diff --git a/examples/grammar.ipynb b/examples/grammar.ipynb
index 5976938..bce7284 100644
--- a/examples/grammar.ipynb
+++ b/examples/grammar.ipynb
@@ -345,13 +345,13 @@
        "<svg xmlns=\"http://www.w3.org/2000/svg\" xmlns:xlink=\"http://www.w3.org/1999/xlink\" width=\"11.871pt\" height=\"41.105pt\" viewBox=\"0 0 11.871 41.105\" version=\"1.1\">\n",
        "<defs>\n",
        "<g>\n",
-       "<symbol overflow=\"visible\" id=\"glyph-1521134086610405-0-0\">\n",
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        "<path style=\"stroke:none;\" d=\"\"/>\n",
        "</symbol>\n",
-       "<symbol overflow=\"visible\" id=\"glyph-1521134086610405-0-1\">\n",
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        "</symbol>\n",
-       "<symbol overflow=\"visible\" id=\"glyph-1521134086610405-0-2\">\n",
+       "<symbol overflow=\"visible\" id=\"glyph-1536359274296654-0-2\">\n",
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        "</symbol>\n",
        "</g>\n",
@@ -360,10 +360,10 @@
        "<path style=\"fill:none;stroke-width:0.3985;stroke-linecap:butt;stroke-linejoin:miter;stroke:rgb(0%,0%,0%);stroke-opacity:1;stroke-miterlimit:10;\" d=\"M 0.0015 -6.594281 L 0.0015 -21.32475 \" transform=\"matrix(1,0,0,-1,5.936,6.394)\"/>\n",
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        "<g style=\"fill:rgb(0%,0%,0%);fill-opacity:1;\">\n",
-       "  <use xlink:href=\"#glyph-1521134086610405-0-1\" x=\"3.321\" y=\"9.468\"/>\n",
+       "  <use xlink:href=\"#glyph-1536359274296654-0-1\" x=\"3.321\" y=\"9.468\"/>\n",
        "</g>\n",
        "<g style=\"fill:rgb(0%,0%,0%);fill-opacity:1;\">\n",
-       "  <use xlink:href=\"#glyph-1521134086610405-0-2\" x=\"3.321\" y=\"37.784\"/>\n",
+       "  <use xlink:href=\"#glyph-1536359274296654-0-2\" x=\"3.321\" y=\"37.784\"/>\n",
        "</g>\n",
        "</g>\n",
        "</svg>\n",
@@ -396,63 +396,21 @@
    "metadata": {},
    "outputs": [
     {
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-       "</g>\n",
-       "</g>\n",
-       "</svg>\n",
-       "\n"
-      ],
-      "text/plain": [
-       "TreeView.LabelledTree({3, 2} directed simple Int64 graph, Any[:*, 8, 4.0])"
-      ]
-     },
-     "execution_count": 12,
-     "metadata": {},
-     "output_type": "execute_result"
+     "ename": "UndefVarError",
+     "evalue": "UndefVarError: seed1! not defined",
+     "output_type": "error",
+     "traceback": [
+      "UndefVarError: seed1! not defined",
+      "",
+      "Stacktrace:",
+      " [1] getproperty(::Module, ::Symbol) at ./sysimg.jl:13",
+      " [2] top-level scope at In[12]:2"
+     ]
     }
    ],
    "source": [
-    "srand(100)\n",
+    "using Random\n",
+    "Random.seed1!(100)\n",
     "rulenode = rand(RuleNode, grammar, :Real, 10)\n",
     "display(rulenode, grammar)"
    ]
@@ -470,18 +428,22 @@
    "metadata": {},
    "outputs": [
     {
-     "data": {
-      "text/plain": [
-       "32.0"
-      ]
-     },
-     "execution_count": 13,
-     "metadata": {},
-     "output_type": "execute_result"
+     "ename": "UndefVarError",
+     "evalue": "UndefVarError: f not defined",
+     "output_type": "error",
+     "traceback": [
+      "UndefVarError: f not defined",
+      "",
+      "Stacktrace:",
+      " [1] top-level scope at none:0",
+      " [2] eval(::Module, ::Any) at ./boot.jl:319",
+      " [3] eval(::RuleNode, ::Grammar) at /Users/rlee18/.julia/dev/ExprRules/src/ExprRules.jl:389",
