Exemple #1
0
        public object ApplyLambda(IList<object> arguments, Environment environment)
        {
            var parameterList = arguments.First() as IList<object>;
            var body = arguments.Skip(1);

            if (parameterList == null)
            {
                throw new ArgumentException("Missing parameter list in lambda!");
            }

            if (!parameterList.All(x => x is SymbolNode))
            {
                throw new ArgumentException("Parameters must be symbols!");
            }

            return new ProcedureNode(parameterList.Cast<SymbolNode>(), body, environment.CreateChildEnvironment());
        }
Exemple #2
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        public object ApplyLet(IList<object> arguments, Environment environment)
        {
            /*
             * (let ((var-a form-a) (var-b form-b)) (+ var-a var-b))
             */

            var bindingList = (IList<object>) arguments.First();
            var bodyforms = arguments.Skip(1).AsEnumerable();

            var localEnv = environment.CreateChildEnvironment();

            foreach (var binding in bindingList.OfType<IList<object>>())
            {
                var symbol = (SymbolNode)binding.First();
                var form = binding.ElementAt(1);

                var value = evaluator.Evaluate(form, localEnv);

                localEnv.DefineSymbol(symbol, value);
            }

            return evaluator.Evaluate(bodyforms, localEnv);
        }
Exemple #3
0
        public object ApplyDefMacro(IList<object> arguments, Environment environment)
        {
            if (arguments.Count != 3)
            {
                throw new ArgumentException("Wrong number of arguments given to defmacro! Expected: " + 3);
            }

            var symbol = arguments.ElementAt(0) as SymbolNode;
            if (symbol == null)
            {
                throw new ArgumentException("First argument to defmacro not a symbol!");
            }

            var parameterList = arguments.ElementAt(1) as IList<object>;
            if (parameterList == null)
            {
                throw new ArgumentException("Second argument to defmacro not a parameterlist!");
            }

            var body = arguments.ElementAt(2);

            var macro = new ProcedureNode(parameterList.Cast<SymbolNode>(), new[] { body }, environment.CreateChildEnvironment(), true);

            environment.DefineSymbol(symbol, macro);

            return symbol;
        }