mosesdecoder/phrase-extract/extract-ordering-main.cpp
2014-01-06 18:03:38 +00:00

690 lines
24 KiB
C++

/*
* extract.cpp
* Modified by: Rohit Gupta CDAC, Mumbai, India
* on July 15, 2012 to implement parallel processing
* Modified by: Nadi Tomeh - LIMSI/CNRS
* Machine Translation Marathon 2010, Dublin
*/
#include <cstdio>
#include <iostream>
#include <fstream>
#include <vector>
#include <string>
#include <stdlib.h>
#include <assert.h>
#include <cstring>
#include <sstream>
#include <map>
#include <set>
#include <vector>
#include "SafeGetline.h"
#include "SentenceAlignment.h"
#include "tables-core.h"
#include "InputFileStream.h"
#include "OutputFileStream.h"
#include "PhraseExtractionOptions.h"
using namespace std;
using namespace MosesTraining;
namespace MosesTraining
{
const long int LINE_MAX_LENGTH = 500000 ;
// HPhraseVertex represents a point in the alignment matrix
typedef pair <int, int> HPhraseVertex;
// Phrase represents a bi-phrase; each bi-phrase is defined by two points in the alignment matrix:
// bottom-left and top-right
typedef pair<HPhraseVertex, HPhraseVertex> HPhrase;
// HPhraseVector is a vector of HPhrases
typedef vector < HPhrase > HPhraseVector;
// SentenceVertices represents, from all extracted phrases, all vertices that have the same positioning
// The key of the map is the English index and the value is a set of the source ones
typedef map <int, set<int> > HSentenceVertices;
REO_POS getOrientWordModel(SentenceAlignment &, REO_MODEL_TYPE, bool, bool,
int, int, int, int, int, int, int,
bool (*)(int, int), bool (*)(int, int));
REO_POS getOrientPhraseModel(SentenceAlignment &, REO_MODEL_TYPE, bool, bool,
int, int, int, int, int, int, int,
bool (*)(int, int), bool (*)(int, int),
const HSentenceVertices &, const HSentenceVertices &);
REO_POS getOrientHierModel(SentenceAlignment &, REO_MODEL_TYPE, bool, bool,
int, int, int, int, int, int, int,
bool (*)(int, int), bool (*)(int, int),
const HSentenceVertices &, const HSentenceVertices &,
const HSentenceVertices &, const HSentenceVertices &,
REO_POS);
void insertVertex(HSentenceVertices &, int, int);
void insertPhraseVertices(HSentenceVertices &, HSentenceVertices &, HSentenceVertices &, HSentenceVertices &,
int, int, int, int);
string getOrientString(REO_POS, REO_MODEL_TYPE);
bool ge(int, int);
bool le(int, int);
bool lt(int, int);
bool isAligned (SentenceAlignment &, int, int);
int sentenceOffset = 0;
std::vector<std::string> Tokenize(const std::string& str,
const std::string& delimiters = " \t");
bool flexScoreFlag = false;
}
namespace MosesTraining
{
class ExtractTask
{
public:
ExtractTask(size_t id, SentenceAlignment &sentence,PhraseExtractionOptions &initoptions, Moses::OutputFileStream &extractFileOrientation)
:m_sentence(sentence),
m_options(initoptions),
m_extractFileOrientation(extractFileOrientation)
{}
void Run();
private:
void extract(SentenceAlignment &);
void addPhrase(SentenceAlignment &, int, int, int, int, string &);
void writePhrasesToFile();
SentenceAlignment &m_sentence;
const PhraseExtractionOptions &m_options;
Moses::OutputFileStream &m_extractFileOrientation;
};
}
int main(int argc, char* argv[])
{
cerr << "PhraseExtract v1.4, written by Philipp Koehn\n"
<< "phrase extraction from an aligned parallel corpus\n";
if (argc < 6) {
cerr << "syntax: extract en de align extract max-length [orientation [ --model [wbe|phrase|hier]-[msd|mslr|mono] ] ";
cerr<<"| --OnlyOutputSpanInfo | --NoTTable | --GZOutput | --IncludeSentenceId | --SentenceOffset n | --InstanceWeights filename ]\n";
exit(1);
}
Moses::OutputFileStream extractFileOrientation;
