diff --git a/src/Evaller.php b/src/Evaller.php
index aad14b9..f9ab0c4 100644
--- a/src/Evaller.php
+++ b/src/Evaller.php
@@ -22,11 +22,9 @@ class Evaller
             // Lookup symbol from env
             return $env->get($ast->getName());
         } elseif ($ast instanceof MList) {
-            $results = [];
-            foreach ($ast->getData() as $val) {
-                $results[] = $this->doEval($val, $env);
-            }
-            return new MList($results);
+            return new MList(array_map(fn ($a) => $this->doEval($a, $env), $ast->getData()));
+        } elseif ($ast instanceof Vector) {
+            return new Vector(array_map(fn ($a) => $this->doEval($a, $env), $ast->getData()));
         } elseif ($ast instanceof Hash) {
             $results = [];
             foreach ($ast->getData() as $key => $val) {
diff --git a/src/Lib/Core.php b/src/Lib/Core.php
index 95d6b91..0ce5e81 100644
--- a/src/Lib/Core.php
+++ b/src/Lib/Core.php
@@ -4,9 +4,10 @@ namespace MadLisp\Lib;
 use Closure;
 use MadLisp\Env;
 use MadLisp\Hash;
+use MadLisp\MadLispException;
 use MadLisp\MList;
 use MadLisp\Symbol;
-use MadLisp\MadLispException;
+use MadLisp\Util;
 
 class Core implements ILib
 {
@@ -130,24 +131,7 @@ class Core implements ILib
         });
 
         $env->set('hash', function (...$args) {
-            if (count($args) % 2 == 1) {
-                throw new MadLispException('uneven number of arguments for hash');
-            }
-
-            $data = [];
-
-            for ($i = 0; $i < count($args) - 1; $i += 2) {
-                $key = $args[$i];
-                $val = $args[$i + 1];
-
-                if (!is_string($key)) {
-                    throw new MadLispException('invalid key for hash (not string)');
-                }
-
-                $data[$key] = $val;
-            }
-
-            return new Hash($data);
+            return Util::makeHash($args);
         });
     }
 }
diff --git a/src/MList.php b/src/MList.php
index 74e296b..fa6d5a1 100644
--- a/src/MList.php
+++ b/src/MList.php
@@ -1,7 +1,7 @@
 <?php
 namespace MadLisp;
 
-class MList extends Collection
+class MList extends Seq
 {
     public function get(int $index)
     {
diff --git a/src/Printer.php b/src/Printer.php
index f3d4d0d..30e8883 100644
--- a/src/Printer.php
+++ b/src/Printer.php
@@ -7,51 +7,34 @@ class Printer
 {
     public function print(array $items): void
     {
-        for ($i = 0; $i < count($items); $i++) {
-            if ($i > 0) {
-                print(' ');
-            }
-            $this->doPrint($items[$i]);
-        }
+        $strings = array_map(fn ($a) => $this->doPrint($a), $items);
+
+        print(implode(' ', $strings));
     }
 
-    private function doPrint($a): void
+    private function doPrint($a): string
     {
         if ($a instanceof Closure) {
-            print('<function>');
+            return '<function>';
         } elseif ($a instanceof MList) {
-            print('(');
-            for ($i = 0; $i < $a->count(); $i++) {
-                if ($i > 0) {
-                    print(' ');
-                }
-                $this->doPrint($a->get($i));
-            }
-            print(')');
+            return '(' . implode(' ', array_map(fn ($b) => $this->doPrint($b), $a->getData())) . ')';
+        } elseif ($a instanceof Vector) {
+            return '[' . implode(' ', array_map(fn ($b) => $this->doPrint($b), $a->getData())) . ']';
         } elseif ($a instanceof Hash) {
-            print('{');
-            $keys = array_keys($a->getData());
-            for ($i = 0; $i < count($keys); $i++) {
-                if ($i > 0) {
-                    print(' ');
-                }
-                $this->doPrint($keys[$i]);
-                print(':');
-                $this->doPrint($a->get($keys[$i]));
-            }
-            print('}');
+            return '{' . implode(' ', array_map(fn ($key, $val) => $this->doPrint($key) . ':' . $this->doPrint($val),
+                                                array_keys($a->getData()), array_values($a->getData()))) . '}';
         } elseif ($a instanceof Symbol) {
-            print($a->getName());
+            return $a->getName();
         } elseif ($a === true) {
-            print('true');
+            return 'true';
         } elseif ($a === false) {
-            print('false');
+            return 'false';
         } elseif ($a === null) {
-            print('null');
+            return 'null';
         } elseif (is_string($a)) {
-            print('"' . $a . '"');
+            return '"' . $a . '"';
         } else {
-            print($a);
+            return $a;
         }
     }
 }
diff --git a/src/Reader.php b/src/Reader.php
index 98ea869..5882b9e 100644
--- a/src/Reader.php
+++ b/src/Reader.php
@@ -19,26 +19,46 @@ class Reader
     {
         if ($tokens[$index] == '(') {
             return $this->readList($tokens, $index);
+        } elseif ($tokens[$index] == '[') {
+            return $this->readVector($tokens, $index);
+        } elseif ($tokens[$index] == '{') {
+            return $this->readHash($tokens, $index);
         } else {
             return $this->readAtom($tokens, $index);
         }
     }
 
