Add [[nodiscard]] where fitting, update unit tests (#49)

include/ss/common.hpp

@@ -32,7 +32,7 @@ void assert_throw_on_error_not_defined() {
                                  "'throw_on_error' is enabled");
 }
 
-inline void* strict_realloc(void* ptr, size_t size) {
+[[nodiscard]] inline void* strict_realloc(void* ptr, size_t size) {
     ptr = std::realloc(ptr, size);
     if (!ptr) {
         throw std::bad_alloc{};
@@ -42,14 +42,16 @@ inline void* strict_realloc(void* ptr, size_t size) {
 }
 
 #if __unix__
-inline ssize_t get_line_file(char*& lineptr, size_t& n, FILE* file) {
+[[nodiscard]] inline ssize_t get_line_file(char*& lineptr, size_t& n,
+                                           FILE* file) {
     return getline(&lineptr, &n, file);
 }
 #else
 
 using ssize_t = intptr_t;
 
-inline ssize_t get_line_file(char*& lineptr, size_t& n, FILE* file) {
+[[nodiscard]] inline ssize_t get_line_file(char*& lineptr, size_t& n,
+                                           FILE* file) {
     std::array<char, get_line_initial_buffer_size> buff;
 
     if (lineptr == nullptr || n < sizeof(buff)) {
@@ -85,8 +87,9 @@ inline ssize_t get_line_file(char*& lineptr, size_t& n, FILE* file) {
 
 #endif
 
-inline ssize_t get_line_buffer(char*& lineptr, size_t& n,
+[[nodiscard]] inline ssize_t get_line_buffer(char*& lineptr, size_t& n,
-                        const char* const csv_data_buffer, size_t csv_data_size,
+                                             const char* const csv_data_buffer,
+                                             size_t csv_data_size,
                                              size_t& curr_char) {
     if (curr_char >= csv_data_size) {
         return -1;
@@ -122,10 +125,10 @@ inline ssize_t get_line_buffer(char*& lineptr, size_t& n,
     return line_used;
 }
 
-inline std::tuple<ssize_t, bool> get_line(char*& buffer, size_t& buffer_size,
+[[nodiscard]] inline std::tuple<ssize_t, bool> get_line(
-                                   FILE* file,
+    char*& buffer, size_t& buffer_size, FILE* file,
-                                   const char* const csv_data_buffer,
+    const char* const csv_data_buffer, size_t csv_data_size,
-                                   size_t csv_data_size, size_t& curr_char) {
+    size_t& curr_char) {
     ssize_t ssize = 0;
     if (file) {
         ssize = get_line_file(buffer, buffer_size, file);

include/ss/converter.hpp

@@ -110,15 +110,15 @@ public:
     // parses line with given delimiter, returns a 'T' object created with
     // extracted values of type 'Ts'
     template <typename T, typename... Ts>
-    T convert_object(line_ptr_type line,
+    [[nodiscard]] T convert_object(
-                     const std::string& delim = default_delimiter) {
+        line_ptr_type line, const std::string& delim = default_delimiter) {
         return to_object<T>(convert<Ts...>(line, delim));
     }
 
     // parses line with given delimiter, returns tuple of objects with
     // extracted values of type 'Ts'
     template <typename... Ts>
-    no_void_validator_tup_t<Ts...> convert(
+    [[nodiscard]] no_void_validator_tup_t<Ts...> convert(
         line_ptr_type line, const std::string& delim = default_delimiter) {
         split(line, delim);
         if (splitter_.valid()) {
@@ -131,13 +131,13 @@ public:
 
     // parses already split line, returns 'T' object with extracted values
     template <typename T, typename... Ts>
-    T convert_object(const split_data& elems) {
+    [[nodiscard]] T convert_object(const split_data& elems) {
         return to_object<T>(convert<Ts...>(elems));
     }
 
     // same as above, but uses cached split line
     template <typename T, typename... Ts>
-    T convert_object() {
+    [[nodiscard]] T convert_object() {
         return to_object<T>(convert<Ts...>());
     }
 
@@ -146,7 +146,8 @@ public:
     // one argument is given which is a class which has a tied
     // method which returns a tuple, returns that type
     template <typename T, typename... Ts>
-    no_void_validator_tup_t<T, Ts...> convert(const split_data& elems) {
+    [[nodiscard]] no_void_validator_tup_t<T, Ts...> convert(
+        const split_data& elems) {
         if constexpr (sizeof...(Ts) == 0 && is_instance_of_v<std::tuple, T>) {
             return convert_impl(elems, static_cast<T*>(nullptr));
         } else if constexpr (tied_class_v<T, Ts...>) {
@@ -162,11 +163,11 @@ public:
 
     // same as above, but uses cached split line
     template <typename T, typename... Ts>
-    no_void_validator_tup_t<T, Ts...> convert() {
+    [[nodiscard]] no_void_validator_tup_t<T, Ts...> convert() {
         return convert<T, Ts...>(splitter_.split_data_);
     }
 
-    bool valid() const {
+    [[nodiscard]] bool valid() const {
         if constexpr (string_error) {
             return error_.empty();
         } else if constexpr (throw_on_error) {
@@ -176,12 +177,12 @@ public:
         }
     }
 
-    const std::string& error_msg() const {
+    [[nodiscard]] const std::string& error_msg() const {
         assert_string_error_defined<string_error>();
         return error_;
     }
 
-    bool unterminated_quote() const {
+    [[nodiscard]] bool unterminated_quote() const {
         return splitter_.unterminated_quote();
     }
 
@@ -207,7 +208,7 @@ private:
         return splitter_.resplit(new_line, new_size, delim);
     }
 
-    size_t size_shifted() {
+    [[nodiscard]] size_t size_shifted() {
         return splitter_.size_shifted();
     }
 
@@ -223,7 +224,8 @@ private:
         }
     }
 
-    std::string error_sufix(const string_range msg, size_t pos) const {
+    [[nodiscard]] std::string error_sufix(const string_range msg,
+                                          size_t pos) const {
         constexpr static auto reserve_size = 32;
         std::string error;
         error.reserve(reserve_size);
@@ -351,7 +353,8 @@ private:
     ////////////////
 
     template <typename... Ts>
-    no_void_validator_tup_t<Ts...> convert_impl(const split_data& elems) {
+    [[nodiscard]] no_void_validator_tup_t<Ts...> convert_impl(
+        const split_data& elems) {
         clear_error();
 
         if (!splitter_.valid()) {
@@ -382,7 +385,7 @@ private:
     }
 
     template <typename... Ts>
-    no_void_validator_tup_t<std::tuple<Ts...>> convert_impl(
+    [[nodiscard]] no_void_validator_tup_t<std::tuple<Ts...>> convert_impl(
         const split_data& elems, const std::tuple<Ts...>*) {
         return convert_impl<Ts...>(elems);
     }
@@ -391,11 +394,11 @@ private:
     // column mapping
     ////////////////
 
-    bool columns_mapped() const {
+    [[nodiscard]] bool columns_mapped() const {
         return !column_mappings_.empty();
     }
 
-    size_t column_position(size_t tuple_position) const {
+    [[nodiscard]] size_t column_position(size_t tuple_position) const {
         if (!columns_mapped()) {
             return tuple_position;
         }
@@ -426,7 +429,7 @@ private:
         }
 
         if constexpr (std::is_same_v<T, std::string>) {
-            extract(msg.first, msg.second, dst);
+            static_cast<void>(extract(msg.first, msg.second, dst));
             return;
         }
 
@@ -472,7 +475,8 @@ private:
     }
 
     template <typename... Ts>
-    no_void_validator_tup_t<Ts...> extract_tuple(const split_data& elems) {
+    [[nodiscard]] no_void_validator_tup_t<Ts...> extract_tuple(
+        const split_data& elems) {
         static_assert(!all_of_v<std::is_void, Ts...>,
                       "at least one parameter must be non void");
         no_void_validator_tup_t<Ts...> ret{};

include/ss/exception.hpp

@@ -12,10 +12,10 @@ class exception : public std::exception {
     std::string msg_;
 
 public:
-    exception(std::string msg): msg_{std::move(msg)} {
+    exception(std::string msg) : msg_{std::move(msg)} {
     }
 
-    char const* what() const noexcept override {
+    [[nodiscard]] char const* what() const noexcept override {
         return msg_.c_str();
     }
 };

include/ss/extract.hpp

@@ -13,8 +13,8 @@
 #include <fast_float/fast_float.h>
 #else
 #include <algorithm>
-#include <cstdlib>
 #include <array>
+#include <cstdlib>
 #endif
 
 namespace ss {
@@ -26,8 +26,8 @@ namespace ss {
 #ifndef SSP_DISABLE_FAST_FLOAT
 
 template <typename T>
-std::enable_if_t<std::is_floating_point_v<T>, std::optional<T>> to_num(
+[[nodiscard]] std::enable_if_t<std::is_floating_point_v<T>, std::optional<T>>
-    const char* const begin, const char* const end) {
+to_num(const char* const begin, const char* const end) {
     T ret;
     auto [ptr, ec] = fast_float::from_chars(begin, end, ret);
 
@@ -40,8 +40,8 @@ std::enable_if_t<std::is_floating_point_v<T>, std::optional<T>> to_num(
 #else
 
 template <typename T>
-std::enable_if_t<std::is_floating_point_v<T>, std::optional<T>> to_num(
+[[nodiscard]] std::enable_if_t<std::is_floating_point_v<T>, std::optional<T>>
-    const char* const begin, const char* const end) {
+to_num(const char* const begin, const char* const end) {
     static_assert(!std::is_same_v<T, long double>,
                   "Conversion to long double is disabled");
 
@@ -114,7 +114,7 @@ using int8 = numeric_wrapper<int8_t>;
 using uint8 = numeric_wrapper<uint8_t>;
 
 template <typename T>
-std::enable_if_t<std::is_integral_v<T>, std::optional<T>> to_num(
+[[nodiscard]] std::enable_if_t<std::is_integral_v<T>, std::optional<T>> to_num(
     const char* const begin, const char* const end) {
     T ret;
     auto [ptr, ec] = std::from_chars(begin, end, ret);
@@ -126,8 +126,9 @@ std::enable_if_t<std::is_integral_v<T>, std::optional<T>> to_num(
 }
 
 template <typename T>
-std::enable_if_t<is_instance_of_v<numeric_wrapper, T>, std::optional<T>> to_num(
+[[nodiscard]] std::enable_if_t<is_instance_of_v<numeric_wrapper, T>,
-    const char* const begin, const char* const end) {
+                               std::optional<T>>
+to_num(const char* const begin, const char* const end) {
     T ret;
     auto [ptr, ec] = std::from_chars(begin, end, ret.value);
 
