private SyntaxTree WithChanges(SourceText newText, IReadOnlyList <TextChangeRange> changes)
{
if (changes == null)
{
throw new ArgumentNullException(nameof(changes));
}
var oldTree = this;
// if changes is entire text do a full reparse
if (changes.Count == 1 && changes[0].Span == new TextSpan(0, this.Length) && changes[0].NewLength == newText.Length)
{
// parser will do a full parse if we give it no changes
changes = null;
oldTree = null;
}
using (var lexer = new InternalSyntax.Lexer(newText, this.Options))
using (var parser = new InternalSyntax.LanguageParser(lexer, oldTree?.GetRoot(), changes))
{
var compilationUnit = (CompilationUnitSyntax)parser.ParseCompilationUnit().CreateRed();
var tree = new ParsedSyntaxTree(newText, newText.Encoding, newText.ChecksumAlgorithm, this.FilePath, this.Options, compilationUnit, parser.Directives);
tree.VerifySource(changes);
return(tree);
}
}
/// <summary>
/// Produces a syntax tree by parsing the source text.
/// </summary>
public static SyntaxTree ParseText(
SourceText text,
CSharpParseOptions options = null,
string path = "",
CancellationToken cancellationToken = default(CancellationToken))
{
if (text == null)
{
throw new ArgumentNullException(nameof(text));
}
options = options ?? CSharpParseOptions.Default;
using (var lexer = new InternalSyntax.Lexer(text, options))
{
using (var parser = new InternalSyntax.LanguageParser(lexer, oldTree: null, changes: null, cancellationToken: cancellationToken))
{
var compilationUnit = (CompilationUnitSyntax)parser.ParseCompilationUnit().CreateRed();
var tree = new ParsedSyntaxTree(text, text.Encoding, text.ChecksumAlgorithm, path, options, compilationUnit, parser.Directives);
tree.VerifySource();
return(tree);
}
}
}
internal DirectiveParser(Lexer lexer, DirectiveStack context)
: base(lexer, LexerMode.Directive, null, null, false)
{
_context = context;
}