private PathToken FromContext(string input, PathTokenType type, PathLexerContext tokenContext)
=> new PathToken(
input,
input.Substring(tokenContext.StartPosition, tokenContext.EndPosition - tokenContext.StartPosition),
type,
tokenContext.StartPosition,
tokenContext.EndPosition);
private static bool IsPathDelimiterNext(PathLexerContext context)
{
return(IsPathDelimiterMattching(new PathLexerContext
{
StartPosition = context.EndPosition,
EndPosition = context.EndPosition + 1,
InputString = context.InputString
}));
}
public IEnumerable <PathToken> Tokenize(string input)
{
var tokenContext = new PathLexerContext
{
StartPosition = 0,
EndPosition = 0,
InputString = input
};
yield return(FromContext(
input,
PathTokenType.StartToken,
tokenContext));
foreach (var symbol in input ?? string.Empty)
{
tokenContext.EndPosition += 1;
var tokenDefinition = definitions.FirstOrDefault(v => v.IsMatched(tokenContext));
if (tokenDefinition != null)
{
yield return(FromContext(
input,
tokenDefinition.Type,
tokenContext));
tokenContext.StartPosition = tokenContext.EndPosition;
}
}
if (tokenContext.StartPosition != tokenContext.EndPosition)
{
yield return(FromContext(
input,
PathTokenType.InvalidSequence,
tokenContext));
}
else
{
yield return(FromContext(
input,
PathTokenType.EndToken,
tokenContext));
}
}
public static bool IsRootDirectoryMattching(PathLexerContext context)
{
return(context.StartPosition == 0 &&
AreEqual(SimpleFileSystemEnvironment.RootPath, context));
}
private static bool IsValidSubdirectory(PathLexerContext context)
{
return(SimpleFileSystemEnvironment.IsValidSubdirectory(context.InputString.Skip(context.StartPosition).Take(context.GetSymbolsCount())));
}
private static bool AreEqual(string pattern, PathLexerContext context)
{
return(pattern.Length == context.GetSymbolsCount() &&
Enumerable.SequenceEqual(pattern, context.InputString.Skip(context.StartPosition).Take(context.GetSymbolsCount())));
}
public static bool IsParentDirectoryMattching(PathLexerContext context)
{
return(AreEqual(SimpleFileSystemEnvironment.ParentDirectoryAlias, context));
}
public static bool IsSubdirectoryMattching(PathLexerContext context)
{
return
((context.EndPosition == context.InputString.Length && IsValidSubdirectory(context)) ||
(context.EndPosition != context.InputString.Length && IsPathDelimiterNext(context) && IsValidSubdirectory(context)));
}
public static bool IsPathDelimiterMattching(PathLexerContext context)
{
return(!IsRootDirectoryMattching(context) &&
context.GetSymbolsCount() == 1 &&
context.InputString[context.StartPosition] == SimpleFileSystemEnvironment.PathDelimiter);
}
public bool IsMatched(PathLexerContext context) => _matching(context);
