// TODO: The method apply() should be defined in class Node
// to report an error. It should be overridden only in classes
// BuiltIn and Closure.
public override Node apply(Node args)
{
Node result = null;
int numArgs = numArguments(args);
switch (symbol.getName())
{
case "begin":
// The value(s) of the last expression is(are) returned
while (args.getCdr().isNull() == false)
{
args = args.getCdr();
}
return(args.getCar());
case "cond":
// The value(s) of the last expression is(are) returned
while (args.getCdr().isNull() == false)
{
args = args.getCdr();
}
return(args.getCar());
case "if":
if (args.getCar() == BoolLit.getInstance(true))
{
return(args.getCdr().getCar());
}
else if (args.getCdr().getCdr().isPair())
{
return(args.getCdr().getCdr().getCar());
}
else
{
return(new StringLit("#unspecified"));
}
case "let":
// The value(s) of the last expression is(are) returned
while (args.getCdr().isNull() == false)
{
args = args.getCdr();
}
return(args.getCar());
case "quote":
return(args.getCdr().getCar());
case "read":
return((Node)args.parser.parseExp());
case "write":
args.print(0);
// Not sure what Node to return here. Probably just return the blank Node
break;
case "symbol?":
// symbol? only accepts 1 argument
if (numArgs != 1)
{
return(new StringLit("Error: wrong number of arguments for 'symbol?'"));
}
else
{
if (args.getCar().isSymbol())
{
return(BoolLit.getInstance(true));
}
else
{
return(BoolLit.getInstance(false));
}
}
case "number?":
// number? only accepts 1 argument
if (numArgs != 1)
{
return(new StringLit("Error: wrong number of arguments for 'number?'"));
}
else
{
if (args.getCar().isNumber())
{
return(BoolLit.getInstance(true));
}
else
{
return(BoolLit.getInstance(false));
}
}
case "car":
if (args.isPair() == false)
{
return(new StringLit("Error: Argument to 'car' is not a pair."));
}
else
{
return(args.getCar());
}
case "cdr":
if (args.isPair() == false)
{
return(new StringLit("Error: Argument to 'cdr' is not a pair."));
}
else
{
return(args.getCdr());
}
case "cons":
// make sure only two arguments are provided
if (args.getCdr().isPair() != true && args.getCdr().getCdr().isNull() == false)
{
return(new StringLit("Error: Function 'cons' requires two arguments."));
}
else
{
return(args);
}
case "set-car!":
// make sure only a list and value are provided
if (args.getCar().isPair() == false || args.getCdr().getCar().isPair() == true || args.getCdr().getCdr().isNull() == false)
{
return(new StringLit("Error: Function 'set-car!' requires a list and value"));
}
else
{
args.getCar().setCar(args.getCdr().getCar());
return(new StringLit("no values returned;"));
}
case "set-cdr!":
// make sure only a list and value are provided
if (args.getCar().isPair() == false || args.getCdr().getCar().isPair() == true || args.getCdr().getCdr().isNull() == false)
{
return(new StringLit("Error: Function 'set-cdr!' requires a list and value"));
}
else
{
args.getCar().setCdr(args.getCdr().getCar());
return(new StringLit("no values returned;"));
}
case "null?":
if (args.getCar().isNull() == true)
{
return(BoolLit.getInstance(true));
}
// null? only accepts one argument
else if (args.getCdr().isPair() == true)
{
return(new StringLit("Error: 'null?' only accept one argument."));
}
else
{
return(BoolLit.getInstance(false));
}
case "pair?":
// pair? only accept one argument
if (args.getCdr().isPair() == true)
{
return(new StringLit("Error: 'pair?' only accepts one argument."));
}
else if (args.getCar().isPair())
{
return(BoolLit.getInstance(true));
}
else
{
return(BoolLit.getInstance(false));
}
case "eq?":
// eq? only accepts two arguments
if (args.getCdr().getCdr().isNull() == false)
{
return(new StringLit("Error: 'eq?' only accepts one argument"));
}
else if (args.getCar() == args.getCdr().getCar()) // Not sure if this is going to work, actually
{
return(BoolLit.getInstance(true));
}
else
{
return(BoolLit.getInstance(false));
}
case "procedure?":
//procedure only accepts 1 argument (I think)
if (args.getCdr().isNull() == false)
{
return(new StringLit("Error: 'procedure?' only accepts one argument"));
}
else if (args.getCar().isProcedure() == true)
{
return(BoolLit.getInstance(true));
}
else
{
return(BoolLit.getInstance(false));
}
default:
break;
}
// Now we check for the binary arithmetic builtins
IntLit num1 = new IntLit(0), num2;
if (symbol.getName() == "b/") // The division function has 1 as the default value instead of 0 when only 1 argument is provided
{
num1 = new IntLit(1);
}
// If the arguments aren't numerical, the IntLit casts will fail and the catch block executes.
