public function valuesOfColumn($column_name)
{
$list = new FList($this->table);
$values = $list->foldl(function ($acc, $record) use($column_name) {
$acc[] = $record[$column_name];
return $acc;
}, array());
return $values;
}
protected function instance_generator_for_fact($term)
{
$var_list = new FList($term->getVariables());
// TODO: if no fact table found
$fact_table = $this->fact_tables[$term->getName()];
$ext_fact_table = isset($this->ext_fact_tables[$term->getName()]) ? $this->ext_fact_tables[$term->getName()] : $fact_table->getEmptyClone();
$select_pattern = $var_list->foldl(function ($acc, $var) {
if ($var->hasValue()) {
$acc[$var->getName()] = $var->getValue();
}
return $acc;
}, array());
// if select_pattern == array(), all record of this fact table are selected.
$instance_table = $fact_table->select($select_pattern);
//$instance_table->view();
$ext_records = $ext_fact_table->select($select_pattern)->records();
$instance_table->insert_array($ext_records, TRUE, TRUE);
//$instance_table->view();
// if $instance_table is EMPTY, throw Exception.
if ($instance_table->isEmpty()) {
throw new LogicException('KBase::instance_generator_for_fact(): no candidates available.');
}
return $instance_table->tuples_gen();
/*
$candidates_input = $var_list->foldl(function($acc, $var) use ($instance_table) {
if($var->hasValue()) {
$acc[] = array($var->getValue());
} else {
$acc[] = $instance_table->valuesOfColumn($var->getName());
}
return $acc;
}, array());
return cartesian_product_gen($candidates_input); // yield array(i1, i2, i3, ...) generator
*/
}