public static void Start()
{
Object.Environment env = Object.Environment.NewEnvironment();
Object.Environment macroEnv = Object.Environment.NewEnvironment();
for (;;)
{
System.Console.Write(PROMPT);
string line = System.Console.ReadLine();
lexer.Lexer l = lexer.Lexer.New(line);
parser.Parser p = parser.Parser.New(l);
ast.Program program = p.ParseProgram();
if (parser.Parser.Errors().Count != 0)
{
printParserErrors(parser.Parser.Errors());
continue;
}
evaluator.macro_expansion.DefineMacros(program, macroEnv);
ast.Node expanded = evaluator.macro_expansion.ExpandMacros(program, macroEnv);
Object.Object evaluated = evaluator.evaluator.Eval(expanded, env);
if (evaluated != null)
{
System.Console.Write(evaluated.Inspect());
System.Console.WriteLine();
}
}
}
public ast.Node EvaluateNode(ast.Node node)
{
if (node is ast.Path)
{
var path = node as ast.Path;
var part = path.partList[0];
var solver = new Solver(node, this);
while (!solver.EvaluatePart(part))
{
if (0 == solver.Level)
{
return(solver.Error(part));
}
solver.Leave();
}
for (var i = 1; i < path.partList.Count; i++)
{
part = path.partList[i];
if (!solver.EvaluatePart(part))
{
return(solver.Error(part));
}
}
return(solver);
}
return(node);
}
public static Object.Object Eval(ast.Node node, Object.Environment env)
{
// Statements
if (node is ast.Program)
{
return(evalProgram((ast.Program)node, env));
}
if (node is ast.BlockStatement)
{
return(evalBlockStatement((ast.BlockStatement)node, env));
}
if (node is ast.ExpressionStatement)
{
return(Eval(((ast.ExpressionStatement)node).Expression, env));
}
if (node is ast.ReturnStatement)
{
Object.Object val = Eval(((ast.ReturnStatement)node).ReturnValue, env);
if (isError(val))
{
return(val);
}
return(new Object.ReturnValue {
Value = val
});
}
if (node is ast.LetStatement)
{
Object.Object val = Eval(((ast.LetStatement)node).Value, env);
if (isError(val))
{
return(val);
}
env.Set(((ast.LetStatement)node).Name.Value, val);
}
// Expressions
if (node is ast.IntegerLiteral) // Go can use a switch here!
{
return new Object.Integer {
Value = ((ast.IntegerLiteral)node).Value
}
}
;
if (node is ast.StringLiteral)
{
return new Object.String {
Value = ((ast.StringLiteral)node).Value
}
}
;
if (node is ast.Boolean)
{
return(nativeToBooleanObject(((ast.Boolean)node).Value));
}
if (node is ast.PrefixExpression)
{
Object.Object right = Eval(((ast.PrefixExpression)node).Right, env);
if (isError(right))
{
return(right);
}
return(evalPrefixExpression(((ast.PrefixExpression)node).Operator, right));
}
if (node is ast.InfixExpression)
{
Object.Object left = Eval(((ast.InfixExpression)node).Left, env);
if (isError(left))
{
return(left);
}
Object.Object right = Eval(((ast.InfixExpression)node).Right, env);
if (isError(right))
{
return(right);
}
return(evalInfixExpression(((ast.InfixExpression)node).Operator, left, right));
}
if (node is ast.IfExpression)
{
return(evalIfExpression((ast.IfExpression)node, env));
}
if (node is ast.Identifier)
{
return(evalIdentifier((ast.Identifier)node, env));
}
if (node is ast.FunctionLiteral)
{
List <ast.Identifier> params_ = ((ast.FunctionLiteral)node).Parameters;
ast.BlockStatement body = ((ast.FunctionLiteral)node).Body;
return(new Object.Function {
Parameters = params_, Env = env, Body = body
});
}
if (node is ast.CallExpression)
{
if (((ast.CallExpression)node).Function.TokenLiteral() == "quote")
{
return(quote_unquote.quote(((ast.CallExpression)node).Arguments[0], env));
}
Object.Object function = Eval(((ast.CallExpression)node).Function, env);
if (isError(function))
{
return(function);
}