// If there are 0 arguments the first cast will fail, and if there are more than 2 an Exception is thrown
try
{
num2 = (IntLit)args.getCar();
// Check for a second argument
if (args.getCdr().isPair() == true)
{
// We do this swap because if we have only 1 argument, we're doing 0 - num2. If we have 2, we're doing num1-num2.
num1 = num2;
num2 = (IntLit)args.getCdr().getCar();
if (args.getCdr().getCdr().isNull() == false)
{
throw new Exception();
}
}
else if (symbol.getName() == "b=" || symbol.getName() == "b<")
{
return(result = new StringLit("Error: binary arithmetic operation '" + symbol.getName() + "' expects two numerical 2 arguments."));
}
}
catch
{
return(result = new StringLit("Error: binary arithmetic operations expect 1 or 2 numerical arguments."));
}
if (symbol.getName() == "b+")
{
result = new IntLit(num1.getInt() + num2.getInt());
}
else if (symbol.getName() == "b-")
{
result = new IntLit(num1.getInt() - num2.getInt());
}
else if (symbol.getName() == "b*")
{
result = new IntLit(num1.getInt() * num2.getInt());
}
else if (symbol.getName() == "b/")
{
if (num2.getInt() == 0)
{
return(result = new StringLit("Error: Dividing by 0."));
}
result = new IntLit(num1.getInt() / num2.getInt());
}
else if (symbol.getName() == "b=")
{
if (num1.getInt() == num2.getInt())
{
result = BoolLit.getInstance(true);
}
else
{
result = BoolLit.getInstance(false);
}
}
else if (symbol.getName() == "b<")
{
if (num1.getInt() < num2.getInt())
{
result = BoolLit.getInstance(true);
}
else
{
result = BoolLit.getInstance(false);
}
}
return(result);
}
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 = new Node();
// TODO: Create and populate the built-in environment and
// create the top-level environment
Tree.Environment env = new Tree.Environment();
Ident id = new Ident("b+");
env.define(id, new BuiltIn(id));
env = new Tree.Environment(env);
Ident test = new Ident("xxxx");
IntLit test2 = new IntLit(3);
env.define(test, test2);
root = (Node) parser.parseExp();
while (root != null)
{
root.eval(env).print(0);
root = (Node) parser.parseExp();
}
// Read-eval-print loop
// TODO: print prompt and evaluate the expression
/*
root = (Node) parser.parseExp();
while (root != null)
{
root.print(0);
root = (Node) parser.parseExp();
}
*/
return 0;
}
//Function for evaluating binary arithmetic operations
private Node apply2(int arg1, int arg2)
{
string name = this.symbol.getName();
bool flag = name.Equals("b+");
Node result;
if (flag)
{
result = new IntLit(arg1 + arg2);
}
else
{
bool flag2 = name.Equals("b-");
if (flag2)
{
result = new IntLit(arg1 - arg2);
}
else
{
bool flag3 = name.Equals("b*");
if (flag3)
{
result = new IntLit(arg1 * arg2);
}
else
{
bool flag4 = name.Equals("b/");
if (flag4)
{
result = new IntLit(arg1 / arg2);
}
else
{
bool flag5 = name.Equals("b=");
if (flag5)
{
result = BoolLit.getInstance(arg1 == arg2);
}
else
{
bool flag6 = name.Equals("b<");
if (flag6)
{
result = BoolLit.getInstance(arg1 < arg2);
}
else
{
Console.Error.WriteLine("Error: unknown built-in function");
result = Nil.getInstance();
}
}
}
}
}
}
return result;
}
// TODO: The method apply() should be defined in class Node
// to report an error. It should be overridden only in classes
// BuiltIn and Closure.
public override Node apply(Node args)
{
// note for all built in functions that need arguments...
//
// the function will never do a test to check whether args is a pair, because
// args is always made a pair in special Regular for launching builtin_function apply.
if (this.symbol.getName().Equals("read"))
{
if (args == null || !args.isNull())
{
Console.WriteLine("Error: Read only needs no arguments for use.");
return(Nil.getInstance());
}
return((Node)Scheme4101.parser.parseExp());
}
else if (this.symbol.getName().Equals("write"))
{
if (args == null || args.isNull())
{
Console.WriteLine("Error: incorrect arguments. Nil passed, which cannot be used.");
return(Nil.getInstance());
}
args.getCar().print(0);
return(Nil.getInstance());
}
else if (this.symbol.getName().equals("set-car!"))
