cdec -A "LanguageModelFsa lm.gz" works

git-svn-id: https://ws10smt.googlecode.com/svn/trunk@490 ec762483-ff6d-05da-a07a-a48fb63a330f

16 files changed, 213 insertions, 84 deletions

diff --git a/decoder/apply_fsa_models.cc b/decoder/apply_fsa_models.cc
index 27773b0d..01de62d3 100755
--- a/decoder/apply_fsa_models.cc
+++ b/decoder/apply_fsa_models.cc
@@ -1,6 +1,7 @@
 #include "apply_fsa_models.h"
 #include "hg.h"
 #include "ff_fsa_dynamic.h"
+#include "ff_from_fsa.h"
 #include "feature_vector.h"
 #include "stringlib.h"
 #include "apply_models.h"
@@ -27,7 +28,9 @@ struct ApplyFsa {
   }
   void ApplyBottomUp() {
     assert(cfg.IsBottomUp());
-    vector<const FeatureFunction*> ffs;
+    FeatureFunctionFromFsa<FsaFeatureFunctionFwd> buff(&fsa);
+    buff.Init(); // mandatory to call this (normally factory would do it)
+    vector<const FeatureFunction*> ffs(1,&buff);
     ModelSet models(weights, ffs);
     IntersectionConfiguration i(cfg.BottomUpAlgorithm(),cfg.pop_limit);
     ApplyModelSet(ih,smeta,models,i,oh);
diff --git a/decoder/apply_fsa_models.h b/decoder/apply_fsa_models.h
index 64ebab39..3dce5e82 100755
--- a/decoder/apply_fsa_models.h
+++ b/decoder/apply_fsa_models.h
@@ -23,7 +23,10 @@ struct ApplyFsaBy {
   int algorithm;
   std::string name() const;
   friend inline std::ostream &operator << (std::ostream &o,ApplyFsaBy const& c) {
-    return o << c.name();
+    o << c.name();
+    if (c.algorithm==BU_CUBE)
+      o << "("<<c.pop_limit<<")";
+    return o;
   }
   explicit ApplyFsaBy(int alg, int poplimit=200);
   ApplyFsaBy(std::string const& name, int poplimit=200);
diff --git a/decoder/apply_models.cc b/decoder/apply_models.cc
index 700296da..635f1a9c 100644
--- a/decoder/apply_models.cc
+++ b/decoder/apply_models.cc
@@ -405,10 +405,10 @@ void ApplyModelSet(const Hypergraph& in,
                    const IntersectionConfiguration& config,
                    Hypergraph* out) {
   //force exhaustive if there's no state req. for model
-  if (models.stateless() || config.algorithm == 0) {
+  if (models.stateless() || config.algorithm == IntersectionConfiguration::FULL) {
     NoPruningRescorer ma(models, smeta, in, out); // avoid overhead of best-first when no state
     ma.Apply();
-  } else if (config.algorithm == 1) {
+  } else if (config.algorithm == IntersectionConfiguration::CUBE) {
     int pl = config.pop_limit;
     const int max_pl_for_large=50;
     if (pl > max_pl_for_large && in.nodes_.size() > 80000) {
diff --git a/decoder/cdec.cc b/decoder/cdec.cc
index 72f0b95e..29070a69 100644
