public List <ExpressionInfo> GenerateOptionals(List <ExpressionInfo> predicates, int numOptionals, int minClause, int maxClause)
{
var optionals = new List <ExpressionInfo>();
for (var i = 0; i < numOptionals; ++i)
{
var clauses = minClause + Rand.Next(maxClause - minClause);
var expressions = new List <ExpressionInfo>();
var used = new List <int>();
for (var j = 0; j < clauses; ++j)
{
int choice;
do
{
choice = Rand.Next(predicates.Count);
}while (used.Contains(choice));
var predicate = predicates[choice];
if (j == 0)
{
var optional = Expression.MakeExpression(ExpressionFunctions.Lookup(ExpressionType.Optional), predicate.Expression);
if (Rand.NextDouble() < 0.25)
{
optional = Expression.NotExpression(optional);
}
expressions.Add(new ExpressionInfo(optional, predicate.Bindings));
}
else
{
expressions.Add(predicate);
}
used.Add(choice);
}
var conjunction = Binary(ExpressionType.And, expressions, out var bindings);
optionals.Add(new ExpressionInfo(conjunction, bindings));
}
return(optionals);
}
/// <summary>
/// Initializes a new instance of the <see cref="Expression"/> class.
/// Built-in expression constructor.
/// </summary>
/// <param name="type">Type of built-in expression from <see cref="ExpressionType"/>.</param>
/// <param name="children">Child expressions.</param>
public Expression(string type, params Expression[] children)
{
Evaluator = ExpressionFunctions.Lookup(type);
Children = children;
}
