// parseList() `parses' special forms, constructs an appropriate
// object of a subclass of Special, and stores a pointer to that
// object in variable form. It would be possible to fully parse
// special forms at this point. Since this causes complications
// when using (incorrect) programs as data, it is easiest to let
// parseList only look at the car for selecting the appropriate
// object from the Special hierarchy and to leave the rest of
// parsing up to the interpreter.
void parseList()
{
if (car.isSymbol())
{
Ident a = (Ident)car;
string type = a.getSymbol();
if (type.Equals("quote"))
{
form = new Quote();
}
//else if (type.Equals("if"))
// form = new If();
//else if (type.Equals("begin"))
// form = new Begin();
//else if (type.Equals("cond"))
// form = new Cond();
//else if (type.Equals("define"))
// form = new Define();
//else if (type.Equals("lambda"))
// form = new Lambda();
//else if (type.Equals("let"))
// form = new Let();
//else if (type.Equals("set!"))
// form = new Set();
else
{
form = new Regular();
}
}
else
{
form = new Regular();
}
}
} // BuiltIn
public virtual Node eval(Environment e)
{
if (this.isSymbol())
{
Ident id = new Ident(this.getName());
return(id.eval(this, e));
}
return(this);
}
public Node eval(Environment env)
{
if(this.isSymbol())
{
id = new Ident(this.getName());
return id.eval(this, env);
}
return this;
}
public virtual Node eval(Environment env)
{
if (this is Ident)
{
iden = new Ident(this.getName());
return(iden.eval(this, env));
}
return(this);
}
} // Cons
// parseList() `parses' special forms, constructs an appropriate
// object of a subclass of Special, and stores a pointer to that
// object in variable form. It would be possible to fully parse
// special forms at this point. Since this causes complications
// when using (incorrect) programs as data, it is easiest to let
// parseList only look at the car for selecting the appropriate
// object from the Special hierarchy and to leave the rest of
// parsing up to the interpreter.
private void parseList()
{
if (car.isSymbol())
{
Ident special = (Ident)car;
switch (special.getName())
{
case "quote":
form = new Quote();
break;
case "lambda":
form = new Lambda();
break;
case "begin":
form = new Begin();
break;
case "if":
form = new If();
break;
case "let":
form = new Let();
break;
case "cond":
form = new Cond();
break;
case "define":
form = new Define();
break;
case "set!":
form = new Set();
break;
default:
form = new Regular();
break;
}
}
else
{
form = new Regular();
}
}
public static int Main(string[] args)
{
// Create scanner that reads from standard input
Scanner scanner = new Scanner(Console.In);
if (args.Length > 1 ||
(args.Length == 1 && ! args[0].Equals("-d")))
{
Console.Error.WriteLine("Usage: mono SPP [-d]");
return 1;
}
// If command line option -d is provided, debug the scanner.
if (args.Length == 1 && args[0].Equals("-d"))
{
// Console.Write("Scheme 4101> ");
Token tok = scanner.getNextToken();
while (tok != null)
{
TokenType tt = tok.getType();
Console.Write(tt);
if (tt == TokenType.INT)
Console.WriteLine(", intVal = " + tok.getIntVal());
else if (tt == TokenType.STRING)
Console.WriteLine(", stringVal = " + tok.getStringVal());
else if (tt == TokenType.IDENT)
Console.WriteLine(", name = " + tok.getName());
else
Console.WriteLine();
// Console.Write("Scheme 4101> ");
tok = scanner.getNextToken();
}
return 0;
}
// Create parser
TreeBuilder builder = new TreeBuilder();
Parser parser = new Parser(scanner, builder);
Node root;
// TODO: Create and populate the built-in environment and
// create the top-level environment
// Read-eval-print loop
Tree.Environment env = new Tree.Environment();
Node id = new Ident("car");
env.define(id, new BuiltIn(id));
id = new Ident("cdr");
env.define(id, new BuiltIn(id));
id = new Ident("cons");
env.define(id, new BuiltIn(id));
id = new Ident("set-car!");
env.define(id, new BuiltIn(id));
id = new Ident("set-cdr!");
env.define(id, new BuiltIn(id));
id = new Ident("null?");
env.define(id, new BuiltIn(id));
id = new Ident("pair?");
env.define(id, new BuiltIn(id));
id = new Ident("eq?");
env.define(id, new BuiltIn(id));
id = new Ident("symbol?");
env.define(id, new BuiltIn(id));
id = new Ident("number?");
env.define(id, new BuiltIn(id));
id = new Ident("b+");
env.define(id, new BuiltIn(id));
id = new Ident("b-");
env.define(id, new BuiltIn(id));
id = new Ident("b*");
env.define(id, new BuiltIn(id));
id = new Ident("b/");
env.define(id, new BuiltIn(id));
id = new Ident("b=");
env.define(id, new BuiltIn(id));
id = new Ident("b<");
env.define(id, new BuiltIn(id));
id = new Ident("procedure?");
env.define(id, new BuiltIn(id));
id = new Ident("read");
env.define(id, new BuiltIn(id));
id = new Ident("write");
env.define(id, new BuiltIn(id));
id = new Ident("display");
env.define(id, new BuiltIn(id));
id = new Ident("newline");
env.define(id, new BuiltIn(id));
id = new Ident("eval");
env.define(id, new BuiltIn(id));
id = new Ident("apply");
env.define(id, new BuiltIn(id));
id = new Ident("interaction-environment");
env.define(id, new BuiltIn(id));
env = new Tree.Environment(env);
// TODO: print prompt and evaluate the expression
root = (Node) parser.parseExp();
while (root != null)
{
root.eval(env).print(0);
root = (Node) parser.parseExp();
}
return 0;
}
//if arg length = 0
private Node apply0()
{
string name = this.symbol.getName();
bool flag = name.Equals("read");
Node result;
if (flag)
{
Parse.Scanner s = new Parse.Scanner(Console.In);
Parse.Parser parser = new Parse.Parser(s, new TreeBuilder());
Node node = (Node)parser.parseExp();
bool flag2 = node != null;
if (flag2)
{
result = node;
}
else
{
result = new Ident("end-of-file");
}
}//end outer if
else
{
bool flag3 = name.Equals("newline");
if (flag3)
{
Console.WriteLine();
result = Unspecific.getInstance();
}
else
{
bool flag4 = name.Equals("interaction-environment");
if (flag4)
{
result = Scheme4101.env;
}
else
{
Console.Error.WriteLine("Error: wrong number of arguments");
result = Nil.getInstance();
}
}
}//end outer else
return result;
}