{
arg1.setCar(arg2);
return(arg1);
}
else if (this.symbol.getName().equals("set-cdr!"))
{
arg1.setCdr(arg2);
return(arg1);
}
else if (this.symbol.getName().Equals("display"))
{
if (args == null || args.isNull())
{
Console.WriteLine("Error: incorrect arguments. Nil passed, which cannot be used.");
return(Nil.getInstance());
}
Tree.BuiltIn.builtIn_display__do_not_print_double_quotes = true;
args.getCar().print(0);
Tree.BuiltIn.builtIn_display__do_not_print_double_quotes = false;
return(Nil.getInstance());
}
else if (this.symbol.getName().Equals("b+"))
{
// if there are no arguments, report error
if (args == null)
{
Console.WriteLine("Error: no arguments given for binary addition operation.");
return(Nil.getInstance());
}
// return zero if there are no arguments
if (args.isNull())
{
return(new IntLit(0));
}
// extend for all argument vars
// and
//check if first args have null
if (args.getCar() != null &&
args.getCdr() != null)
{
bool twoArguments_or_more;
// check if second argument is is nil.
if (args.getCdr().isNull())
{
twoArguments_or_more = false;
}
// see if there is a second item , ... and check that last tail of args is nil.
else if (args.getCdr().getCar() != null && args.getCdr().getCdr().isNull())
{
twoArguments_or_more = true;
}
else if (args.getCdr().getCar() != null && !args.getCdr().getCdr().isNull())
{
Console.WriteLine("Error: cannot process more than two args for binary addition.");
return(Nil.getInstance());
}
else
{
Console.WriteLine("Error: in b+ , one of arguments for expression has null node.");
return(Nil.getInstance());
}
if (twoArguments_or_more == false)
{
// check if argument is an intLit
if (args.getCar().isNumber())
{
// return the sole int lit node.
return(args.getCar());
}
else
{
Console.WriteLine("Error: in b+ , one of arguments for expression has null node.");
return(Nil.getInstance());
}
}
else
{
if (!args.getCar().isNumber() || !args.getCdr().getCar().isNumber())
{
Console.WriteLine("Error: arguments must be IntLit for binary addition.");
return(Nil.getInstance());
}
else
{
IntLit int1 = (IntLit)args.getCar();
IntLit int2 = (IntLit)args.getCdr().getCar();
return(new IntLit(int1.getInt() + int2.getInt()));
}
}
}
else
{
Console.WriteLine("Error: in b+ , there is a null external node");
return(Nil.getInstance());
}
}
else if (this.symbol.getName().Equals("b-"))
{
// if there are no arguments, report error
if (args == null || args.isNull())
{
Console.WriteLine("Error: no arguments given for binary subtraction operation.");
return(Nil.getInstance());
}
// extend for all argument vars
// and
//check if any args have null or nil.
if (args != null && args.getCar() != null &&
args.getCdr() != null && args.getCdr().getCar() != null &&
args.getCdr().getCdr().isNull())
{
if (!args.getCar().isNumber() || !args.getCdr().getCar().isNumber())
{
Console.WriteLine("Error: arguments must be IntLit for binary subtraction.");
return(Nil.getInstance());
}
else
{
IntLit int1 = (IntLit)args.getCar();
IntLit int2 = (IntLit)args.getCdr().getCar();
return(new IntLit(int1.getInt() - int2.getInt()));
}
}
else
{
Console.WriteLine("Error: more than two arguments for binary subtraction is not permissable.");
return(Nil.getInstance());
}
}
else if (this.symbol.getName().Equals("b*"))
{
// if there are no arguments, report error
if (args == null || args.isNull())
{
Console.WriteLine("Error: no arguments given for binary multiplication operation.");
return(Nil.getInstance());
}
// extend for all argument vars
// and
//check if any args have null or nil.
if (args != null && args.getCar() != null &&
args.getCdr() != null && args.getCdr().getCar() != null &&
args.getCdr().getCdr().isNull())
{
if (!args.getCar().isNumber() || !args.getCdr().getCar().isNumber())
{
Console.WriteLine("Error: arguments must be IntLit for binary multiplication.");
return(Nil.getInstance());
}
else
{
IntLit int1 = (IntLit)args.getCar();
IntLit int2 = (IntLit)args.getCdr().getCar();
return(new IntLit(int1.getInt() * int2.getInt()));
}
}
else
{
Console.WriteLine("Error: more than two arguments for binary multiplication is not permissable.");
return(Nil.getInstance());
}
}
else if (this.symbol.getName().Equals("b/"))
{
// if there are no arguments, report error
if (args == null || args.isNull())
{
Console.WriteLine("Error: no arguments given for binary division operation.");
return(Nil.getInstance());
}
// extend for all argument vars
// and
//check if any args have null or nil.