const char* const &fileNameE = argv[1];
const char* const &fileNameF = argv[2];
const char* const &fileNameA = argv[3];
const string fileNameExtract = string(argv[4]);
PhraseExtractionOptions options(atoi(argv[5]));
for(int i=6; i<argc; i++) {
if (strcmp(argv[i],"--OnlyOutputSpanInfo") == 0) {
options.initOnlyOutputSpanInfo(true);
} else if (strcmp(argv[i],"orientation") == 0 || strcmp(argv[i],"--Orientation") == 0) {
options.initOrientationFlag(true);
} else if (strcmp(argv[i],"--FlexibilityScore") == 0) {
options.initFlexScoreFlag(true);
} else if (strcmp(argv[i],"--NoTTable") == 0) {
options.initTranslationFlag(false);
} else if (strcmp(argv[i], "--IncludeSentenceId") == 0) {
options.initIncludeSentenceIdFlag(true);
} else if (strcmp(argv[i], "--SentenceOffset") == 0) {
if (i+1 >= argc || argv[i+1][0] < '0' || argv[i+1][0] > '9') {
cerr << "extract: syntax error, used switch --SentenceOffset without a number" << endl;
exit(1);
}
sentenceOffset = atoi(argv[++i]);
} else if (strcmp(argv[i], "--GZOutput") == 0) {
options.initGzOutput(true);
} else if (strcmp(argv[i], "--InstanceWeights") == 0) {
if (i+1 >= argc) {
cerr << "extract: syntax error, used switch --InstanceWeights without file name" << endl;
exit(1);
}
options.initInstanceWeightsFile(argv[++i]);
} else if (strcmp(argv[i], "--Debug") == 0) {
options.debug = true;
} else if (strcmp(argv[i], "--MinPhraseLength") == 0) {
options.minPhraseLength = atoi(argv[++i]);
} else if (strcmp(argv[i], "--Separator") == 0) {
options.separator = argv[++i];
} else if(strcmp(argv[i],"--model") == 0) {
if (i+1 >= argc) {
cerr << "extract: syntax error, no model's information provided to the option --model " << endl;
exit(1);
}
char* modelParams = argv[++i];
char* modelName = strtok(modelParams, "-");
char* modelType = strtok(NULL, "-");
// REO_MODEL_TYPE intModelType;
if(strcmp(modelName, "wbe") == 0) {
options.initWordModel(true);
if(strcmp(modelType, "msd") == 0)
options.initWordType(REO_MSD);
else if(strcmp(modelType, "mslr") == 0)
options.initWordType(REO_MSLR);
else if(strcmp(modelType, "mono") == 0 || strcmp(modelType, "monotonicity") == 0)
options.initWordType(REO_MONO);
else {
cerr << "extract: syntax error, unknown reordering model type: " << modelType << endl;
exit(1);
}
} else if(strcmp(modelName, "phrase") == 0) {
options.initPhraseModel(true);
if(strcmp(modelType, "msd") == 0)
options.initPhraseType(REO_MSD);
else if(strcmp(modelType, "mslr") == 0)
options.initPhraseType(REO_MSLR);
else if(strcmp(modelType, "mono") == 0 || strcmp(modelType, "monotonicity") == 0)
options.initPhraseType(REO_MONO);
else {
cerr << "extract: syntax error, unknown reordering model type: " << modelType << endl;
exit(1);
}
} else if(strcmp(modelName, "hier") == 0) {
options.initHierModel(true);
if(strcmp(modelType, "msd") == 0)
options.initHierType(REO_MSD);
else if(strcmp(modelType, "mslr") == 0)
options.initHierType(REO_MSLR);
else if(strcmp(modelType, "mono") == 0 || strcmp(modelType, "monotonicity") == 0)
options.initHierType(REO_MONO);
else {
cerr << "extract: syntax error, unknown reordering model type: " << modelType << endl;
exit(1);
}
} else {
cerr << "extract: syntax error, unknown reordering model: " << modelName << endl;
exit(1);
}
options.initAllModelsOutputFlag(true);
} else {
cerr << "extract: syntax error, unknown option '" << string(argv[i]) << "'\n";
exit(1);
}
}
// default reordering model if no model selected
// allows for the old syntax to be used
if(options.isOrientationFlag() && !options.isAllModelsOutputFlag()) {
options.initWordModel(true);
options.initWordType(REO_MSD);
}
// open input files