@@ -149,7 +150,8 @@ struct unsupported_type {
 } /* namespace errors */
 
 template <typename T>
-std::enable_if_t<!std::is_integral_v<T> && !std::is_floating_point_v<T> &&
+[[nodiscard]] std::enable_if_t<!std::is_integral_v<T> &&
+                                   !std::is_floating_point_v<T> &&
                                    !is_instance_of_v<std::optional, T> &&
                                    !is_instance_of_v<std::variant, T> &&
                                    !is_instance_of_v<numeric_wrapper, T>,
@@ -161,7 +163,8 @@ extract(const char*, const char*, T&) {
 }
 
 template <typename T>
-std::enable_if_t<std::is_integral_v<T> || std::is_floating_point_v<T> ||
+[[nodiscard]] std::enable_if_t<std::is_integral_v<T> ||
+                                   std::is_floating_point_v<T> ||
                                    is_instance_of_v<numeric_wrapper, T>,
                                bool>
 extract(const char* begin, const char* end, T& value) {
@@ -174,8 +177,8 @@ extract(const char* begin, const char* end, T& value) {
 }
 
 template <typename T>
-std::enable_if_t<is_instance_of_v<std::optional, T>, bool> extract(
+[[nodiscard]] std::enable_if_t<is_instance_of_v<std::optional, T>, bool>
-    const char* begin, const char* end, T& value) {
+extract(const char* begin, const char* end, T& value) {
     typename T::value_type raw_value;
     if (extract(begin, end, raw_value)) {
         value = raw_value;
@@ -186,7 +189,8 @@ std::enable_if_t<is_instance_of_v<std::optional, T>, bool> extract(
 }
 
 template <typename T, size_t I>
-bool extract_variant(const char* begin, const char* end, T& value) {
+[[nodiscard]] bool extract_variant(const char* begin, const char* end,
+                                   T& value) {
     using IthType = std::variant_alternative_t<I, std::decay_t<T>>;
     IthType ithValue;
     if (extract<IthType>(begin, end, ithValue)) {
@@ -199,7 +203,7 @@ bool extract_variant(const char* begin, const char* end, T& value) {
 }
 
 template <typename T>
-std::enable_if_t<is_instance_of_v<std::variant, T>, bool> extract(
+[[nodiscard]] std::enable_if_t<is_instance_of_v<std::variant, T>, bool> extract(
     const char* begin, const char* end, T& value) {
     return extract_variant<T, 0>(begin, end, value);
 }
@@ -209,7 +213,8 @@ std::enable_if_t<is_instance_of_v<std::variant, T>, bool> extract(
 ////////////////
 
 template <>
-inline bool extract(const char* begin, const char* end, bool& value) {
+[[nodiscard]] inline bool extract(const char* begin, const char* end,
+                                  bool& value) {
     if (end == begin + 1) {
         if (*begin == '1') {
             value = true;
@@ -236,19 +241,21 @@ inline bool extract(const char* begin, const char* end, bool& value) {
 }
 
 template <>
-inline bool extract(const char* begin, const char* end, char& value) {
+[[nodiscard]] inline bool extract(const char* begin, const char* end,
+                                  char& value) {
     value = *begin;
     return (end == begin + 1);
 }
 
 template <>
-inline bool extract(const char* begin, const char* end, std::string& value) {
+[[nodiscard]] inline bool extract(const char* begin, const char* end,
+                                  std::string& value) {
     value = std::string{begin, end};
     return true;
 }
 
 template <>
-inline bool extract(const char* begin, const char* end,
+[[nodiscard]] inline bool extract(const char* begin, const char* end,
                                   std::string_view& value) {
     value = std::string_view{begin, static_cast<size_t>(end - begin)};
     return true;

include/ss/parser.hpp

@@ -75,7 +75,7 @@ public:
     parser(const parser& other) = delete;
     parser& operator=(const parser& other) = delete;
 
-    bool valid() const {
+    [[nodiscard]] bool valid() const {
         if constexpr (string_error) {
             return error_.empty();
         } else if constexpr (throw_on_error) {
@@ -85,12 +85,12 @@ public:
         }
     }
 
-    const std::string& error_msg() const {
+    [[nodiscard]] const std::string& error_msg() const {
         assert_string_error_defined<string_error>();
         return error_;
     }
 
-    bool eof() const {
+    [[nodiscard]] bool eof() const {
         return eof_;
     }
 
@@ -99,21 +99,21 @@ public:
     }
 
     template <typename T, typename... Ts>
-    T get_object() {
+    [[nodiscard]] T get_object() {
         return to_object<T>(get_next<Ts...>());
     }
 
-    size_t line() const {
+    [[nodiscard]] size_t line() const {
         return reader_.line_number_ > 0 ? reader_.line_number_ - 1
                                         : reader_.line_number_;
     }
 
-    size_t position() const {
+    [[nodiscard]] size_t position() const {
         return reader_.chars_read_;
     }
 
     template <typename T, typename... Ts>
-    no_void_validator_tup_t<T, Ts...> get_next() {
+    [[nodiscard]] no_void_validator_tup_t<T, Ts...> get_next() {
         std::optional<std::string> error;
 
         if (!eof_) {
@@ -164,12 +164,12 @@ public:
         return value;
     }
 
-    std::string raw_header() const {
+    [[nodiscard]] std::string raw_header() const {
         assert_ignore_header_not_defined();
         return raw_header_;
     }
 
-    std::vector<std::string> header() {
+    [[nodiscard]] std::vector<std::string> header() {
         assert_ignore_header_not_defined();
         clear_error();
 
@@ -188,7 +188,7 @@ public:
         return split_header;
     }
 
-    bool field_exists(const std::string& field) {
+    [[nodiscard]] bool field_exists(const std::string& field) {
         assert_ignore_header_not_defined();
         clear_error();
 
@@ -273,11 +273,11 @@ public:
             iterator& operator=(const iterator& other) = delete;
             iterator& operator=(iterator&& other) = delete;
 
-            value& operator*() {
+            [[nodiscard]] value& operator*() {
                 return value_;
             }
 
-            value* operator->() {
+            [[nodiscard]] value* operator->() {
                 return &value_;
             }
 
@@ -302,13 +302,15 @@ public:
                 return result;
             }
 
-            friend bool operator==(const iterator& lhs, const iterator& rhs) {
+            [[nodiscard]] friend bool operator==(const iterator& lhs,
+                                                 const iterator& rhs) {
                 return (lhs.parser_ == nullptr && rhs.parser_ == nullptr) ||
                        (lhs.parser_ == rhs.parser_ &&
                         &lhs.value_ == &rhs.value_);
             }
 
-            friend bool operator!=(const iterator& lhs, const iterator& rhs) {
+            [[nodiscard]] friend bool operator!=(const iterator& lhs,
+                                                 const iterator& rhs) {
                 return !(lhs == rhs);
             }
 
@@ -320,11 +322,11 @@ public:
         iterable(parser<Options...>* parser) : parser_{parser} {
         }
 
-        iterator begin() {
+        [[nodiscard]] iterator begin() {
             return ++iterator{parser_};
         }
 
-        iterator end() {
+        [[nodiscard]] iterator end() {
             return iterator{};
         }
 
@@ -333,12 +335,12 @@ public:
     };
 
     template <typename... Ts>
-    auto iterate() {
+    [[nodiscard]] auto iterate() {
         return iterable<false, Ts...>{this};
     }
 
     template <typename... Ts>
-    auto iterate_object() {
+    [[nodiscard]] auto iterate_object() {
         return iterable<true, Ts...>{this};
     }
 
@@ -376,7 +378,7 @@ public:
             return composite_with(std::move(value));
         }
 
-        std::tuple<Ts...> values() {
+        [[nodiscard]] std::tuple<Ts...> values() {
             return values_;
         }
 
@@ -399,7 +401,7 @@ public:
 
     private:
         template <typename T>
-        composite<Ts..., T> composite_with(T&& new_value) {
+        [[nodiscard]] composite<Ts..., T> composite_with(T&& new_value) {
             auto merged_values =
                 std::tuple_cat(std::move(values_),
                                std::tuple<T>{parser_.valid()
@@ -429,7 +431,7 @@ public:
         }
 
         template <typename U, typename... Us>
-        no_void_validator_tup_t<U, Us...> try_same() {
+        [[nodiscard]] no_void_validator_tup_t<U, Us...> try_same() {
             parser_.clear_error();
             auto value =
                 parser_.reader_.converter_.template convert<U, Us...>();
@@ -450,8 +452,8 @@ public:
     // tries to convert a line and returns a composite which is
     // able to try additional conversions in case of failure
     template <typename... Ts, typename Fun = none>
-    composite<std::optional<no_void_validator_tup_t<Ts...>>> try_next(
+    [[nodiscard]] composite<std::optional<no_void_validator_tup_t<Ts...>>>
-        Fun&& fun = none{}) {
+    try_next(Fun&& fun = none{}) {
         assert_throw_on_error_not_defined<throw_on_error>();
         using Ret = no_void_validator_tup_t<Ts...>;
         return try_invoke_and_make_composite<
@@ -461,7 +463,7 @@ public:
     // identical to try_next but returns composite with object instead of a
     // tuple
     template <typename T, typename... Ts, typename Fun = none>
-    composite<std::optional<T>> try_object(Fun&& fun = none{}) {
+    [[nodiscard]] composite<std::optional<T>> try_object(Fun&& fun = none{}) {
         assert_throw_on_error_not_defined<throw_on_error>();
         return try_invoke_and_make_composite<
             std::optional<T>>(get_object<T, Ts...>(), std::forward<Fun>(fun));
@@ -512,7 +514,8 @@ private:
     }
 
     template <typename T, typename Fun = none>
-    composite<T> try_invoke_and_make_composite(T&& value, Fun&& fun) {
+    [[nodiscard]] composite<T> try_invoke_and_make_composite(T&& value,
+                                                             Fun&& fun) {
         if (valid()) {
             try_invoke(*value, std::forward<Fun>(fun));
         }
@@ -528,7 +531,8 @@ private:
                       "cannot use this method when 'ignore_header' is defined");
     }
 
-    bool strict_split(header_splitter& splitter, std::string& header) {
+    [[nodiscard]] bool strict_split(header_splitter& splitter,
+                                    std::string& header) {
         if (header.empty()) {
             return false;
         }
@@ -575,7 +579,7 @@ private:
         }
     }
 
-    std::optional<size_t> header_index(const std::string& field) {
+    [[nodiscard]] std::optional<size_t> header_index(const std::string& field) {
         auto it = std::find(header_.begin(), header_.end(), field);
 
         if (it == header_.end()) {
@@ -846,7 +850,7 @@ private:
         reader& operator=(const reader& other) = delete;
 
         // read next line each time in order to set eof_
-        bool read_next() {
+        [[nodiscard]] bool read_next() {
             next_line_converter_.clear_error();
             size_t size = 0;
             while (size == 0) {
@@ -938,7 +942,7 @@ private:
             std::swap(converter_, next_line_converter_);
         }
 
-        bool multiline_limit_reached(size_t& limit) {
+        [[nodiscard]] bool multiline_limit_reached(size_t& limit) {
             if constexpr (multiline::size > 0) {
                 if (limit++ >= multiline::size) {
                     next_line_converter_.handle_error_multiline_limit_reached();
@@ -948,7 +952,7 @@ private:
             return false;
         }
 
-        bool escaped_eol(size_t size) {
+        [[nodiscard]] bool escaped_eol(size_t size) {
             const char* curr = nullptr;
             for (curr = next_line_buffer_ + size - 1;
                  curr >= next_line_buffer_ &&
@@ -958,7 +962,7 @@ private:
             return (next_line_buffer_ - curr + size) % 2 == 0;
         }
 
-        bool unterminated_quote() {
+        [[nodiscard]] bool unterminated_quote() {
             return next_line_converter_.unterminated_quote();
         }
 
@@ -973,7 +977,7 @@ private:
             }
         }
 
-        size_t remove_eol(char*& buffer, size_t ssize) {
+        [[nodiscard]] size_t remove_eol(char*& buffer, size_t ssize) {
             if (buffer[ssize - 1] != '\n') {
                 crlf_ = false;
                 return ssize;
@@ -1003,7 +1007,8 @@ private:
             first_size += second_size;
         }
 