if (args != null && args.getCar() != null &&
args.getCdr() != null && args.getCdr().getCar() != null &&
args.getCdr().getCdr().isNull())
{
if (!args.getCar().isNumber() || !args.getCdr().getCar().isNumber())
{
Console.WriteLine("Error: arguments must be IntLit for binary division.");
return(Nil.getInstance());
}
else
{
IntLit int1 = (IntLit)args.getCar();
IntLit int2 = (IntLit)args.getCdr().getCar();
if (int2.getInt() == 0)
{
Console.WriteLine("Error: input not acceptable. cannot divide by zero.");
return(Nil.getInstance());
}
else
{
return(new IntLit(int1.getInt() / int2.getInt()));
}
}
}
else
{
Console.WriteLine("Error: more than two arguments for binary division is not permissable.");
return(Nil.getInstance());
}
}
else if (this.symbol.getName().Equals("b="))
{
// if there are no arguments, report error
if (args == null || args.isNull())
{
Console.WriteLine("Error: no arguments given for binary equality test operation.");
return(Nil.getInstance());
}
// extend for all argument vars
// and
//check if any args have null or nil.
if (args != null && args.getCar() != null &&
args.getCdr() != null && args.getCdr().getCar() != null &&
args.getCdr().getCdr().isNull())
{
if (!args.getCar().isNumber() || !args.getCdr().getCar().isNumber())
{
Console.WriteLine("Error: arguments must be IntLit for binary equality test.");
return(Nil.getInstance());
}
else
{
IntLit int1 = (IntLit)args.getCar();
IntLit int2 = (IntLit)args.getCdr().getCar();
bool resultOfTest = (int1.getInt() == int2.getInt());
if (resultOfTest)
{
return(BoolLit.getInstance(true));
}
else
{
return(BoolLit.getInstance(false));
}
}
}
else
{
Console.WriteLine("Error: more than two arguments for binary equality test is not permissable.");
return(Nil.getInstance());
}
}
else if (this.symbol.getName().Equals("b<"))
{
// if there are no arguments, report error
if (args == null || args.isNull())
{
Console.WriteLine("Error: no arguments given for binary less than test operation.");
return(Nil.getInstance());
}
// extend for all argument vars
// and
//check if any args have null or nil.
if (args != null && args.getCar() != null &&
args.getCdr() != null && args.getCdr().getCar() != null &&
args.getCdr().getCdr().isNull())
{
if (!args.getCar().isNumber() || !args.getCdr().getCar().isNumber())
{
Console.WriteLine("Error: arguments must be IntLit for binary less than test.");
return(Nil.getInstance());
}
else
{
IntLit int1 = (IntLit)args.getCar();
IntLit int2 = (IntLit)args.getCdr().getCar();
bool resultOfTest = (int1.getInt() < int2.getInt());
if (resultOfTest)
{
return(BoolLit.getInstance(true));
}
else
{
return(BoolLit.getInstance(false));
}
}
}
else
{
Console.WriteLine("Error: more than two arguments for binary less than test is not permissable.");
return(Nil.getInstance());
}
}
else if (this.symbol.getName().Equals("b>"))
{
// if there are no arguments, report error
if (args == null || args.isNull())
{
Console.WriteLine("Error: no arguments given for binary greater than test operation.");
return(Nil.getInstance());
}
// extend for all argument vars
// and
//check if any args have null or nil.
if (args != null && args.getCar() != null &&
args.getCdr() != null && args.getCdr().getCar() != null &&
args.getCdr().getCdr().isNull())
{
if (!args.getCar().isNumber() || !args.getCdr().getCar().isNumber())
{
Console.WriteLine("Error: arguments must be IntLit for binary greater than test.");
return(Nil.getInstance());
}
else
{
IntLit int1 = (IntLit)args.getCar();
IntLit int2 = (IntLit)args.getCdr().getCar();
bool resultOfTest = (int1.getInt() > int2.getInt());
if (resultOfTest)
{
return(BoolLit.getInstance(true));
}
else
{
return(BoolLit.getInstance(false));
}
}
}
else
{
Console.WriteLine("Error: more than two arguments for binary greater than test is not permissable.");
return(Nil.getInstance());
}
}
else if (this.symbol.getName().Equals("b<="))
{
// if there are no arguments, report error
if (args == null || args.isNull())
{
Console.WriteLine("Error: no arguments given for binary less than equal than test operation.");
return(Nil.getInstance());
}
// extend for all argument vars
// and
//check if any args have null or nil.