Moses::InputFileStream eFile(fileNameE);
Moses::InputFileStream fFile(fileNameF);
Moses::InputFileStream aFile(fileNameA);
istream *eFileP = &eFile;
istream *fFileP = &fFile;
istream *aFileP = &aFile;
istream *iwFileP = NULL;
auto_ptr<Moses::InputFileStream> instanceWeightsFile;
if (options.getInstanceWeightsFile().length()) {
instanceWeightsFile.reset(new Moses::InputFileStream(options.getInstanceWeightsFile()));
iwFileP = instanceWeightsFile.get();
}
// open output files
if (options.isOrientationFlag()) {
string fileNameExtractOrientation = fileNameExtract + ".o" + (options.isGzOutput()?".gz":"");
extractFileOrientation.Open(fileNameExtractOrientation.c_str());
}
int i = sentenceOffset;
while(true) {
i++;
if (i%10000 == 0) cerr << "." << flush;
char englishString[LINE_MAX_LENGTH];
char foreignString[LINE_MAX_LENGTH];
char alignmentString[LINE_MAX_LENGTH];
char weightString[LINE_MAX_LENGTH];
SAFE_GETLINE((*eFileP), englishString, LINE_MAX_LENGTH, '\n', __FILE__);
if (eFileP->eof()) break;
SAFE_GETLINE((*fFileP), foreignString, LINE_MAX_LENGTH, '\n', __FILE__);
SAFE_GETLINE((*aFileP), alignmentString, LINE_MAX_LENGTH, '\n', __FILE__);
if (iwFileP) {
SAFE_GETLINE((*iwFileP), weightString, LINE_MAX_LENGTH, '\n', __FILE__);
}
SentenceAlignment sentence;
// cout << "read in: " << englishString << " & " << foreignString << " & " << alignmentString << endl;
//az: output src, tgt, and alingment line
if (options.isOnlyOutputSpanInfo()) {
cout << "LOG: SRC: " << foreignString << endl;
cout << "LOG: TGT: " << englishString << endl;
cout << "LOG: ALT: " << alignmentString << endl;
cout << "LOG: PHRASES_BEGIN:" << endl;
}
if (sentence.create( englishString, foreignString, alignmentString, weightString, i, false)) {
ExtractTask *task = new ExtractTask(i-1, sentence, options, extractFileOrientation);
task->Run();
delete task;
}
if (options.isOnlyOutputSpanInfo()) cout << "LOG: PHRASES_END:" << endl; //az: mark end of phrases
}
eFile.Close();
fFile.Close();
aFile.Close();
//az: only close if we actually opened it
if (!options.isOnlyOutputSpanInfo()) {
if (options.isOrientationFlag()) {
extractFileOrientation.Close();
}
}
}
namespace MosesTraining
{
void ExtractTask::Run()
{
extract(m_sentence);
}
void ExtractTask::extract(SentenceAlignment &sentence)
{
int countE = sentence.target.size();
int countF = sentence.source.size();
HPhraseVector inboundPhrases;
HSentenceVertices inTopLeft;
HSentenceVertices inTopRight;
HSentenceVertices inBottomLeft;
HSentenceVertices inBottomRight;
HSentenceVertices outTopLeft;
HSentenceVertices outTopRight;
HSentenceVertices outBottomLeft;
HSentenceVertices outBottomRight;
HSentenceVertices::const_iterator it;
bool relaxLimit = m_options.isHierModel();
bool buildExtraStructure = m_options.isPhraseModel() || m_options.isHierModel();
// check alignments for target phrase startE...endE
// loop over extracted phrases which are compatible with the word-alignments
for(int startE=0; startE<countE; startE++) {
for(int endE=startE;
(endE<countE && (relaxLimit || endE<startE+m_options.maxPhraseLength));
endE++) {
int minF = 9999;
int maxF = -1;
vector< int > usedF = sentence.alignedCountS;
for(int ei=startE; ei<=endE; ei++) {
for(size_t i=0; i<sentence.alignedToT[ei].size(); i++) {
int fi = sentence.alignedToT[ei][i];
if (fi<minF) {
minF = fi;
}
if (fi>maxF) {
maxF = fi;
}
usedF[ fi ]--;
}
}
if (maxF >= 0 && // aligned to any source words at all
(relaxLimit || maxF-minF < m_options.maxPhraseLength)) { // source phrase within limits
// check if source words are aligned to out of bound target words
bool out_of_bounds = false;
