public static object ParseStringLiteral(char ch, StringIterator reader)
{
if (ch != '"')
{
return(null);
}
var builder = new StringBuilder();
reader.Read();
while (true)
{
var pk = reader.Peek();
if (pk == -1)
{
break;
}
ch = (char)pk;
if (ch == '"')
{
reader.Read();
break;
}
builder.Append(ch);
reader.Read();
}
return(builder);
}
public IEnumerable <object> Process(string str, int index = 0)
{
char ch;
var reader = new StringIterator(str, index);
while (reader.Peek() != -1)
{
ch = (char)reader.Peek();
bool resolved = false;
foreach (var func in functions)
{
var result = func(ch, reader);
if (result == null)
{
continue;
}
if (result != Eat)
{
yield return(result);
}
resolved = true;
break;
}
if (!resolved)
{
throw new Exception("Unexpected character " + ch);
}
}
}
public static object ParseIdentifier(char ch, StringIterator reader)
{
if (!char.IsLetter(ch) && ch != '_')
{
return(null);
}
var builder = new StringBuilder();
builder.Append(ch);
reader.Read();
while (true)
{
var pk = reader.Peek();
if (pk == -1)
{
break;
}
ch = (char)pk;
if (!char.IsLetterOrDigit(ch) && ch != '_')
{
break;
}
builder.Append(ch);
reader.Read();
}
return(builder.ToString());
}
public static object EatWhitespace(char ch, StringIterator reader)
{
if (char.IsWhiteSpace(ch))
{
reader.Read();
return(Eat);
}
else
{
return(null);
}
}
public static object ParseComment(char ch, StringIterator reader)
{
if (ch != '-' || (char)reader.Peek(2) != '-')
{
return(null);
}
while (true)
{
int pk = reader.Peek();
if (pk == -1 || pk == (char)'\n')
{
break;
}
reader.Read();
}
return(Eat);
}
public static object ParseFloat(char ch, StringIterator reader)
{
if (!char.IsDigit(ch) && !(ch == '-' && char.IsDigit((char)reader.Peek(2))))
{
return(null);
}
var builder = new StringBuilder();
builder.Append(ch);
reader.Read(); //read
while (true)
{
var pk = reader.Peek();
if (pk == -1)
{
break;
}
ch = (char)pk;
if (ch == 'e')
{
if (reader.Peek(2) == (int)'-' || reader.Peek(2) == (int)'+')
{
reader.Read();
builder.Append("e");
builder.Append((char)reader.Read());
}
}
else if (ch != '.' && !char.IsDigit(ch))
{
break;
}
else
{
builder.Append(ch);
reader.Read();
}
}
return(float.Parse(builder.ToString(), CultureInfo.InvariantCulture));
}