if (args != null && args.getCar() != null &&
args.getCdr() != null && args.getCdr().getCar() != null &&
args.getCdr().getCdr().isNull())
{
if (!args.getCar().isNumber() || !args.getCdr().getCar().isNumber())
{
Console.WriteLine("Error: arguments must be IntLit for binary less than equal than test.");
return(Nil.getInstance());
}
else
{
IntLit int1 = (IntLit)args.getCar();
IntLit int2 = (IntLit)args.getCdr().getCar();
bool resultOfTest = (int1.getInt() <= int2.getInt());
if (resultOfTest)
{
return(BoolLit.getInstance(true));
}
else
{
return(BoolLit.getInstance(false));
}
}
}
else
{
Console.WriteLine("Error: more than two arguments for binary less than equal than test is not permissable.");
return(Nil.getInstance());
}
}
else if (this.symbol.getName().Equals("b>="))
{
// if there are no arguments, report error
if (args == null || args.isNull())
{
Console.WriteLine("Error: no arguments given for binary greater than equal than test operation.");
return(Nil.getInstance());
}
// extend for all argument vars
// and
//check if any args have null or nil.
if (args != null && args.getCar() != null &&
args.getCdr() != null && args.getCdr().getCar() != null &&
args.getCdr().getCdr().isNull())
{
if (!args.getCar().isNumber() || !args.getCdr().getCar().isNumber())
{
Console.WriteLine("Error: arguments must be IntLit for binary greater than equal than test.");
return(Nil.getInstance());
}
else
{
IntLit int1 = (IntLit)args.getCar();
IntLit int2 = (IntLit)args.getCdr().getCar();
bool resultOfTest = (int1.getInt() >= int2.getInt());
if (resultOfTest)
{
return(BoolLit.getInstance(true));
}
else
{
return(BoolLit.getInstance(false));
}
}
}
else
{
Console.WriteLine("Error: more than two arguments for binary greater than equal than test is not permissable.");
return(Nil.getInstance());
}
}
else if (this.symbol.getName().Equals("null?"))
{
// if there are no arguments, report error
if (args == null || args.isNull())
{
Console.WriteLine("Error: no arguments given for testing null evaluation.");
return(Nil.getInstance());
}
// extend for all argument vars
// check if number of args is correct
bool argument_number_good = false;
if (args != null && args.getCar() != null &&
args.getCdr() != null && args.getCdr().isNull())
{
argument_number_good = true;
}
if (argument_number_good)
{
if (args.getCar().isNull())
{
return(BoolLit.getInstance(true));
}
else
{
return(BoolLit.getInstance(false));
}
}
else
{
Console.WriteLine("Error: wrong number of arguments for test. only need 1 cons node with nil tail for argument.");
return(Nil.getInstance());
}
}
else if (this.symbol.getName().Equals("symbol?"))
{
// if there are no arguments, report error
if (args == null || args.isNull())
{
Console.WriteLine("Error: no arguments given for testing symbol evaluation.");
return(Nil.getInstance());
}
// extend for all argument vars
// check if number of args is correct
bool argument_number_good = false;
if (args != null && args.getCar() != null &&
args.getCdr() != null && args.getCdr().isNull())
{
argument_number_good = true;
}
if (argument_number_good)
{
if (args.getCar().isSymbol())
{
return(BoolLit.getInstance(true));
}
else
{
return(BoolLit.getInstance(false));
}
}
else
{
Console.WriteLine("Error: wrong number of arguments for test. only need 1 cons node with nil tail for argument.");
return(Nil.getInstance());
}
}
else if (this.symbol.getName().Equals("number?"))
{
// if there are no arguments, report error
if (args == null || args.isNull())
{
Console.WriteLine("Error: no arguments given for testing number evaluation.");
return(Nil.getInstance());
}
// extend for all argument vars
// check if number of args is correct
bool argument_number_good = false;
if (args != null && args.getCar() != null &&
args.getCdr() != null && args.getCdr().isNull())
{
argument_number_good = true;
}
if (argument_number_good)
{
if (args.getCar().isNumber())
{
return(BoolLit.getInstance(true));
}
else
{
return(BoolLit.getInstance(false));
}
}
else
{
Console.WriteLine("Error: wrong number of arguments for test. only need 1 cons node with nil tail for argument.");
return(Nil.getInstance());
}
}
else if (this.symbol.getName().Equals("boolean?"))