-        bool append_next_line_to_buffer(char*& buffer, size_t& line_size,
+        [[nodiscard]] bool append_next_line_to_buffer(char*& buffer,
+                                                      size_t& line_size,
                                                       size_t buffer_size) {
             undo_remove_eol(buffer, line_size, buffer_size);
 
@@ -1023,7 +1028,7 @@ private:
             return true;
         }
 
-        std::string get_buffer() {
+        [[nodiscard]] std::string get_buffer() {
             return std::string{next_line_buffer_, next_line_size_};
         }
 

include/ss/restrictions.hpp

@@ -10,7 +10,7 @@ template <typename T, auto... Values>
 struct ax {
 private:
     template <auto X, auto... Xs>
-    bool ss_valid_impl(const T& x) const {
+    [[nodiscard]] bool ss_valid_impl(const T& x) const {
         if constexpr (sizeof...(Xs) != 0) {
             return x != X && ss_valid_impl<Xs...>(x);
         }
@@ -18,11 +18,11 @@ private:
     }
 
 public:
-    bool ss_valid(const T& value) const {
+    [[nodiscard]] bool ss_valid(const T& value) const {
         return ss_valid_impl<Values...>(value);
     }
 
-    const char* error() const {
+    [[nodiscard]] const char* error() const {
         return "value excluded";
     }
 };
@@ -35,7 +35,7 @@ template <typename T, auto... Values>
 struct nx {
 private:
     template <auto X, auto... Xs>
-    bool ss_valid_impl(const T& x) const {
+    [[nodiscard]] bool ss_valid_impl(const T& x) const {
         if constexpr (sizeof...(Xs) != 0) {
             return x == X || ss_valid_impl<Xs...>(x);
         }
@@ -43,11 +43,11 @@ private:
     }
 
 public:
-    bool ss_valid(const T& value) const {
+    [[nodiscard]] bool ss_valid(const T& value) const {
         return ss_valid_impl<Values...>(value);
     }
 
-    const char* error() const {
+    [[nodiscard]] const char* error() const {
         return "value excluded";
     }
 };
@@ -61,28 +61,28 @@ public:
 
 template <typename T, auto N>
 struct gt {
-    bool ss_valid(const T& value) const {
+    [[nodiscard]] bool ss_valid(const T& value) const {
         return value > N;
     }
 };
 
 template <typename T, auto N>
 struct gte {
-    bool ss_valid(const T& value) const {
+    [[nodiscard]] bool ss_valid(const T& value) const {
         return value >= N;
     }
 };
 
 template <typename T, auto N>
 struct lt {
-    bool ss_valid(const T& value) const {
+    [[nodiscard]] bool ss_valid(const T& value) const {
         return value < N;
     }
 };
 
 template <typename T, auto N>
 struct lte {
-    bool ss_valid(const T& value) const {
+    [[nodiscard]] bool ss_valid(const T& value) const {
         return value <= N;
     }
 };
@@ -93,7 +93,7 @@ struct lte {
 
 template <typename T, auto Min, auto Max>
 struct ir {
-    bool ss_valid(const T& value) const {
+    [[nodiscard]] bool ss_valid(const T& value) const {
         return value >= Min && value <= Max;
     }
 };
@@ -104,7 +104,7 @@ struct ir {
 
 template <typename T, auto Min, auto Max>
 struct oor {
-    bool ss_valid(const T& value) const {
+    [[nodiscard]] bool ss_valid(const T& value) const {
         return value < Min || value > Max;
     }
 };
@@ -115,11 +115,11 @@ struct oor {
 
 template <typename T>
 struct ne {
-    bool ss_valid(const T& value) const {
+    [[nodiscard]] bool ss_valid(const T& value) const {
         return !value.empty();
     }
 
-    const char* error() const {
+    [[nodiscard]] const char* error() const {
         return "empty field";
     }
 };

include/ss/splitter.hpp

@@ -28,7 +28,7 @@ private:
 public:
     using line_ptr_type = std::conditional_t<is_const_line, const char*, char*>;
 
-    bool valid() const {
+    [[nodiscard]] bool valid() const {
         if constexpr (string_error) {
             return error_.empty();
         } else if constexpr (throw_on_error) {
@@ -38,12 +38,12 @@ public:
         }
     }
 
-    const std::string& error_msg() const {
+    [[nodiscard]] const std::string& error_msg() const {
         assert_string_error_defined<string_error>();
         return error_;
     }
 
-    bool unterminated_quote() const {
+    [[nodiscard]] bool unterminated_quote() const {
         return unterminated_quote_;
     }
 
@@ -61,7 +61,7 @@ private:
     ////////////////
 
     // number of characters the end of line is shifted backwards
-    size_t size_shifted() const {
+    [[nodiscard]] size_t size_shifted() const {
         return escaped_;
     }
 
@@ -192,19 +192,19 @@ private:
     // matching
     ////////////////
 
-    bool match(const char* const curr, char delim) {
+    [[nodiscard]] bool match(const char* const curr, char delim) {
         return *curr == delim;
     };
 
-    bool match(const char* const curr, const std::string& delim) {
+    [[nodiscard]] bool match(const char* const curr, const std::string& delim) {
         return std::strncmp(curr, delim.c_str(), delim.size()) == 0;
     };
 
-    size_t delimiter_size(char) {
+    [[nodiscard]] size_t delimiter_size(char) {
         return 1;
     }
 
-    size_t delimiter_size(const std::string& delim) {
+    [[nodiscard]] size_t delimiter_size(const std::string& delim) {
         return delim.size();
     }
 
@@ -225,7 +225,7 @@ private:
     }
 
     template <typename Delim>
-    std::tuple<size_t, bool> match_delimiter(line_ptr_type begin,
+    [[nodiscard]] std::tuple<size_t, bool> match_delimiter(line_ptr_type begin,
                                                            const Delim& delim) {
         line_ptr_type end = begin;
 

include/ss/type_traits.hpp

@@ -366,12 +366,12 @@ constexpr bool is_instance_of_v = is_instance_of<Template, Ts...>::value;
 ////////////////
 
 template <class T, std::size_t... Is, class U>
-T to_object_impl(std::index_sequence<Is...>, U&& data) {
+[[nodiscard]] T to_object_impl(std::index_sequence<Is...>, U&& data) {
     return {std::get<Is>(std::forward<U>(data))...};
 }
 
 template <class T, class U>
-T to_object(U&& data) {
+[[nodiscard]] T to_object(U&& data) {
     using NoRefU = std::decay_t<U>;
     if constexpr (is_instance_of_v<std::tuple, NoRefU>) {
         return to_object_impl<

ssp.hpp

@@ -381,12 +381,12 @@ constexpr bool is_instance_of_v = is_instance_of<Template, Ts...>::value;
 ////////////////
 
 template <class T, std::size_t... Is, class U>
-T to_object_impl(std::index_sequence<Is...>, U&& data) {
+[[nodiscard]] T to_object_impl(std::index_sequence<Is...>, U&& data) {
     return {std::get<Is>(std::forward<U>(data))...};
 }
 
 template <class T, class U>
-T to_object(U&& data) {
+[[nodiscard]] T to_object(U&& data) {
     using NoRefU = std::decay_t<U>;
     if constexpr (is_instance_of_v<std::tuple, NoRefU>) {
         return to_object_impl<
@@ -409,10 +409,10 @@ class exception : public std::exception {
     std::string msg_;
 
 public:
-    exception(std::string msg): msg_{std::move(msg)} {
+    exception(std::string msg) : msg_{std::move(msg)} {
     }
 
-    char const* what() const noexcept override {
+    [[nodiscard]] char const* what() const noexcept override {
         return msg_.c_str();
     }
 };
@@ -505,7 +505,7 @@ template <typename T, auto... Values>
 struct ax {
 private:
     template <auto X, auto... Xs>
-    bool ss_valid_impl(const T& x) const {
+    [[nodiscard]] bool ss_valid_impl(const T& x) const {
         if constexpr (sizeof...(Xs) != 0) {
             return x != X && ss_valid_impl<Xs...>(x);
         }
@@ -513,11 +513,11 @@ private:
     }
 
 public:
-    bool ss_valid(const T& value) const {
+    [[nodiscard]] bool ss_valid(const T& value) const {
         return ss_valid_impl<Values...>(value);
     }
 
-    const char* error() const {
+    [[nodiscard]] const char* error() const {
         return "value excluded";
     }
 };
@@ -530,7 +530,7 @@ template <typename T, auto... Values>
 struct nx {
 private:
     template <auto X, auto... Xs>
-    bool ss_valid_impl(const T& x) const {
+    [[nodiscard]] bool ss_valid_impl(const T& x) const {
         if constexpr (sizeof...(Xs) != 0) {
             return x == X || ss_valid_impl<Xs...>(x);
         }
@@ -538,11 +538,11 @@ private:
     }
 
 public:
-    bool ss_valid(const T& value) const {
+    [[nodiscard]] bool ss_valid(const T& value) const {
         return ss_valid_impl<Values...>(value);
     }
 
-    const char* error() const {
+    [[nodiscard]] const char* error() const {
         return "value excluded";
     }
 };
@@ -556,28 +556,28 @@ public:
 
 template <typename T, auto N>
 struct gt {
-    bool ss_valid(const T& value) const {
+    [[nodiscard]] bool ss_valid(const T& value) const {
         return value > N;
     }
 };
 
 template <typename T, auto N>
 struct gte {
-    bool ss_valid(const T& value) const {
+    [[nodiscard]] bool ss_valid(const T& value) const {
         return value >= N;
     }
 };
 
 template <typename T, auto N>
 struct lt {
-    bool ss_valid(const T& value) const {
+    [[nodiscard]] bool ss_valid(const T& value) const {
         return value < N;
     }
 };
 
 template <typename T, auto N>
 struct lte {
-    bool ss_valid(const T& value) const {
+    [[nodiscard]] bool ss_valid(const T& value) const {
         return value <= N;
     }
 };
@@ -588,7 +588,7 @@ struct lte {
 
 template <typename T, auto Min, auto Max>
 struct ir {
-    bool ss_valid(const T& value) const {
+    [[nodiscard]] bool ss_valid(const T& value) const {
         return value >= Min && value <= Max;
     }
 };
@@ -599,7 +599,7 @@ struct ir {
 
 template <typename T, auto Min, auto Max>
 struct oor {
-    bool ss_valid(const T& value) const {
+    [[nodiscard]] bool ss_valid(const T& value) const {
         return value < Min || value > Max;
     }
 };
@@ -610,11 +610,11 @@ struct oor {
 
 template <typename T>
 struct ne {
-    bool ss_valid(const T& value) const {
+    [[nodiscard]] bool ss_valid(const T& value) const {
         return !value.empty();
     }
 
-    const char* error() const {
+    [[nodiscard]] const char* error() const {
         return "empty field";
     }
 };
@@ -648,7 +648,7 @@ void assert_throw_on_error_not_defined() {
                                  "'throw_on_error' is enabled");
 }
 
-inline void* strict_realloc(void* ptr, size_t size) {
+[[nodiscard]] inline void* strict_realloc(void* ptr, size_t size) {
     ptr = std::realloc(ptr, size);
     if (!ptr) {
         throw std::bad_alloc{};
@@ -658,14 +658,16 @@ inline void* strict_realloc(void* ptr, size_t size) {
 }
 
 #if __unix__
-inline ssize_t get_line_file(char*& lineptr, size_t& n, FILE* file) {
+[[nodiscard]] inline ssize_t get_line_file(char*& lineptr, size_t& n,
+                                           FILE* file) {
     return getline(&lineptr, &n, file);
 }
 #else
 
 using ssize_t = intptr_t;
 
