// See www.openfst.org for extensive documentation on this weighted
  // finite-state transducer library.
  
  #include <fst/script/fst-class.h>
  #include <fst/script/script-impl.h>
  #include <fst/script/union.h>
  
  namespace fst {
  namespace script {
  
  void Union(MutableFstClass *fst1, const FstClass &fst2) {
    if (!internal::ArcTypesMatch(*fst1, fst2, "Union")) {
      fst1->SetProperties(kError, kError);
      return;
    }
    UnionArgs args(fst1, fst2);
    Apply<Operation<UnionArgs>>("Union", fst1->ArcType(), &args);
  }
  
  REGISTER_FST_OPERATION(Union, StdArc, UnionArgs);
  REGISTER_FST_OPERATION(Union, LogArc, UnionArgs);
  REGISTER_FST_OPERATION(Union, Log64Arc, UnionArgs);
  
  }  // namespace script
  }  // namespace fst