diff --git a/src/coders/commons.cpp b/src/coders/commons.cpp
index ff86b5a3..1f1b38a4 100644
--- a/src/coders/commons.cpp
+++ b/src/coders/commons.cpp
@@ -16,13 +16,18 @@ inline double power(double base, int64_t power) {
 
 parsing_error::parsing_error(
     std::string message,
-    std::string filename,
-    std::string source,
+    std::string_view filename,
+    std::string_view source,
     uint pos,
     uint line,
     uint linestart)
-    : std::runtime_error(message), filename(filename), source(source), 
+    : std::runtime_error(message), filename(filename), 
       pos(pos), line(line), linestart(linestart) {
+        size_t end = source.find("\n", linestart);
+    if (end == std::string::npos) {
+        end = source.length();
+    }
+    source = source.substr(linestart, end-linestart);
 }
 
 std::string parsing_error::errorLog() const {
@@ -30,11 +35,7 @@ std::string parsing_error::errorLog() const {
     uint linepos = pos - linestart;
     ss << "parsing error in file '" << filename;
     ss << "' at " << (line+1) << ":" << linepos << ": " << this->what() << "\n";
-    size_t end = source.find("\n", linestart);
-    if (end == std::string::npos) {
-        end = source.length();
-    }
-    ss << source.substr(linestart, end-linestart) << "\n";
+    ss << source << "\n";
     for (uint i = 0; i < linepos; i++) {
         ss << " ";
     }
@@ -43,8 +44,8 @@ std::string parsing_error::errorLog() const {
 }
 
 BasicParser::BasicParser(
-    const std::string& file,
-    const std::string& source
+    std::string_view file,
+    std::string_view source
 ) : filename(file), source(source) {
 }
 
@@ -164,7 +165,7 @@ char BasicParser::peek() {
     return source[pos];
 }
 
-std::string BasicParser::readUntil(char c) {
+std::string_view BasicParser::readUntil(char c) {
     int start = pos;
     while (hasNext() && source[pos] != c) {
         pos++;
@@ -185,7 +186,7 @@ std::string BasicParser::parseName() {
     while (hasNext() && is_identifier_part(source[pos])) {
         pos++;
     }
-    return source.substr(start, pos-start);
+    return std::string(source.substr(start, pos-start));
 }
 
 int64_t BasicParser::parseSimpleInt(int base) {
diff --git a/src/coders/commons.hpp b/src/coders/commons.hpp
index afebda89..c45d4f28 100644
--- a/src/coders/commons.hpp
+++ b/src/coders/commons.hpp
@@ -61,8 +61,8 @@ public:
 
     parsing_error(
         std::string message, 
-        std::string filename, 
-        std::string source, 
+        std::string_view filename, 
+        std::string_view source, 
         uint pos, 
         uint line, 
         uint linestart
@@ -72,8 +72,8 @@ public:
 
 class BasicParser {
 protected:
-    const std::string& filename;
-    const std::string& source;
+    std::string_view filename;
+    std::string_view source;
     uint pos = 0;
     uint line = 1;
     uint linestart = 0;
@@ -95,13 +95,13 @@ protected:
     parsing_error error(std::string message);
 
 public:
-    std::string readUntil(char c);
+    std::string_view readUntil(char c);
     std::string parseName();
     bool hasNext();
     char peek();
     char nextChar();
 
-    BasicParser(const std::string& file, const std::string& source);
+    BasicParser(std::string_view file, std::string_view source);
 };
 
 #endif // CODERS_COMMONS_HPP_
diff --git a/src/coders/json.cpp b/src/coders/json.cpp
index 36313314..b8db4402 100644
--- a/src/coders/json.cpp
+++ b/src/coders/json.cpp
@@ -11,6 +11,16 @@
 using namespace json;
 using namespace dynamic;
 
+class Parser : BasicParser {
+    std::unique_ptr<dynamic::List> parseList();
+    std::unique_ptr<dynamic::Map> parseObject();
+    dynamic::Value parseValue();
+public:
+    Parser(std::string_view filename, std::string_view source);
+    
+    std::unique_ptr<dynamic::Map> parse();
+};
+
 inline void newline(
     std::stringstream& ss, 
     bool nice, uint indent, 
@@ -126,7 +136,7 @@ std::string json::stringify(
     return ss.str();
 }
 
