generator: add methods to generate closed item sets

src/generator.cpp

@@ -26,9 +26,70 @@
 
 #include "generator.hpp"
 
+#include <queue>
+
 
 namespace solar {
 
+std::set<item_t> generator_t::get_set(const std::string &nonterm) {
+	std::set<item_t> set;
+
+	auto entries = rules.equal_range(nonterm);
+	for (auto entry = entries.first; entry != entries.second; ++entry)
+		set.insert(entry->second);
+
+	return set;
+}
+
+void generator_t::close_set(std::set<item_t> *set) {
+	std::queue<item_t> queue;
+	for (const item_t &item : *set)
+		queue.emplace(item);
+
+	for (; !queue.empty(); queue.pop()) {
+		const item_t &cur = queue.front();
+		if (!cur.has_next())
+			continue;
+
+		const symbol_t &sym = cur.get_next_symbol();
+		if (sym.get_type() != SYMBOL_TYPE_NONTERM)
+			continue;
+
+		for (const item_t &item : get_set(sym.get_value())) {
+			if (set->insert(item).second)
+				queue.push(item);
+		}
+	}
+}
+
+void generator_t::print_item(const item_t &item) {
+	printf("%s |=", item.get_lhs().c_str());
+
+	for (size_t i = 0; i <= item.get_rhs().size(); i++) {
+		if (i == item.get_point())
+			printf(" .");
+
+		if (i == item.get_rhs().size())
+			break;
+
+		switch (item.get_rhs()[i].get_type()) {
+		case SYMBOL_TYPE_CHAR:
+			printf(" '%c'", item.get_rhs()[i].get_value()[0]);
+			break;
+
+		default:
+			printf(" %s", item.get_rhs()[i].get_value().c_str());
+		}
+	}
+
+	printf("\n");
+}
+
+void generator_t::print_set(const std::set<item_t> &set) {
+	for (const item_t &item : set)
+		print_item(item);
+}
+
 generator_t::generator_t(const std::set<item_t> &rules0) {
 	for (item_t rule : rules0) {
 		rules.emplace(rule.get_lhs(), rule);
@@ -39,6 +100,10 @@ generator_t::generator_t(const std::set<item_t> &rules0) {
 		}
 	}
 
+	std::set<item_t> set0 = get_set("");
+	close_set(&set0);
+
+	print_set(set0);
 }
 
 }

src/generator.hpp

@@ -39,6 +39,12 @@ private:
 	std::multimap<std::string, item_t> rules;
 	std::multimap<symbol_t, item_t> items;
 
+	void close_set(std::set<item_t> *set);
+	std::set<item_t> get_set(const std::string &nonterm);
+
+	void print_item(const item_t &item);
+	void print_set(const std::set<item_t> &set);
+
 public:
 	generator_t(const std::set<item_t> &rules0);
 };

src/item.hpp

@@ -69,7 +69,7 @@ struct item_t : public std::tuple<std::string, std::vector<symbol_t>, unsigned>
 		get_point()++;
 	}
 
-	symbol_t get_next_symbol() const {
+	const symbol_t & get_next_symbol() const {
 		return get_rhs()[get_point()];
 	}
 };