Issue #22 - can't stringify assoc arrays

Detect if the array in question is considered associative -- keys are not a sequential range of numbers starting from 0. If it is associative, convert it to an object and allow the stringify process to turn it into a HJSON object representation.

Author: sprak3000

src/HJSON/HJSONStringifier.php

@@ -239,6 +239,17 @@ private function str($value, $hasComment = null, $noIndent = null, $isRootObject
             case 'array':
                 $isArray = is_array($value);
 
+                $isAssocArray = function (array $arr) {
+                    if (array() === $arr) {
+                        return false;
+                    }
+                    return array_keys($arr) !== range(0, count($arr) - 1);
+                };
+                if ($isArray && $isAssocArray($value)) {
+                    $value = (object) $value;
+                    $isArray = false;
+                }
+
                 $kw = null;
                 $kwl = null; // whitespace & comments
                 if ($this->keepWsc) {
@@ -324,7 +335,7 @@ private function str($value, $hasComment = null, $noIndent = null, $isRootObject
                         }
                     } else {
                         foreach ($value as $k => $vvv) {
-                            $v = $this->str($value->$k);
+                            $v = $this->str($vvv);
                             if ($v !== null) {
                                 $partial[] = $this->quoteName($k) . ($startsWithNL($v) ? ':' : ': ') . $v;
                             }

tests/assets/pass1_result.hjson

@@ -8,6 +8,14 @@
   }
   {}
   []
+  {
+    1: foo
+    3: bar
+  }
+  {
+    foo: foo
+    bar: bar
+  }
   -42
   true
   false

tests/assets/pass1_result.json

@@ -7,6 +7,14 @@
   },
   {},
   [],
+  {
+    "1": "foo",
+    "3": "bar"
+  },
+  {
+    "foo": "foo",
+    "bar": "bar"
+  },
   -42,
   true,
   false,

tests/assets/pass1_test.json

@@ -3,6 +3,14 @@
     {"object with 1 member":["array with 1 element"]},
     {},
     [],
+    {
+        "1": "foo",
+        "3": "bar"
+    },
+    {
+        "foo": "foo",
+        "bar": "bar"
+    },
     -42,
     true,
     false,