List <Object.Object> args = evalExpressions(((ast.CallExpression)node).Arguments, env);
if (args.Count == 1 && isError(args[0]))
{
return(args[0]);
}
return(applyFunction(function, args));
}
if (node is ast.ArrayLiteral)
{
List <Object.Object> elements = evalExpressions(((ast.ArrayLiteral)node).Elements, env);
if (elements.Count == 1 && isError(elements[0]))
{
return(elements[0]);
}
return(new Object.Array {
Elements = elements
});
}
if (node is ast.IndexExpression)
{
Object.Object left = Eval(((ast.IndexExpression)node).Left, env);
if (isError(left))
{
return(left);
}
Object.Object index = Eval(((ast.IndexExpression)node).Index, env);
if (isError(index))
{
return(index);
}
return(evalIndexExpression(left, index));
}
if (node is ast.HashLiteral)
{
return(evalHashLiteral((ast.HashLiteral)node, env));
}
return(null);
}
public Solver(ast.Node node, Solver context) : base(context)
{
limit = node;
this.context = context;
list = nillable;
}
public static error Compile(ast.Node node)
{
if (node is ast.Program)
{
foreach (ast.Statement s in ((ast.Program)node).Statements)
{
error err = Compile(s);
if (err != null)
{
return(err);
}
}
return(null);
}
if (node is ast.ExpressionStatement)
{
error err = Compile(((ast.ExpressionStatement)node).Expression);
if (err != null)
{
return(err);
}
emit(code.OpPop);
return(null);
}
if (node is ast.InfixExpression)
{
ast.InfixExpression _node = (ast.InfixExpression)node;
error err;
if (_node.Operator == "<")
{
err = Compile(_node.Right);
if (err != null)
{
return(err);
}
err = Compile(_node.Left);
if (err != null)
{
return(err);
}
emit(code.OpGreaterThan);
return(null);
}
err = Compile(_node.Left);
if (err != null)
{
return(err);
}
err = Compile(_node.Right);
if (err != null)
{
return(err);
}
switch (_node.Operator)
{
case "+":
emit(code.OpAdd);
break;
case "-":
emit(code.OpSub);
break;
case "*":
emit(code.OpMul);
break;
case "/":
emit(code.OpDiv);
break;
case ">":
emit(code.OpGreaterThan);
break;
case "==":
emit(code.OpEqual);
break;
case "!=":
emit(code.OpNotEqual);
break;
default:
return(string.Format("unknown operator {0}", _node.Operator));
}
return(null);
}
if (node is ast.IntegerLiteral)
{
Object.Integer integer = new Object.Integer {
Value = ((ast.IntegerLiteral)node).Value
};
emit(code.OpConstant, (Opcode)addConstant(integer));
return(null);
}
if (node is ast.Boolean)
{
if (((ast.Boolean)node).Value)
{
emit(code.OpTrue);
}
else
{
emit(code.OpFalse);
}
return(null);
}
if (node is ast.PrefixExpression)
{
ast.PrefixExpression _node = (ast.PrefixExpression)node;
error err = Compile(_node.Right);
if (err != null)
{
return(err);
}
switch (_node.Operator)
{
case "!":
emit(code.OpBang);
break;
case "-":
emit(code.OpMinus);
break;
default:
return(string.Format("unknown operator {0}", _node.Operator));
}
return(null);
}
if (node is ast.IfExpression)
{
ast.IfExpression _node = (ast.IfExpression)node;
error err = Compile(_node.Condition);
if (err != null)
{
return(err);
}
//Emit an 'OpJumpNotTruthy' with bogus value
int jumpNotTruthyPos = emit(code.OpJumpNotTruthy, 9999);
err = Compile(_node.Consequence);
if (err != null)
{
return(err);
}
if (lastInstructionIs(code.OpPop))
{
removeLastPop();
}
// Emit an 'OpJump' with a bogus value
int jumpPos = emit(code.OpJump, 9999);
int afterConsequencePos = currentInstructions().Count;
changeOperand(jumpNotTruthyPos, afterConsequencePos);
if (_node.Alternative == null)
{
emit(code.OpNull);
}
else
{
err = Compile(_node.Alternative);
if (err != null)
{
return(err);
}
if (lastInstructionIs(code.OpPop))
{
removeLastPop();
}
}
int afterAlternativePos = currentInstructions().Count;
changeOperand(jumpPos, afterAlternativePos);
