/// <summary>
/// Get an element from the set.
/// </summary>
/// <returns>An element if non-empty.</returns>
public T Element()
{
var model = this.Solver.Satisfiable(this.Set);
if (!model.HasValue)
{
throw new ZenException("No element exists in state set.");
}
var assignment = new Dictionary <object, object>();
foreach (var kv in this.ArbitraryMapping)
{
var value = this.Solver.Get(model.Value, kv.Value);
assignment[kv.Key] = value;
}
var interpreterEnv = new ExpressionEvaluatorEnvironment(assignment);
return(CommonUtilities.ConvertSymbolicResultToCSharp <T>(this.ZenExpression.Accept(new ExpressionEvaluator(false), interpreterEnv)));
}
/// <summary>
/// Get an element from the set.
/// </summary>
/// <returns>An element if non-empty.</returns>
public Option <T> Element()
{
var model = this.Solver.Satisfiable(this.Set);
if (!model.HasValue)
{
return(Option.None <T>());
}
var assignment = new Dictionary <object, object>();
foreach (var kv in this.ArbitraryMapping)
{
var value = this.Solver.Get(model.Value, kv.Value);
assignment[kv.Key] = value;
}
var interpreterEnv = new ExpressionEvaluatorEnvironment(assignment);
var result = CommonUtilities.ConvertSymbolicResultToCSharp <T>(this.ZenExpression.Accept(new ExpressionEvaluator(false), interpreterEnv));
return(Option.Some(result));
}
/// <summary>
/// Generate inputs that exercise different program paths.
/// </summary>
/// <param name="function">The function.</param>
/// <param name="precondition">A precondition.</param>
/// <param name="input">The symbolic input.</param>
/// <param name="backend">The backend to use.</param>
/// <returns>A collection of inputs.</returns>
public static IEnumerable <T1> GenerateInputs <T1, T2>(
Func <Zen <T1>, Zen <T2> > function,
Func <Zen <T1>, Zen <bool> > precondition,
Zen <T1> input,
Backend backend)
{
var expression = function(input).Simplify();
var assume = precondition(input).Simplify();
(T2, PathConstraint) interpretFunction(T1 e)
{
var assignment = ModelCheckerFactory.CreateModelChecker(backend, null).ModelCheck(input == e);
var evaluator = new ExpressionEvaluator(true);
var env = new ExpressionEvaluatorEnvironment(assignment);
return((T2)expression.Accept(evaluator, env), evaluator.PathConstraint);
}
Option <T1> findFunction(Zen <bool> e) => SymbolicEvaluator.Find(e, input, backend);
return(GenerateInputsSage(assume, findFunction, interpretFunction));
}