     private function readList(array $tokens, int &$index): MList
+    {
+        return new MList($this->readCollection($tokens, $index, ')'));
+    }
+
+    private function readVector(array $tokens, int &$index): Vector
+    {
+        return new Vector($this->readCollection($tokens, $index, ']'));
+    }
+
+    private function readHash(array $tokens, int &$index): Hash
+    {
+        $contents = $this->readCollection($tokens, $index, '}');
+        return Util::makeHash($contents);
+    }
+
+    private function readCollection(array $tokens, int &$index, string $endTag): array
     {
         $result = [];
 
         // start tag
         $index++;
 
-        while ($tokens[$index] != ')') {
+        while ($tokens[$index] != $endTag) {
             $result[] = $this->readForm($tokens, $index);
         }
 
         // end tag
         $index++;
 
-        return new MList($result);
+        return $result;
     }
 
     private function readAtom(array $tokens, int &$index)
diff --git a/src/Seq.php b/src/Seq.php
new file mode 100644
index 0000000..d79d9ed
--- /dev/null
+++ b/src/Seq.php
@@ -0,0 +1,7 @@
+<?php
+namespace MadLisp;
+
+abstract class Seq extends Collection
+{
+
+}
\ No newline at end of file
diff --git a/src/Tokenizer.php b/src/Tokenizer.php
index c930fff..1f523d7 100644
--- a/src/Tokenizer.php
+++ b/src/Tokenizer.php
@@ -28,7 +28,7 @@ class Tokenizer
                 // Inside string, add all characters
                 $current .= $c;
 
-                // Stop at double quote
+                // Stop at first double quote
                 if ($c == '"') {
                     $addCurrent();
                     $isString = false;
diff --git a/src/Util.php b/src/Util.php
new file mode 100644
index 0000000..ca10111
--- /dev/null
+++ b/src/Util.php
@@ -0,0 +1,27 @@
+<?php
+namespace MadLisp;
+
+class Util
+{
+    public static function makeHash(array $args): Hash
+    {
+        if (count($args) % 2 == 1) {
+            throw new MadLispException('uneven number of arguments for hash');
+        }
+
+        $data = [];
+
+        for ($i = 0; $i < count($args) - 1; $i += 2) {
+            $key = $args[$i];
+            $val = $args[$i + 1];
+
+            if (!is_string($key)) {
+                throw new MadLispException('invalid key for hash (not string)');
+            }
+
+            $data[$key] = $val;
+        }
+
+        return new Hash($data);
+    }
+}
diff --git a/src/Vector.php b/src/Vector.php
new file mode 100644
index 0000000..20d229e
--- /dev/null
+++ b/src/Vector.php
@@ -0,0 +1,14 @@
+<?php
+namespace MadLisp;
+
+class Vector extends Seq
+{
+    public function get(int $index)
+    {
+        if ($this->has($index)) {
+            return $this->data[$index];
+        }
+
+        throw new MadLispException("vector does not contain index $index");
+    }
+}
\ No newline at end of file