public Symbol Evaluate(Symbol symbol)
{
if (symbol is Expression expression && expression.Count > 0)
{
Expression.Builder builder = new Expression.Builder(expression);
for (int i = 0; i < builder.Count; i++)
{
if (builder.Arguments[i] is Expression)
{
builder.Arguments[i] = Evaluate(builder[i]);
}
}
if (Evaluators.TryGetValue(builder[0], out var evaluator))
{
symbol = evaluator.Evaluate(builder.Build(), this);
}
}
History.Insert(0, symbol);
for (int i = 0; i < Math.Min(History.Count, 10); i++)
{
Variable[Atom.OfHistory(i)] = History[i];
}
return(symbol);
}