Lots of work.

23 files changed, 1914 insertions, 465 deletions

diff --git a/.clang-format b/.clang-format
index 87aff92..50883a6 100644
--- a/.clang-format
+++ b/.clang-format
@@ -30,7 +30,6 @@ AlignConsecutiveMacros:
   PadOperators:    false
 AlignEscapedNewlines: Left
 AlignOperands:   false
-AlignTrailingComments: Never
 AllowAllArgumentsOnNextLine: false
 AllowAllParametersOfDeclarationOnNextLine: false
 AllowShortBlocksOnASingleLine: Never
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 7358151..f0e9aff 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -19,14 +19,15 @@ add_library(fud SHARED
     source/libfud.cpp
     source/fud_allocator.cpp
     source/fud_assert.cpp
-    source/fud_memory.cpp
+    source/fud_format.cpp
+    source/fud_directory.cpp
     source/fud_c_file.cpp
+    source/fud_memory.cpp
+    source/fud_sqlite.cpp
     source/fud_string_view.cpp
     source/fud_string.cpp
     source/fud_utf8.cpp
     source/fud_utf8_iterator.cpp
-    source/fud_sqlite.cpp
-    source/fud_directory.cpp
 )
 
 include(cmake/warnings.cmake)
@@ -39,7 +40,7 @@ target_link_libraries(fud ${SQLite3_LIBRARIES})
 
 set_target_properties(
     fud PROPERTIES
-    CXX_STANDARD 20
+    CXX_STANDARD 23
     C_STANDARD 23
     CXX_EXTENSIONS OFF
     C_EXTENSIONS OFF
@@ -89,9 +90,11 @@ install(FILES ${CMAKE_CURRENT_BINARY_DIR}/FudConfig.cmake
 set(FUD_HEADERS
     "include/libfud.hpp"
     "include/fud_allocator.hpp"
+    "include/fud_algorithm.hpp"
     "include/fud_array.hpp"
     "include/fud_assert.hpp"
     "include/fud_c_file.hpp"
+    "include/fud_c_string.hpp"
     "include/fud_directory.hpp"
     "include/fud_fud_type_traits.hpp"
     "include/fud_memory.hpp"
@@ -105,6 +108,7 @@ set(FUD_HEADERS
     "include/fud_unique_array.hpp"
     "include/fud_utf8.hpp"
     "include/fud_utf8_iterator.hpp"
+    "include/fud_vector.hpp"
 )
 
