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#pragma once
#include "moses/Syntax/PHyperedge.h"
#include "Forest.h"
#include "HyperTree.h"
#include "RuleMatcher.h"
namespace Moses
{
namespace Syntax
{
namespace F2S
{
// Rule matcher based on the algorithm from this paper:
//
// Hui Zhang, Min Zhang, Haizhou Li, and Chew Lim Tan
// "Fast Translation Rule Matching for Syntax-based Statistical Machine
// Translation"
// In proceedings of EMNLP 2009
//
template<typename Callback>
class RuleMatcherHyperTree : public RuleMatcher<Callback>
{
public:
RuleMatcherHyperTree(const HyperTree &);
~RuleMatcherHyperTree() {}
void EnumerateHyperedges(const Forest::Vertex &, Callback &);
private:
// Frontier node sequence.
typedef std::vector<const Forest::Vertex *> FNS;
// An AnnotatedFNS is a FNS annotated with the set of forest hyperedges that
// constitute the tree fragment from which it was derived.
struct AnnotatedFNS {
FNS fns;
std::vector<const Forest::Hyperedge *> fragment;
};
// A MatchItem is like the FP structure in Zhang et al. (2009), but it also
// records the set of forest hyperedges that constitute the matched tree
// fragment.
struct MatchItem {
AnnotatedFNS annotatedFNS;
const HyperTree::Node *trieNode;
};
// Implements the Cartsian product operation from line 16 of Algorithm 4
// (Zhang et al., 2009), which in this implementation also involves
// combining the fragment information associated with the FNS objects.
void CartesianProduct(const std::vector<AnnotatedFNS> &,
const std::vector<AnnotatedFNS> &,
std::vector<AnnotatedFNS> &);
int CountCommas(const HyperPath::NodeSeq &);
bool MatchChildren(const std::vector<Forest::Vertex *> &,
const HyperPath::NodeSeq &, std::size_t, std::size_t);
void PropagateNextLexel(const MatchItem &);
int SubSeqLength(const HyperPath::NodeSeq &, int);
const HyperTree &m_ruleTrie;
PHyperedge m_hyperedge;
std::queue<MatchItem> m_queue; // Called "SFP" in Zhang et al. (2009)
};
} // namespace F2S
} // namespace Syntax
} // namespace Moses
// Implementation
#include "RuleMatcherHyperTree-inl.h"
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