+      " [4] top-level scope at In[13]:1"
+     ]
     }
    ],
    "source": [
-    "eval(rulenode, grammar)"
+    "Core.eval(rulenode, grammar)"
    ]
   },
   {
@@ -499,7 +461,7 @@
     {
      "data": {
       "text/plain": [
-       ":(8 * 4.0)"
+       ":(f(B))"
       ]
      },
      "execution_count": 14,
@@ -526,7 +488,7 @@
     {
      "data": {
       "text/plain": [
-       "2{15,4}"
+       "3{6}"
       ]
      },
      "execution_count": 15,
@@ -535,7 +497,7 @@
     }
    ],
    "source": [
-    "srand(0)\n",
+    "Random.seed!(0)\n",
     "sample(rulenode)"
    ]
   },
@@ -554,7 +516,7 @@
     {
      "data": {
       "text/plain": [
-       "2{15,4}"
+       "3{6}"
       ]
      },
      "execution_count": 16,
@@ -563,7 +525,7 @@
     }
    ],
    "source": [
-    "srand(3)\n",
+    "Random.seed!(3)\n",
     "sample(rulenode, :Real, grammar)"
    ]
   },
@@ -582,7 +544,7 @@
     {
      "data": {
       "text/plain": [
-       "ExprRules.NodeLoc(2{15,4}, 1)"
+       "NodeLoc(3{6}, 1)"
       ]
      },
      "execution_count": 17,
@@ -591,7 +553,7 @@
     }
    ],
    "source": [
-    "srand(1)\n",
+    "Random.seed!(1)\n",
     "loc = sample(NodeLoc, rulenode)"
    ]
   },
@@ -610,7 +572,7 @@
     {
      "data": {
       "text/plain": [
-       "15,"
+       "6,"
       ]
      },
      "execution_count": 18,
@@ -638,77 +600,61 @@
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        "</g>\n",
        "</g>\n",
        "</svg>\n",
        "\n"
       ],
       "text/plain": [
-       "TreeView.LabelledTree({7, 6} directed simple Int64 graph, Any[:*, :*, 9, :*, 3, 6, 4.0])"
+       "TreeView.LabelledTree({6, 5} directed simple Int64 graph, Any[:f, :*, 9, :*, 4, 9])"
       ]
      },
      "execution_count": 19,
@@ -717,7 +663,7 @@
     }
    ],
    "source": [
-    "srand(28)\n",
+    "Random.seed!(28)\n",
     "insert!(rulenode, loc, rand(RuleNode, grammar, :Real, 3))\n",
     "display(rulenode, grammar)"
    ]
@@ -815,7 +761,7 @@
     {
      "data": {
       "text/plain": [
-       "6-element Array{ExprRules.RuleNode,1}:\n",
+       "6-element Array{RuleNode,1}:\n",
        " 1{2,2}\n",
        " 1{2,3}\n",
        " 1{3,2}\n",
@@ -912,40 +858,23 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 26,
+   "execution_count": null,
    "metadata": {},
-   "outputs": [
-    {
-     "name": "stdout",
-     "output_type": "stream",
-     "text": [
-      ":(1 + (1 + 2))\n",
-      "├─ :+\n",
-      "├─ 1\n",
-      "└─ :(1 + 2)\n",
-      "   ├─ :+\n",
-      "   ├─ 1\n",
-      "   └─ 2\n"
-     ]
-    }
-   ],
-   "source": [
-    "ex = get_executable(tree, grammar)\n",
-    "print_tree(ex)"
-   ]
+   "outputs": [],
+   "source": []
   }
  ],
  "metadata": {
   "kernelspec": {
-   "display_name": "Julia 0.6.2",
+   "display_name": "Julia 0.7.0",
    "language": "julia",
-   "name": "julia-0.6"
+   "name": "julia-0.7"
   },
   "language_info": {
    "file_extension": ".jl",
    "mimetype": "application/julia",
    "name": "julia",
-   "version": "0.6.2"
+   "version": "0.7.0"
   }
  },
  "nbformat": 4,
diff --git a/src/ExprRules.jl b/src/ExprRules.jl
index 2b4d9ca..9707d9c 100644
--- a/src/ExprRules.jl
+++ b/src/ExprRules.jl
@@ -3,7 +3,6 @@ __precompile__()
 module ExprRules
 
 import TreeView: walk_tree
-import Random: srand
 using StatsBase
 using AbstractTrees
 using Nullables