diff --git a/alib2cli/src/lexer/CharSequenceBase.h b/alib2cli/src/lexer/CharSequenceBase.h
index 6ea9ed496d42f6cc4d6a3dc8c9f785c6868482eb..8ec74b42bf931dc1ab83f57119d50e8ecc4b50f4 100644
--- a/alib2cli/src/lexer/CharSequenceBase.h
+++ b/alib2cli/src/lexer/CharSequenceBase.h
@@ -6,13 +6,14 @@
 namespace cli {
 
 class CharSequenceBase {
+	std::string putbackBuffer;
+
 protected:
 	const char * linePtr;
 	bool endOfTransmition = false;
 	bool endOfSequence = false;
 
 	virtual void fetch ( bool readNextLine ) = 0;
-	std::string putbackBuffer;
 
 public:
 	CharSequenceBase ( ) = default;
@@ -40,7 +41,7 @@ public:
 		if ( ! putbackBuffer.empty ( ) ) {
 			putbackBuffer.pop_back ( );
 		} else {
-			if ( * linePtr )
+			if ( * linePtr != 0 )
 				++ linePtr;
 			if ( * linePtr == '\0' )
 				fetch ( readNextLine );
diff --git a/aql2/src/prompt/ReadlineCharSequence.h b/aql2/src/prompt/ReadlineCharSequence.h
index d234211824566173343f572666cfaaf2d7512792..a7fd8c914a2cd52c9123d4c3d6a4fe853b91a532 100644
--- a/aql2/src/prompt/ReadlineCharSequence.h
+++ b/aql2/src/prompt/ReadlineCharSequence.h
@@ -23,13 +23,13 @@ class ReadlineCharSequence final : public cli::CharSequenceBase {
 	bool forceReadLine = false;
 
 	void fetch ( bool readNextLine ) override {
-		if ( readNextLine == false && forceReadLine == false ) {
+		if ( ! readNextLine && ! forceReadLine ) {
 			this->endOfSequence = true;
 			return;
 		}
 
 		char * read = ::readline ( first ? "> ": "+ " );
-		if ( ! read ) {
+		if ( read == nullptr ) {
 			this->endOfTransmition = true;
 			return;
 		}
diff --git a/aql2/src/prompt/ReadlinePromptHistory.h b/aql2/src/prompt/ReadlinePromptHistory.h
index 4e37c808076f04bcd346e2f325c07599edfabc57..fd7533488d8f5a5780a5a3b8e148e38bcd636bd1 100644
--- a/aql2/src/prompt/ReadlinePromptHistory.h
+++ b/aql2/src/prompt/ReadlinePromptHistory.h
@@ -66,7 +66,7 @@ class ReadlinePromptHistory {
 	static void history_transform ( Callable callable ) {
 		HIST_ENTRY ** history = history_list ( );
 		if ( history ) {
-			unsigned i = 0;
+			int i = 0;
 			while ( * history ) {
 				char * tmp = callable ( ( * history )->line );
 				replace_history_entry ( i, tmp, ( * history )->data );