public static char Expect(this ISequence <char> cs, char expected)
{
var c = cs.GetNext();
if (c != expected)
{
throw TokenizingException.UnexpectedCharacter(expected, c, cs.CurrentLocation);
}
return(c);
}
public IResult <Token> Parse(ParseState <char> state)
{
var input = state.Input;
// Attempt to read through an arbitrary c# code literal. We can largely do this by
// counting braces, but we have to get a bit more involved when we deal with
// braces which are quoted as chars and strings: '{' and "{".
// C# is a complicated language and this parser does not want to be complicated. It is expected
// that the verbatim contents of this block are passed, opaquely, to roslyn for compilation.
// This parser will not attempt in any way to recognize the contents of the C# block or provide
// helpful diagnostics/recovery. If the user doesn't balance their {} brackets, they're going
// to get an exception and a hard stop.
var startConsumed = input.Consumed;
var a = input.GetNext();
var b = input.Peek();
if (a != 'c' || b != '#')
{
input.PutBack(a);
return(state.Fail(this, ""));
}
input.GetNext();
while (char.IsWhiteSpace(input.Peek()))
{
input.GetNext();
}
input.Expect('{');
int braceCount = 1;
var buffer = new List <char>();
while (true)
{
var c = input.GetNext();
if (c == '\0')
{
TokenizingException.UnexpectedEndOfInput(input.CurrentLocation);
}
if (c == '\'')
{
buffer.Add(c);
c = input.GetNext();
buffer.Add(c);
if (c == '\\')
{
c = input.GetNext();
buffer.Add(c);
c = input.GetNext();
while (c != '\'')
{
buffer.Add(c);
c = input.GetNext();
}
}
else
{
c = input.Expect('\'');
}
buffer.Add(c);
continue;
}
if (c == '"')
{
buffer.Add(c);
while (true)
{
c = input.GetNext();
if (c == '\0')
{
TokenizingException.UnexpectedEndOfInput(input.CurrentLocation);
}
if (c == '"')
{
break;
}
if (c == '\\')
{
buffer.Add(c);
c = input.GetNext();
}
buffer.Add(c);
}
buffer.Add(c);
continue;
}
if (c == '@' && input.Peek() == '"')
{
buffer.Add(c);
buffer.Add(input.GetNext());
while (true)
{
c = input.GetNext();
if (c == '\0')
{
TokenizingException.UnexpectedEndOfInput(input.CurrentLocation);
}
if (c == '"')
{
if (input.Peek() != '"')
{
break;
}
buffer.Add(c);
c = input.GetNext();
}
buffer.Add(c);
}
buffer.Add(c);
continue;
}
if (c == '{')
{
braceCount++;
buffer.Add(c);
continue;
}
if (c == '}')
{
braceCount--;
if (braceCount == 0)
{
break;
}
buffer.Add(c);
continue;
}
buffer.Add(c);
}
//_chars.Expect('}');
return(state.Success(this, Token.CSharpLiteral(new string(buffer.ToArray())), input.Consumed - startConsumed, input.CurrentLocation));
}