{
// if there are no arguments, report error
if (args == null || args.isNull())
{
Console.WriteLine("Error: no arguments given for testing boolean evaluation.");
return(Nil.getInstance());
}
// extend for all argument vars
// check if number of args is correct
bool argument_number_good = false;
if (args != null && args.getCar() != null &&
args.getCdr() != null && args.getCdr().isNull())
{
argument_number_good = true;
}
if (argument_number_good)
{
if (args.getCar().isBool())
{
return(BoolLit.getInstance(true));
}
else
{
return(BoolLit.getInstance(false));
}
}
else
{
Console.WriteLine("Error: wrong number of arguments for test. only need 1 cons node with nil tail for argument.");
return(Nil.getInstance());
}
}
else if (this.symbol.getName().Equals("procedure?"))
{
// if there are no arguments, report error
if (args == null || args.isNull())
{
Console.WriteLine("Error: no arguments given for testing procedure evaluation.");
return(Nil.getInstance());
}
// extend for all argument vars
// check if number of args is correct
bool argument_number_good = false;
if (args != null && args.getCar() != null &&
args.getCdr() != null && args.getCdr().isNull())
{
argument_number_good = true;
}
if (argument_number_good)
{
if (args.getCar().isProcedure())
{
return(BoolLit.getInstance(true));
}
else
{
return(BoolLit.getInstance(false));
}
}
else
{
Console.WriteLine("Error: wrong number of arguments for test. only need 1 cons node with nil tail for argument.");
return(Nil.getInstance());
}
}
else if (this.symbol.getName().Equals("pair?"))
{
// if there are no arguments, report error
if (args == null || args.isNull())
{
Console.WriteLine("Error: no arguments given for testing pair evaluation.");
return(Nil.getInstance());
}
// extend for all argument vars
// check if number of args is correct
bool argument_number_good = false;
if (args != null && args.getCar() != null &&
args.getCdr() != null && args.getCdr().isNull())
{
argument_number_good = true;
}
if (argument_number_good)
{
if (args.getCar().isPair())
{
return(BoolLit.getInstance(true));
}
else
{
return(BoolLit.getInstance(false));
}
}
else
{
Console.WriteLine("Error: wrong number of arguments for test. only need 1 cons node with nil tail for argument.");
return(Nil.getInstance());
}
}
else if (this.symbol.getName().Equals("environment?"))
{
// if there are no arguments, report error
if (args == null || args.isNull())
{
Console.WriteLine("Error: no arguments given for testing environment evaluation.");
return(Nil.getInstance());
}
// extend for all argument vars
// check if number of args is correct
bool argument_number_good = false;
if (args != null && args.getCar() != null &&
args.getCdr() != null && args.getCdr().isNull())
{
argument_number_good = true;
}
if (argument_number_good)
{
if (args.getCar().isEnvironment())
{
return(BoolLit.getInstance(true));
}
else
{
return(BoolLit.getInstance(false));
}
}
else
{
Console.WriteLine("Error: wrong number of arguments for test. only need 1 cons node with nil tail for argument.");
return(Nil.getInstance());
}
}
else if (this.symbol.getName().Equals("string?"))
{
// if there are no arguments, report error
if (args == null || args.isNull())
{
Console.WriteLine("Error: no arguments given for testing string evaluation.");
return(Nil.getInstance());
}
// extend for all argument vars
// check if number of args is correct
bool argument_number_good = false;
if (args != null && args.getCar() != null &&
args.getCdr() != null && args.getCdr().isNull())
{
argument_number_good = true;
}
if (argument_number_good)
{
if (args.getCar().isString())
{
return(BoolLit.getInstance(true));
}
else
{
return(BoolLit.getInstance(false));
}
}
else
{
Console.WriteLine("Error: wrong number of arguments for test. only need 1 cons node with nil tail for argument.");
return(Nil.getInstance());
}
}
// working on predicate built in : eq?
else if (this.symbol.getName().Equals("eq?"))
{
// if there are no arguments, report error
if (args == null || args.isNull())
{
Console.WriteLine("Error: no arguments given for eq? test operation.");
return(Nil.getInstance());
}
// extend for all argument vars
// and
//check if any args have null or nil.
if (args != null && args.getCar() != null &&
args.getCdr() != null && args.getCdr().getCar() != null &&
args.getCdr().getCdr().isNull())
{
//if (!args.getCar () || !args.getCdr ().getCar () )
// check nil/null? first
// first car is nil but second item is not nil...