 set_target_properties(fud PROPERTIES PUBLIC_HEADER "${FUD_HEADERS}")
diff --git a/include/fud_algorithm.hpp b/include/fud_algorithm.hpp
new file mode 100644
index 0000000..e3d5d3b
--- /dev/null
+++ b/include/fud_algorithm.hpp
@@ -0,0 +1,162 @@
+/*
+ * libfud
+ * Copyright 2024 Dominick Allen
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef FUD_ALGORITHM_HPP
+#define FUD_ALGORITHM_HPP
+
+#include "fud_span.hpp"
+
+#include <concepts>
+#include <limits>
+#include <optional>
+#include <type_traits>
+
+namespace fud {
+
+template <std::integral T>
+class Iota {
+  public:
+    constexpr Iota() noexcept : m_value{}, m_increment{static_cast<T>(1)}, m_limit{std::numeric_limits<T>::max()}
+    {
+    }
+
+    constexpr Iota(T value) noexcept :
+        m_value{value}, m_increment{static_cast<T>(1)}, m_limit{std::numeric_limits<T>::max()}
+    {
+    }
+
+    constexpr Iota(T value, T increment) noexcept :
+        m_value{value}, m_increment{increment}, m_limit{std::numeric_limits<T>::max()}
+    {
+    }
+
+    constexpr Iota(T value, T increment, T limit) noexcept : m_value{value}, m_increment{increment}, m_limit{limit}
+    {
+    }
+
+    constexpr std::optional<T> operator()() noexcept
+    {
+        auto value = m_value;
+        if (m_increment > 0) {
+            if (m_limit - m_increment < m_value) {
+                return std::nullopt;
+            }
+        } else {
+            if (m_limit + m_increment + 1 >= m_value) {
+                return std::nullopt;
+            }
+        }
+        m_value += m_increment;
+        return value;
+    }
+
+    void set(T value) {
+        m_value = value;
+    }
+
+  private:
+    T m_value;
+    const T m_increment;
+    const T m_limit;
+};
+
+template <typename T, size_t Size, typename Func>
+Span<T, Size> forEach(Span<T, Size> input, Func&& mapFunc)
+{
+    for (auto& element : input) {
+        element = std::forward<Func>(mapFunc)(element);
+    }
+
+    return input;
+}
+
+template <typename T, typename U, size_t Size, typename Func>
+Span<T, Size> mapTo(Span<T, Size> input, Span<U, Size> output, Func&& mapFunc)
+{
+    for (auto idx = 0; idx < input.size(); ++idx) {
+        output[idx] = std::forward<Func>(mapFunc)(input[idx]);
+    }
+
+    return input;
+}
+
+template <typename T, size_t Size, typename Func, typename Builder, typename Output>
+auto map(Span<T, Size> input, Func&& mapFunc, Builder&& builder) -> decltype(std::forward<Builder>(builder)())
+{
+    Output output{std::forward<Builder>(builder)()};
+    for (auto idx = 0; idx < input.size() && idx < output.size(); ++idx) {
+        output[idx] = std::forward<Func>(mapFunc)(input[idx]);
+    }
+
+    return input;
+}
+
+template <typename Generator, typename Builder>
+auto generate(Builder&& builder, Generator&& generator) -> decltype(std::forward<Builder>(builder)())
+{
+    using Output = decltype(std::forward<Builder>(builder)());
+    Output output{std::forward<Builder>(builder)()};
+    for (auto idx = 0; idx < output.size(); ++idx) {
+        output[idx] = std::forward<Generator>(generator)();
+    }
+
+    return output;
+}
+
+template <typename T, size_t Size, typename Func>
+bool allOf(Span<T, Size> input, Func&& predicate)
+{
+    bool result = input.size() > 0;
+    for (size_t idx = 0; result && idx < input.size(); ++idx) {
+        result = result && std::forward<Func>(predicate)(input[idx]);
+    }
+    return result;
+}
+
+template <typename Generator, typename Func>
+bool allOf(Generator&& generator, Func&& predicate)
+{
+    bool result = true;
+    while (auto val = std::forward<Generator>(generator)()) {
+        result = result && std::forward<Func>(predicate)(*val);
+    }
+    return result;
+}
+
+template <typename T, size_t Size, typename Func>
+bool anyOf(Span<T, Size> input, Func&& predicate)
+{
+    bool result = !(input.size() > 0);
+    for (size_t idx = 0; result && idx < input.size(); ++idx) {
+        result = result || std::forward<Func>(predicate)(input[idx]);
+    }
+    return result;
+}
+
+template <typename Generator, typename Func>
+bool anyOf(Generator&& generator, Func&& predicate)
+{
+    bool result = false;
+    while (auto val = std::forward<Generator>(generator)()) {
+        result = result || std::forward<Func>(predicate)(*val);
+    }
+    return result;
+}
+
+} // namespace fud
+
+#endif
diff --git a/include/fud_array.hpp b/include/fud_array.hpp
index 4e2c702..807621a 100644
--- a/include/fud_array.hpp
+++ b/include/fud_array.hpp
@@ -18,9 +18,9 @@
 #ifndef FUD_ARRAY_HPP
 #define FUD_ARRAY_HPP
 
-#include "fud_memory.hpp"
+#include <cstddef>
 
-#include <cstdlib>
+#include "fud_memory.hpp"
 
