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#include <algorithm>
#include <vector>
#include <queue>
#include <boost/functional/hash.hpp>
#include <unordered_map>
#include "tree_fragment.h"
#include "translator.h"
#include "hg.h"
#include "sentence_metadata.h"
#include "filelib.h"
#include "stringlib.h"
#include "tdict.h"
#include "verbose.h"
using namespace std;
struct Tree2StringGrammarNode {
map<unsigned, Tree2StringGrammarNode> next;
vector<TRulePtr> rules;
};
void ReadTree2StringGrammar(istream* in, Tree2StringGrammarNode* root) {
string line;
while(getline(*in, line)) {
size_t pos = line.find("|||");
assert(pos != string::npos);
assert(pos > 3);
unsigned xc = 0;
while (line[pos - 1] == ' ') { --pos; xc++; }
cdec::TreeFragment rule_src(line.substr(0, pos), true);
Tree2StringGrammarNode* cur = root;
ostringstream os;
int lhs = -(rule_src.root & cdec::ALL_MASK);
// build source RHS for SCFG projection
// TODO - this is buggy - it will generate a well-formed SCFG rule
// but it will not generate source strings correctly
vector<int> frhs;
for (auto sym : rule_src) {
cur = &cur->next[sym];
if (sym) {
if (cdec::IsFrontier(sym)) { // frontier symbols -> variables
int nt = (sym & cdec::ALL_MASK);
frhs.push_back(-nt);
} else if (cdec::IsTerminal(sym)) {
frhs.push_back(sym);
}
}
}
os << '[' << TD::Convert(-lhs) << "] |||";
for (auto x : frhs) {
os << ' ';
if (x < 0)
os << '[' << TD::Convert(-x) << ']';
else
os << TD::Convert(x);
}
pos += 3 + xc;
while(line[pos] == ' ') { ++pos; }
os << " ||| " << line.substr(pos);
TRulePtr rule(new TRule(os.str()));
cur->rules.push_back(rule);
}
}
struct ParserState {
ParserState() : in_iter(), node() {}
cdec::TreeFragment::iterator in_iter;
ParserState(const cdec::TreeFragment::iterator& it, Tree2StringGrammarNode* n) :
in_iter(it),
input_node_idx(it.node_idx()),
node(n) {}
ParserState(const cdec::TreeFragment::iterator& it, Tree2StringGrammarNode* n, const ParserState& p) :
in_iter(it),
future_work(p.future_work),
input_node_idx(p.input_node_idx),
node(n) {}
vector<ParserState> future_work;
int input_node_idx; // lhs of top level NT
Tree2StringGrammarNode* node;
};
struct Tree2StringTranslatorImpl {
Tree2StringGrammarNode root;
Tree2StringTranslatorImpl(const boost::program_options::variables_map& conf) {
ReadFile rf(conf["grammar"].as<vector<string>>()[0]);
ReadTree2StringGrammar(rf.stream(), &root);
}
bool Translate(const string& input,
SentenceMetadata* smeta,
const vector<double>& weights,
Hypergraph* minus_lm_forest) {
cdec::TreeFragment input_tree(input, false);
Hypergraph hg;
hg.ReserveNodes(input_tree.nodes.size());
vector<int> tree2hg(input_tree.nodes.size() + 1, -1);
queue<ParserState> q;
q.push(ParserState(input_tree.begin(), &root));
unsigned tree_top = q.front().input_node_idx;
while(!q.empty()) {
ParserState& s = q.front();
if (s.in_iter.at_end()) { // completed a traversal of a subtree
//cerr << "I traversed a subtree of the input rooted at node=" << s.input_node_idx << " sym=" <<
// TD::Convert(input_tree.nodes[s.input_node_idx].lhs & cdec::ALL_MASK) << endl;
if (s.node->rules.size()) {
TailNodeVector tail;
int& node_id = tree2hg[s.input_node_idx];
if (node_id < 0)
node_id = hg.AddNode(-(input_tree.nodes[s.input_node_idx].lhs & cdec::ALL_MASK))->id_;
for (auto& n : s.future_work) {
int& nix = tree2hg[n.input_node_idx];
if (nix < 0)
nix = hg.AddNode(-(input_tree.nodes[n.input_node_idx].lhs & cdec::ALL_MASK))->id_;
tail.push_back(nix);
}
for (auto& r : s.node->rules) {
assert(tail.size() == r->Arity());
HG::Edge* new_edge = hg.AddEdge(r, tail);
new_edge->feature_values_ = r->GetFeatureValues();
// TODO: set i and j
hg.ConnectEdgeToHeadNode(new_edge, &hg.nodes_[node_id]);
}
for (auto& w : s.future_work)
q.push(w);
} else {
//cerr << "I can't build anything :(\n";
}
} else { // more input tree to match
unsigned sym = *s.in_iter;
if (cdec::IsLHS(sym)) {
auto nit = s.node->next.find(sym);
if (nit != s.node->next.end()) {
//cerr << "MATCHED LHS: " << TD::Convert(sym & cdec::ALL_MASK) << endl;
q.push(ParserState(++s.in_iter, &nit->second, s));
}
} else if (cdec::IsRHS(sym)) {
//cerr << "Attempting to match RHS: " << TD::Convert(sym & cdec::ALL_MASK) << endl;
cdec::TreeFragment::iterator var = s.in_iter;
var.truncate();
auto nit1 = s.node->next.find(sym);
auto nit2 = s.node->next.find(*var);
if (nit2 != s.node->next.end()) {
//cerr << "MATCHED VAR RHS: " << TD::Convert(sym & cdec::ALL_MASK) << endl;
ParserState new_s(++var, &nit2->second, s);
ParserState new_work(s.in_iter.remainder(), &root);
new_s.future_work.push_back(new_work); // if this traversal of the input succeeds, future_work goes on the q
q.push(new_s);
}
if (nit1 != s.node->next.end()) {
//cerr << "MATCHED FULL RHS: " << TD::Convert(sym & cdec::ALL_MASK) << endl;
q.push(ParserState(++s.in_iter, &nit1->second, s));
}
} else if (cdec::IsTerminal(sym)) {
auto nit = s.node->next.find(sym);
if (nit != s.node->next.end()) {
//cerr << "MATCHED TERMINAL: " << TD::Convert(sym) << endl;
q.push(ParserState(++s.in_iter, &nit->second, s));
}
} else {
cerr << "This can never happen!\n"; abort();
}
}
q.pop();
}
int goal = tree2hg[tree_top];
if (goal < 0) return false;
//cerr << "Goal node: " << goal << endl;
hg.TopologicallySortNodesAndEdges(goal);
hg.Reweight(weights);
// there might be nodes that cannot be derived
// the following takes care of them
vector<bool> prune(hg.edges_.size(), false);
hg.PruneEdges(prune, true);
//hg.PrintGraphviz();
minus_lm_forest->swap(hg);
return true;
}
};
Tree2StringTranslator::Tree2StringTranslator(const boost::program_options::variables_map& conf) :
pimpl_(new Tree2StringTranslatorImpl(conf)) {}
bool Tree2StringTranslator::TranslateImpl(const string& input,
SentenceMetadata* smeta,
const vector<double>& weights,
Hypergraph* minus_lm_forest) {
return pimpl_->Translate(input, smeta, weights, minus_lm_forest);
}
void Tree2StringTranslator::ProcessMarkupHintsImpl(const map<string, string>& kv) {
}
void Tree2StringTranslator::SentenceCompleteImpl() {
}
std::string Tree2StringTranslator::GetDecoderType() const {
return "tree2string";
}
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