for(int fi=minF; fi<=maxF && !out_of_bounds; fi++)
if (usedF[fi]>0) {
// cout << "ouf of bounds: " << fi << "\n";
out_of_bounds = true;
}
// cout << "doing if for ( " << minF << "-" << maxF << ", " << startE << "," << endE << ")\n";
if (!out_of_bounds) {
// start point of source phrase may retreat over unaligned
for(int startF=minF;
(startF>=0 &&
(relaxLimit || startF>maxF-m_options.maxPhraseLength) && // within length limit
(startF==minF || sentence.alignedCountS[startF]==0)); // unaligned
startF--)
// end point of source phrase may advance over unaligned
for(int endF=maxF;
(endF<countF &&
(relaxLimit || endF<startF+m_options.maxPhraseLength) && // within length limit
(endF - startF + 1 > m_options.minPhraseLength) && // within length limit
(endF==maxF || sentence.alignedCountS[endF]==0)); // unaligned
endF++) { // at this point we have extracted a phrase
if(buildExtraStructure) { // phrase || hier
if(endE-startE < m_options.maxPhraseLength && endF-startF < m_options.maxPhraseLength) { // within limit
inboundPhrases.push_back(HPhrase(HPhraseVertex(startF,startE),
HPhraseVertex(endF,endE)));
insertPhraseVertices(inTopLeft, inTopRight, inBottomLeft, inBottomRight,
startF, startE, endF, endE);
} else
insertPhraseVertices(outTopLeft, outTopRight, outBottomLeft, outBottomRight,
startF, startE, endF, endE);
} else {
string orientationInfo = "";
if(m_options.isWordModel()) {
REO_POS wordPrevOrient, wordNextOrient;
bool connectedLeftTopP = isAligned( sentence, startF-1, startE-1 );
bool connectedRightTopP = isAligned( sentence, endF+1, startE-1 );
bool connectedLeftTopN = isAligned( sentence, endF+1, endE+1 );
bool connectedRightTopN = isAligned( sentence, startF-1, endE+1 );
wordPrevOrient = getOrientWordModel(sentence, m_options.isWordType(), connectedLeftTopP, connectedRightTopP, startF, endF, startE, endE, countF, 0, 1, &ge, &lt);
wordNextOrient = getOrientWordModel(sentence, m_options.isWordType(), connectedLeftTopN, connectedRightTopN, endF, startF, endE, startE, 0, countF, -1, &lt, &ge);
orientationInfo += getOrientString(wordPrevOrient, m_options.isWordType()) + " " + getOrientString(wordNextOrient, m_options.isWordType());
if(m_options.isAllModelsOutputFlag())
" | | ";
}
addPhrase(sentence, startE, endE, startF, endF, orientationInfo);
}
}
}
}
}
}
}
REO_POS getOrientWordModel(SentenceAlignment & sentence, REO_MODEL_TYPE modelType,
bool connectedLeftTop, bool connectedRightTop,
int startF, int endF, int startE, int endE, int countF, int zero, int unit,
bool (*ge)(int, int), bool (*lt)(int, int) )
{
if( connectedLeftTop && !connectedRightTop)
return LEFT;
if(modelType == REO_MONO)
return UNKNOWN;
if (!connectedLeftTop && connectedRightTop)
return RIGHT;
if(modelType == REO_MSD)
return UNKNOWN;
for(int indexF=startF-2*unit; (*ge)(indexF, zero) && !connectedLeftTop; indexF=indexF-unit)
connectedLeftTop = isAligned(sentence, indexF, startE-unit);
for(int indexF=endF+2*unit; (*lt)(indexF,countF) && !connectedRightTop; indexF=indexF+unit)
connectedRightTop = isAligned(sentence, indexF, startE-unit);
if(connectedLeftTop && !connectedRightTop)
return DRIGHT;
else if(!connectedLeftTop && connectedRightTop)
return DLEFT;
return UNKNOWN;
}
// to be called with countF-1 instead of countF
REO_POS getOrientPhraseModel (SentenceAlignment & sentence, REO_MODEL_TYPE modelType,
bool connectedLeftTop, bool connectedRightTop,
int startF, int endF, int startE, int endE, int countF, int zero, int unit,
bool (*ge)(int, int), bool (*lt)(int, int),
const HSentenceVertices & inBottomRight, const HSentenceVertices & inBottomLeft)
{
HSentenceVertices::const_iterator it;
