void EvalIf(MethodCallExpression exp, State state)
{
EvalExpression(exp.Arguments[0], state);
var test = state.CurrentBlock.Formulas.Pop();
var condition = FormulaRef.Condition(test);
state.CurrentBlock.Formulas.Push(condition);
state.Conditions.Push(condition);
state.PushBlock();
condition.IfTrue = state.CurrentBlock;
}
void EvalElse(MethodCallExpression exp, State state)
{
state.PopBlock();
var prevCondition = state.Conditions.Pop();
state.Conditions.Push(prevCondition);
state.PushBlock();
prevCondition.IfFalse = state.CurrentBlock;
}