...

2 files changed, 37 insertions, 0 deletions

diff --git a/include/cru/parse/Grammar.hpp b/include/cru/parse/Grammar.hpp
index dd4741df..5935e703 100644
--- a/include/cru/parse/Grammar.hpp
+++ b/include/cru/parse/Grammar.hpp
@@ -21,6 +21,9 @@ class Grammar : public Object {
   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_; }
diff --git a/src/parse/Grammar.cpp b/src/parse/Grammar.cpp
index 8d929212..a2dd14d4 100644
--- a/src/parse/Grammar.cpp
+++ b/src/parse/Grammar.cpp
@@ -35,4 +35,38 @@ Production* Grammar::CreateProduction(String name, Nonterminal* left,
   return production;
 }
 
+bool Grammar::RemoveSymbol(Symbol* symbol) {
+  for (auto production : productions_) {
+    if (production->GetLeft() == symbol) return false;
+    for (auto s : production->GetRight()) {
+      if (s == symbol) return false;
+    }
+  }
+
+  auto i = std::find(symbols_.begin(), symbols_.end(), symbol);
+
+  if (i == symbols_.cend()) return false;
+
+  symbols_.erase(i);
+
+  if (auto t = dynamic_cast<Terminal*>(symbol)) {
+    terminals_.erase(std::find(terminals_.begin(), terminals_.end(), t));
+  } else if (auto n = dynamic_cast<Nonterminal*>(symbol)) {
+    nonterminals_.erase(
+        std::find(nonterminals_.begin(), nonterminals_.end(), n));
+  }
+
+  delete symbol;
+
+  return true;
+}
+
+bool Grammar::RemoveProduction(Production* production) {
+  auto i = std::find(productions_.begin(), productions_.end(), production);
+  if (i == productions_.cend()) return false;
+  productions_.erase(i);
+  delete production;
+  return true;
+}
+
 }  // namespace cru::parse