public static Object process(Object o)
{
if (o is string)
{
string s = (string)o;
if (s[0] == '"')
{
return(s.Substring(1, s.Length - 2));
}
if (s[0] == '&')
{
if ((s.Length > 1) && s[1] == '\"')
{
return(Symbol.make(s.Substring(2, s.Length - 3)));
}
else
{
return(Symbol.make(s));
}
}
if (s[0] >= '0' && s[0] <= '9')
{
return(tryNum(s));
}
if ((s[0] == '-' || s[0] == '+') && s.Length > 1 &&
(s[1] >= '0' && s[1] <= '9'))
{
return(tryNum(s));
}
if (s.Equals("#f"))
{
return(Runtime._false);
}
if (s.Equals("#t"))
{
return(Runtime._true);
}
if (s.StartsWith("#\\"))
{
if (s.Length == 3)
{
return(s[2]);
}
string ss = s.Substring(2, s.Length - 2);
switch (ss)
{
case "Newline": return('\n');
case "Tab": return('\t');
case "Space": return(' ');
case "LBR": return('(');
case "RBR": return(')');
case "Semicolon": return(';');
}
if (ss.Length > 5)
{
if (ss.Substring(0, 5).Equals("ASCII"))
{
return((char)(Int32.Parse(ss.Substring(5, ss.Length - 5))));
}
}
if (s.Equals("#\\"))
{
return('\\');
}
return(Symbol.make("Char(" + s + ")"));
}
Symbol sym = Symbol.make(s);
return(sym);
}
else if (o is pospair)
{
pospair pp = (pospair)o;
return(new Pair(annotatetag, new Pair(new Pair(pp.sfile, new Pair(pp.line, new Pair(pp.col, null))),
new Pair(process(pp.s), null))));
}
else if (o is Pair)
{
Pair p = (Pair)o;
if (p.car != null)
{
string pc = null;
if (p.car is string)
{
pc = (string)p.car;
}
else if (p.car is pospair)
{
pc = ((pospair)(p.car)).s;
}
if (pc != null)
{
Object oo = null;
if (pc.Equals("'"))
{
oo = thequote;
}
else if (pc.Equals(","))
{
oo = theunquote;
}
else if (pc.Equals("`"))
{
oo = thequasiquote;
}
else if (pc.Equals(",@"))
{
oo = thesplicing;
}
if (oo != null)
{
return(new Pair(new Pair(oo, new Pair(process(p.cadr()), null)),
process(p.cddr())));
}
}
}
p.car = process(p.car);
p.cdr = process(p.cdr);
return(p);
}
return(o);
}
public static Object aread(ExtendedReader r)
{
Object prev_p = null;
Stack top = new Stack();
char[] c = new char[1];
bool rd = true;
bool annotate = r.annotate;
int state = 0;
string s = "";
pospair strt = null;
pospair crnt = null;
System.Collections.Stack st = new System.Collections.Stack();
System.Collections.Stack pos = new System.Collections.Stack();
while (true)
{
char ch;
if (!rd)
{
if (top.Count > 0)
{
return(top.Pop());
}
else
{
return(null);
}
}
int n = r.Read(c, 0, 1);
if (annotate)
{
crnt = new pospair(r.file, r.linepos, r.cpos);
}
if (n == 0)
{
rd = false; // stop
ch = ' '; // simulate end of something
goto cont;
}
ch = c[0]; //Console.Write(ch);
cont:
if (state == 0)
{
switch (ch)
{
case '(':
{
// start a new list;
Pair p = new Pair(null, null);
top.Push(p);
st.Push(p);
pos.Push(0); // will fill car first
prev_p = p;
break;
}
case ')':
{
// pop a list
if (top.Count < 1)
{
throw new
Meta.Scripting.MBaseException(new Pair(Symbol.make("READER-ERROR-AT:"),
prev_p));
}
Object p = top.Pop();
if (p is Pair)
{
Pair pp = (Pair)p;
if (pp.car == null && pp.cdr == null)
{
p = null;
}
}
st.Pop(); // discard it
pos.Pop(); //discard it
if (!popper(st, pos, p))
{
return(p);
}
if (p != null)
{
prev_p = p;
}
state = 0;
break;
}
case '.':
{
s = "" + ch; strt = crnt; state = 6;
break;
}
case ';':
{
state = 4; // comment started
break;
}
case ' ':
case '\n':
case '\t':
case '\r':
case '\f':
{ // just skip
break;
}
case '\"': // start a string literal
{
s = "" + ch; strt = crnt;
state = 2;
break;
}
case '\'':
case '`': // immediate
{
s = "" + ch; strt = crnt;
if (!popper(st, pos, s))
{
return(s);
}
s = "";
break;
}
case ',': // delay
{
s = "" + ch; strt = crnt;
state = 5;
break;
}
case '&': // another delayed reader
{
s = "" + ch; strt = crnt;
state = 7;
break;
}
default: // all other chars starts atoms
{
s = "" + ch; // start a new one;
strt = crnt;
state = 1; // atom processing
break;
}
}
}
else if (state == 1)
{
if (ch == '(' || ch == ')' || Char.IsWhiteSpace(ch) || ch == ';')
{
// atom ends here, sorry
if (annotate)
{
strt.s = s;
if (!popper(st, pos, strt))
{
return(strt);
}
}
else
{
if (!popper(st, pos, s))
{
return(s);
}
}
if (s != null)
{
prev_p = s;
}
s = "";
state = 0;
goto cont; // now process the termination character in a new state
}
else
{
s = s + ch; // add a char to an atom
}
}
else if (state == 2)
{
if (ch == '\\')
{
state = 3;
}
else if (ch == '\"')
{
s = s + ch;
state = 1;
ch = ' '; // simulate an end of atom
goto cont;
}
else
{
s = s + ch;
}
}
else if (state == 3)
{
if (ch == 'n')
{
ch = '\n';
}
else if (ch == 't')
{
ch = '\t';
}
s = s + ch; state = 2;
}
else if (state == 4)
{
if (ch == '\n')
{
state = 0; // comment line finished
}
}
else if (state == 5)
{
if (ch == '@')
{
s += ch;
}
if (!popper(st, pos, s))
{
return(s);
}
state = 0;
if (ch != '@')
{
goto cont; // otherwise read next char
}
}
else if (state == 6)
{
if (ch == '.')
{
s += ch; state = 1;
}
else
{
state = 0;
pos.Pop();
pos.Push(1); // will fill cdr, not a new cons cell
goto cont;
}
}
else if (state == 7)
{
if (ch == '\"')
{
s += ch;
state = 2;
}
else
{
state = 1;
goto cont;
}
}
}
}