if((connectedLeftTop && !connectedRightTop) ||
//(startE == 0 && startF == 0) ||
//(startE == sentence.target.size()-1 && startF == sentence.source.size()-1) ||
((it = inBottomRight.find(startE - unit)) != inBottomRight.end() &&
it->second.find(startF-unit) != it->second.end()))
return LEFT;
if(modelType == REO_MONO)
return UNKNOWN;
if((!connectedLeftTop && connectedRightTop) ||
((it = inBottomLeft.find(startE - unit)) != inBottomLeft.end() && it->second.find(endF + unit) != it->second.end()))
return RIGHT;
if(modelType == REO_MSD)
return UNKNOWN;
connectedLeftTop = false;
for(int indexF=startF-2*unit; (*ge)(indexF, zero) && !connectedLeftTop; indexF=indexF-unit)
if(connectedLeftTop = (it = inBottomRight.find(startE - unit)) != inBottomRight.end() &&
it->second.find(indexF) != it->second.end())
return DRIGHT;
connectedRightTop = false;
for(int indexF=endF+2*unit; (*lt)(indexF, countF) && !connectedRightTop; indexF=indexF+unit)
if(connectedRightTop = (it = inBottomLeft.find(startE - unit)) != inBottomLeft.end() &&
it->second.find(indexF) != it->second.end())
return DLEFT;
return UNKNOWN;
}
// to be called with countF-1 instead of countF
REO_POS getOrientHierModel (SentenceAlignment & sentence, REO_MODEL_TYPE modelType,
bool connectedLeftTop, bool connectedRightTop,
int startF, int endF, int startE, int endE, int countF, int zero, int unit,
bool (*ge)(int, int), bool (*lt)(int, int),
const HSentenceVertices & inBottomRight, const HSentenceVertices & inBottomLeft,
const HSentenceVertices & outBottomRight, const HSentenceVertices & outBottomLeft,
REO_POS phraseOrient)
{
HSentenceVertices::const_iterator it;
if(phraseOrient == LEFT ||
(connectedLeftTop && !connectedRightTop) ||
// (startE == 0 && startF == 0) ||
//(startE == sentence.target.size()-1 && startF == sentence.source.size()-1) ||
((it = inBottomRight.find(startE - unit)) != inBottomRight.end() &&
it->second.find(startF-unit) != it->second.end()) ||
((it = outBottomRight.find(startE - unit)) != outBottomRight.end() &&
it->second.find(startF-unit) != it->second.end()))
return LEFT;
if(modelType == REO_MONO)
return UNKNOWN;
if(phraseOrient == RIGHT ||
(!connectedLeftTop && connectedRightTop) ||
((it = inBottomLeft.find(startE - unit)) != inBottomLeft.end() &&
it->second.find(endF + unit) != it->second.end()) ||
((it = outBottomLeft.find(startE - unit)) != outBottomLeft.end() &&
it->second.find(endF + unit) != it->second.end()))
return RIGHT;
if(modelType == REO_MSD)
return UNKNOWN;
if(phraseOrient != UNKNOWN)
return phraseOrient;
connectedLeftTop = false;
for(int indexF=startF-2*unit; (*ge)(indexF, zero) && !connectedLeftTop; indexF=indexF-unit) {
if((connectedLeftTop = (it = inBottomRight.find(startE - unit)) != inBottomRight.end() &&
it->second.find(indexF) != it->second.end()) ||
(connectedLeftTop = (it = outBottomRight.find(startE - unit)) != outBottomRight.end() &&
it->second.find(indexF) != it->second.end()))
return DRIGHT;
}
connectedRightTop = false;
for(int indexF=endF+2*unit; (*lt)(indexF, countF) && !connectedRightTop; indexF=indexF+unit) {
if((connectedRightTop = (it = inBottomLeft.find(startE - unit)) != inBottomLeft.end() &&
it->second.find(indexF) != it->second.end()) ||
(connectedRightTop = (it = outBottomLeft.find(startE - unit)) != outBottomLeft.end() &&
it->second.find(indexF) != it->second.end()))
return DLEFT;
}
return UNKNOWN;
}
bool isAligned ( SentenceAlignment &sentence, int fi, int ei )
{
if (ei == -1 && fi == -1)
return true;
if (ei <= -1 || fi <= -1)
return false;
if ((size_t)ei == sentence.target.size() && (size_t)fi == sentence.source.size())
