public ILispValue Lookup(Symbol name)
{
ILispValue value;
if (!_Variables.TryGetValue(name, out value))
{
return(_ParentEnvironment.Lookup(name));
}
return(value);
}
private static ILispValue EvaluateInvocation(Symbol funcName, IList <ILispValue> args, ILispEnvironment environment)
{
ILispValue func = environment.Lookup(funcName);
if (func.Type != LispValueType.Lambda)
{
throw new TypeMismatchException(new Symbol("function"), LispValueType.Lambda, func.Type);
}
ILispLambda lambda = (ILispLambda)func;
IList <ILispValue> parameterValues = args.Select(arg => Evaluate(arg, environment)).ToList();
return(lambda.Execute(BindParameters(lambda, parameterValues)));
}
public static ILispValue Evaluate(ILispValue value, ILispEnvironment environment)
{
switch (value.Type)
{
case LispValueType.Boolean:
case LispValueType.Char:
case LispValueType.Lambda:
case LispValueType.Number:
case LispValueType.String:
default:
return(value);
case LispValueType.Symbol:
return(environment.Lookup((Symbol)value));
case LispValueType.List:
return(EvaluateList((List)value, environment));
}
}