--- a/decoder/cdec.cc
+++ b/decoder/cdec.cc
@@ -68,7 +68,7 @@ inline string str(char const* name,po::variables_map const& conf) {
 shared_ptr<FeatureFunction> make_ff(string const& ffp,bool verbose_feature_functions,char const* pre="") {
   string ff, param;
   SplitCommandAndParam(ffp, &ff, &param);
-  cerr << "Feature: " << ff;
+  cerr << pre << "feature: " << ff;
   if (param.size() > 0) cerr << " (with config parameters '" << param << "')\n";
   else cerr << " (no config parameters)\n";
   shared_ptr<FeatureFunction> pf = ff_registry.Create(ff, param);
@@ -470,7 +470,9 @@ int main(int argc, char** argv) {
   vector<shared_ptr<FeatureFunction> > pffs,prelm_only_ffs;
   vector<const FeatureFunction*> late_ffs,prelm_ffs;
   if (conf.count("feature_function") > 0) {
-    const vector<string>& add_ffs = conf["feature_function"].as<vector<string> >();
+    vector<string> add_ffs;
+//    const vector<string>& add_ffs = conf["feature_function"].as<vector<string> >();
+    store_conf(conf,"feature_function",&add_ffs);
     for (int i = 0; i < add_ffs.size(); ++i) {
       pffs.push_back(make_ff(add_ffs[i],verbose_feature_functions));
       FeatureFunction const* p=pffs.back().get();
@@ -484,7 +486,9 @@ int main(int argc, char** argv) {
     }
   }
   if (conf.count("prelm_feature_function") > 0) {
-    const vector<string>& add_ffs = conf["prelm_feature_function"].as<vector<string> >();
+    vector<string> add_ffs;
+    store_conf(conf,"prelm_feature_function",&add_ffs);
+//    const vector<string>& add_ffs = conf["prelm_feature_function"].as<vector<string> >();
     for (int i = 0; i < add_ffs.size(); ++i) {
       prelm_only_ffs.push_back(make_ff(add_ffs[i],verbose_feature_functions,"prelm-only "));
       prelm_ffs.push_back(prelm_only_ffs.back().get());
@@ -494,12 +498,16 @@ int main(int argc, char** argv) {
   vector<shared_ptr<FsaFeatureFunction> > fsa_ffs;
   vector<string> fsa_names;
   store_conf(conf,"fsa_feature_function",&fsa_names);
+  for (int i=0;i<fsa_names.size();++i)
+    fsa_ffs.push_back(make_fsa_ff(fsa_names[i],verbose_feature_functions,"FSA "));
   if (fsa_ffs.size()>1) {
     //FIXME: support N fsa ffs.
     cerr<<"Only the first fsa FF will be used (FIXME).\n";
-    fsa_names.resize(1);
-    for (int i=0;i<fsa_names.size();++i)
-      fsa_ffs.push_back(make_fsa_ff(fsa_names[i],verbose_feature_functions,"FSA "));
+    fsa_ffs.resize(1);
+  }
+  if (!fsa_ffs.empty()) {
+    cerr<<"FSA: ";
+    show_all_features(fsa_ffs,feature_weights,cerr,cerr,true,true);
   }
 
