private function expandSubLists(Environment $env, ListForm $form)
{
if (!count($form->toArray())) {
return $form;
}
return new ListForm(array_merge([$form->nth(0)], $this->expandList($env, $form->cdr())));
}
public function evaluate(Environment $env, ListForm $args)
{
$pairs = $args->toArray();
foreach ($pairs as $pair) {
list($predicate, $trueForm) = $pair->toArray();
if ($predicate->evaluate($env)) {
return $trueForm->evaluate($env);
}
}
return null;
}
private function wrapSymbols(ListForm $rawBody)
{
$wrappedBody = array_map(function ($form) {
if ($form instanceof ListForm) {
return $this->wrapSymbols($form);
}
if (is_string($form)) {
return new SymbolForm($form);
}
return $form;
}, $rawBody->toArray());
return new ListForm($wrappedBody);
}
private function evaluateArgs(Environment $env, ListForm $args)
{
return array_map(function ($arg) use($env) {
return $arg->evaluate($env);
}, $args->toArray());
}
