Add rudimentary graph validation

grammar/fbp.peg

@@ -19,6 +19,31 @@
 
   var serialize, indexOf = [].indexOf || function(item) { for (var i = 0, l = this.length; i < l; i++) { if (i in this && this[i] === item) return i; } return -1; };
 
+  parser.validateContents = function(graph, options) {
+    // Ensure all nodes have a component
+    if (graph.processes) {
+      Object.keys(graph.processes).forEach(function (node) {
+        if (!graph.processes[node].component) {
+          throw new Error('Node "' + node + '" does not have a component defined');
+        }
+      });
+    }
+    // Ensure all edges have nodes defined
+    if (graph.connections) {
+      graph.connections.forEach(function (edge) {
+        if (edge.tgt && !graph.processes[edge.tgt.process]) {
+          if (edge.data) {
+            throw new Error('IIP containing "' + edge.data + '" is connected to an undefined target node');
+          }
+          throw new Error('Edge from "' + edge.src.process + '" port "' + edge.src.port + '" is connected to an undefined target node');
+        }
+        if (edge.src && !graph.processes[edge.src.process]) {
+          throw new Error('Edge to "' + edge.tgt.process + '" port "' + edge.tgt.port + '" is connected to an undefined source node');
+        }
+      });
+    }
+  };
+
   parser.serialize = function(graph) {
     var conn, getInOutName, getName, i, inPort, input, len, name, namedComponents, outPort, output, process, ref, ref1, ref2, src, srcName, srcPort, srcProcess, tgt, tgtName, tgtPort, tgtProcess;
     if (options == null) {
@@ -163,6 +188,11 @@
       }
     }
     result.caseSensitive = options.caseSensitive;
+
+    if (typeof options.validateContents === 'undefined' || options.validateContents) {
+      parser.validateContents(result);
+    }
+
     return result;
   }