the using keyword is a token.

[ryzngard]

Scratch that, static is a token. I guess it's left most child nodes and tokens excluding the using keyword

[davidwengier]

What about the start position just being the using keywords span end, plus end trivia length?

[ryzngard]

Is it guarantee that the end trivia is attached to the using keyword? That's the only thing I wasn't sure of. I'm rusty on my Roslyn syntax

[davidwengier]

Guaranteed, no idea. From a quick test, it was.