public void TestIsTrueAlwaysFalseFunction()
{
var expr = AlwaysFalseFunction.CreateAlwaysFalseFunctionCall();
var scope = AchievementScriptInterpreter.GetGlobalScope();
ParseErrorExpression error;
Assert.That(expr.IsTrue(scope, out error), Is.False);
Assert.That(error, Is.Null);
}
internal static ExpressionBase InvertExpression(ExpressionBase expression)
{
// logical inversion
var condition = expression as ConditionalExpression;
if (condition != null)
{
var newConditions = new List <ExpressionBase>(condition._conditions.Count);
foreach (var oldCondition in condition._conditions)
{
newConditions.Add(InvertExpression(oldCondition));
}
switch (condition.Operation)
{
case ConditionalOperation.Not:
// !(!A) => A
return(newConditions[0]);
case ConditionalOperation.And:
// !(A && B) => !A || !B
return(new ConditionalExpression(ConditionalOperation.Or, newConditions));
case ConditionalOperation.Or:
// !(A || B) => !A && !B
return(new ConditionalExpression(ConditionalOperation.And, newConditions));
default:
throw new NotImplementedException("Unsupported condition operation");
}
}
// comparative inversion
var comparison = expression as ComparisonExpression;
if (comparison != null)
{
// !(A == B) => A != B, !(A < B) => A >= B, ...
return(new ComparisonExpression(
comparison.Left,
ComparisonExpression.GetOppositeComparisonOperation(comparison.Operation),
comparison.Right));
}
// boolean constant
var boolean = expression as BooleanConstantExpression;
if (boolean != null)
{
return(new BooleanConstantExpression(!boolean.Value));
}
// special handling for built-in functions
var function = expression as FunctionCallExpression;
if (function != null && function.Parameters.Count() == 0)
{
if (function.FunctionName.Name == "always_true")
{
return(AlwaysFalseFunction.CreateAlwaysFalseFunctionCall());
}
if (function.FunctionName.Name == "always_false")
{
return(AlwaysTrueFunction.CreateAlwaysTrueFunctionCall());
}
}
// unsupported inversion
return(new ParseErrorExpression("! operator cannot be applied to " + expression.Type, expression));
}