Lttoolbox API examples

Basic example

This is a simple C++/lttoolbox version of the 'beer' program in Morphological dictionaries

// g++ -I/usr/local/include/lttoolbox-3.2 -I/usr/local/lib -llttoolbox3 lt_beer.cc -o lt-beer

#include <cwchar>
#include <cstdio>
#include <cerrno>
#include <string>
#include <iostream>
#include <list>
#include <set>

#include <lttoolbox/ltstr.h>

// LtLocale::tryToSetLocale()
#include <lttoolbox/lt_locale.h>

// Transducer class
#include <lttoolbox/transducer.h>

// Alphabet class
#include <lttoolbox/alphabet.h>

// Pool class
#include <lttoolbox/pool.h>

// State class
#include <lttoolbox/state.h>

// TransExe class
#include <lttoolbox/trans_exe.h>

int main (int argc, char** argv)
{
  Alphabet alphabet;
  Transducer t;

  // Set locale
  LtLocale::tryToSetLocale();

  // Include symbols into alphabet, keeping the values
  alphabet.includeSymbol(L"<n>");
  alphabet.includeSymbol(L"<sg>");
  alphabet.includeSymbol(L"<pl>");

  int n_sym = alphabet(L"<n>");
  int sg_sym = alphabet(L"<sg>");
  int pl_sym = alphabet(L"<pl>");
  // Initial state
  int initial = t.getInitial();

  // build "beer" manually
  int beer = initial;
  // these are the transitions b:b e:e e:e r:r
  beer = t.insertSingleTransduction(alphabet(L'b',L'b'), beer);
  beer = t.insertSingleTransduction(alphabet(L'e',L'e'), beer);
  beer = t.insertSingleTransduction(alphabet(L'e',L'e'), beer);
  beer = t.insertSingleTransduction(alphabet(L'r',L'r'), beer);
  // these are 0:<n> 0:<sg>
  beer = t.insertSingleTransduction(alphabet(0, n_sym), beer);
  beer = t.insertSingleTransduction(alphabet(0, sg_sym), beer);
  t.setFinal(beer);

  // build "beers" manually
  int beers = t.getInitial();
  beers = t.insertSingleTransduction(alphabet(L'b',L'b'), beers);
  beers = t.insertSingleTransduction(alphabet(L'e',L'e'), beers);
  beers = t.insertSingleTransduction(alphabet(L'e',L'e'), beers);
  beers = t.insertSingleTransduction(alphabet(L'r',L'r'), beers);

  // this transition is s:0
  beers = t.insertSingleTransduction(alphabet(L's', 0), beers);
  beers = t.insertSingleTransduction(alphabet(0, n_sym), beers);
  beers = t.insertSingleTransduction(alphabet(0, pl_sym), beers);
  t.setFinal(beers);

  t.minimize();

  //Rather than try to convert between Transducer and TransExe, we'll
  //just write and read.
  FILE* fst=fopen("beer.fst", "w");
  t.write(fst);
  fclose(fst);
  fst=fopen("beer.fst", "r");

  TransExe te;
  te.read(fst, alphabet);
  fclose(fst);

  Pool<vector<int> > *pool = new Pool<vector<int> >(1, vector<int>(50));
  State *initial_state = new State(pool);
  initial_state->init(te.getInitial());
  State current_state = *initial_state;

  wstring input, output=L"";

  set<Node *> anfinals;
  anfinals.insert(te.getFinals().begin(), te.getFinals().end());

  FILE* in=stdin;

  bool reading=true;
  // This is our runtime: see if the input matches
  while (reading)
  {
    wchar_t val = (wchar_t)fgetwc(in);
    if(val==WEOF||iswspace(val))
    {
      reading=false;
    }
    else
    {
      if (!reading)
      {
        // At the end. We don't need to do anything but
        // leave the loop in this simplistic example
        break;
      }
      else
      {
        current_state.step(val);
        alphabet.getSymbol(input, val);
      }
    }
  }

  if (current_state.isFinal(anfinals))
  {
    // Not used, just don't want it to be empty...
    set<wchar_t> escaped;
    escaped.insert(L'$');
    output = current_state.filterFinals(anfinals, alphabet, escaped);

    wcout << input << output << endl;
  }
  else
  {
    wcout << L"Unrecognised: " << input << endl;
  }

  return 0;
}

we can simplify the building of the transducers like this:

  // build "beer" manually
  int beer = initial;
  // these are the transitions b:b e:e e:e r:r
  beer = t.insertSingleTransduction(alphabet(L'b',L'b'), beer);
  beer = t.insertSingleTransduction(alphabet(L'e',L'e'), beer);
  beer = t.insertSingleTransduction(alphabet(L'e',L'e'), beer);
  beer = t.insertSingleTransduction(alphabet(L'r',L'r'), beer);

  int beersg = beer;
  // these are 0:<n> 0:<sg>
  beersg = t.insertSingleTransduction(alphabet(0, n_sym), beersg);
  beersg = t.insertSingleTransduction(alphabet(0, sg_sym), beersg);
  t.setFinal(beersg);

  // build "beers" manually
  int beerpl = beer;
  beerpl = t.insertSingleTransduction(alphabet(L's', 0), beerpl);
  beerpl = t.insertSingleTransduction(alphabet(0, n_sym), beerpl);
  beerpl = t.insertSingleTransduction(alphabet(0, pl_sym), beerpl);
  t.setFinal(beerpl);

Writing/reading several transducers to the same file

// g++ -o test test.cc -I/home/fran/local/include/lttoolbox-3.2 -L/home/fran/local/lib -llttoolbox3 

#include <cwchar>
#include <cstdio>
#include <iostream>
#include <set>

#include <lttoolbox/ltstr.h>
#include <lttoolbox/lt_locale.h>
#include <lttoolbox/transducer.h>
#include <lttoolbox/alphabet.h>
#include <lttoolbox/regexp_compiler.h>
#include <lttoolbox/compression.h>

int main (int argc, char** argv)
{
  map<int, Transducer> patterns;
  Alphabet a;
  RegexpCompiler re;

  LtLocale::tryToSetLocale();

  FILE *output = stdout;
  FILE *fst = fopen(argv[1], "w+");

  // Build transducers

  a.includeSymbol(L"<n>");
  
  re.initialize(&a);  
  re.compile(L"foo");
  patterns[1] = re.getTransducer();
  re.initialize(&a);  
  re.compile(L"bar");
  patterns[2] = re.getTransducer();
  re.initialize(&a);  
  re.compile(L"baz");
  patterns[3] = re.getTransducer();

  // Write out the transducers

  a.write(fst);
  Compression::multibyte_write(patterns.size(), fst);
  fwprintf(output, L"Patterns: %d, Alphabet: %d\n", patterns.size(), a.size());

  for(map<int, Transducer>::iterator it = patterns.begin(); it != patterns.end(); it++)
  {
    wchar_t buf[50];
    memset(buf, '\0', sizeof(buf));
    swprintf(buf, 50, L"%d", it->first);
    wstring id(buf);
    fwprintf(output, L"= %S =============================\n", id.c_str());
    it->second.show(a, output);
  
    Compression::wstring_write(id, fst);
    it->second.write(fst);
  }

  fclose(fst);
  fwprintf(output, L"\n\n");

  // Now read in the transducers that we have written out, one by one.

  FILE *new_fst = fopen(argv[1], "r");
  Alphabet new_alphabet;
  map<wstring, Transducer> transducers;

  new_alphabet.read(new_fst);
  int len = Compression::multibyte_read(new_fst);  

  while(len > 0)
  { 
    int len2 = Compression::multibyte_read(new_fst);
    wstring name = L"";
    while(len2 > 0)
    {
      name += static_cast<wchar_t>(Compression::multibyte_read(new_fst));
      len2--;
    }
    transducers[name].read(new_fst);
    len--;
  }
  fwprintf(output, L"Patterns: %d, Alphabet: %d\n", transducers.size(), new_alphabet.size());

  for(map<wstring, Transducer>::iterator it = transducers.begin(); it != transducers.end(); it++)
  {
    fwprintf(output, L"= %S =============================\n", it->first.c_str());
    it->second.minimize();
    it->second.show(a, output);
  }

  fclose(new_fst);
  
  return 0;
}