public static Pair FromArrayAt(Object[] array, int pos)
{
Pair retval = null;
for (int i = array.Length - 1; i >= pos; i--)
{
retval = Pair.Cons(array[i], retval);
}
return(retval);
}
static public Pair read_list(Pair list_so_far, TextReader str)
{
object token = read_token(str);
if (token == null) // at the end of the stream, but no list. this is bad.
{
throw new Exception("Error parsing list: " + Util.Dump(Pair.reverse(list_so_far)).TrimEnd(new char[] { ')' })); // a continuation would be handy here
}
if (right_paren_token.Equals(token))
{
return(Pair.reverse(list_so_far)); // if this far we're cool
}
else if (start_vector_token.Equals(token))
{
return(read_list(Pair.Cons(read_vector(str), list_so_far), str));
}
else if (left_paren_token.Equals(token))
{
// if (str is DocumentReader)
// {
// DocumentReader documentReader = (DocumentReader) str;
// //EditPoint startEditPoint = documentReader.editPoint.CreateEditPoint();
// //startEditPoint.CharLeft(1);
// int startEditPointLine = documentReader.Line;
// int startEditPointCol = documentReader.Col;
// Pair curList = read_list(null,str);
// // if (curList != null)
// // curList.marker = new Marker(documentReader.document, startEditPointLine, startEditPointCol, documentReader.Line, documentReader.Col + 1, "");//startEditPoint.GetText(documentReader.editPoint));
// return read_list(Pair.Cons(curList, list_so_far), str);
// }
// else
return(read_list(Pair.Cons(read_list(null, str), list_so_far), str));
}
else if (IsMember(list_so_far, token))
{
AddMemberToCar(list_so_far, token);
return(read_list(list_so_far, str));
}
else
{
return(read_list(Pair.Cons(token, list_so_far), str));
}
}
public static object read_token(TextReader str)
{
if (str.Peek() == -1)
{
return(null);
}
char c = (char)str.Read();
if (Char.IsWhiteSpace(c)) // is_char_whitespace(c)) // .IsWhiteSpace(c))
{
return(read_token(str));
}
else if (c.Equals(';'))
{
str.ReadLine();
/*
* char curr = (char) str.Read();
* Console.WriteLine("skipping chars: ");
* while (!c.Equals('\n') && !c.Equals('\r') && (str.Peek() != -1))
* {
*
* curr = (char) str.Read();
* Console.Write(curr);
* }
* Console.WriteLine("skipping line");
*/
return(read_token(str));
}
else if (c.Equals('('))
{
return(left_paren_token);
}
else if (c.Equals(')'))
{
return(right_paren_token);
}
else if (c.Equals('\'')) // Quote
{
object curr = read(str);
Pair newpair = new Pair(curr);
return(Pair.Cons(Symbol.Create("quote"), newpair));
}
else if (c.Equals('"'))
{
char curr = (char)str.Read();
string strtok = "";
while (!curr.Equals('"'))
{
strtok += curr;
int curr_as_int = str.Read();
if (curr_as_int == -1)
{
throw new Exception("Error parsing string: \"" + strtok + "\"");
}
else
{
curr = (char)curr_as_int;
}
}
return(strtok);
}
else if (c.Equals('#')) // Boolean OR Character OR Vector
{
char curr = (char)str.Read();
if (curr.Equals('\\')) // itsa char
{
return((char)str.Read());
}
else if (curr.Equals('('))
{
return(start_vector_token);
}
else // itsa bool
{
if (curr.Equals('t'))
{
return(true);
}
else
{
return(false); // should maybe also check for #a, etc.
}
}
}
else if (Char.IsNumber(c) || (c.Equals('-') && !Char.IsWhiteSpace((char)str.Peek())))
{
string numstr = new string(c, 1);
while (Char.IsNumber((char)str.Peek()) || ((char)str.Peek()).Equals('.'))
{
numstr += (char)str.Read();
}
if (numstr.IndexOf('.') != -1)
{
return(Convert.ToSingle(numstr));
}
else
{
return(Convert.ToInt32(numstr));
}
}
else //if (Char.IsLetter(c))
{
string symstr = new string(c, 1);
while (!Char.IsWhiteSpace((char)str.Peek()) && !((char)str.Peek()).Equals(')') && (str.Peek() != -1))
{
symstr += (char)str.Read();
}
return(Symbol.Create(symstr));
}
}
public object Call(Object[] args)
{
return(Pair.Cons(args[0], args[1] as Pair));
}
public object Eval(TextReader str)
{
//Console.WriteLine("starting eval");
Object evaledObj = null;
Object parsedObj = Util.read(str);
if (parsedObj is Pair)
{
if (macros.Count > 0)
{
// bool curRunHidden = DebugInfo.RunHidden;
// DebugInfo.RunHidden = true; //don't debug the macro expension code
Closure macroExpand = initEnv.Apply(Symbol.Create("macro-expand")) as Closure;
parsedObj = macroExpand.Eval(new Object[] { parsedObj });
// DebugInfo.RunHidden = curRunHidden;
}
Pair p = parsedObj as Pair;
switch (p.car.ToString())
{
case "define":
Expression expr = null;
Symbol def = null;
if (p.cdr.car is Pair) // (define (fn x y) body)
{
Pair def_and_args = p.cdr.car as Pair;
Pair body = p.cdr.cdr;
Pair syms = def_and_args.cdr;
def = Symbol.Create(def_and_args.car.ToString());
expr = Expression.Parse(Pair.Cons(Symbol.Create("lambda"), Pair.Cons(syms, body)));
// Debug.WriteLine(def + "-->" + expr);
}
else // (define fn (lambda (x y) body))
{
def = Symbol.Create(p.cdr.car.ToString());
expr = Expression.Parse(p.cdr.cdr.car);
}
//initEnv = new Extended_Env(new Pair(def), new Pair(null), initEnv);
//Object value = Eval(expr);
//Console.WriteLine("defining: " + def);
// expr.Mark(p);
initEnv.Bind(def, Eval(expr));
break;
case "macro":
Symbol name = p.cdr.car as Symbol;
// Console.WriteLine("macrodef" + name + " " + Expression.Parse(p.cdr.cdr.car).Eval(initEnv).ToString());
Closure transformer = (Closure)Expression.Parse(p.cdr.cdr.car).Eval(initEnv);
this.macros[name] = transformer;
// Console.WriteLine("macro: " + name);
break;
default:
// need to call macro-expand in here. but how?
evaledObj = Util.Dump(Eval(Expression.Parse(parsedObj)));
break;
}
}
else
{
evaledObj = Util.Dump(Eval(Expression.Parse(parsedObj)));
}
if (str.Peek() == -1)
{
return(evaledObj);
}
else
{
return(Eval(str));
}
}