   if (late_freeze) {
@@ -646,7 +654,6 @@ int main(int argc, char** argv) {
     maybe_prune(forest,conf,"beam_prune","density_prune","+LM",srclen);
 
 
-
     if (!fsa_ffs.empty()) {
       Timer t("Target FSA rescoring:");
       if (!has_late_models)
@@ -654,6 +661,7 @@ int main(int argc, char** argv) {
       Hypergraph fsa_forest;
       assert(fsa_ffs.size()==1);
       ApplyFsaBy cfg(str("apply_fsa_by",conf),pop_limit);
+      cerr << "FSA rescoring with "<<cfg<<" "<<fsa_ffs[0]->describe()<<endl;
       ApplyFsaModels(forest,smeta,*fsa_ffs[0],feature_weights,cfg,&fsa_forest);
       forest.swap(fsa_forest);
       forest.Reweight(feature_weights);
diff --git a/decoder/cdec_ff.cc b/decoder/cdec_ff.cc
index 1ef50eb1..98d4711f 100644
--- a/decoder/cdec_ff.cc
+++ b/decoder/cdec_ff.cc
@@ -13,21 +13,23 @@
 #include "ff_register.h"
 
 void register_feature_functions() {
-  RegisterFsaImpl<SameFirstLetter>(true,false);
-  RegisterFsaImpl<LongerThanPrev>(true,false);
-  RegisterFF<LanguageModel>();
-  RegisterFsaImpl<LanguageModelFsa>(true,false); // same as LM but using fsa wrapper
-  ff_registry.Register("LanguageModelFsaDynamic",new FFFactory<FeatureFunctionFromFsa<FsaFeatureFunctionDynamic<LanguageModelFsa> > >); // test correctness of FsaFeatureFunctionDynamic erasure
+  //TODO: these are worthless example target FSA ffs.  remove later
+  RegisterFsaImpl<SameFirstLetter>(true);
+  RegisterFsaImpl<LongerThanPrev>(true);
+  RegisterFsaImpl<ShorterThanPrev>(true);
+//  ff_registry.Register("LanguageModelFsaDynamic",new FFFactory<FeatureFunctionFromFsa<FsaFeatureFunctionDynamic<LanguageModelFsa> > >); // to test correctness of FsaFeatureFunctionDynamic erasure
+  RegisterFsaDynToFF<LanguageModelFsa>();
+  RegisterFsaImpl<LanguageModelFsa>(true); // same as LM but using fsa wrapper
   RegisterFsaDynToFF<SameFirstLetter>();
 
+  RegisterFF<LanguageModel>();
+
   RegisterFF<WordPenalty>();
   RegisterFF<SourceWordPenalty>();
   RegisterFF<ArityPenalty>();
   RegisterFF<BLEUModel>();
 
-  //TODO: worthless example target FSA ffs.  remove later
   ff_registry.Register(new FFFactory<WordPenaltyFromFsa>); // same as WordPenalty, but implemented using ff_fsa
-  ff_registry.Register(new FFFactory<FeatureFunctionFromFsa<ShorterThanPrev> >);
 
   //TODO: use for all features the new Register which requires static FF::usage(false,false) give name
 #ifdef HAVE_RANDLM
diff --git a/decoder/ff.cc b/decoder/ff.cc
index 5c52ca2b..68249b42 100644
--- a/decoder/ff.cc
+++ b/decoder/ff.cc
@@ -36,47 +36,10 @@ Features FeatureFunction::single_feature(WordID feat) {
 }
 
 Features ModelSet::all_features(std::ostream *warn,bool warn0) {
-  typedef Features FFS;
-  FFS ffs;
-#define WARNFF(x) do { if (warn) { *warn << "WARNING: "<< x ; *warn<<endl; } } while(0)
-  typedef std::map<WordID,string> FFM;
-  FFM ff_from;
-  for (unsigned i=0;i<models_.size();++i) {
-    FeatureFunction const& ff=*models_[i];
-    string const& ffname=ff.name_;
-    FFS si=ff.features();
-    if (si.empty()) {
-      WARNFF(ffname<<" doesn't yet report any feature IDs - either supply feature weight, or use --no_freeze_feature_set, or implement features() method");
-    }
-    unsigned n0=0;
-    for (unsigned j=0;j<si.size();++j) {
-      WordID fid=si[j];
-      if (!fid) ++n0;
-      if (fid >= weights_.size())
-        weights_.resize(fid+1);
-      if (warn0 || fid) {
-        pair<FFM::iterator,bool> i_new=ff_from.insert(FFM::value_type(fid,ffname));
-        if (i_new.second) {
-          if (fid)
-            ffs.push_back(fid);
-          else
-            WARNFF("Feature id 0 for "<<ffname<<" (models["<<i<<"]) - probably no weight provided.  Don't freeze feature ids to see the name");
-        } else {
-          WARNFF(ffname<<" (models["<<i<<"]) tried to define feature "<<FD::Convert(fid)<<" already defined earlier by "<<i_new.first->second);
-        }
-      }
-    }
-    if (n0)
-      WARNFF(ffname<<" (models["<<i<<"]) had "<<n0<<" unused features (--no_freeze_feature_set to see them)");
-  }
-  return ffs;
-#undef WARNFF
+  return ::all_features(models_,weights_,warn,warn0);
 }
 
