From b2054386014e3604c7a16c6dad0415bf790c06b2 Mon Sep 17 00:00:00 2001
From: IlushaShurupov <ilusha.main@gmail.com>
Date: Sat, 12 Aug 2023 08:27:50 +0300
Subject: [PATCH] CFG remove unused rules

---
 Containers/public/List.hpp   |  1 +
 Parser/private/CfGrammar.cpp | 11 +++++++++++
 Parser/public/CfGrammar.hpp  |  8 ++++++++
 3 files changed, 20 insertions(+)

diff --git a/Containers/public/List.hpp b/Containers/public/List.hpp
index 26ab926..075c45f 100644
--- a/Containers/public/List.hpp
+++ b/Containers/public/List.hpp
@@ -157,6 +157,7 @@ namespace tp {
 		[[nodiscard]] Node* find(const TypeArg data) const {
 			Node* found = mFirst;
 			for (alni i = 0; data != found->data; i++) {
+				if (i == length()) return nullptr;
 				if (!found->next) {
 					return nullptr;
 				}
diff --git a/Parser/private/CfGrammar.cpp b/Parser/private/CfGrammar.cpp
index f23ac40..b2e4b6f 100644
--- a/Parser/private/CfGrammar.cpp
+++ b/Parser/private/CfGrammar.cpp
@@ -128,11 +128,22 @@ bool CfGrammar::compile() {
 		}
 	}
 
+	List<String> remove;
 	for (auto nonTerminal : mNonTerminals) {
 		if (!nonTerminal->val.references.size() && nonTerminal->key != startTerminal) {
 			printf("Non-terminal '%s' is defined but not used\n", nonTerminal->key.read());
+			remove.pushBack(nonTerminal->key);
 		}
 	}
 
+	for (auto rem : remove) {
+		auto nonTerminal = &mNonTerminals.get(rem.data());
+		for (auto referencing : nonTerminal->referencing) {
+			referencing->val->references.remove(nonTerminal->rules.first()->data->id);
+		}
+		for (auto rule : nonTerminal->rules) {
+			rules.removeNode(rules.find(*rule.data()));
+		}
+	}
 	return true;
 }
\ No newline at end of file
diff --git a/Parser/public/CfGrammar.hpp b/Parser/public/CfGrammar.hpp
index 391b250..e33db89 100644
--- a/Parser/public/CfGrammar.hpp
+++ b/Parser/public/CfGrammar.hpp
@@ -12,10 +12,18 @@ namespace tp {
 				String id;
 				bool isTerminal = false;
 				bool isEpsilon = false;
+
+				bool operator==(const Arg& in) const {
+					return (id == in.id) && (isEpsilon == in.isEpsilon) && (isTerminal == in.isTerminal);
+				}
 			};
 
 			String id;
 			List<Arg> args;
+
+			bool operator==(const Rule& in) const {
+				return (id == in.id) && (args == in.args);
+			}
 		};
 
 		struct Sentence {