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#ifndef GRAMMAR_H_
#define GRAMMAR_H_
#include <vector>
#include <map>
#include <set>
#include <boost/shared_ptr.hpp>
#include "lattice.h"
#include "trule.h"
struct RuleBin {
virtual ~RuleBin();
virtual int GetNumRules() const = 0;
virtual TRulePtr GetIthRule(int i) const = 0;
virtual int Arity() const = 0;
};
struct GrammarIter {
virtual ~GrammarIter();
virtual const RuleBin* GetRules() const = 0;
virtual const GrammarIter* Extend(int symbol) const = 0;
};
struct Grammar {
typedef std::map<WordID, std::vector<TRulePtr> > Cat2Rules;
static const std::vector<TRulePtr> NO_RULES;
virtual ~Grammar();
virtual const GrammarIter* GetRoot() const = 0;
virtual bool HasRuleForSpan(int i, int j, int distance) const;
// cat is the category to be rewritten
inline const std::vector<TRulePtr>& GetAllUnaryRules() const {
return unaries_;
}
// get all the unary rules that rewrite category cat
inline const std::vector<TRulePtr>& GetUnaryRulesForRHS(const WordID& cat) const {
Cat2Rules::const_iterator found = rhs2unaries_.find(cat);
if (found == rhs2unaries_.end())
return NO_RULES;
else
return found->second;
}
protected:
Cat2Rules rhs2unaries_; // these must be filled in by subclasses!
std::vector<TRulePtr> unaries_;
};
typedef boost::shared_ptr<Grammar> GrammarPtr;
class TGImpl;
struct TextGrammar : public Grammar {
TextGrammar();
TextGrammar(const std::string& file);
void SetMaxSpan(int m) { max_span_ = m; }
virtual const GrammarIter* GetRoot() const;
void AddRule(const TRulePtr& rule);
void ReadFromFile(const std::string& filename);
virtual bool HasRuleForSpan(int i, int j, int distance) const;
const std::vector<TRulePtr>& GetUnaryRules(const WordID& cat) const;
private:
int max_span_;
boost::shared_ptr<TGImpl> pimpl_;
};
struct GlueGrammar : public TextGrammar {
// read glue grammar from file
explicit GlueGrammar(const std::string& file);
GlueGrammar(const std::string& goal_nt, const std::string& default_nt); // "S", "X"
virtual bool HasRuleForSpan(int i, int j, int distance) const;
};
struct PassThroughGrammar : public TextGrammar {
PassThroughGrammar(const Lattice& input, const std::string& cat);
virtual bool HasRuleForSpan(int i, int j, int distance) const;
private:
std::vector<std::set<int> > has_rule_; // index by [i][j]
};
#endif
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