Add the solution, based in check if the node names are valid, this is…

… done at output process of the node and the edge. Since the problem just occurs when outputting, more especially in the generate dot file, with don't accept nodes with certain names. I did this way, so would have less impact in the rest of the code.

lib/graphviz.rb

@@ -82,6 +82,9 @@ class GraphViz
   attr_accessor :edge
   alias_method :edge_attrs, :edge
 
+  ## Restricted node names list
+  @reserved_node_names = []
+
   @elements_order = nil
 
   def add_node( xNodeName, hOpts = {} )
@@ -102,6 +105,9 @@ def add_nodes(node_name, options = {})
      if node_name.kind_of? Array
         node_name.each { |n| add_nodes(n, options.clone) }
      else
+        puts node_name.class
+        #if node_name in @reserved_node_names
+        #end
         node = @hoNodes[node_name]
 
         if node.nil?
@@ -596,6 +602,7 @@ def output( hOpts = {} )
                xOutputWithoutFile +
                [tmpPath]
 
+        puts xCmd
         xOutput << output_from_command( xCmd )
       end
 

lib/graphviz/edge.rb

@@ -162,7 +162,13 @@ def output( oGraphType ) #:nodoc:
             xLink = " -- "
          end
 
-         xOut = self.node_one + xLink + self.node_two
+         # reserved words, they aren't accepted in dot as node name
+         reserved_names = ["node", "edge","graph", "digraph", "subgraph", "strict"]
+
+         xOut = reserved_names.include?(self.node_one) ? "" << "_" + self.node_one : "" << self.node_one
+         xOut = xOut << xLink
+         xOut = reserved_names.include?(self.node_two) ? xOut << "_" + self.node_two : xOut << self.node_two
+         #xOut = self.node_one + xLink + self.node_two
          xAttr = ""
          xSeparator = ""
          @edge_attributes.data.each do |k, v|

lib/graphviz/node.rb

@@ -134,11 +134,16 @@ def pg #:nodoc:
       end
 
       def output #:nodoc:
+         # reserved words, they aren't accepted in dot as node name
+         reserved_names = ["node", "edge","graph", "digraph", "subgraph", "strict"]
          #node_id = @node_id.clone
          #node_id = '"' << node_id << '"' if node_id.match( /^[a-zA-Z_]+[a-zA-Z0-9_\.]*$/ ).nil?
          node_id = GraphViz.escape(@node_id)
 
-         xOut = "" << node_id
+         # add a check to see if the node names are valid
+         # if they aren't is added an _ before
+         # and the print staies the same, because of the label
+         xOut = reserved_names.include?(node_id) ? "" << "_" + node_id : "" << node_id
          xAttr = ""
          xSeparator = ""