public static SyntaxNode Unparenthesize(
this ISyntaxFacts syntaxFacts, SyntaxNode node)
{
SyntaxToken openParenToken;
SyntaxNode operand;
SyntaxToken closeParenToken;
if (syntaxFacts.IsParenthesizedPattern(node))
{
syntaxFacts.GetPartsOfParenthesizedPattern(node,
out openParenToken, out operand, out closeParenToken);
}
else
{
syntaxFacts.GetPartsOfParenthesizedExpression(node,
out openParenToken, out operand, out closeParenToken);
}
var leadingTrivia = openParenToken.LeadingTrivia
.Concat(openParenToken.TrailingTrivia)
.Where(t => !syntaxFacts.IsElastic(t))
.Concat(operand.GetLeadingTrivia());
var trailingTrivia = operand.GetTrailingTrivia()
.Concat(closeParenToken.LeadingTrivia)
.Where(t => !syntaxFacts.IsElastic(t))
.Concat(closeParenToken.TrailingTrivia);
var resultNode = operand
.WithLeadingTrivia(leadingTrivia)
.WithTrailingTrivia(trailingTrivia);
// If there's no trivia between the original node and the tokens around it, then add
// elastic markers so the formatting engine will spaces if necessary to keep things
// parseable.
if (resultNode.GetLeadingTrivia().Count == 0)
{
var previousToken = node.GetFirstToken().GetPreviousToken();
if (previousToken.TrailingTrivia.Count == 0 &&
syntaxFacts.IsWordOrNumber(previousToken) &&
syntaxFacts.IsWordOrNumber(resultNode.GetFirstToken()))
{
resultNode = resultNode.WithPrependedLeadingTrivia(syntaxFacts.ElasticMarker);
}
}
if (resultNode.GetTrailingTrivia().Count == 0)
{
var nextToken = node.GetLastToken().GetNextToken();
if (nextToken.LeadingTrivia.Count == 0 &&
syntaxFacts.IsWordOrNumber(nextToken) &&
syntaxFacts.IsWordOrNumber(resultNode.GetLastToken()))
{
resultNode = resultNode.WithAppendedTrailingTrivia(syntaxFacts.ElasticMarker);
}
}
return(resultNode);
}
public static SyntaxNode GetPatternOfParenthesizedPattern(
this ISyntaxFacts syntaxFacts,
SyntaxNode node
)
{
syntaxFacts.GetPartsOfParenthesizedPattern(node, out _, out var pattern, out _);
return(pattern);
}
private static bool IsLegalPattern(
ISyntaxFacts syntaxFacts,
SyntaxNode pattern,
bool designatorsLegal
)
{
// It is illegal to create a pattern that has a designator under a not-pattern or or-pattern
if (syntaxFacts.IsBinaryPattern(pattern))
{
syntaxFacts.GetPartsOfBinaryPattern(pattern, out var left, out _, out var right);
designatorsLegal = designatorsLegal && !syntaxFacts.IsOrPattern(pattern);
return(IsLegalPattern(syntaxFacts, left, designatorsLegal) &&
IsLegalPattern(syntaxFacts, right, designatorsLegal));
}
if (syntaxFacts.IsNotPattern(pattern))
{
syntaxFacts.GetPartsOfUnaryPattern(pattern, out _, out var subPattern);
return(IsLegalPattern(syntaxFacts, subPattern, designatorsLegal: false));
}
if (syntaxFacts.IsParenthesizedPattern(pattern))
{
syntaxFacts.GetPartsOfParenthesizedPattern(
pattern,
out _,
out var subPattern,
out _
);
return(IsLegalPattern(syntaxFacts, subPattern, designatorsLegal));
}
if (syntaxFacts.IsDeclarationPattern(pattern))
{
syntaxFacts.GetPartsOfDeclarationPattern(pattern, out _, out var designator);
return(designator == null || designatorsLegal);
}
if (syntaxFacts.IsRecursivePattern(pattern))
{
syntaxFacts.GetPartsOfRecursivePattern(
pattern,
out _,
out _,
out _,
out var designator
);
return(designator == null || designatorsLegal);
}
if (syntaxFacts.IsVarPattern(pattern))
{
return(designatorsLegal);
}
return(true);
}
private static bool IsLegalPattern(ISyntaxFacts syntaxFacts, SyntaxNode pattern, bool designatorsLegal)
{
// It is illegal to create a pattern that has a designator under a not-pattern or or-pattern
if (syntaxFacts.IsBinaryPattern(pattern))
{
syntaxFacts.GetPartsOfBinaryPattern(pattern, out var left, out _, out var right);
designatorsLegal = designatorsLegal && !syntaxFacts.IsOrPattern(pattern);
return(IsLegalPattern(syntaxFacts, left, designatorsLegal) &&
IsLegalPattern(syntaxFacts, right, designatorsLegal));
}
if (syntaxFacts.IsNotPattern(pattern))
{
// it's fine to have `not string s` (or `not (string s)`) as long as we're currently in a location where
// designators are legal themselves.
syntaxFacts.GetPartsOfUnaryPattern(pattern, out _, out var subPattern);
if (syntaxFacts.IsParenthesizedPattern(subPattern))
{
subPattern = syntaxFacts.GetPatternOfParenthesizedPattern(subPattern);
}
if (syntaxFacts.IsDeclarationPattern(subPattern))
{
return(designatorsLegal);
}
return(IsLegalPattern(syntaxFacts, subPattern, designatorsLegal: false));
}
if (syntaxFacts.IsParenthesizedPattern(pattern))
{
syntaxFacts.GetPartsOfParenthesizedPattern(pattern, out _, out var subPattern, out _);
return(IsLegalPattern(syntaxFacts, subPattern, designatorsLegal));
}
if (syntaxFacts.IsDeclarationPattern(pattern))
{
syntaxFacts.GetPartsOfDeclarationPattern(pattern, out _, out var designator);
return(designator == null || designatorsLegal);
}
if (syntaxFacts.IsRecursivePattern(pattern))
{
syntaxFacts.GetPartsOfRecursivePattern(pattern, out _, out _, out _, out var designator);
return(designator == null || designatorsLegal);
}
if (syntaxFacts.IsVarPattern(pattern))
{
return(designatorsLegal);
}
return(true);
}