public IEnumerable <IToken> LexIntern(string text)
{
var input = new Reader(text);
var position = 0;
var builder = new StringBuilder();
while (true)
{
if (!input.Valid)
{
yield break;
}
var c = input.Slurp();
if (char.IsDigit(c) ||
'+' == c ||
'-' == c)
{
do
{
builder.Append(c);
}while (input.Accept(char.IsDigit, ref c));
if (input.Accept('.'))
{
builder.Append('.');
while (input.Accept(char.IsDigit, ref c))
{
builder.Append(c);
}
}
yield return(new VerbatimToken(Number, position, builder.ToString()));
position += builder.Length;
builder.Clear();
continue;
}
switch (c)
{
case '[':
yield return(new VerbatimToken(OpenBracket, position, OpenBracket.Id));
break;
case ']':
yield return(new VerbatimToken(CloseBracket, position, CloseBracket.Id));
break;
case '{':
yield return(new VerbatimToken(OpenBrace, position, OpenBrace.Id));
break;
case '}':
yield return(new VerbatimToken(CloseBrace, position, CloseBrace.Id));
break;
case ',':
yield return(new VerbatimToken(Comma, position, Comma.Id));
break;
case ':':
yield return(new VerbatimToken(Colon, position, Colon.Id));
break;
case '"':
builder.Append(c);
while (input.Accept(x => x != '"', ref c))
{
builder.Append(c);
}
if (!input.Accept('"'))
{
yield break;
}
builder.Append('"');
yield return(new VerbatimToken(String, position, builder.ToString()));
position += builder.Length;
builder.Clear();
break;
case ' ':
case '\n':
case '\r':
case '\t':
builder.Append(c);
while (input.Accept(char.IsWhiteSpace, ref c))
{
builder.Append(c);
}
yield return(new VerbatimToken(Whitespace, position, builder.ToString()));
position += builder.Length;
builder.Clear();
break;
case 'n':
if (!input.Accept('u'))
{
yield break;
}
if (!input.Accept('l'))
{
yield break;
}
if (!input.Accept('l'))
{
yield break;
}
yield return(new VerbatimToken(Null, position, Null.Id));
position += 3;
break;
case 't':
if (!input.Accept('r'))
{
yield break;
}
if (!input.Accept('u'))
{
yield break;
}
if (!input.Accept('e'))
{
yield break;
}
yield return(new VerbatimToken(True, position, True.Id));
position += 3;
break;
case 'f':
if (!input.Accept('a'))
{
yield break;
}
if (!input.Accept('l'))
{
yield break;
}
if (!input.Accept('s'))
{
yield break;
}
if (!input.Accept('e'))
{
yield break;
}
yield return(new VerbatimToken(False, position, False.Id));
position += 4;
break;
}
position++;
}
}