anchor.diff:  
   default(doc_root) -> "src";
   default(out_dir) -> "src";
  -default(module_ext) -> "".
  +default(module_ext) -> "";
  +default(source_ext) -> ".peg".
   
   compile_neo(Source, Target, Config) ->
     case code:which(neotoma) of
  
positive.code:         0 -> Seen;
          _ -> referenced_pegs1(sets:to_list(New), Config,
                                sets:union(New, Seen))
      end.
negative.code: %%          "src" by defualt
  %% module_ext: characters to append to the module's name.
  %%             "" by default
  %% source_ext: extension of peg source files
  -module(rebar_neotoma_compiler).
  
  -export([compile/2]).
  