-void ModelSet::show_features(std::ostream &out,std::ostream &warn,bool warn_zero_wt)
-{
-  typedef Features FFS;
-  FFS ffs=all_features(&warn,warn_zero_wt);
+void show_features(Features const& ffs,DenseWeightVector const& weights_,std::ostream &out,std::ostream &warn,bool warn_zero_wt) {
   out << "Weight  Feature\n";
   for (unsigned i=0;i<ffs.size();++i) {
     WordID fid=ffs[i];
@@ -86,7 +49,12 @@ void ModelSet::show_features(std::ostream &out,std::ostream &warn,bool warn_zero
       warn<<"WARNING: "<<fname<<" has 0 weight."<<endl;
     out << wt << "  " << fname<<endl;
   }
+}
 
+void ModelSet::show_features(std::ostream &out,std::ostream &warn,bool warn_zero_wt)
+{
+//  ::show_features(all_features(),weights_,out,warn,warn_zero_wt);
+  show_all_features(models_,weights_,out,warn,warn_zero_wt,warn_zero_wt);
 }
 
 // Hiero and Joshua use log_10(e) as the value, so I do to
diff --git a/decoder/ff.h b/decoder/ff.h
index e3bfe392..fe4411cd 100644
--- a/decoder/ff.h
+++ b/decoder/ff.h
@@ -13,6 +13,7 @@
 #include <cstring>
 #include "fdict.h"
 #include "hg.h"
+#include "feature_vector.h"
 
 class SentenceMetadata;
 class FeatureFunction;  // see definition below
@@ -54,7 +55,7 @@ public:
   // returns the number of bytes of context that this feature function will
   // (maximally) use.  By default, 0 ("stateless" models in Hiero/Joshua).
   // NOTE: this value is fixed for the instance of your class, you cannot
-  // use different amounts of memory for different nodes in the forest.
+  // use different amounts of memory for different nodes in the forest.  this will be read as soon as you create a ModelSet, then fixed forever on
   inline int NumBytesContext() const { return state_size_; }
 
   // Compute the feature values and (if this applies) the estimates of the
@@ -196,6 +197,52 @@ class ArityPenalty : public FeatureFunction {
   const double value_;
 };
 
+void show_features(Features const& features,DenseWeightVector const& weights,std::ostream &out,std::ostream &warn,bool warn_zero_wt=true); //show features and weights
+
+template <class FFp>
+Features all_features(std::vector<FFp> const& models_,DenseWeightVector &weights_,std::ostream *warn=0,bool warn_fid_0=false) {
+  using namespace std;
+  Features ffs;
+#define WARNFF(x) do { if (warn) { *warn << "WARNING: "<< x << endl; } } while(0)
+  typedef map<WordID,string> FFM;
+  FFM ff_from;
+  for (unsigned i=0;i<models_.size();++i) {
+    string const& ffname=models_[i]->name_;
+    Features si=models_[i]->features();
+    if (si.empty()) {
+      WARNFF(ffname<<" doesn't yet report any feature IDs - either supply feature weight, or use --no_freeze_feature_set, or implement features() method");
+    }
+    unsigned n0=0;
+    for (unsigned j=0;j<si.size();++j) {
+      WordID fid=si[j];
+      if (!fid) ++n0;
+      if (fid >= weights_.size())
+        weights_.resize(fid+1);
+      if (warn_fid_0 || fid) {
+        pair<FFM::iterator,bool> i_new=ff_from.insert(FFM::value_type(fid,ffname));
+        if (i_new.second) {
+          if (fid)
+            ffs.push_back(fid);
+          else
+            WARNFF("Feature id 0 for "<<ffname<<" (models["<<i<<"]) - probably no weight provided.  Don't freeze feature ids to see the name");
+        } else {
+          WARNFF(ffname<<" (models["<<i<<"]) tried to define feature "<<FD::Convert(fid)<<" already defined earlier by "<<i_new.first->second);
+        }
+      }
+    }
+    if (n0)
+      WARNFF(ffname<<" (models["<<i<<"]) had "<<n0<<" unused features (--no_freeze_feature_set to see them)");
+  }
+  return ffs;
+#undef WARNFF
+}
+
+template <class FFp>
+void show_all_features(std::vector<FFp> const& models_,DenseWeightVector &weights_,std::ostream &out,std::ostream &warn,bool warn_fid_0=true,bool warn_zero_wt=true) {
+  return show_features(all_features(models_,weights_,&warn,warn_fid_0),weights_,out,warn,warn_zero_wt);
+}
+
+
 // this class is a set of FeatureFunctions that can be used to score, rescore,
 // etc. a (translation?) forest
 class ModelSet {
@@ -224,7 +271,8 @@ class ModelSet {
 