-inline ssize_t get_line_file(char*& lineptr, size_t& n, FILE* file) {
+[[nodiscard]] inline ssize_t get_line_file(char*& lineptr, size_t& n,
+                                           FILE* file) {
     std::array<char, get_line_initial_buffer_size> buff;
 
     if (lineptr == nullptr || n < sizeof(buff)) {
@@ -701,8 +703,9 @@ inline ssize_t get_line_file(char*& lineptr, size_t& n, FILE* file) {
 
 #endif
 
-inline ssize_t get_line_buffer(char*& lineptr, size_t& n,
+[[nodiscard]] inline ssize_t get_line_buffer(char*& lineptr, size_t& n,
-                        const char* const csv_data_buffer, size_t csv_data_size,
+                                             const char* const csv_data_buffer,
+                                             size_t csv_data_size,
                                              size_t& curr_char) {
     if (curr_char >= csv_data_size) {
         return -1;
@@ -738,10 +741,10 @@ inline ssize_t get_line_buffer(char*& lineptr, size_t& n,
     return line_used;
 }
 
-inline std::tuple<ssize_t, bool> get_line(char*& buffer, size_t& buffer_size,
+[[nodiscard]] inline std::tuple<ssize_t, bool> get_line(
-                                   FILE* file,
+    char*& buffer, size_t& buffer_size, FILE* file,
-                                   const char* const csv_data_buffer,
+    const char* const csv_data_buffer, size_t csv_data_size,
-                                   size_t csv_data_size, size_t& curr_char) {
+    size_t& curr_char) {
     ssize_t ssize = 0;
     if (file) {
         ssize = get_line_file(buffer, buffer_size, file);
@@ -1079,7 +1082,7 @@ private:
 public:
     using line_ptr_type = std::conditional_t<is_const_line, const char*, char*>;
 
-    bool valid() const {
+    [[nodiscard]] bool valid() const {
         if constexpr (string_error) {
             return error_.empty();
         } else if constexpr (throw_on_error) {
@@ -1089,12 +1092,12 @@ public:
         }
     }
 
-    const std::string& error_msg() const {
+    [[nodiscard]] const std::string& error_msg() const {
         assert_string_error_defined<string_error>();
         return error_;
     }
 
-    bool unterminated_quote() const {
+    [[nodiscard]] bool unterminated_quote() const {
         return unterminated_quote_;
     }
 
@@ -1112,7 +1115,7 @@ private:
     ////////////////
 
     // number of characters the end of line is shifted backwards
-    size_t size_shifted() const {
+    [[nodiscard]] size_t size_shifted() const {
         return escaped_;
     }
 
@@ -1243,19 +1246,19 @@ private:
     // matching
     ////////////////
 
-    bool match(const char* const curr, char delim) {
+    [[nodiscard]] bool match(const char* const curr, char delim) {
         return *curr == delim;
     };
 
-    bool match(const char* const curr, const std::string& delim) {
+    [[nodiscard]] bool match(const char* const curr, const std::string& delim) {
         return std::strncmp(curr, delim.c_str(), delim.size()) == 0;
     };
 
-    size_t delimiter_size(char) {
+    [[nodiscard]] size_t delimiter_size(char) {
         return 1;
     }
 
-    size_t delimiter_size(const std::string& delim) {
+    [[nodiscard]] size_t delimiter_size(const std::string& delim) {
         return delim.size();
     }
 
@@ -1276,7 +1279,7 @@ private:
     }
 
     template <typename Delim>
-    std::tuple<size_t, bool> match_delimiter(line_ptr_type begin,
+    [[nodiscard]] std::tuple<size_t, bool> match_delimiter(line_ptr_type begin,
                                                            const Delim& delim) {
         line_ptr_type end = begin;
 
@@ -1545,8 +1548,8 @@ namespace ss {
 #ifndef SSP_DISABLE_FAST_FLOAT
 
 template <typename T>
-std::enable_if_t<std::is_floating_point_v<T>, std::optional<T>> to_num(
+[[nodiscard]] std::enable_if_t<std::is_floating_point_v<T>, std::optional<T>>
-    const char* const begin, const char* const end) {
+to_num(const char* const begin, const char* const end) {
     T ret;
     auto [ptr, ec] = fast_float::from_chars(begin, end, ret);
 
@@ -1559,8 +1562,8 @@ std::enable_if_t<std::is_floating_point_v<T>, std::optional<T>> to_num(
 #else
 
 template <typename T>
-std::enable_if_t<std::is_floating_point_v<T>, std::optional<T>> to_num(
+[[nodiscard]] std::enable_if_t<std::is_floating_point_v<T>, std::optional<T>>
-    const char* const begin, const char* const end) {
+to_num(const char* const begin, const char* const end) {
     static_assert(!std::is_same_v<T, long double>,
                   "Conversion to long double is disabled");
 
@@ -1633,7 +1636,7 @@ using int8 = numeric_wrapper<int8_t>;
 using uint8 = numeric_wrapper<uint8_t>;
 
 template <typename T>
-std::enable_if_t<std::is_integral_v<T>, std::optional<T>> to_num(
+[[nodiscard]] std::enable_if_t<std::is_integral_v<T>, std::optional<T>> to_num(
     const char* const begin, const char* const end) {
     T ret;
     auto [ptr, ec] = std::from_chars(begin, end, ret);
@@ -1645,8 +1648,9 @@ std::enable_if_t<std::is_integral_v<T>, std::optional<T>> to_num(
 }
 
 template <typename T>
-std::enable_if_t<is_instance_of_v<numeric_wrapper, T>, std::optional<T>> to_num(
+[[nodiscard]] std::enable_if_t<is_instance_of_v<numeric_wrapper, T>,
-    const char* const begin, const char* const end) {
+                               std::optional<T>>
+to_num(const char* const begin, const char* const end) {
     T ret;
     auto [ptr, ec] = std::from_chars(begin, end, ret.value);
 
@@ -1668,7 +1672,8 @@ struct unsupported_type {
 } /* namespace errors */
 
 template <typename T>
-std::enable_if_t<!std::is_integral_v<T> && !std::is_floating_point_v<T> &&
+[[nodiscard]] std::enable_if_t<!std::is_integral_v<T> &&
+                                   !std::is_floating_point_v<T> &&
                                    !is_instance_of_v<std::optional, T> &&
                                    !is_instance_of_v<std::variant, T> &&
                                    !is_instance_of_v<numeric_wrapper, T>,
@@ -1680,7 +1685,8 @@ extract(const char*, const char*, T&) {
 }
 
 template <typename T>
-std::enable_if_t<std::is_integral_v<T> || std::is_floating_point_v<T> ||
+[[nodiscard]] std::enable_if_t<std::is_integral_v<T> ||
+                                   std::is_floating_point_v<T> ||
                                    is_instance_of_v<numeric_wrapper, T>,
                                bool>
 extract(const char* begin, const char* end, T& value) {
@@ -1693,8 +1699,8 @@ extract(const char* begin, const char* end, T& value) {
 }
 
 template <typename T>
-std::enable_if_t<is_instance_of_v<std::optional, T>, bool> extract(
+[[nodiscard]] std::enable_if_t<is_instance_of_v<std::optional, T>, bool>
-    const char* begin, const char* end, T& value) {
+extract(const char* begin, const char* end, T& value) {
     typename T::value_type raw_value;
     if (extract(begin, end, raw_value)) {
         value = raw_value;
@@ -1705,7 +1711,8 @@ std::enable_if_t<is_instance_of_v<std::optional, T>, bool> extract(
 }
 
 template <typename T, size_t I>
-bool extract_variant(const char* begin, const char* end, T& value) {
+[[nodiscard]] bool extract_variant(const char* begin, const char* end,
+                                   T& value) {
     using IthType = std::variant_alternative_t<I, std::decay_t<T>>;
     IthType ithValue;
     if (extract<IthType>(begin, end, ithValue)) {
@@ -1718,7 +1725,7 @@ bool extract_variant(const char* begin, const char* end, T& value) {
 }
 
 template <typename T>
-std::enable_if_t<is_instance_of_v<std::variant, T>, bool> extract(
+[[nodiscard]] std::enable_if_t<is_instance_of_v<std::variant, T>, bool> extract(
     const char* begin, const char* end, T& value) {
     return extract_variant<T, 0>(begin, end, value);
 }
@@ -1728,7 +1735,8 @@ std::enable_if_t<is_instance_of_v<std::variant, T>, bool> extract(
 ////////////////
 
 template <>
-inline bool extract(const char* begin, const char* end, bool& value) {
+[[nodiscard]] inline bool extract(const char* begin, const char* end,
+                                  bool& value) {
     if (end == begin + 1) {
         if (*begin == '1') {
             value = true;
@@ -1755,19 +1763,21 @@ inline bool extract(const char* begin, const char* end, bool& value) {
 }
 
 template <>
-inline bool extract(const char* begin, const char* end, char& value) {
+[[nodiscard]] inline bool extract(const char* begin, const char* end,
+                                  char& value) {
     value = *begin;
     return (end == begin + 1);
 }
 
 template <>
-inline bool extract(const char* begin, const char* end, std::string& value) {
+[[nodiscard]] inline bool extract(const char* begin, const char* end,
+                                  std::string& value) {
     value = std::string{begin, end};
     return true;
 }
 
 template <>
-inline bool extract(const char* begin, const char* end,
+[[nodiscard]] inline bool extract(const char* begin, const char* end,
                                   std::string_view& value) {
     value = std::string_view{begin, static_cast<size_t>(end - begin)};
     return true;
@@ -1876,15 +1886,15 @@ public:
     // parses line with given delimiter, returns a 'T' object created with
     // extracted values of type 'Ts'
     template <typename T, typename... Ts>
-    T convert_object(line_ptr_type line,
+    [[nodiscard]] T convert_object(
-                     const std::string& delim = default_delimiter) {
+        line_ptr_type line, const std::string& delim = default_delimiter) {
         return to_object<T>(convert<Ts...>(line, delim));
     }
 
     // parses line with given delimiter, returns tuple of objects with
     // extracted values of type 'Ts'
     template <typename... Ts>
-    no_void_validator_tup_t<Ts...> convert(
+    [[nodiscard]] no_void_validator_tup_t<Ts...> convert(
         line_ptr_type line, const std::string& delim = default_delimiter) {
         split(line, delim);
         if (splitter_.valid()) {
@@ -1897,13 +1907,13 @@ public:
 
     // parses already split line, returns 'T' object with extracted values
     template <typename T, typename... Ts>
-    T convert_object(const split_data& elems) {
+    [[nodiscard]] T convert_object(const split_data& elems) {
         return to_object<T>(convert<Ts...>(elems));
     }
 
     // same as above, but uses cached split line
     template <typename T, typename... Ts>
-    T convert_object() {
+    [[nodiscard]] T convert_object() {
         return to_object<T>(convert<Ts...>());
     }
 
@@ -1912,7 +1922,8 @@ public:
     // one argument is given which is a class which has a tied
     // method which returns a tuple, returns that type
     template <typename T, typename... Ts>
-    no_void_validator_tup_t<T, Ts...> convert(const split_data& elems) {
+    [[nodiscard]] no_void_validator_tup_t<T, Ts...> convert(
+        const split_data& elems) {
         if constexpr (sizeof...(Ts) == 0 && is_instance_of_v<std::tuple, T>) {
             return convert_impl(elems, static_cast<T*>(nullptr));
         } else if constexpr (tied_class_v<T, Ts...>) {
@@ -1928,11 +1939,11 @@ public:
 