 namespace fud {
 
diff --git a/include/fud_c_string.hpp b/include/fud_c_string.hpp
new file mode 100644
index 0000000..44e0dc8
--- /dev/null
+++ b/include/fud_c_string.hpp
@@ -0,0 +1,55 @@
+/*
+ * libfud
+ * Copyright 2024 Dominick Allen
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef FUD_C_STRING_HPP
+#define FUD_C_STRING_HPP
+
+#include <climits>
+#include <cstddef>
+#include <sys/types.h>
+
+
+namespace fud {
+
+constexpr ssize_t cStringLength(const char* str, size_t maxLength)
+{
+    if (str == nullptr || maxLength > (SSIZE_MAX - 1)) {
+        return -1;
+    }
+
+    ssize_t size = 0;
+
+    while (str[size] != 0 && static_cast<size_t>(size) < maxLength) {
+        size++;
+    }
+
+    if (str[size] != 0 && static_cast<size_t>(size) == maxLength) {
+        return static_cast<ssize_t>(maxLength) + 1;
+    }
+
+    return size;
+}
+
+constexpr ssize_t cStringLength(const char* str)
+{
+    constexpr auto maxLength = SSIZE_MAX - 1;
+    return cStringLength(str, maxLength);
+}
+
+} // namespace fud
+
+#endif
diff --git a/include/fud_format.hpp b/include/fud_format.hpp
index 8985faf..ea32bd8 100644
--- a/include/fud_format.hpp
+++ b/include/fud_format.hpp
@@ -18,275 +18,179 @@
 #ifndef FUD_FORMAT_HPP
 #define FUD_FORMAT_HPP
 
-#include "fud_assert.hpp"
+// #include "fud_assert.hpp"
 #include "fud_result.hpp"
-#include "fud_span.hpp"
 #include "fud_status.hpp"
 #include "fud_string_view.hpp"
+#include "fud_utf8.hpp"
 
-#include <format> // for std::format_string
 #include <cstdint>
 #include <optional>
+#include <variant>
 
 namespace fud {
 
-template <size_t Size>
-using CharSpan = Span<char, Size>;
-
-template <typename... Args>
-using FormatLiteral = std::format_string<Args...>;
+struct FormatAlign
+{
+    enum class Value : uint8_t
+    {
+        Left,
+        Right,
+        Center
+    };
+
+    constexpr static std::optional<FormatAlign> from(utf8 letter)
+    {
+        FormatAlign formatAlign;
+        switch (letter) {
+        case '<':
+            formatAlign.value = Value::Left;
+            break;
+        case '>':
+            formatAlign.value = Value::Right;
+            break;
+        case '^':
+            formatAlign.value = Value::Center;
+            break;
+        default:
+            return std::nullopt;
+        }
 
-template <typename... Args, size_t Size>
-Result<size_t, FudStatus> format(CharSpan<Size> buffer, FormatLiteral<Args...> formatLiteral, Args&&... args);
+        return formatAlign;
+    }
 
-enum class FormatAlign : uint8_t  {
-    Left,
-    Right,
-    Center
+    Value value;
 };
 
 struct FormatFill {
     FormatAlign align;
-    char fill;
+    utf8 fill;
+
+    constexpr static Result<std::optional<FormatFill>, FudStatus> parse(StringView formatView) {
+        // "{:A<X}"
+        using RetType = Result<std::optional<FormatFill>, FudStatus>;
+        if (formatView.length() < 3) {
+            return RetType::okay(std::nullopt);
+        }
+
+        const auto* data = formatView.data();
+        if (data[0] != 'A') {
+            return RetType::okay(std::nullopt);
+        }
+
+        auto align = FormatAlign::from(data[1]);
+        if (!align.has_value()) {
+            return FudStatus::FormatInvalid;
+        }
+
+        auto fill = data[2];
+        if (!Ascii::valid(fill)) {
+            return FudStatus::Utf8Invalid;
+        }
+
+        return RetType::okay(FormatFill{*align, fill});
+    }
 };
 
-enum class FormatSign : uint8_t {
+enum class FormatSign : uint8_t
+{
     Plus,
     Minus,
     Space
 };
 
-struct FormatSpec {
-    std::optional<FormatFill> fill;
-    std::optional<FormatSign> formatSign;
-    uint32_t minWidth;
+enum class FormatStringType : uint8_t
+{
+    String,
+    Escaped,
 };
 
