adding loader arg for #1

README.ipynb

@@ -39,11 +39,11 @@
    "cell_type": "code",
    "execution_count": 1,
    "metadata": {
-    "collapsed": true
+    "collapsed": false
    },
    "outputs": [],
    "source": [
-    "%load_ext yamlmagic"
+    "%reload_ext yamlmagic"
    ]
   },
   {
@@ -209,6 +209,130 @@
     "x"
    ]
   },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "By default, `yaml.SafeLoader` will be used, which won't allow the [powerful but dangerous](http://pyyaml.org/wiki/PyYAMLDocumentation#LoadingYAML) (and unportable) [`!python/` tags](http://pyyaml.org/wiki/PyYAMLDocumentation#YAMLtagsandPythontypes). If you'd like to use them, provide the `-l` (or `--loader`) argument with a `BaseLoader` subclass available via a local variable..."
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 6,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [],
+   "source": [
+    "from yaml import Loader\n",
+    "class FooLoader(Loader):\n",
+    "    # some special things you have built\n",
+    "    pass"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 7,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "data": {
+      "application/javascript": [
+       "\n",
+       "            require(\n",
+       "                [\n",
+       "                    \"notebook/js/codecell\",\n",
+       "                    \"codemirror/mode/yaml/yaml\"\n",
+       "                ],\n",
+       "                function(cc){\n",
+       "                    cc.CodeCell.options_default.highlight_modes.magic_yaml = {\n",
+       "                        reg: [\"^%%yaml\"]\n",
+       "                    }\n",
+       "                }\n",
+       "            );\n",
+       "            "
+      ],
+      "text/plain": [
+       "<IPython.core.display.Javascript object>"
+      ]
+     },
+     "metadata": {},
+     "output_type": "display_data"
+    },
+    {
+     "data": {
+      "text/plain": [
+       "[{'a': 1.0, 'b': 2.0}]"
+      ]
+     },
+     "execution_count": 7,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "%%yaml --loader FooLoader\n",
+    "- a: !!python/float 1\n",
+    "  b: !!python/float 2"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "...or dotted-notation path to a loader:"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 8,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "data": {
+      "application/javascript": [
+       "\n",
+       "            require(\n",
+       "                [\n",
+       "                    \"notebook/js/codecell\",\n",
+       "                    \"codemirror/mode/yaml/yaml\"\n",
+       "                ],\n",
+       "                function(cc){\n",
+       "                    cc.CodeCell.options_default.highlight_modes.magic_yaml = {\n",
+       "                        reg: [\"^%%yaml\"]\n",
+       "                    }\n",
+       "                }\n",
+       "            );\n",
+       "            "
+      ],
+      "text/plain": [
+       "<IPython.core.display.Javascript object>"
+      ]
+     },
+     "metadata": {},
+     "output_type": "display_data"
+    },
+    {
+     "data": {
+      "text/plain": [
+       "[{'a': 1.0, 'b': 2.0}]"
+      ]
+     },
+     "execution_count": 8,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "%%yaml --loader yaml.Loader\n",
+    "- a: !!python/float 1\n",
+    "  b: !!python/float 2"
+   ]
+  },
   {
    "cell_type": "markdown",
    "metadata": {},