return true;
if ((size_t)ei >= sentence.target.size() || (size_t)fi >= sentence.source.size())
return false;
for(size_t i=0; i<sentence.alignedToT[ei].size(); i++)
if (sentence.alignedToT[ei][i] == fi)
return true;
return false;
}
bool ge(int first, int second)
{
return first >= second;
}
bool le(int first, int second)
{
return first <= second;
}
bool lt(int first, int second)
{
return first < second;
}
void insertVertex( HSentenceVertices & corners, int x, int y )
{
set<int> tmp;
tmp.insert(x);
pair< HSentenceVertices::iterator, bool > ret = corners.insert( pair<int, set<int> > (y, tmp) );
if(ret.second == false) {
ret.first->second.insert(x);
}
}
void insertPhraseVertices(
HSentenceVertices & topLeft,
HSentenceVertices & topRight,
HSentenceVertices & bottomLeft,
HSentenceVertices & bottomRight,
int startF, int startE, int endF, int endE)
{
insertVertex(topLeft, startF, startE);
insertVertex(topRight, endF, startE);
insertVertex(bottomLeft, startF, endE);
insertVertex(bottomRight, endF, endE);
}
string getOrientString(REO_POS orient, REO_MODEL_TYPE modelType)
{
switch(orient) {
case LEFT:
return "mono";
break;
case RIGHT:
return "swap";
break;
case DRIGHT:
return "dright";
break;
case DLEFT:
return "dleft";
break;
case UNKNOWN:
switch(modelType) {
case REO_MONO:
return "nomono";
break;
case REO_MSD:
return "other";
break;
case REO_MSLR:
return "dright";
break;
}
break;
}
return "";
}
int getClass(const std::string &str)
{
size_t pos = str.find("swap");
if (pos == str.npos) {
return 0;
}
else if (pos == 0) {
return 1;
}
else {
return 2;
}
}
void ExtractTask::addPhrase( SentenceAlignment &sentence, int startE, int endE, int startF, int endF , string &orientationInfo)
{
if (m_options.isOnlyOutputSpanInfo()) {
cout << startF << " " << endF << " " << startE << " " << endE << endl;
return;
}
const string &sep = m_options.separator;
m_extractFileOrientation << sentence.sentenceID << " " << sep << " ";
m_extractFileOrientation << getClass(orientationInfo) << " " << sep << " ";
// position
m_extractFileOrientation << startF << " " << endF << " " << sep << " ";
// start
m_extractFileOrientation << "<s> ";
for(int fi=0; fi<startF; fi++) {
m_extractFileOrientation << sentence.source[fi] << " ";
}
m_extractFileOrientation << sep << " ";
// middle
for(int fi=startF; fi<=endF; fi++) {
m_extractFileOrientation << sentence.source[fi] << " ";
}
m_extractFileOrientation << sep << " ";
// end
for(int fi=endF+1; fi<sentence.source.size(); fi++) {
m_extractFileOrientation << sentence.source[fi] << " ";
}
m_extractFileOrientation << "</s> ";
// target
/*
for(int ei=startE; ei<=endE; ei++) {
m_extractFileOrientation << sentence.target[ei] << " ";
}
*/
m_extractFileOrientation << endl;
}
/** tokenise input string to vector of string. each element has been separated by a character in the delimiters argument.
The separator can only be 1 character long. The default delimiters are space or tab
*/
std::vector<std::string> Tokenize(const std::string& str,
const std::string& delimiters)
{
std::vector<std::string> tokens;
// Skip delimiters at beginning.
std::string::size_type lastPos = str.find_first_not_of(delimiters, 0);
// Find first "non-delimiter".
std::string::size_type pos = str.find_first_of(delimiters, lastPos);
while (std::string::npos != pos || std::string::npos != lastPos) {
// Found a token, add it to the vector.
tokens.push_back(str.substr(lastPos, pos - lastPos));
// Skip delimiters. Note the "not_of"
lastPos = str.find_first_not_of(delimiters, pos);
// Find next "non-delimiter"
pos = str.find_first_of(delimiters, lastPos);
}
return tokens;
}
}