   bool stateless() const { return !state_size_; }
   Features all_features(std::ostream *warnings=0,bool warn_fid_zero=false); // this will warn about duplicate features as well (one function overwrites the feature of another).  also resizes weights_ so it is large enough to hold the (0) weight for the largest reported feature id.  since 0 is a NULL feature id, it's never included.  if warn_fid_zero, then even the first 0 id is
-  void show_features(std::ostream &out,std::ostream &warn,bool warn_zero_wt=true); //show features and weights
+  void show_features(std::ostream &out,std::ostream &warn,bool warn_zero_wt=true);
+
  private:
   std::vector<const FeatureFunction*> models_;
   std::vector<double> weights_;
diff --git a/decoder/ff_factory.cc b/decoder/ff_factory.cc
index 767cc675..25d37648 100644
--- a/decoder/ff_factory.cc
+++ b/decoder/ff_factory.cc
@@ -17,10 +17,9 @@ void UntypedFactoryRegistry::clear() {
   reg_.clear();
 }
 
-bool UntypedFactoryRegistry::parse_debug(std::string & param) {
+bool UntypedFactoryRegistry::parse_debug(std::string & p) {
   int pl=debug_pre.size();
   bool space=false;
-  std::string p=param;
   bool debug=match_begin(p,debug_pre)&&
     (p.size()==pl || (space=(p[pl]==' ')));
   if (debug)
@@ -70,13 +69,7 @@ FsaFFRegistry fsa_ff_registry;
 FFRegistry ff_registry;
 
 /*
-namespace {
-struct null_deleter
-{
-  template <class F>
-  void operator()(F const& f) const {  }
-};
-
+#include "null_deleter.h"
 boost::shared_ptr<FsaFFRegistry> global_fsa_ff_registry(&fsa_ff_registry,null_deleter());
 boost::shared_ptr<FFRegistry> global_ff_registry(&ff_registry,null_deleter());
 */
diff --git a/decoder/ff_from_fsa.h b/decoder/ff_from_fsa.h
index ec1a28fa..26aca048 100755
--- a/decoder/ff_from_fsa.h
+++ b/decoder/ff_from_fsa.h
@@ -28,7 +28,12 @@ class FeatureFunctionFromFsa : public FeatureFunction {
   typedef WordID *W;
   typedef WordID const* WP;
 public:
-  FeatureFunctionFromFsa(std::string const& param) : ff(param) {
+  template <class I>
+  FeatureFunctionFromFsa(I const& param) : ff(param) {
+    debug_=true; // because factory won't set until after we construct.
+  }
+  template <class I>
+  FeatureFunctionFromFsa(I & param) : ff(param) {
     debug_=true; // because factory won't set until after we construct.
   }
 
