public function answer(KnowledgeState $state)
{
$state_value = $state->value($this->name);
foreach ($this->answers as $answer) {
$answer_value = $answer->value;
// If this is the default option, return it always.
if ($answer_value === null) {
return $answer;
}
// If the value is a variable, try to resolve it.
if (KnowledgeState::is_variable($answer_value)) {
$answer_value = $state->resolve($answer_value);
}
if ($state_value == $answer_value) {
return $answer;
}
}
// We didn't find an appropriate answer :O
return null;
}
private function createNewState()
{
$state = $this->readState($this->kb_file);
if (!empty($_GET['goals'])) {
foreach (explode(',', $_GET['goals']) as $goal) {
$state->goalStack->push($goal);
}
} else {
foreach ($state->goals as $goal) {
$state->goalStack->push($goal->name);
// Also push any answer values that are variables as goals
// to be solved.
foreach ($goal->answers as $answer) {
if (KnowledgeState::is_variable($answer->value)) {
$state->goalStack->push(substr($answer->value, 1));
}
}
}
}
return $state;
}