     // same as above, but uses cached split line
     template <typename T, typename... Ts>
-    no_void_validator_tup_t<T, Ts...> convert() {
+    [[nodiscard]] no_void_validator_tup_t<T, Ts...> convert() {
         return convert<T, Ts...>(splitter_.split_data_);
     }
 
-    bool valid() const {
+    [[nodiscard]] bool valid() const {
         if constexpr (string_error) {
             return error_.empty();
         } else if constexpr (throw_on_error) {
@@ -1942,12 +1953,12 @@ public:
         }
     }
 
-    const std::string& error_msg() const {
+    [[nodiscard]] const std::string& error_msg() const {
         assert_string_error_defined<string_error>();
         return error_;
     }
 
-    bool unterminated_quote() const {
+    [[nodiscard]] bool unterminated_quote() const {
         return splitter_.unterminated_quote();
     }
 
@@ -1973,7 +1984,7 @@ private:
         return splitter_.resplit(new_line, new_size, delim);
     }
 
-    size_t size_shifted() {
+    [[nodiscard]] size_t size_shifted() {
         return splitter_.size_shifted();
     }
 
@@ -1989,7 +2000,8 @@ private:
         }
     }
 
-    std::string error_sufix(const string_range msg, size_t pos) const {
+    [[nodiscard]] std::string error_sufix(const string_range msg,
+                                          size_t pos) const {
         constexpr static auto reserve_size = 32;
         std::string error;
         error.reserve(reserve_size);
@@ -2117,7 +2129,8 @@ private:
     ////////////////
 
     template <typename... Ts>
-    no_void_validator_tup_t<Ts...> convert_impl(const split_data& elems) {
+    [[nodiscard]] no_void_validator_tup_t<Ts...> convert_impl(
+        const split_data& elems) {
         clear_error();
 
         if (!splitter_.valid()) {
@@ -2148,7 +2161,7 @@ private:
     }
 
     template <typename... Ts>
-    no_void_validator_tup_t<std::tuple<Ts...>> convert_impl(
+    [[nodiscard]] no_void_validator_tup_t<std::tuple<Ts...>> convert_impl(
         const split_data& elems, const std::tuple<Ts...>*) {
         return convert_impl<Ts...>(elems);
     }
@@ -2157,11 +2170,11 @@ private:
     // column mapping
     ////////////////
 
-    bool columns_mapped() const {
+    [[nodiscard]] bool columns_mapped() const {
         return !column_mappings_.empty();
     }
 
-    size_t column_position(size_t tuple_position) const {
+    [[nodiscard]] size_t column_position(size_t tuple_position) const {
         if (!columns_mapped()) {
             return tuple_position;
         }
@@ -2192,7 +2205,7 @@ private:
         }
 
         if constexpr (std::is_same_v<T, std::string>) {
-            extract(msg.first, msg.second, dst);
+            static_cast<void>(extract(msg.first, msg.second, dst));
             return;
         }
 
@@ -2238,7 +2251,8 @@ private:
     }
 
     template <typename... Ts>
-    no_void_validator_tup_t<Ts...> extract_tuple(const split_data& elems) {
+    [[nodiscard]] no_void_validator_tup_t<Ts...> extract_tuple(
+        const split_data& elems) {
         static_assert(!all_of_v<std::is_void, Ts...>,
                       "at least one parameter must be non void");
         no_void_validator_tup_t<Ts...> ret{};
@@ -2327,7 +2341,7 @@ public:
     parser(const parser& other) = delete;
     parser& operator=(const parser& other) = delete;
 
-    bool valid() const {
+    [[nodiscard]] bool valid() const {
         if constexpr (string_error) {
             return error_.empty();
         } else if constexpr (throw_on_error) {
@@ -2337,12 +2351,12 @@ public:
         }
     }
 
-    const std::string& error_msg() const {
+    [[nodiscard]] const std::string& error_msg() const {
         assert_string_error_defined<string_error>();
         return error_;
     }
 
-    bool eof() const {
+    [[nodiscard]] bool eof() const {
         return eof_;
     }
 
@@ -2351,21 +2365,21 @@ public:
     }
 
     template <typename T, typename... Ts>
-    T get_object() {
+    [[nodiscard]] T get_object() {
         return to_object<T>(get_next<Ts...>());
     }
 
-    size_t line() const {
+    [[nodiscard]] size_t line() const {
         return reader_.line_number_ > 0 ? reader_.line_number_ - 1
                                         : reader_.line_number_;
     }
 
-    size_t position() const {
+    [[nodiscard]] size_t position() const {
         return reader_.chars_read_;
     }
 
     template <typename T, typename... Ts>
-    no_void_validator_tup_t<T, Ts...> get_next() {
+    [[nodiscard]] no_void_validator_tup_t<T, Ts...> get_next() {
         std::optional<std::string> error;
 
         if (!eof_) {
@@ -2416,12 +2430,12 @@ public:
         return value;
     }
 
-    std::string raw_header() const {
+    [[nodiscard]] std::string raw_header() const {
         assert_ignore_header_not_defined();
         return raw_header_;
     }
 
-    std::vector<std::string> header() {
+    [[nodiscard]] std::vector<std::string> header() {
         assert_ignore_header_not_defined();
         clear_error();
 
@@ -2440,7 +2454,7 @@ public:
         return split_header;
     }
 
-    bool field_exists(const std::string& field) {
+    [[nodiscard]] bool field_exists(const std::string& field) {
         assert_ignore_header_not_defined();
         clear_error();
 
@@ -2525,11 +2539,11 @@ public:
             iterator& operator=(const iterator& other) = delete;
             iterator& operator=(iterator&& other) = delete;
 
-            value& operator*() {
+            [[nodiscard]] value& operator*() {
                 return value_;
             }
 
-            value* operator->() {
+            [[nodiscard]] value* operator->() {
                 return &value_;
             }
 
@@ -2554,13 +2568,15 @@ public:
                 return result;
             }
 
-            friend bool operator==(const iterator& lhs, const iterator& rhs) {
+            [[nodiscard]] friend bool operator==(const iterator& lhs,
+                                                 const iterator& rhs) {
                 return (lhs.parser_ == nullptr && rhs.parser_ == nullptr) ||
                        (lhs.parser_ == rhs.parser_ &&
                         &lhs.value_ == &rhs.value_);
             }
 
-            friend bool operator!=(const iterator& lhs, const iterator& rhs) {
+            [[nodiscard]] friend bool operator!=(const iterator& lhs,
+                                                 const iterator& rhs) {
                 return !(lhs == rhs);
             }
 
@@ -2572,11 +2588,11 @@ public:
         iterable(parser<Options...>* parser) : parser_{parser} {
         }
 
-        iterator begin() {
+        [[nodiscard]] iterator begin() {
             return ++iterator{parser_};
         }
 
-        iterator end() {
+        [[nodiscard]] iterator end() {
             return iterator{};
         }
 
@@ -2585,12 +2601,12 @@ public:
     };
 
     template <typename... Ts>
-    auto iterate() {
+    [[nodiscard]] auto iterate() {
         return iterable<false, Ts...>{this};
     }
 
     template <typename... Ts>
-    auto iterate_object() {
+    [[nodiscard]] auto iterate_object() {
         return iterable<true, Ts...>{this};
     }
 
@@ -2628,7 +2644,7 @@ public:
             return composite_with(std::move(value));
         }
 
-        std::tuple<Ts...> values() {
+        [[nodiscard]] std::tuple<Ts...> values() {
             return values_;
         }
 
@@ -2651,7 +2667,7 @@ public:
 
     private:
         template <typename T>
-        composite<Ts..., T> composite_with(T&& new_value) {
+        [[nodiscard]] composite<Ts..., T> composite_with(T&& new_value) {
             auto merged_values =
                 std::tuple_cat(std::move(values_),
                                std::tuple<T>{parser_.valid()
@@ -2681,7 +2697,7 @@ public:
         }
 
         template <typename U, typename... Us>
-        no_void_validator_tup_t<U, Us...> try_same() {
+        [[nodiscard]] no_void_validator_tup_t<U, Us...> try_same() {
             parser_.clear_error();
             auto value =
                 parser_.reader_.converter_.template convert<U, Us...>();
@@ -2702,8 +2718,8 @@ public:
     // tries to convert a line and returns a composite which is
     // able to try additional conversions in case of failure
     template <typename... Ts, typename Fun = none>
-    composite<std::optional<no_void_validator_tup_t<Ts...>>> try_next(
+    [[nodiscard]] composite<std::optional<no_void_validator_tup_t<Ts...>>>
-        Fun&& fun = none{}) {
+    try_next(Fun&& fun = none{}) {
         assert_throw_on_error_not_defined<throw_on_error>();
         using Ret = no_void_validator_tup_t<Ts...>;
         return try_invoke_and_make_composite<
@@ -2713,7 +2729,7 @@ public:
     // identical to try_next but returns composite with object instead of a
     // tuple
     template <typename T, typename... Ts, typename Fun = none>
-    composite<std::optional<T>> try_object(Fun&& fun = none{}) {
+    [[nodiscard]] composite<std::optional<T>> try_object(Fun&& fun = none{}) {
         assert_throw_on_error_not_defined<throw_on_error>();
         return try_invoke_and_make_composite<
             std::optional<T>>(get_object<T, Ts...>(), std::forward<Fun>(fun));
@@ -2764,7 +2780,8 @@ private:
     }
 
     template <typename T, typename Fun = none>
-    composite<T> try_invoke_and_make_composite(T&& value, Fun&& fun) {
+    [[nodiscard]] composite<T> try_invoke_and_make_composite(T&& value,
+                                                             Fun&& fun) {
         if (valid()) {
             try_invoke(*value, std::forward<Fun>(fun));
         }
@@ -2780,7 +2797,8 @@ private:
                       "cannot use this method when 'ignore_header' is defined");
     }
 
-    bool strict_split(header_splitter& splitter, std::string& header) {
+    [[nodiscard]] bool strict_split(header_splitter& splitter,
+                                    std::string& header) {
         if (header.empty()) {
             return false;
         }
@@ -2827,7 +2845,7 @@ private:
         }
     }
 
-    std::optional<size_t> header_index(const std::string& field) {
+    [[nodiscard]] std::optional<size_t> header_index(const std::string& field) {
         auto it = std::find(header_.begin(), header_.end(), field);
 
         if (it == header_.end()) {
@@ -3098,7 +3116,7 @@ private:
         reader& operator=(const reader& other) = delete;
 
         // read next line each time in order to set eof_
-        bool read_next() {
+        [[nodiscard]] bool read_next() {
             next_line_converter_.clear_error();
             size_t size = 0;
             while (size == 0) {
@@ -3190,7 +3208,7 @@ private:
             std::swap(converter_, next_line_converter_);
         }
 
-        bool multiline_limit_reached(size_t& limit) {
+        [[nodiscard]] bool multiline_limit_reached(size_t& limit) {
             if constexpr (multiline::size > 0) {
                 if (limit++ >= multiline::size) {
                     next_line_converter_.handle_error_multiline_limit_reached();
@@ -3200,7 +3218,7 @@ private:
             return false;
         }
 