// or the other way around (vice versa)
if ((args.getCar().isNull() && !args.getCdr().getCar().isNull()) ||
(!args.getCar().isNull() && args.getCdr().getCar().isNull()))
{
return(BoolLit.getInstance(false));
}
// success: both nil
else if (args.getCar().isNull() && args.getCdr().getCar().isNull())
{
return(BoolLit.getInstance(true));
}
// first car is type symbol but second item is not symbol...
// or the other way around (vice versa)
else if ((args.getCar().isSymbol() && !args.getCdr().getCar().isSymbol()) ||
(!args.getCar().isSymbol() && args.getCdr().getCar().isSymbol()))
{
return(BoolLit.getInstance(false));
}
// check if both symbol now...
else if (args.getCar().isSymbol() && args.getCdr().getCar().isSymbol())
{
// check if the symbol's are identical
if (args.getCar().getName().Equals(args.getCdr().getCar().getName()))
{
// success: both same symbol!
return(BoolLit.getInstance(true));
}
else
{
return(BoolLit.getInstance(false));
}
}
// first car is type number but second item is not number...
// or the other way around (vice versa)
else if ((args.getCar().isNumber() && !args.getCdr().getCar().isNumber()) ||
(!args.getCar().isNumber() && args.getCdr().getCar().isNumber()))
{
return(BoolLit.getInstance(false));
}
// check if both number now...
else if (args.getCar().isNumber() && args.getCdr().getCar().isNumber())
{
// cast to new IntLits
IntLit intLit_1 = (IntLit)args.getCar();
IntLit intLit_2 = (IntLit)args.getCdr().getCar();
// check if the int values's are equal
if (intLit_1.getInt() == intLit_2.getInt())
{
// success: both same integer!
return(BoolLit.getInstance(true));
}
else
{
return(BoolLit.getInstance(false));
}
}
// first car is type boolean but second item is not boolean...
// or the other way around (vice versa)
else if ((args.getCar().isBool() && !args.getCdr().getCar().isBool()) ||
(!args.getCar().isBool() && args.getCdr().getCar().isBool()))
{
return(BoolLit.getInstance(false));
}
// check if both boolean now...
else if (args.getCar().isBool() && args.getCdr().getCar().isBool())
{
// cast nodes as new booleanNodes
BoolLit boolVal1 = (BoolLit)args.getCar();
BoolLit boolVal2 = (BoolLit)args.getCdr().getCar();
// check if the bool's equal
if (boolVal1.Equals(boolVal2))
{
// success: both same bool!
return(BoolLit.getInstance(true));
}
else
{
return(BoolLit.getInstance(false));
}
}
// first car is type builtIn but second item is not builtIn...
// or the other way around (vice versa)
else if ((args.getCar().isBuiltIn() && !args.getCdr().getCar().isBuiltIn()) ||
(!args.getCar().isBuiltIn() && args.getCdr().getCar().isBuiltIn()))
{
return(BoolLit.getInstance(false));
}
// check if both builtIn now...
else if (args.getCar().isBuiltIn() && args.getCdr().getCar().isBuiltIn())
{
// cast nodes as new builtIn
BuiltIn builtIn_val_1 = (BuiltIn)args.getCar();
BuiltIn builtIn_val_2 = (BuiltIn)args.getCdr().getCar();
// check if the builtIn's are identical
if (builtIn_val_1.getSymbol().Equals(builtIn_val_2.getSymbol()))
{
// success: both same builtIn!
return(BoolLit.getInstance(true));
}
else
{
return(BoolLit.getInstance(false));
}
}
// by process of elimination
//now
// a object that ends up tested here would be surely a closure...
// first car is type closure but second item is not closure...
// or the other way around (vice versa)
else if ((args.getCar().isProcedure() && !args.getCdr().getCar().isProcedure()) ||
(!args.getCar().isProcedure() && args.getCdr().getCar().isProcedure()))
{
return(BoolLit.getInstance(false));
}
// check if both closure now...
else if (args.getCar().isProcedure() && args.getCdr().getCar().isProcedure())
{
// cast nodes as new builtIn
Closure closure_val_1 = (Closure)args.getCar();
Closure closure_val_2 = (Closure)args.getCdr().getCar();
// check if the closure's are identical
if (closure_val_1.Equals(closure_val_2))
{
// success: both same closure!
return(BoolLit.getInstance(true));
}
else
{
return(BoolLit.getInstance(false));
}
}
// first car is type environment but second item is not environment...
