diff --git a/src/Lib/Collections.php b/src/Lib/Collections.php
index d9bf3a7..9561665 100644
--- a/src/Lib/Collections.php
+++ b/src/Lib/Collections.php
@@ -150,7 +150,11 @@ class Collections implements ILib
         $env->set('chunk', new CoreFunc('chunk', 'Divide first argument (sequence) into new sequences with length of second argument (int).', 2, 2,
             function (Seq $a, int $len) {
                 $chunks = array_chunk($a->getData(), $len);
-                return $a::new(array_map(fn ($b) => $a::new($b), $chunks));
+                $data = [];
+                foreach ($chunks as $c) {
+                    $data[] = $a::new($c);
+                }
+                return $a::new($data);
             }
         ));
 
@@ -159,7 +163,11 @@ class Collections implements ILib
                 // This is used by quasiquote, so we need to always return
                 // a list for it to work properly.
 
-                $data = array_map(fn ($a) => $a->getData(), $args);
+                $data = [];
+                foreach ($args as $a) {
+                    $data[] = $a->getData();
+                }
+
                 return new MList(array_merge(...$data));
             }
         ));
diff --git a/src/Lib/Database.php b/src/Lib/Database.php
index c0b9da0..a889832 100644
--- a/src/Lib/Database.php
+++ b/src/Lib/Database.php
@@ -29,13 +29,15 @@ class Database implements ILib
         ));
 
         $env->set('db-query', new CoreFunc('db-query', 'Execute a database query.', 2, 4,
-            function (PDO $pdo, string $sql, ?Collection $args, bool $rowVectors = false) {
+            function (PDO $pdo, string $sql, ?Collection $args = null, bool $rowVectors = false) {
                 $stmt = $pdo->prepare($sql);
                 $stmt->execute($args ? $args->getData() : []);
                 $rows = $stmt->fetchAll($rowVectors ? PDO::FETCH_NUM : PDO::FETCH_ASSOC);
-                return new Vector(
-                    array_map(fn ($row) => $rowVectors ? new Vector($row) : new Hash($row), $rows)
-                );
+                $data = [];
+                foreach ($rows as $row) {
+                    $data[] = $rowVectors ? new Vector($row) : new Hash($row);
+                }
+                return new Vector($data);
             }
         ));
 
diff --git a/src/Lib/Types.php b/src/Lib/Types.php
index 5e92aab..1c5a565 100644
--- a/src/Lib/Types.php
+++ b/src/Lib/Types.php
@@ -30,7 +30,17 @@ class Types implements ILib
         ));
 
         $env->set('str', new CoreFunc('str', 'Convert arguments to string and concatenate them together.', 0, -1,
-            fn (...$args) => implode('', array_map([$this, 'getStrValue'], $args))
+            function (...$args) {
+                $data = [];
+                foreach ($args as $a) {
+                    if ($a instanceof Symbol) {
+                        $data[] = $a->getName();
+                    } else {
+                        $data[] = strval($a);
+                    }
+                }
+                return implode('', $data);
+            }
         ));
 
         $env->set('symbol', new CoreFunc('symbol', 'Convert argument to symbol.', 1, 1,
@@ -167,13 +177,4 @@ class Types implements ILib
             fn ($a) => $a % 2 !== 0
         ));
     }
-
-    private function getStrValue($a)
-    {
-        if ($a instanceof Symbol) {
-            return $a->getName();
-        }
-
-        return strval($a);
-    }
 }