@@ -234,7 +239,7 @@ public:
     assert(left_end(w2,w2+2)==w2+1);
   }
 
-  // override from FeatureFunction; should be called by factory after constructor.
+  // override from FeatureFunction; should be called by factory after constructor.  we'll also call in our own ctor
   void Init() {
     ff.Init();
     ff.sync();
@@ -246,6 +251,7 @@ public:
     SetStateSize(ssz+state_offset);
     assert(!ssz == !M); // no fsa state <=> markov order 0
   }
+
 private:
   Impl ff;
   int M; // markov order (ctx len)
diff --git a/decoder/ff_fsa.h b/decoder/ff_fsa.h
index 6416151c..18e90bf1 100755
--- a/decoder/ff_fsa.h
+++ b/decoder/ff_fsa.h
@@ -91,6 +91,12 @@ struct FsaFeatureFunctionBase : public FsaFeatureFunctionData {
 public:
   int fid_; // you can have more than 1 feature of course.
 
+  std::string describe() const {
+    std::ostringstream o;
+    o<<*this;
+    return o.str();
+  }
+
   // can override to different return type, e.g. just return feats:
   Featval describe_features(FeatureVector const& feats) const {
     return feats.get(fid_);
diff --git a/decoder/ff_fsa_data.h b/decoder/ff_fsa_data.h
index 2f0c55b8..e60bce45 100755
--- a/decoder/ff_fsa_data.h
+++ b/decoder/ff_fsa_data.h
@@ -20,7 +20,6 @@ struct FsaFeatureFunctionData
   FsaFeatureFunctionData *sync_to_;
 
   void sync() const { // call this if you modify any fields after your constructor is done
-
     if (sync_to_) {
       DBGINIT("sync to "<<*sync_to_);
       *sync_to_=*this;
@@ -31,7 +30,7 @@ struct FsaFeatureFunctionData
   }
 
   friend std::ostream &operator<<(std::ostream &o,FsaFeatureFunctionData const& d) {
-    o << "[FSA "<<d.name_<<" features="<<FD::Convert(d.features_)<<" start=";
+    o << "[FSA "<<d.name_<<" features="<<FD::Convert(d.features_)<<" state_bytes="<<d.state_bytes()<<" end='"<<d.end_phrase()<<"' start=";
     d.print_state(o,d.start_state());
     o<<"]";
     return o;
@@ -62,7 +61,7 @@ struct FsaFeatureFunctionData
   int n_features() const {
     return features_.size();
   }
-  int state_bytes() const { return ssz; } // or override this
+  int state_bytes() const { return ssz; }
   void const* start_state() const {
     return start.begin();
   }
diff --git a/decoder/ff_fsa_dynamic.h b/decoder/ff_fsa_dynamic.h
index d03fddee..6f75bbe5 100755
--- a/decoder/ff_fsa_dynamic.h
+++ b/decoder/ff_fsa_dynamic.h
@@ -38,6 +38,8 @@ struct FsaFeatureFunction : public FsaFeatureFunctionData {
   virtual void print_state(std::ostream &o,void const*state) const {
     FsaFeatureFunctionData::print_state(o,state);
   }
+  virtual std::string describe() const { return "[FSA unnamed_dynamic_fsa_feature]"; }
+
   //end_phrase()
   virtual ~FsaFeatureFunction() {}
 
@@ -62,6 +64,10 @@ struct FsaFeatureFunctionDynamic : public FsaFeatureFunction {
   }
   int markov_order() const { return d().markov_order(); }
 
+  std::string describe() const   {
+    return d().describe();
+  }
+
   virtual void ScanAccum(SentenceMetadata const& smeta,Hypergraph::Edge const& edge,
                         WordID w,void const* state,void *next_state,Accum *a) const {
     return d().ScanAccum(smeta,edge,w,state,next_state,a);
@@ -105,19 +111,96 @@ struct FsaFeatureFunctionDynamic : public FsaFeatureFunction {
   }
 
   virtual void Init() {
-    d().sync_to_=(FsaFeatureFunction*)this;
+    d().sync_to_=(FsaFeatureFunctionData*)this;
     d().Init();
     d().sync();
   }
 