-        bool escaped_eol(size_t size) {
+        [[nodiscard]] bool escaped_eol(size_t size) {
             const char* curr = nullptr;
             for (curr = next_line_buffer_ + size - 1;
                  curr >= next_line_buffer_ &&
@@ -3210,7 +3228,7 @@ private:
             return (next_line_buffer_ - curr + size) % 2 == 0;
         }
 
-        bool unterminated_quote() {
+        [[nodiscard]] bool unterminated_quote() {
             return next_line_converter_.unterminated_quote();
         }
 
@@ -3225,7 +3243,7 @@ private:
             }
         }
 
-        size_t remove_eol(char*& buffer, size_t ssize) {
+        [[nodiscard]] size_t remove_eol(char*& buffer, size_t ssize) {
             if (buffer[ssize - 1] != '\n') {
                 crlf_ = false;
                 return ssize;
@@ -3255,7 +3273,8 @@ private:
             first_size += second_size;
         }
 
-        bool append_next_line_to_buffer(char*& buffer, size_t& line_size,
+        [[nodiscard]] bool append_next_line_to_buffer(char*& buffer,
+                                                      size_t& line_size,
                                                       size_t buffer_size) {
             undo_remove_eol(buffer, line_size, buffer_size);
 
@@ -3275,7 +3294,7 @@ private:
             return true;
         }
 
-        std::string get_buffer() {
+        [[nodiscard]] std::string get_buffer() {
             return std::string{next_line_buffer_, next_line_size_};
         }
 

test/test_converter.cpp

@@ -1,5 +1,4 @@
 #include "test_helpers.hpp"
-#include <algorithm>
 #include <ss/converter.hpp>
 
 TEST_CASE("converter test split") {
@@ -11,7 +10,8 @@ TEST_CASE("converter test split") {
         {" x x x x | x ", {" x x x x ", " x "}, "|"},
         {"a::b::c::d", {"a", "b", "c", "d"}, "::"},
         {"x\t-\ty", {"x", "y"}, "\t-\t"},
-                {"x", {"x"}, ","}} // clang-format on
+        {"x", {"x"}, ","}} 
+        // clang-format on
     ) {
         auto split = c.split(s, delim);
         CHECK_EQ(split.size(), expected.size());
@@ -278,36 +278,37 @@ TEST_CASE_TEMPLATE("converter test valid conversions with exceptions", T, int,
 TEST_CASE_TEMPLATE("converter test invalid conversions", T, int, ss::uint8) {
     ss::converter c;
 
-    c.convert<T>("");
+    std::ignore = c.convert<T>("");
     REQUIRE_FALSE(c.valid());
 
-    c.convert<T>("1", "");
+    std::ignore = c.convert<T>("1", "");
     REQUIRE_FALSE(c.valid());
 
-    c.convert<T>("10", "");
+    std::ignore = c.convert<T>("10", "");
     REQUIRE_FALSE(c.valid());
 
-    c.convert<T, void>("");
+    std::ignore = c.convert<T, void>("");
     REQUIRE_FALSE(c.valid());
 
-    c.convert<T, void>(",junk");
+    std::ignore = c.convert<T, void>(",junk");
     REQUIRE_FALSE(c.valid());
 
-    c.convert<void, T>("junk,");
+    std::ignore = c.convert<void, T>("junk,");
     REQUIRE_FALSE(c.valid());
 
-    c.convert<T>("x");
+    std::ignore = c.convert<T>("x");
     REQUIRE_FALSE(c.valid());
 
-    c.convert<T, void>("x");
+    std::ignore = c.convert<T, void>("x");
     REQUIRE_FALSE(c.valid());
 
-    c.convert<T, void>("x,junk");
+    std::ignore = c.convert<T, void>("x,junk");
     REQUIRE_FALSE(c.valid());
 
-    c.convert<void, T>("junk,x");
+    std::ignore = c.convert<void, T>("junk,x");
     REQUIRE_FALSE(c.valid());
 
+    std::ignore =
         c.convert<void, std::variant<T, double>, double>("junk;.5.5;6", ";");
     REQUIRE_FALSE(c.valid());
 }
@@ -316,34 +317,36 @@ TEST_CASE_TEMPLATE("converter test invalid conversions with exceptions", T, int,
                    ss::uint8) {
     ss::converter<ss::throw_on_error> c;
 
-    REQUIRE_EXCEPTION(c.convert<T>(""));
+    REQUIRE_EXCEPTION(std::ignore = c.convert<T>(""));
-    REQUIRE_EXCEPTION(c.convert<T>("1", ""));
+    REQUIRE_EXCEPTION(std::ignore = c.convert<T>("1", ""));
-    REQUIRE_EXCEPTION(c.convert<T>("10", ""));
+    REQUIRE_EXCEPTION(std::ignore = c.convert<T>("10", ""));
-    REQUIRE_EXCEPTION(c.convert<T, void>(""));
+    REQUIRE_EXCEPTION(std::ignore = c.convert<T, void>(""));
-    REQUIRE_EXCEPTION(c.convert<T, void>(",junk"));
+    REQUIRE_EXCEPTION(std::ignore = c.convert<T, void>(",junk"));
-    REQUIRE_EXCEPTION(c.convert<void, T>("junk,"));
+    REQUIRE_EXCEPTION(std::ignore = c.convert<void, T>("junk,"));
-    REQUIRE_EXCEPTION(c.convert<T>("x"));
+    REQUIRE_EXCEPTION(std::ignore = c.convert<T>("x"));
-    REQUIRE_EXCEPTION(c.convert<T, void>("x"));
+    REQUIRE_EXCEPTION(std::ignore = c.convert<T, void>("x"));
-    REQUIRE_EXCEPTION(c.convert<T, void>("x,junk"));
+    REQUIRE_EXCEPTION(std::ignore = c.convert<T, void>("x,junk"));
-    REQUIRE_EXCEPTION(c.convert<void, T>("junk,x"));
+    REQUIRE_EXCEPTION(std::ignore = c.convert<void, T>("junk,x"));
     REQUIRE_EXCEPTION(
-        c.convert<void, std::variant<T, double>, double>("junk;.5.5;6", ";"));
+        std::ignore =
+            c.convert<void, std::variant<T, double>, double>("junk;.5.5;6",
+                                                             ";"));
 }
 
 TEST_CASE_TEMPLATE("converter test ss:ax restriction (all except)", T, int,
                    ss::uint8) {
     ss::converter c;
 
-    c.convert<ss::ax<T, 0>>("0");
+    std::ignore = c.convert<ss::ax<T, 0>>("0");
     REQUIRE_FALSE(c.valid());
 
-    c.convert<ss::ax<T, 0, 1, 2>>("1");
+    std::ignore = c.convert<ss::ax<T, 0, 1, 2>>("1");
     REQUIRE_FALSE(c.valid());
 
-    c.convert<void, char, ss::ax<T, 0, 1, 2>>("junk,c,1");
+    std::ignore = c.convert<void, char, ss::ax<T, 0, 1, 2>>("junk,c,1");
     REQUIRE_FALSE(c.valid());
 
-    c.convert<ss::ax<T, 1>, char>("1,c");
+    std::ignore = c.convert<ss::ax<T, 1>, char>("1,c");
     REQUIRE_FALSE(c.valid());
     {
         T tup = c.convert<ss::ax<T, 1>>("3");
@@ -367,10 +370,11 @@ TEST_CASE_TEMPLATE(
     ss::uint8) {
     ss::converter<ss::throw_on_error> c;
 
-    REQUIRE_EXCEPTION(c.convert<ss::ax<T, 0>>("0"));
+    REQUIRE_EXCEPTION(std::ignore = c.convert<ss::ax<T, 0>>("0"));
-    REQUIRE_EXCEPTION(c.convert<ss::ax<T, 0, 1, 2>>("1"));
+    REQUIRE_EXCEPTION(std::ignore = c.convert<ss::ax<T, 0, 1, 2>>("1"));
-    REQUIRE_EXCEPTION(c.convert<void, char, ss::ax<T, 0, 1, 2>>("junk,c,1"));
+    REQUIRE_EXCEPTION(
-    REQUIRE_EXCEPTION(c.convert<ss::ax<T, 1>, char>("1,c"));
+        std::ignore = c.convert<void, char, ss::ax<T, 0, 1, 2>>("junk,c,1"));
+    REQUIRE_EXCEPTION(std::ignore = c.convert<ss::ax<T, 1>, char>("1,c"));
 
     try {
         {
@@ -393,13 +397,13 @@ TEST_CASE_TEMPLATE(
 TEST_CASE("converter test ss:nx restriction (none except)") {
     ss::converter c;
 
-    c.convert<ss::nx<int, 1>>("3");
+    std::ignore = c.convert<ss::nx<int, 1>>("3");
     REQUIRE_FALSE(c.valid());
 
-    c.convert<char, ss::nx<int, 1, 2, 69>>("c,3");
+    std::ignore = c.convert<char, ss::nx<int, 1, 2, 69>>("c,3");
     REQUIRE_FALSE(c.valid());
 
-    c.convert<ss::nx<int, 1>, char>("3,c");
+    std::ignore = c.convert<ss::nx<int, 1>, char>("3,c");
     REQUIRE_FALSE(c.valid());
 
     {
@@ -427,9 +431,10 @@ TEST_CASE("converter test ss:nx restriction (none except)") {
 TEST_CASE("converter test ss:nx restriction (none except) with exceptions") {
     ss::converter<ss::throw_on_error> c;
 
-    REQUIRE_EXCEPTION(c.convert<ss::nx<int, 1>>("3"));
+    REQUIRE_EXCEPTION(std::ignore = c.convert<ss::nx<int, 1>>("3"));
-    REQUIRE_EXCEPTION(c.convert<char, ss::nx<int, 1, 2, 69>>("c,3"));
+    REQUIRE_EXCEPTION(std::ignore =
-    REQUIRE_EXCEPTION(c.convert<ss::nx<int, 1>, char>("3,c"));
+                          c.convert<char, ss::nx<int, 1, 2, 69>>("c,3"));
+    REQUIRE_EXCEPTION(std::ignore = c.convert<ss::nx<int, 1>, char>("3,c"));
 
     try {
         {
@@ -461,13 +466,13 @@ TEST_CASE_TEMPLATE("converter test ss:ir restriction (in range)", T, int,
                    ss::uint8) {
     ss::converter c;
 
-    c.convert<ss::ir<T, 0, 2>>("3");
+    std::ignore = c.convert<ss::ir<T, 0, 2>>("3");
     REQUIRE_FALSE(c.valid());
 
-    c.convert<char, ss::ir<T, 4, 69>>("c,3");
+    std::ignore = c.convert<char, ss::ir<T, 4, 69>>("c,3");
     REQUIRE_FALSE(c.valid());
 
-    c.convert<ss::ir<T, 1, 2>, char>("3,c");
+    std::ignore = c.convert<ss::ir<T, 1, 2>, char>("3,c");
     REQUIRE_FALSE(c.valid());
 
     {
@@ -497,9 +502,9 @@ TEST_CASE_TEMPLATE(
     ss::uint8) {
     ss::converter<ss::throw_on_error> c;
 
-    REQUIRE_EXCEPTION(c.convert<ss::ir<T, 0, 2>>("3"));
+    REQUIRE_EXCEPTION(std::ignore = c.convert<ss::ir<T, 0, 2>>("3"));
-    REQUIRE_EXCEPTION(c.convert<char, ss::ir<T, 4, 69>>("c,3"));
+    REQUIRE_EXCEPTION(std::ignore = c.convert<char, ss::ir<T, 4, 69>>("c,3"));
-    REQUIRE_EXCEPTION(c.convert<ss::ir<T, 1, 2>, char>("3,c"));
+    REQUIRE_EXCEPTION(std::ignore = c.convert<ss::ir<T, 1, 2>, char>("3,c"));
 
     try {
         {
@@ -530,16 +535,16 @@ TEST_CASE_TEMPLATE(
 TEST_CASE("converter test ss:oor restriction (out of range)") {
     ss::converter c;
 
