// From a syntax node, create a list of trivia node that encapsulates the same text. We use SkippedTokens trivia
// to encapsulate the tokens, plus extract trivia from those tokens into the trivia list because:
// - We want leading trivia and trailing trivia to be directly visible in the trivia list, not on the tokens
// inside the skipped tokens trivia.
// - We have to expose structured trivia directives.
//
// Several options controls how diagnostics are handled:
// "preserveDiagnostics" means existing diagnostics are preserved, otherwise they are thrown away
// "addDiagnostic", if not Nothing, is added as a diagnostics
// "addDiagnosticsToFirstTokenOnly" means that "addDiagnostics" is attached only to the first token, otherwise
// it is attached to all tokens.
private static SyntaxList <SyntaxNode> CreateSkippedTrivia(SyntaxNode node, bool preserveDiagnostics, bool addDiagnosticToFirstTokenOnly, DiagnosticInfo addDiagnostic)
{
if (node.Kind == SyntaxKind.SkippedTokensTrivia)
{
// already skipped trivia
if (addDiagnostic != null)
{
////node = node.AddError(addDiagnostic); TODO
}
return(node);
}
IList <DiagnosticInfo> diagnostics = new List <DiagnosticInfo>();
var tokenListBuilder = SyntaxListBuilder <SyntaxToken> .Create();
node.CollectConstituentTokensAndDiagnostics(tokenListBuilder, diagnostics);
// Adjust diagnostics based on input.
if (!preserveDiagnostics)
{
diagnostics.Clear();
}
if (addDiagnostic != null)
{
diagnostics.Add(addDiagnostic);
}
var skippedTriviaBuilder = new SkippedTriviaBuilder(preserveDiagnostics, addDiagnosticToFirstTokenOnly, diagnostics);
// Get through each token and add it.
for (int i = 0; i < tokenListBuilder.Count; i++)
{
SyntaxToken currentToken = tokenListBuilder[i];
skippedTriviaBuilder.AddToken(currentToken, isFirst: (i == 0), isLast: (i == tokenListBuilder.Count - 1));
}
return(skippedTriviaBuilder.GetTriviaList());
}