From 6fcfa075f8afeb6726606b0a9e7dd387ae022818 Mon Sep 17 00:00:00 2001
From: IlushaShurupov <ilusha.main@gmail.com>
Date: Fri, 11 Aug 2023 16:04:02 +0300
Subject: [PATCH] Generate sentences from cf grammar. Fix list initialization
 from copy constructor

---
 Containers/public/List.hpp   |  4 +--
 Parser/applications/Cfg.cpp  |  6 +++-
 Parser/private/CfGrammar.cpp | 65 ++++++++++++++++++++++++++++++++++++
 Parser/public/CfGrammar.hpp  | 13 +++++++-
 4 files changed, 84 insertions(+), 4 deletions(-)

diff --git a/Containers/public/List.hpp b/Containers/public/List.hpp
index 85a49bf..e80b50c 100644
--- a/Containers/public/List.hpp
+++ b/Containers/public/List.hpp
@@ -72,7 +72,7 @@ namespace tp {
 	public:
 
 		List() = default;
-
+		List(const List& in) { this->operator=(in);	}
 		List(const InitialierList<Type>& list) { operator=(list); }
 
 		[[nodiscard]] inline Node* first() const { return mFirst; }
@@ -146,7 +146,7 @@ namespace tp {
 		}
 
 		[[nodiscard]] Node* findIdx(Index idx) const {
-			DEBUG_ASSERT(!mFirst || idx > mLength - 1)
+			DEBUG_ASSERT(mFirst && idx < mLength && idx >= 0)
 			Node* found = mFirst;
 			for (int i = 0; i != idx; i++) {
 				found = found->next;
diff --git a/Parser/applications/Cfg.cpp b/Parser/applications/Cfg.cpp
index 6b22bb5..23ad5ac 100644
--- a/Parser/applications/Cfg.cpp
+++ b/Parser/applications/Cfg.cpp
@@ -23,7 +23,11 @@ void run(const String& source) {
 
 	printf("Grammar accepted.\n");
 
-	printf("Example text formed from grammar : TODO\n");
+	List<CfGrammar::Sentence> sentences;
+	grammar.generateSentences(sentences);
+
+	printf("Example sentences formed from grammar: \n");
+	for (auto sentence : sentences) tp::CfGrammar::printSentence(sentence.data());
 
 	CfGrammar::deinitializeCfGrammarParser(state);
 }
diff --git a/Parser/private/CfGrammar.cpp b/Parser/private/CfGrammar.cpp
index a265f51..5901eca 100644
--- a/Parser/private/CfGrammar.cpp
+++ b/Parser/private/CfGrammar.cpp
@@ -2,8 +2,73 @@
 #include "NewPlacement.hpp"
 #include "CfGrammar.hpp"
 
+#include "Timing.hpp"
+
 using namespace tp;
 
+void CfGrammar::generateSentences(List<Sentence>& out) {
+	constexpr ualni maxTime = 1000;
+	constexpr ualni maxSentences = 40;
+	constexpr ualni maxQueue = 20000;
+
+	List<Sentence> queue;
+	Timer timer(maxTime);
+
+	// add start production
+	Sentence start;
+	start.terms.pushBack( { startTerminal, false } );
+	queue.pushBack(start);
+
+	PASS:
+
+	auto const sentential = &queue.first()->data;
+	bool isSentence = true;
+	ualni termIdx = 0;
+	for (auto term : sentential->terms) {
+		if (term->terminal) {
+			termIdx++;
+			continue;
+		}
+
+		auto nonTerminal = &mNonTerminals.get(term->id);
+		for (auto production : nonTerminal->rules) {
+			queue.pushBack(*sentential);
+			auto copy = &queue.last()->data;
+
+			auto appendTerm = copy->terms.findIdx(termIdx);
+			auto deleteTerm = appendTerm;
+			for (auto arg : production->args) {
+				auto newTerm = copy->terms.newNode({ arg->id, arg->isTerminal });
+				copy->terms.attach(newTerm, appendTerm);
+				appendTerm = newTerm;
+			}
+			copy->terms.removeNode(deleteTerm);
+		}
+
+		isSentence = false;
+		termIdx++;
+	}
+	if (isSentence) out.pushBack(*sentential);
+	queue.popFront();
+
+
+	bool stop = false;
+	stop |= !queue.length();
+	stop |= timer.isTimeout();
+	stop |= queue.length() > maxQueue;
+	stop |= out.length() > maxSentences;
+
+	if (!stop) goto PASS;
+}
+
+void CfGrammar::printSentence(Sentence& in) {
+	printf("Sentence:");
+	for (auto term : in.terms) {
+		printf(" %s", term->id.read());
+	}
+	printf("\n");
+}
+
 bool CfGrammar::compile() {
 
 	if (!rules.length()) {
diff --git a/Parser/public/CfGrammar.hpp b/Parser/public/CfGrammar.hpp
index 8e4a4f7..f8b650e 100644
--- a/Parser/public/CfGrammar.hpp
+++ b/Parser/public/CfGrammar.hpp
@@ -18,6 +18,14 @@ namespace tp {
 			List<Arg> args;
 		};
 
+		struct Sentence {
+			struct Term {
+				String id;
+				bool terminal;
+			};
+			List<Term> terms;
+		};
+
 		List<Rule> rules;
 		String startTerminal;
 
@@ -41,7 +49,10 @@ namespace tp {
 		bool parse(CfGrammarParserState* context, const String& source);
 		bool compile();
 
-		bool isAmbiguous();
+		void generateSentences(List<Sentence>& out);
+		static void printSentence(Sentence& in);
+
+	private:
 		void optimize();
 	};
 }
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