public void Build(IParser parser, ExecutionContext context, ISet<string> chain)
{
Tree = null;
Queue<IToken> queue = parser.Tokenize(Convert.ToString(Value));
Dependees = context.NewSet();
foreach (IToken token in queue) { if (token.IsVariable) { Dependees.Add(token.Name); } }
Stack<IToken> stack = parser.BuildStack(queue);
Tree = parser.CreateTree(stack);
}
public void CheckCircularReference(IParser parser, ExecutionContext context, ISet<string> chain, object input)
{
foreach (string dependee in Dependees) {
if (chain.Contains(dependee)) {
throw new CircularReferenceException(dependee, string.IsNullOrEmpty(Name) ? Convert.ToString(Value) : Name);
}
ContextValue value;
if (context.TryGetContext(dependee, input, out value) && value.ContextType == Albatross.Expression.ContextType.Expression) {
ISet<string> newChain = context.NewSet();
newChain.AddRange(chain).Add(dependee);
if (value.Tree == null) {
value.Build(parser, context, newChain);
}
value.CheckCircularReference(parser, context, newChain, input);
}
}
}
public object GetValue(IParser parser, ExecutionContext context, object input)
{
if (ContextType == Albatross.Expression.ContextType.Expression) {
ISet<string> chain = context.NewSet();
if (!string.IsNullOrEmpty(Name)) { chain.Add(Name); }
if (Tree == null) {
Build(parser, context, chain);
}
CheckCircularReference(parser, context, chain, input);
object value = parser.Eval(Tree, new Func<string, object>(name => context.GetValue(name, input)));
if (value != null && DataType != null && DataType != value.GetType()) {
value = Convert.ChangeType(value, DataType);
}
return value;
} else {
return Value;
}
}
