generator: move LR(0)-specific code to generator_lr0_t

src/generator.cpp

@@ -62,7 +62,7 @@ void generator_t::close_set(std::set<item_t> *set) {
 	}
 }
 
-void generator_t::generate_itemsets() {
+void generator_t::generate() {
 	std::queue<std::pair<std::set<item_t>, size_t>> queue;
 
 	{
@@ -136,8 +136,6 @@ generator_t::generator_t(const grammar_t &grammar0) : grammar(grammar0) {
 
 		rule_ids.insert(std::make_pair(rule, i));
 	}
-
-	generate_itemsets();
 }
 
 }

src/generator.hpp

@@ -56,11 +56,8 @@ private:
 	std::map<std::set<item_t>, size_t> itemsets;
 
 	std::map<std::pair<size_t, symbol_t>, size_t> shifts;
-	std::map<size_t, size_t> reductions;
 	std::map<std::pair<size_t, std::string>, size_t> gotos;
 
-	std::set<size_t> shift_conflicts;
-
 
 	void close_set(std::set<item_t> *set);
 	std::set<item_t> get_set(const std::string &nonterm);
@@ -69,20 +66,10 @@ private:
 		return itemsets.insert(std::make_pair(set, itemsets.size()));
 	}
 
-	void add_reduction(size_t from, size_t to) {
-		if (reductions.count(from))
-			throw conflict_error("reduce/reduce conflict");
-		if (shift_conflicts.count(from))
-			throw conflict_error("shift/reduce conflict");
-
-		reductions.insert(std::make_pair(from, to));
-	}
-
 	void add_shift(size_t from, const symbol_t &sym, size_t to) {
-		if (reductions.count(from))
+		if (has_reduce_conflict(from, sym))
 			throw conflict_error("shift/reduce conflict");
 
-		shift_conflicts.insert(from);
 		shifts.insert(std::make_pair(std::make_pair(from, sym), to));
 	}
 
@@ -90,7 +77,11 @@ private:
 		gotos.insert(std::make_pair(std::make_pair(from, nonterm), to));
 	}
 
-	void generate_itemsets();
+protected:
+	virtual bool has_reduce_conflict(size_t from, const symbol_t &sym) = 0;
+	virtual void add_reduction(size_t from, size_t to) = 0;
+
+	generator_t(const grammar_t &grammar0);
 
 public:
 	const grammar_t & get_grammar() const {
@@ -109,10 +100,6 @@ public:
 		return itemsets.size();
 	}
 
-	const std::map<size_t, size_t> & get_reductions() const {
-		return reductions;
-	}
-
 	const std::map<std::pair<size_t, symbol_t>, size_t> & get_shifts() const {
 		return shifts;
 	}
@@ -121,8 +108,9 @@ public:
 		return gotos;
 	}
 
-protected:
-	generator_t(const grammar_t &grammar0);
+	virtual ~generator_t() {}
+
+	void generate();
 };
 
 }

src/generator_lr0.cpp

@@ -25,3 +25,25 @@
 
 
 #include "generator_lr0.hpp"
+
+
+namespace solar {
+
+bool generator_lr0_t::has_reduce_conflict(size_t from, const symbol_t &sym) {
+	(void)sym;
+	return reductions.count(from);
+}
+
+void generator_lr0_t::add_reduction(size_t from, size_t to) {
+	if (reductions.count(from))
+		throw conflict_error("reduce/reduce conflict");
+
+	for (const symbol_t &sym : get_terminals()) {
+		if (get_shifts().count(std::make_pair(from, sym)))
+			throw conflict_error("shift/reduce conflict");
+	}
+
+	reductions.insert(std::make_pair(from, to));
+}
+
+}

src/generator_lr0.hpp

@@ -32,8 +32,21 @@
 namespace solar {
 
 class generator_lr0_t : public generator_t {
+private:
+	std::map<size_t, size_t> reductions;
+
+protected:
+	virtual bool has_reduce_conflict(size_t from, const symbol_t &sym);
+	virtual void add_reduction(size_t from, size_t to);
+
 public:
-	generator_lr0_t(const grammar_t &grammar) : generator_t(grammar) {}
+	const std::map<size_t, size_t> & get_reductions() const {
+		return reductions;
+	}
+
+	generator_lr0_t(const grammar_t &grammar) : generator_t(grammar) {
+		generate();
+	}
 };
 
 }

src/output.cpp

@@ -33,7 +33,7 @@
 
 namespace solar {
 
-output_t::output_t(const generator_t *generator0, const char *header, const char *source)
+output_t::output_t(const generator_lr0_t *generator0, const char *header, const char *source)
 	: prefix_str("parse_"),
 	  token_prefix_str("TOK_"),
 	  stack_size(100),

src/output.hpp

@@ -26,7 +26,7 @@
 
 #pragma once
 
-#include "generator.hpp"
+#include "generator_lr0.hpp"
 
 #include <cstdio>
 
@@ -39,7 +39,7 @@ private:
 	std::string token_prefix_str;
 	unsigned stack_size;
 
-	const generator_t *generator;
+	const generator_lr0_t *generator;
 
 	std::string header_filename;
 
@@ -73,7 +73,7 @@ private:
 	void emit_source();
 
 public:
-	output_t(const generator_t *generator0, const char *header, const char *source);
+	output_t(const generator_lr0_t *generator0, const char *header, const char *source);
 	~output_t();
 
 	void write();