private static bool IsMember(Pair list_so_far, object token)
{
return ((list_so_far != null) && (list_so_far.car is Pair) &&
(token is Symbol) && (((Symbol)token).IsMember()));
}
public Pair(object car, Pair cdr)
{
this.car= car; this.cdr = cdr;
}
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);
}
}
private static void AddMemberToCar(Pair pair, object token)
{
((Pair)pair.car).member = ((Symbol) token).val.Substring(1);
((Pair)pair.car).hasMember = true;
}
public static Type GetType(String tname, Pair prefixes)
{
Type type = GetType(tname);
if (type != null)
return type;
foreach (string prefix in prefixes)
{
type = GetType(prefix + "." + tname);
if (type != null)
return type;
}
return null;
}
public static 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 PairEnumerator(Pair pair)
{
this.pair = pair; this.current = null;
}
// TODO: new cons for each?
public static Pair reverse(Pair pair)
{
if (pair == null)
return null;
else
{
//TODO: change recursive copy to single copy
Pair p = pair.Clone();
p.cdr = null;
return append(reverse(pair.cdr), p);
/*
Pair p = new Pair(pair.car);
p.Info = pair.Info;
return append(reverse(pair.cdr), p);*/
}
}
public static Pair Cons(object obj, object p)
{
if (p != null)
throw new Exception("dotted pairs not supported");
Pair newPair = new Pair(obj);
newPair.cdr = null;
return newPair;
}
public static Pair Cons(object obj, Pair p)
{
Pair newPair = new Pair(obj);
newPair.cdr = p;
return newPair;
}
// TODO: new cons for each?
public static Pair append(Pair ls1, Pair ls2)
{
if (ls1 == null)
return ls2;
else
{
Pair p = ls1.Clone();
p.cdr = append(ls1.cdr, ls2);
return p;
/* Pair p = Pair.Cons(ls1.car, append(ls1.cdr, ls2));
p.Info = ls1.Info;
return p;*/
}
}
