From 74bb9cd27242b9320f99ff4d2b50c3051576cc14 Mon Sep 17 00:00:00 2001
From: crupest <crupest@outlook.com>
Date: Tue, 8 Feb 2022 16:53:51 +0800
Subject: ...

---
 include/cru/parse/Grammar.h | 62 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 62 insertions(+)
 create mode 100644 include/cru/parse/Grammar.h

(limited to 'include/cru/parse/Grammar.h')

diff --git a/include/cru/parse/Grammar.h b/include/cru/parse/Grammar.h
new file mode 100644
index 00000000..7dd1eec0
--- /dev/null
+++ b/include/cru/parse/Grammar.h
@@ -0,0 +1,62 @@
+#pragma once
+#include "Production.h"
+
+#include <unordered_map>
+#include <vector>
+
+namespace cru::parse {
+class CRU_PARSE_API Grammar : public Object {
+ public:
+  Grammar();
+
+  CRU_DELETE_COPY(Grammar)
+  CRU_DELETE_MOVE(Grammar)
+
+  ~Grammar() override;
+
+ public:
+  void SetStartSymbol(Nonterminal* start_symbol);
+
+  Terminal* CreateTerminal(String name);
+  Nonterminal* CreateNonterminal(String name);
+  Production* CreateProduction(String name, Nonterminal* left,
+                               std::vector<Symbol*> right);
+
+  bool RemoveSymbol(Symbol* symbol);
+  bool RemoveProduction(Production* production);
+
+ public:  // Getters
+  Nonterminal* GetStartSymbol() const { return start_symbol_; }
+  const std::vector<Terminal*>& GetTerminals() const { return terminals_; }
+  const std::vector<Nonterminal*>& GetNonterminals() const {
+    return nonterminals_;
+  }
+  const std::vector<Symbol*>& GetSymbols() const { return symbols_; }
+  const std::vector<Production*>& GetProductions() const {
+    return productions_;
+  }
+
+  Grammar* Clone() const;
+
+ public:  // Algorithms
+  std::unordered_map<Nonterminal*, std::vector<Production*>>
+  GenerateLeftProductionMap() const;
+
+  // Algorithm 4.19.
+  // Require grammar has no cycles or empty-productions.
+  void EliminateLeftRecursions();
+
+  // Algorithm 4.21
+  void LeftFactor();
+
+ public:
+  String ProductionsToString() const;
+
+ private:
+  Nonterminal* start_symbol_ = nullptr;
+  std::vector<Terminal*> terminals_;
+  std::vector<Nonterminal*> nonterminals_;
+  std::vector<Symbol*> symbols_;
+  std::vector<Production*> productions_;
+};
+}  // namespace cru::parse
-- 
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