public function testIsVariable() { $var = variable(1); $list = cons(1, 2); $this->assertTrue(isVariable($var)); $this->assertFalse(isVariable($list)); }
function walkStar($v, $s) { $v = walk($v, $s); if (isVariable($v)) { return $v; } elseif (isPair($v)) { return cons(walkStar(car($v), $s), walkStar(cdr($v), $s)); } else { return $v; } }