-  FsaFeatureFunctionDynamic(std::string const& param) : impl(param) {
+  template <class I>
+  FsaFeatureFunctionDynamic(I const& param) : impl(param) {
     Init();
   }
 private:
   Impl impl;
+};
+
+// constructor takes ptr or shared_ptr to Impl, otherwise same as above - note: not virtual
+template <class Impl>
+struct FsaFeatureFunctionPimpl : public FsaFeatureFunctionData {
+  typedef boost::shared_ptr<Impl const> Pimpl;
+  static const bool simple_phrase_score=Impl::simple_phrase_score;
+  Impl const& d() const { return *p_; }
+  int markov_order() const { return d().markov_order(); }
+
+  std::string describe() const   {
+    return d().describe();
+  }
+
+  void ScanAccum(SentenceMetadata const& smeta,Hypergraph::Edge const& edge,
+                        WordID w,void const* state,void *next_state,Accum *a) const {
+    return d().ScanAccum(smeta,edge,w,state,next_state,a);
+  }
+
+  void ScanPhraseAccum(SentenceMetadata const& smeta,Hypergraph::Edge const & edge,
+                              WordID const* i, WordID const* end,
+                              void const* state,void *next_state,Accum *a) const {
+    return d().ScanPhraseAccum(smeta,edge,i,end,state,next_state,a);
+  }
+
+  void ScanPhraseAccumOnly(SentenceMetadata const& smeta,Hypergraph::Edge const& edge,
+                           WordID const* i, WordID const* end,
+                           void const* state,Accum *a) const {
+    return d().ScanPhraseAccumOnly(smeta,edge,i,end,state,a);
+  }
+
+  void *ScanPhraseAccumBounce(SentenceMetadata const& smeta,Hypergraph::Edge const& edge,WordID const* i, WordID const* end,void *cs,void *ns,Accum *a) const {
+    return d().ScanPhraseAccumBounce(smeta,edge,i,end,cs,ns,a);
+  }
 
+  int early_score_words(SentenceMetadata const& smeta,Hypergraph::Edge const& edge,WordID const* i, WordID const* end,Accum *accum) const {
+    return d().early_score_words(smeta,edge,i,end,accum);
+  }
+
+  static std::string usage(bool param,bool verbose) {
+    return Impl::usage(param,verbose);
+  }
+
+  std::string usage_v(bool param,bool verbose) const {
+    return Impl::usage(param,verbose);
+  }
+
+  void print_state(std::ostream &o,void const*state) const {
+    return d().print_state(o,state);
+  }
+
+#if 0
+  // this and Init() don't touch p_ because we want to leave the original alone.
+      void init_name_debug(std::string const& n,bool debug) {
+    FsaFeatureFunctionData::init_name_debug(n,debug);
+  }
+#endif
+  void Init() {
+    p_=hold_pimpl_.get();
+#if 0
+    d().sync_to_=static_cast<FsaFeatureFunctionData*>(this);
+    d().Init();
+#endif
+    *static_cast<FsaFeatureFunctionData*>(this)=d();
+  }
+
+  FsaFeatureFunctionPimpl(Impl const* const p) : hold_pimpl_(p,null_deleter()) {
+    Init();
+  }
+  FsaFeatureFunctionPimpl(Pimpl const& p) : hold_pimpl_(p) {
+    Init();
+  }
+private:
+  Impl const* p_;
+  Pimpl hold_pimpl_;
 };
 
+typedef FsaFeatureFunctionPimpl<FsaFeatureFunction> FsaFeatureFunctionFwd; // allow ff_from_fsa for an existing dynamic-type ff (as opposed to usual register a wrapped known-type FSA in ff_register, which is more efficient)
+//typedef FsaFeatureFunctionDynamic<FsaFeatureFunctionFwd> DynamicFsaFeatureFunctionFwd;  //if you really need to have a dynamic fsa facade that's also a dynamic fsa
 