// or the other way around (vice versa)
else if ((args.getCar().isEnvironment() && !args.getCdr().getCar().isEnvironment()) ||
(!args.getCar().isEnvironment() && args.getCdr().getCar().isEnvironment()))
{
return(BoolLit.getInstance(false));
}
// check if both environment now...
else if (args.getCar().isEnvironment() && args.getCdr().getCar().isEnvironment())
{
// cast nodes as new Environment
Environment environ_1 = (Environment)args.getCar();
Environment environ_2 = (Environment)args.getCdr().getCar();
// check if the environment's are identical
if (environ_1.Equals(environ_2))
{
// success: both same environment!
return(BoolLit.getInstance(true));
}
else
{
return(BoolLit.getInstance(false));
}
}
// first car is type String but second item is not String...
// or the other way around (vice versa)
else if ((args.getCar().isString() && !args.getCdr().getCar().isString()) ||
(!args.getCar().isString() && args.getCdr().getCar().isString()))
{
return(BoolLit.getInstance(false));
}
// check if both String now...
else if (args.getCar().isString() && args.getCdr().getCar().isString())
{
// cast nodes as new StringLits
StringLit String_1 = (StringLit)args.getCar();
StringLit String_2 = (StringLit)args.getCdr().getCar();
// check if the StringLit's are identical
if (String_1.getString().Equals(String_2.getString()))
{
// success: both same StringLit!
return(BoolLit.getInstance(true));
}
else
{
return(BoolLit.getInstance(false));
}
}
// eq? test note: there is one caveat. If the items are both quote terms... this will be handled directly in regular eval
// first car is type Pair but second item is not Pair...
// or the other way around (vice versa)
else if ((args.getCar().isPair() && !args.getCdr().getCar().isPair()) ||
(!args.getCar().isPair() && args.getCdr().getCar().isPair()))
{
return(BoolLit.getInstance(false));
}
// check if both are type Pair now...
else if (args.getCar().isPair() && args.getCdr().getCar().isPair())
{
// cast nodes as new cons Pair
Cons cons_1 = (Cons)args.getCar();
Cons cons_2 = (Cons)args.getCdr().getCar();
// check if the Cons's are identical
if (cons_1.Equals(cons_2))
{
// success: both same pair reference!
return(BoolLit.getInstance(true));
}
else
{
return(BoolLit.getInstance(false));
}
// illegal function for argument
}
else
{
Console.WriteLine("Error: Argument types for eq? cannot be recognized in context.");
return(Nil.getInstance());
}
}
else
{
Console.WriteLine("Error: null parameter _ or _ more than two arguments for eq? test is not permissable.");
return(Nil.getInstance());
}
}
else if (this.symbol.getName().Equals("car"))
{
// if there are no arguments, report error
if (args == null || args.isNull())
{
Console.WriteLine("Error: no arguments given for car operation.");
return(Nil.getInstance());
}
// check if args first item given is a pair and check if the number of arguments given is correctly 1
if (args.getCar() != null && args.getCdr() != null && args.getCdr().isNull())
{
if (args.getCar().isPair())
{
if (args.getCar().getCar() != null)
{
return(args.getCar().getCar());
}
else
{
Console.WriteLine("Error: for car function_ , one of arguments to return is null.");
return(Nil.getInstance());
}
}
else
{
Console.WriteLine("Error: for car function_ , item given is not a pair.");
return(Nil.getInstance());
}
}
else
{
Console.WriteLine("Error: wrong number of arguments for car, tail is not nil. or element in arguments is null.");
return(Nil.getInstance());
}
}
else if (this.symbol.getName().Equals("cdr"))
{
// if there are no arguments, report error
if (args == null || args.isNull())
{
Console.WriteLine("Error: no arguments given for cdr operation.");
return(Nil.getInstance());
}
// check if args first item given is a pair and check if the number of arguments given is correctly 1
if (args.getCar() != null && args.getCar().isPair() && args.getCdr() != null && args.getCdr().isNull())
{
// check if argument's cdr is not null
if (args.getCar().getCdr() != null)
{
return(args.getCar().getCdr());
}
else
{
Console.WriteLine("Error: for cdr function_ , one of arguments to return is null.");
return(Nil.getInstance());
}
}
else
{
Console.WriteLine("Error: for cdr, item is not pair or wrong number of arguments for cdr: tail is not nil. or element in arguments is null.");
return(Nil.getInstance());
}
}
else
{
Console.WriteLine("Error: builtin is not identifiable.");
return(Nil.getInstance());
}
}