-    c.convert<ss::oor<int, 1, 5>>("3");
+    std::ignore = c.convert<ss::oor<int, 1, 5>>("3");
     REQUIRE_FALSE(c.valid());
 
-    c.convert<ss::oor<int, 0, 2>>("2");
+    std::ignore = c.convert<ss::oor<int, 0, 2>>("2");
     REQUIRE_FALSE(c.valid());
 
-    c.convert<char, ss::oor<int, 0, 1>, void>("c,1,junk");
+    std::ignore = c.convert<char, ss::oor<int, 0, 1>, void>("c,1,junk");
     REQUIRE_FALSE(c.valid());
 
-    c.convert<ss::oor<int, 1, 20>, char>("1,c");
+    std::ignore = c.convert<ss::oor<int, 1, 20>, char>("1,c");
     REQUIRE_FALSE(c.valid());
 
     {
@@ -564,10 +569,12 @@ TEST_CASE("converter test ss:oor restriction (out of range)") {
 TEST_CASE("converter test ss:oor restriction (out of range) with exceptions") {
     ss::converter<ss::throw_on_error> c;
 
-    REQUIRE_EXCEPTION(c.convert<ss::oor<int, 1, 5>>("3"));
+    REQUIRE_EXCEPTION(std::ignore = c.convert<ss::oor<int, 1, 5>>("3"));
-    REQUIRE_EXCEPTION(c.convert<ss::oor<int, 0, 2>>("2"));
+    REQUIRE_EXCEPTION(std::ignore = c.convert<ss::oor<int, 0, 2>>("2"));
-    REQUIRE_EXCEPTION(c.convert<char, ss::oor<int, 0, 1>, void>("c,1,junk"));
+    REQUIRE_EXCEPTION(
-    REQUIRE_EXCEPTION(c.convert<ss::oor<int, 1, 20>, char>("1,c"));
+        std::ignore = c.convert<char, ss::oor<int, 0, 1>, void>("c,1,junk"));
+    REQUIRE_EXCEPTION(std::ignore =
+                          c.convert<ss::oor<int, 1, 20>, char>("1,c"));
 
     try {
         {
@@ -608,19 +615,19 @@ inline bool ss::extract(const char* begin, const char* end,
 TEST_CASE("converter test ss:ne restriction (not empty)") {
     ss::converter c;
 
-    c.convert<ss::ne<std::string>>("");
+    std::ignore = c.convert<ss::ne<std::string>>("");
     REQUIRE_FALSE(c.valid());
 
-    c.convert<int, ss::ne<std::string>>("3,");
+    std::ignore = c.convert<int, ss::ne<std::string>>("3,");
     REQUIRE_FALSE(c.valid());
 
-    c.convert<ss::ne<std::string>, int>(",3");
+    std::ignore = c.convert<ss::ne<std::string>, int>(",3");
     REQUIRE_FALSE(c.valid());
 
-    c.convert<void, ss::ne<std::string>, int>("junk,,3");
+    std::ignore = c.convert<void, ss::ne<std::string>, int>("junk,,3");
     REQUIRE_FALSE(c.valid());
 
-    c.convert<ss::ne<std::vector<int>>>("");
+    std::ignore = c.convert<ss::ne<std::vector<int>>>("");
     REQUIRE_FALSE(c.valid());
 
     {
@@ -643,11 +650,12 @@ TEST_CASE("converter test ss:ne restriction (not empty)") {
 TEST_CASE("converter test ss:ne restriction (not empty) with exceptions") {
     ss::converter<ss::throw_on_error> c;
 
-    REQUIRE_EXCEPTION(c.convert<ss::ne<std::string>>(""));
+    REQUIRE_EXCEPTION(std::ignore = c.convert<ss::ne<std::string>>(""));
-    REQUIRE_EXCEPTION(c.convert<int, ss::ne<std::string>>("3,"));
+    REQUIRE_EXCEPTION(std::ignore = c.convert<int, ss::ne<std::string>>("3,"));
-    REQUIRE_EXCEPTION(c.convert<ss::ne<std::string>, int>(",3"));
+    REQUIRE_EXCEPTION(std::ignore = c.convert<ss::ne<std::string>, int>(",3"));
-    REQUIRE_EXCEPTION(c.convert<void, ss::ne<std::string>, int>("junk,,3"));
+    REQUIRE_EXCEPTION(std::ignore =
-    REQUIRE_EXCEPTION(c.convert<ss::ne<std::vector<int>>>(""));
+                          c.convert<void, ss::ne<std::string>, int>("junk,,3"));
+    REQUIRE_EXCEPTION(std::ignore = c.convert<ss::ne<std::vector<int>>>(""));
 
     try {
         {
@@ -675,22 +683,22 @@ TEST_CASE(
     "converter test ss:lt ss::lte ss::gt ss::gte restriction (in range)") {
     ss::converter c;
 
-    c.convert<ss::lt<int, 3>>("3");
+    std::ignore = c.convert<ss::lt<int, 3>>("3");
     REQUIRE_FALSE(c.valid());
 
-    c.convert<ss::lt<int, 2>>("3");
+    std::ignore = c.convert<ss::lt<int, 2>>("3");
     REQUIRE_FALSE(c.valid());
 
-    c.convert<ss::gt<int, 3>>("3");
+    std::ignore = c.convert<ss::gt<int, 3>>("3");
     REQUIRE_FALSE(c.valid());
 
-    c.convert<ss::gt<int, 4>>("3");
+    std::ignore = c.convert<ss::gt<int, 4>>("3");
     REQUIRE_FALSE(c.valid());
 
-    c.convert<ss::lte<int, 2>>("3");
+    std::ignore = c.convert<ss::lte<int, 2>>("3");
     REQUIRE_FALSE(c.valid());
 
-    c.convert<ss::gte<int, 4>>("3");
+    std::ignore = c.convert<ss::gte<int, 4>>("3");
     REQUIRE_FALSE(c.valid());
 
     {
@@ -734,12 +742,12 @@ TEST_CASE("converter test ss:lt ss::lte ss::gt ss::gte restriction (in range) "
           "with exception") {
     ss::converter<ss::throw_on_error> c;
 
-    REQUIRE_EXCEPTION(c.convert<ss::lt<int, 3>>("3"));
+    REQUIRE_EXCEPTION(std::ignore = c.convert<ss::lt<int, 3>>("3"));
-    REQUIRE_EXCEPTION(c.convert<ss::lt<int, 2>>("3"));
+    REQUIRE_EXCEPTION(std::ignore = c.convert<ss::lt<int, 2>>("3"));
-    REQUIRE_EXCEPTION(c.convert<ss::gt<int, 3>>("3"));
+    REQUIRE_EXCEPTION(std::ignore = c.convert<ss::gt<int, 3>>("3"));
-    REQUIRE_EXCEPTION(c.convert<ss::gt<int, 4>>("3"));
+    REQUIRE_EXCEPTION(std::ignore = c.convert<ss::gt<int, 4>>("3"));
-    REQUIRE_EXCEPTION(c.convert<ss::lte<int, 2>>("3"));
+    REQUIRE_EXCEPTION(std::ignore = c.convert<ss::lte<int, 2>>("3"));
-    REQUIRE_EXCEPTION(c.convert<ss::gte<int, 4>>("3"));
+    REQUIRE_EXCEPTION(std::ignore = c.convert<ss::gte<int, 4>>("3"));
 
     try {
         {
@@ -784,14 +792,14 @@ TEST_CASE("converter test ss:lt ss::lte ss::gt ss::gte restriction (in range) "
 
 TEST_CASE("converter test error mode") {
     ss::converter<ss::string_error> c;
-    c.convert<int>("junk");
+    std::ignore = c.convert<int>("junk");
     CHECK_FALSE(c.valid());
     CHECK_FALSE(c.error_msg().empty());
 }
 
 TEST_CASE("converter test throw on error mode") {
     ss::converter<ss::throw_on_error> c;
-    REQUIRE_EXCEPTION(c.convert<int>("junk"));
+    REQUIRE_EXCEPTION(std::ignore = c.convert<int>("junk"));
 }
 
 TEST_CASE("converter test converter with quotes spacing and escaping") {
@@ -908,7 +916,7 @@ TEST_CASE("converter test invalid split conversions") {
 
     {
         // mismatched quote
-        c.convert<std::string, std::string, double, char>(
+        std::ignore = c.convert<std::string, std::string, double, char>(
             buff(R"(  "just  , some ,   "12.3","a"  )"));
         CHECK_FALSE(c.valid());
         CHECK_FALSE(c.unterminated_quote());
@@ -917,7 +925,7 @@ TEST_CASE("converter test invalid split conversions") {
 
     {
         // unterminated quote
-        c.convert<std::string, std::string, double, std::string>(
+        std::ignore = c.convert<std::string, std::string, double, std::string>(
             buff(R"(  ju\,st  ,  "so,me"  ,   12.34     ,   "str""ings)"));
         CHECK_FALSE(c.valid());
         CHECK(c.unterminated_quote());
@@ -926,7 +934,7 @@ TEST_CASE("converter test invalid split conversions") {
 
     {
         // unterminated escape
-        c.convert<std::string, std::string, double, std::string>(
+        std::ignore = c.convert<std::string, std::string, double, std::string>(
             buff(R"(just,some,2,strings\)"));
         CHECK_FALSE(c.valid());
         CHECK_FALSE(c.unterminated_quote());
@@ -935,7 +943,7 @@ TEST_CASE("converter test invalid split conversions") {
 
     {
         // unterminated escape while quoting
-        c.convert<std::string, std::string, double, std::string>(
+        std::ignore = c.convert<std::string, std::string, double, std::string>(
             buff(R"(just,some,2,"strings\)"));
         CHECK_FALSE(c.valid());
         CHECK_FALSE(c.unterminated_quote());
@@ -944,7 +952,7 @@ TEST_CASE("converter test invalid split conversions") {
 
     {
         // unterminated escaped quote
-        c.convert<std::string, std::string, double, std::string>(
+        std::ignore = c.convert<std::string, std::string, double, std::string>(
             buff(R"(just,some,2,"strings\")"));
         CHECK_FALSE(c.valid());
         CHECK(c.unterminated_quote());
@@ -958,27 +966,32 @@ TEST_CASE("converter test invalid split conversions with exceptions") {
         c;
 
     // mismatched quote
-    REQUIRE_EXCEPTION(c.convert<std::string, std::string, double, char>(
+    REQUIRE_EXCEPTION(std::ignore =
+                          c.convert<std::string, std::string, double, char>(
                               buff(R"(  "just  , some ,   "12.3","a"  )")));
     CHECK_FALSE(c.unterminated_quote());
 
     // unterminated quote
-    REQUIRE_EXCEPTION(c.convert<std::string, std::string, double, std::string>(
+    REQUIRE_EXCEPTION(
+        std::ignore = c.convert<std::string, std::string, double, std::string>(
             buff(R"(  ju\,st  ,  "so,me"  ,   12.34     ,   "str""ings)")));
     CHECK(c.unterminated_quote());
 
