Naive LISP implementation in PHP. For something more complete, check out Lisphp.
Check out the s-expression blog posts explaining the implementation of Ilias.
use Igorw\Ilias\Program;
use Igorw\Ilias\Lexer;
use Igorw\Ilias\Reader;
use Igorw\Ilias\FormTreeBuilder;
use Igorw\Ilias\Walker;
use Igorw\Ilias\Environment;
$program = new Program(
new Lexer(),
new Reader(),
new FormTreeBuilder(),
new Walker()
);
$env = Environment::standard();
$value = $program->evaluate($env, '(+ 1 2)');
var_dump($value);will output:
int(3)