return(null);
}
if (node is ast.BlockStatement)
{
foreach (ast.Statement s in ((ast.BlockStatement)node).Statements)
{
error err = Compile(s);
if (err != null)
{
return(err);
}
}
return(null);
}
if (node is ast.LetStatement)
{
ast.LetStatement _node = (ast.LetStatement)node;
symbol_table.Symbol symbol = symbol_table.Define(ref c.symbolTable, _node.Name.Value);
error err = Compile(_node.Value);
if (err != null)
{
return(err);
}
if (symbol.Scope == symbol_table.GlobalScope)
{
emit(code.OpSetGlobal, symbol.Index);
}
else
{
emit(code.OpSetLocal, symbol.Index);
}
return(null);
}
if (node is ast.Identifier)
{
ast.Identifier _node = (ast.Identifier)node;
symbol_table.Symbol symbol = symbol_table.Resolve(ref c.symbolTable, _node.Value);
if (symbol == null)
{
return(string.Format("undefined variable {0}", _node.Value));
}
loadSymbols(symbol);
return(null);
}
if (node is ast.StringLiteral)
{
ast.StringLiteral _node = (ast.StringLiteral)node;
Object.String str = new Object.String {
Value = _node.Value
};
emit(code.OpConstant, addConstant(str));
return(null);
}
if (node is ast.ArrayLiteral)
{
ast.ArrayLiteral _node = (ast.ArrayLiteral)node;
foreach (ast.Expression el in _node.Elements)
{
error err = Compile(el);
if (err != null)
{
return(err);
}
}
emit(code.OpArray, _node.Elements.Count);
return(null);
}
if (node is ast.HashLiteral)
{
ast.HashLiteral _node = (ast.HashLiteral)node;
// the sorting is not strictly needed and was only done to pass the test
// since the test assumes a specific order for the keys
foreach (KeyValuePair <Expression, Expression> k in _node.Pairs)
{
error err = Compile(k.Key);
if (err != null)
{
return(err);
}
err = Compile(_node.Pairs[k.Key]);
if (err != null)
{
return(err);
}
}
emit(code.OpHash, _node.Pairs.Count * 2);
return(null);
}
if (node is ast.IndexExpression)
{
ast.IndexExpression _node = (ast.IndexExpression)node;
error err = Compile(_node.Left);
if (err != null)
{
return(err);
}
err = Compile(_node.Index);
if (err != null)
{
return(err);
}
emit(code.OpIndex);
return(null);
}
if (node is ast.FunctionLiteral)
{
ast.FunctionLiteral _node = (ast.FunctionLiteral)node;
enterScope();
if (_node.Name != null && _node.Name != "")
{
symbol_table.DefineFunctionName(ref c.symbolTable, _node.Name);
}
foreach (ast.Identifier p in _node.Parameters)
{
symbol_table.Define(ref c.symbolTable, p.Value);
}
error err = Compile(_node.Body);
if (err != null)
{
return(err);
}
if (lastInstructionIs(code.OpPop))
{
replaceLastPopWithReturn();
}
if (!lastInstructionIs(code.OpReturnValue))
{
emit(code.OpReturn);
}
List <symbol_table.Symbol> freeSymbols = c.symbolTable.FreeSymbols;
int numLocals = c.symbolTable.numDefinitions;
Instructions instructions = leaveScope();
foreach (symbol_table.Symbol s in freeSymbols)
{
loadSymbols(s);
}
Object.CompiledFunction compiledFn = new Object.CompiledFunction
{
Instructions = instructions,
NumLocals = numLocals,
NumParameters = _node.Parameters.Count,
};
int fnIndex = addConstant(compiledFn);
emit(code.OpClosure, fnIndex, freeSymbols.Count);
return(null);
}
if (node is ast.ReturnStatement)
{
ast.ReturnStatement _node = (ast.ReturnStatement)node;
error err = Compile(_node.ReturnValue);
if (err != null)
{
return(err);
}
emit(code.OpReturnValue);
return(null);
}
if (node is ast.CallExpression)
{
ast.CallExpression _node = (ast.CallExpression)node;
error err = Compile(_node.Function);
if (err != null)
{
return(err);
}
foreach (Expression a in _node.Arguments)
{
err = Compile(a);
if (err != null)
{
return(err);
}
}
emit(code.OpCall, _node.Arguments.Count);
return(null);
}
return(null);
}