     // unterminated escape
-    REQUIRE_EXCEPTION(c.convert<std::string, std::string, double, std::string>(
+    REQUIRE_EXCEPTION(
+        std::ignore = c.convert<std::string, std::string, double, std::string>(
             buff(R"(just,some,2,strings\)")));
     CHECK_FALSE(c.unterminated_quote());
 
     // unterminated escape while quoting
-    REQUIRE_EXCEPTION(c.convert<std::string, std::string, double, std::string>(
+    REQUIRE_EXCEPTION(
+        std::ignore = c.convert<std::string, std::string, double, std::string>(
             buff(R"(just,some,2,"strings\)")));
     CHECK_FALSE(c.unterminated_quote());
 
     // unterminated escaped quote
-    REQUIRE_EXCEPTION(c.convert<std::string, std::string, double, std::string>(
+    REQUIRE_EXCEPTION(
+        std::ignore = c.convert<std::string, std::string, double, std::string>(
             buff(R"(just,some,2,"strings\")")));
     CHECK(c.unterminated_quote());
 }

test/test_extractions_without_fast_float.cpp

@@ -1,5 +1,4 @@
 #include "test_helpers.hpp"
-#include <algorithm>
 
 #define SSP_DISABLE_FAST_FLOAT
 #include <ss/extract.hpp>

test/test_helpers.hpp

@@ -212,6 +212,7 @@ template <typename T>
         }
     };
 
+    // Evade small string optimization
     out.reserve(sizeof(out) + 1);
 
     copy_if_whitespaces();

test/test_parser1.hpp

@@ -12,7 +12,8 @@
 #include <unordered_set>
 
 namespace {
-[[maybe_unused]] void replace_all(std::string& s, const std::string& from,
+#ifdef _WIN32
+void replace_all(std::string& s, const std::string& from,
                  const std::string& to) {
     if (from.empty()) return;
     size_t start_pos = 0;
@@ -21,6 +22,7 @@ namespace {
         start_pos += to.length();
     }
 }
+#endif
 
 template <typename... Ts>
 void expect_error_on_command(ss::parser<Ts...>& p,
@@ -56,7 +58,7 @@ struct X {
     double d;
     std::string s;
 
-    std::string to_string() const {
+    [[nodiscard]] std::string to_string() const {
         if (s == empty) {
             return "";
         }
@@ -67,14 +69,15 @@ struct X {
             .append(delim)
             .append(s);
     }
-    auto tied() const {
+
+    [[nodiscard]] auto tied() const {
         return std::tie(i, d, s);
     }
 };
 
 template <typename T>
-std::enable_if_t<ss::has_m_tied_t<T>, bool> operator==(const T& lhs,
+[[nodiscard]] std::enable_if_t<ss::has_m_tied_t<T>, bool> operator==(
-                                                       const T& rhs) {
+    const T& lhs, const T& rhs) {
     return lhs.tied() == rhs.tied();
 }
 

test/test_parser1_1.cpp

@@ -57,7 +57,7 @@ struct Y {
             .append(s3);
     }
 
-    auto tied() const {
+    [[nodiscard]] auto tied() const {
         return std::tie(s1, s2, s3);
     }
 };
@@ -115,7 +115,8 @@ TEST_CASE_TEMPLATE("test line method", T, ParserOptionCombinations) {
     CHECK_EQ(p.line(), expected_line);
 
     while (!p.eof()) {
-        auto _ = p.template get_next<std::string, std::string, std::string>();
+        std::ignore =
+            p.template get_next<std::string, std::string, std::string>();
         ++expected_line;
         CHECK_EQ(p.line(), expected_line);
     }

test/test_parser1_2.cpp

@@ -51,12 +51,14 @@ TEST_CASE_TEMPLATE("test moving of parsed composite values", T,
     // to compile is enough
     return;
     auto [p, _] = make_parser<buffer_mode, ErrorMode>("", "");
+    std::ignore =
         p.template try_next<my_string, my_string, my_string>()
             .template or_else<my_string, my_string, my_string, my_string>(
                 [](auto&&) {})
             .template or_else<my_string>([](auto&) {})
             .template or_else<xyz>([](auto&&) {})
-        .template or_object<xyz, my_string, my_string, my_string>([](auto&&) {})
+            .template or_object<xyz, my_string, my_string, my_string>(
+                [](auto&&) {})
             .template or_else<std::tuple<my_string, my_string, my_string>>(
                 [](auto&, auto&, auto&) {});
 }
@@ -73,7 +75,7 @@ TEST_CASE_TEMPLATE("parser test string error mode", BufferMode, std::true_type,
     auto [p, _] = make_parser<BufferMode::value, ss::string_error>(f.name, ",");
 
     REQUIRE_FALSE(p.eof());
-    p.template get_next<int>();
+    std::ignore = p.template get_next<int>();
     CHECK_FALSE(p.valid());
     CHECK_FALSE(p.error_msg().empty());
 }
@@ -92,7 +94,7 @@ TEST_CASE_TEMPLATE("parser throw on error mode", BufferMode, std::true_type,
 
     REQUIRE_FALSE(p.eof());
     try {
-        p.template get_next<int>();
+        std::ignore = p.template get_next<int>();
         FAIL("Expected exception...");
     } catch (const std::exception& e) {
         CHECK_FALSE(std::string{e.what()}.empty());
@@ -148,6 +150,7 @@ TEST_CASE_TEMPLATE("test quote multiline", T, ParserOptionCombinations) {
         make_parser<buffer_mode, ErrorMode, ss::quote<'"'>>(f.name, ",");
     while (!p.eof()) {
         auto command = [&p_no_multiline = p_no_multiline] {
+            std::ignore =
                 p_no_multiline.template get_next<int, double, std::string>();
         };
         expect_error_on_command(p_no_multiline, command);

test/test_parser1_3.cpp

@@ -83,7 +83,7 @@ void test_unterminated_line(const std::vector<std::string>& lines,
     size_t line = 0;
     while (!p.eof()) {
         auto command = [&p = p] {
-            p.template get_next<int, double, std::string>();
+            std::ignore = p.template get_next<int, double, std::string>();
         };
 
         if (line == bad_line) {

test/test_parser1_4.cpp

@@ -228,7 +228,7 @@ void test_invalid_fields(const std::vector<std::string>& lines,
         auto [p, _] = make_parser<buffer_mode, ErrorMode>(f.name, ",");
         auto command = [&p = p, &fields = fields] {
             p.use_fields(fields.at(0));
-            p.template get_next<std::string, std::string>();
+            std::ignore = p.template get_next<std::string, std::string>();
         };
         check_header(p);
 
@@ -428,7 +428,7 @@ TEST_CASE_TEMPLATE("test invalid header", T, ParserOptionCombinations) {
     {
         auto [p, _] =
             make_parser<buffer_mode, ErrorMode, ss::quote<'"'>>(f.name);
-        auto command = [&p = p] { p.header(); };
+        auto command = [&p = p] { std::ignore = p.header(); };
         expect_error_on_command(p, command);
         CHECK_EQ(p.raw_header(), "\"Int");
     }
@@ -437,7 +437,7 @@ TEST_CASE_TEMPLATE("test invalid header", T, ParserOptionCombinations) {
         auto [p, _] =
             make_parser<buffer_mode, ErrorMode, ss::quote<'"'>, ss::multiline>(
                 f.name);
-        auto command = [&p = p] { p.header(); };
+        auto command = [&p = p] { std::ignore = p.header(); };
         expect_error_on_command(p, command);
         CHECK_EQ(p.raw_header(), "\"Int");
     }
@@ -445,7 +445,7 @@ TEST_CASE_TEMPLATE("test invalid header", T, ParserOptionCombinations) {
     {
         auto [p, _] = make_parser<buffer_mode, ErrorMode, ss::quote<'"'>,
                                   ss::escape<'\\'>, ss::multiline>(f.name);
-        auto command = [&p = p] { p.header(); };
+        auto command = [&p = p] { std::ignore = p.header(); };
         expect_error_on_command(p, command);
         CHECK_EQ(p.raw_header(), "\"Int");
     }
@@ -460,7 +460,7 @@ TEST_CASE_TEMPLATE("test invalid header", T, ParserOptionCombinations) {
     {
         auto [p, _] =
             make_parser<buffer_mode, ErrorMode, ss::escape<'\\'>>(f.name);
-        auto command = [&p = p] { p.header(); };
+        auto command = [&p = p] { std::ignore = p.header(); };
         expect_error_on_command(p, command);
         CHECK_EQ(p.raw_header(), "Int\\");
     }
@@ -468,7 +468,7 @@ TEST_CASE_TEMPLATE("test invalid header", T, ParserOptionCombinations) {
     {
         auto [p, _] = make_parser<buffer_mode, ErrorMode, ss::escape<'\\'>,
                                   ss::multiline>(f.name);
-        auto command = [&p = p] { p.header(); };
+        auto command = [&p = p] { std::ignore = p.header(); };
         expect_error_on_command(p, command);
         CHECK_EQ(p.raw_header(), "Int\\");
     }
@@ -476,7 +476,7 @@ TEST_CASE_TEMPLATE("test invalid header", T, ParserOptionCombinations) {
     {
         auto [p, _] = make_parser<buffer_mode, ErrorMode, ss::escape<'\\'>,
                                   ss::quote<'"'>, ss::multiline>(f.name);
-        auto command = [&p = p] { p.header(); };
+        auto command = [&p = p] { std::ignore = p.header(); };
         expect_error_on_command(p, command);
         CHECK_EQ(p.raw_header(), "Int\\");
     }

test/test_parser2.hpp

@@ -85,7 +85,7 @@ struct column {
 };
 
 template <typename... Ts>
-column make_column(const std::string& input_header,
+[[nodiscard]] column make_column(const std::string& input_header,
                                  const std::vector<field>& input_fields) {
     using setup = ss::setup<Ts...>;
     std::vector<field> filtered_fields;
@@ -127,8 +127,8 @@ column make_column(const std::string& input_header,
 }
 
 template <typename... Ts>
-std::vector<std::string> generate_csv_data(const std::vector<field>& data,
+[[nodiscard]] std::vector<std::string> generate_csv_data(
-                                           const std::string& delim) {
+    const std::vector<field>& data, const std::string& delim) {
     (void)delim;
     using setup = ss::setup<Ts...>;
     constexpr static auto escape = '\\';

test/test_parser2_1.cpp

@@ -9,4 +9,3 @@ TEST_CASE("parser test various cases version 2 segment 1") {
     test_option_combinations3<escape>();
 #endif
 }
-

test/test_parser2_2.cpp

@@ -10,4 +10,3 @@ TEST_CASE("parser test various cases version 2 segment 2") {
     test_option_combinations3<escape, quote>();
 #endif
 }
-

test/test_parser2_3.cpp

@@ -11,4 +11,3 @@ TEST_CASE("parser test various cases version 2 segment 3") {
     test_option_combinations3<quote, multiline>();
 #endif
 }
-

test/test_parser2_4.cpp

@@ -12,4 +12,3 @@ TEST_CASE("parser test various cases version 2 segment 4") {
     test_option_combinations3<escape, quote, multiline_r>();
 #endif
 }
-

test/test_parser2_5.cpp

@@ -13,4 +13,3 @@ TEST_CASE("parser test various cases version 2 segment 5") {
     test_option_combinations<escape, quote, multiline, trimr>();
 #endif
 }
-

test/test_parser2_6.cpp

@@ -8,4 +8,3 @@ TEST_CASE("parser test various cases version 2 segment 6") {
 
     test_option_combinations3<escape, quote, multiline>();
 }
-