 //TODO: combine 2 (or N) FsaFeatureFunction (type erased)
 
diff --git a/decoder/ff_register.h b/decoder/ff_register.h
index f0828ca3..70e1c1c6 100755
--- a/decoder/ff_register.h
+++ b/decoder/ff_register.h
@@ -36,11 +36,15 @@ inline void RegisterFF() {
 }
 
 template <class FsaImpl>
-inline void RegisterFsaDynToFF(bool prefix=true) {
+inline void RegisterFsaDynToFF(std::string name,bool prefix=true) {
   typedef FsaFeatureFunctionDynamic<FsaImpl> DynFsa;
-  std::string name=FsaImpl::usage(false,false);
   ff_registry.Register(prefix?"DynamicFsa"+name:name,new FFFactory<FeatureFunctionFromFsa<DynFsa> >);
 }
 
+template <class FsaImpl>
+inline void RegisterFsaDynToFF(bool prefix=true) {
+  RegisterFsaDynToFF<FsaImpl>(FsaImpl::usage(false,false),prefix);
+}
+
 
 #endif
diff --git a/decoder/filelib.h b/decoder/filelib.h
index af66dd05..4da4bc4f 100644
--- a/decoder/filelib.h
+++ b/decoder/filelib.h
@@ -8,6 +8,7 @@
 #include <boost/shared_ptr.hpp>
 #include <stdexcept>
 #include "gzstream.h"
+#include "null_deleter.h"
 
 bool FileExists(const std::string& file_name);
 bool DirectoryExists(const std::string& dir_name);
@@ -15,9 +16,6 @@ bool DirectoryExists(const std::string& dir_name);
 // reads from standard in if filename is -
 // uncompresses if file ends with .gz
 // otherwise, reads from a normal file
-struct file_null_deleter {
-    void operator()(void*) const {}
-};
 
 template <class Stream>
 struct BaseFile {
@@ -57,7 +55,7 @@ class ReadFile : public BaseFile<std::istream> {
   void Init(const std::string& filename) {
     filename_=filename;
     if (is_std()) {
-      ps_=PS(&std::cin,file_null_deleter());
+      ps_=PS(&std::cin,null_deleter());
     } else {
       if (!FileExists(filename)) {
         std::cerr << "File does not exist: " << filename << std::endl;
@@ -85,7 +83,7 @@ class WriteFile : public BaseFile<std::ostream> {
   void Init(const std::string& filename) {
     filename_=filename;
     if (is_std()) {
-      ps_=PS(&std::cout,file_null_deleter());
+      ps_=PS(&std::cout,null_deleter());
     } else {
       char const* file=filename_.c_str(); // just in case the gzstream keeps using the filename for longer than the constructor, e.g. inflateReset2.  warning in valgrind that I'm hoping will disappear - it makes no sense.
       ps_=PS(EndsWith(filename, ".gz") ?
diff --git a/decoder/fsa-hiero.ini b/decoder/fsa-hiero.ini
index 19f88421..3eb8b3d2 100755
--- a/decoder/fsa-hiero.ini
+++ b/decoder/fsa-hiero.ini
@@ -1,7 +1,6 @@
 formalism=scfg
+fsa_feature_function=LanguageModelFsa debug lm.gz -n LM
 scfg_extra_glue_grammar=glue-lda.scfg
-feature_function=ShorterThanPrev debug
-feature_function=LongerThanPrev
 grammar=grammar.hiero
 show_tree_structure=true
 weights=weights.hiero
diff --git a/decoder/null_deleter.h b/decoder/null_deleter.h
new file mode 100755
index 00000000..082ab453
--- /dev/null
+++ b/decoder/null_deleter.h
@@ -0,0 +1,9 @@
+#ifndef NULL_DELETER_H
+#define NULL_DELETER_H
+
+struct null_deleter {
+    void operator()(void*) const {}
+    void operator()(void const*) const {}
+};
+
+#endif