/// <summary>
/// Reads an OpenLisp.NET list expression.
/// </summary>
/// <param name="reader"></param>
/// <param name="openLispList"></param>
/// <param name="start"></param>
/// <param name="end"></param>
/// <returns></returns>
public static OpenLispVal ReadList(TokensReader reader, OpenLispList openLispList, char start, char end)
{
string token = reader.Next();
if (token[0] == start)
{
while ((token = reader.Peek()) != null && token[0] != end)
{
openLispList.Conj(ReadForm(reader));
}
if (token == null)
{
throw new ParseError("expected '" + end + "', got EOF");
}
reader.Next();
return(openLispList);
}
throw new ParseError("expected '" + start + "'");
}
/// <summary>
/// This static method recursively processes
/// OpenLisp.NET forms and tokenizes them.
/// </summary>
/// <param name="reader"></param>
/// <returns></returns>
public static OpenLispVal ReadForm(TokensReader reader)
{
string token = reader.Peek();
if (token == null)
{
throw new OpenLispContinue();
}
OpenLispVal form = null;
switch (token)
{
case "'":
reader.Next();
return(new OpenLispList(new OpenLispSymbol("quote"),
ReadForm(reader)));
case "`":
reader.Next();
return(new OpenLispList(new OpenLispSymbol("quasiquote"),
ReadForm(reader)));
case "~":
reader.Next();
return(new OpenLispList(new OpenLispSymbol("unquote"),
ReadForm(reader)));
case "~@":
reader.Next();
return(new OpenLispList(new OpenLispSymbol("splice-unquote"),
ReadForm(reader)));
case "^":
reader.Next();
OpenLispVal meta = ReadForm(reader);
return(new OpenLispList(new OpenLispSymbol("with-meta"),
ReadForm(reader),
meta));
case "@":
reader.Next();
return(new OpenLispList(new OpenLispSymbol("deref"),
ReadForm(reader)));
case "(": form = ReadList(reader, new OpenLispList(), '(', ')'); break;
case ")": throw new ParseError("unexpected ')'");
case "[": form = ReadList(reader, new OpenLispVector(), '[', ']'); break;
case "]": throw new ParseError("unexpected ']'");
case "{": form = ReadHashMap(reader); break;
case "}": throw new ParseError("unexpected '}'");
default: form = ReadAtom(reader); break;
}
return(form);
}