-Parser::Parser(const std::string& filename, const std::string& source) 
+Parser::Parser(std::string_view filename, std::string_view source) 
     : BasicParser(filename, source) {    
 }
 
diff --git a/src/coders/json.hpp b/src/coders/json.hpp
index 1643ce35..6dfe9c8e 100644
--- a/src/coders/json.hpp
+++ b/src/coders/json.hpp
@@ -14,16 +14,6 @@
 #include <unordered_map>
 
 namespace json {
-    class Parser : public BasicParser {
-        std::unique_ptr<dynamic::List> parseList();
-        std::unique_ptr<dynamic::Map> parseObject();
-        dynamic::Value parseValue();
-    public:
-        Parser(const std::string& filename, const std::string& source);
-        
-        std::unique_ptr<dynamic::Map> parse();
-    };
-
     std::unique_ptr<dynamic::Map> parse(const std::string& filename, const std::string& source);
     std::unique_ptr<dynamic::Map> parse(const std::string& source);
 
diff --git a/src/coders/toml.cpp b/src/coders/toml.cpp
index 26bc5d17..dfa0e467 100644
--- a/src/coders/toml.cpp
+++ b/src/coders/toml.cpp
@@ -14,7 +14,7 @@
 
 using namespace toml;
 
-class Reader : public BasicParser {
+class Reader : BasicParser {
     SettingsHandler& handler;
 
     void skipWhitespace() override {
@@ -83,8 +83,8 @@ class Reader : public BasicParser {
 public:
     Reader(
         SettingsHandler& handler,
-        const std::string& file, 
-        const std::string& source) 
+        std::string_view file, 
+        std::string_view source) 
     : BasicParser(file, source), handler(handler) {
     }
 
diff --git a/src/coders/xml.cpp b/src/coders/xml.cpp
index 59842ff2..0f96efed 100644
--- a/src/coders/xml.cpp
+++ b/src/coders/xml.cpp
@@ -177,7 +177,7 @@ const std::string& Document::getEncoding() const {
     return encoding;
 }
 
-Parser::Parser(const std::string& filename, const std::string& source) 
+Parser::Parser(std::string_view filename, std::string_view source) 
     : BasicParser(filename, source) {
 }
 
@@ -250,7 +250,7 @@ std::string Parser::parseText() {
         }
         nextChar();
     }
-    return source.substr(start, pos-start);
+    return std::string(source.substr(start, pos-start));
 }
 
 inline bool is_xml_identifier_start(char c) {
@@ -270,7 +270,7 @@ std::string Parser::parseXMLName() {
     while (hasNext() && is_xml_identifier_part(source[pos])) {
         pos++;
     }
-    return source.substr(start, pos-start);
+    return std::string(source.substr(start, pos-start));
 }
 
 xmlelement Parser::parseElement() {
diff --git a/src/coders/xml.hpp b/src/coders/xml.hpp
index f8da875d..aff5288c 100644
--- a/src/coders/xml.hpp
+++ b/src/coders/xml.hpp
@@ -108,7 +108,7 @@ namespace xml {
         const std::string& getEncoding() const;
     };
 
-    class Parser : public BasicParser {
+    class Parser : BasicParser {
         xmldocument document;
 
         xmlelement parseOpenTag();
@@ -118,7 +118,7 @@ namespace xml {
         std::string parseText();
         std::string parseXMLName();
     public:
-        Parser(const std::string& filename, const std::string& source);
+        Parser(std::string_view filename, std::string_view source);
 
         xmldocument parse();
     };
diff --git a/src/frontend/locale.cpp b/src/frontend/locale.cpp
index 2afb23f6..1c9730b8 100644
--- a/src/frontend/locale.cpp
+++ b/src/frontend/locale.cpp
@@ -35,8 +35,8 @@ const std::string& langs::Lang::getId() const {
     return locale;
 }
 
-/* Language key-value txt files parser */
-class Reader : public BasicParser {
+// @brief Language key-value txt files parser
+class Reader : BasicParser {
     void skipWhitespace() override {
         BasicParser::skipWhitespace();
         if (hasNext() && source[pos] == '#') {
@@ -47,7 +47,7 @@ class Reader : public BasicParser {
         }
     }
 public:
-    Reader(const std::string& file, const std::string& source) : BasicParser(file, source) {
+    Reader(std::string_view file, std::string_view source) : BasicParser(file, source) {
     }
 
     void read(langs::Lang& lang, std::string prefix) {
diff --git a/src/frontend/menu.cpp b/src/frontend/menu.cpp
index e8a9b5fc..3796f88c 100644
--- a/src/frontend/menu.cpp
+++ b/src/frontend/menu.cpp
@@ -46,11 +46,12 @@ gui::page_loader_func menus::create_page_loader(Engine* engine) {
             name = query.substr(0, index);
             
             auto map = std::make_shared<Map>();
-            BasicParser parser("query for "+name, argstr);
+            auto filename = "query for "+name;
+            BasicParser parser(filename, argstr);
             while (parser.hasNext()) {
-                auto key = parser.readUntil('=');
+                auto key = std::string(parser.readUntil('='));
                 parser.nextChar();
-                auto value = parser.readUntil('&');
+                auto value = std::string(parser.readUntil('&'));
                 map->put(key, value);
             }
             args.push_back(map);