-namespace detail {
-
-template <typename Arg, typename... Args, size_t Size>
-Result<size_t, FudStatus> formatHelper(
-    CharSpan<Size> buffer,
-    size_t formattedSize,
-    StringView formatView,
-    Arg&& arg,
-    Args&&... args);
-
-template <typename Arg, typename... Args, size_t Size>
-Result<size_t, FudStatus> formatHelper(
-    CharSpan<Size> buffer,
-    size_t formattedSize,
-    StringView formatView,
-    Arg&& arg);
-
-template <size_t Size>
-Result<size_t, FudStatus> formatHelper(
-    CharSpan<Size> buffer,
-    size_t formattedSize,
-    StringView formatView);
-
-} // namespace detail
-
-template <typename... Args, size_t Size>
-Result<size_t, FudStatus> format(CharSpan<Size> buffer, FormatLiteral<Args...> formatLiteral, Args&&... args)
+enum class FormatIntegerType : uint8_t
 {
-    static_assert(Size > 0);
-
-    if (buffer.data() == nullptr) {
-        return FudStatus::NullPointer;
-    }
-
-    StringView formatView{formatLiteral.get()};
-
-    if (formatView.length() == 0 || formatView.data()[0] == '\0') {
-        return 0U;
-    }
-
-    size_t argCount = sizeof...(args);
-    static_cast<void>(argCount);
-
-    size_t formattedSize = 0;
+    BinaryLower,
+    BinaryUpper,
+    Character,
+    Decimal,
+    Octal,
+    HexLower,
+    HexUpper,
+};
 
-    return detail::formatHelper(buffer, formattedSize, formatView, std::forward<Args>(args)...);
-}
+enum class FormatCharacterType : uint8_t
+{
+    BinaryLower,
+    BinaryUpper,
+    Character,
+    Decimal,
+    Octal,
+    HexLower,
+    HexUpper,
+};
 
-namespace detail {
+enum class FormatBoolType : uint8_t
+{
+    BinaryLower,
+    BinaryUpper,
+    Character,
+    Decimal,
+    Octal,
+    HexLower,
+    HexUpper,
+};
 
-#define FUDETAIL_ADVANCE_FORMAT(FORMAT_VIEW, ADVANCE_BY) \
-    fudAssert(ADVANCE_BY <= FORMAT_VIEW.m_length); \
-    FORMAT_VIEW.m_length -= ADVANCE_BY; \
-    FORMAT_VIEW.m_data += ADVANCE_BY; \
+enum class FormatFloatingType : uint8_t
+{
+    FloatHexLower,
+    FloatHexUpper,
+    ScientificLower,
+    ScientificUpper,
+    Fixed,
+    GeneralLower,
+    GeneralUpper
+};
 
-constexpr bool findBracket(size_t& copyLength, StringView formatView)
+enum class FormatPointerType : uint8_t
 {
-    while (copyLength < formatView.m_length) {
-        if (formatView.m_data[copyLength] == '{') {
-            return true;
-        }
-        copyLength++;
-    }
+    HexLower,
+    HexUpper
+};
 
-    return false;
-}
+using FormatType = std::variant< // break
+    std::monostate,
+    FormatStringType,
+    FormatIntegerType,
+    FormatCharacterType,
+    FormatBoolType,
+    FormatFloatingType,
+    FormatPointerType>;
 
-template <size_t Size>
-size_t copyRemaining(
-    CharSpan<Size> buffer,
-    size_t formattedSize,
-    StringView& formatView,
-    size_t copyLength)
-{
-    fudAssert(copyLength <= formatView.length());
-    if (copyLength + formattedSize > Size) {
-        copyLength = Size - formattedSize;
-    }
-    auto copyResult = copyMem(
-        buffer.data() + formattedSize,
-        Size - formattedSize,
-        formatView.m_data,
-        copyLength);
-    fudAssert(copyResult == FudStatus::Success);
-    FUDETAIL_ADVANCE_FORMAT(formatView, copyLength);
-    return formattedSize + copyLength;
-}
-
-template <typename Arg, size_t Size>
-Result<size_t, FudStatus> handleSpec(
-    CharSpan<Size> buffer,
-    size_t formattedSize,
-    StringView& formatView,
-    Arg&& arg,
-    bool& consumed)
-{
-    fudAssert(formattedSize < Size);
-    fudAssert(formatView.length() > 1);
-
-    if (formatView.m_data[1] == '{') {
-        consumed = false;
-        buffer[formattedSize] = '{';
-        FUDETAIL_ADVANCE_FORMAT(formatView, 2);
-        return formattedSize + 1;
-    }
+struct FormatSpec;
+using FormatSpecResult = Result<FormatSpec, FudStatus>;
 
-    static_cast<void>(arg);
-    buffer[formattedSize] = 'X';
-    formattedSize += 1;
-    size_t index = 0;
-    for (; index < formatView.m_length; ++index) {
-        if (formatView.m_data[index] == '}') {
-            break;
-        }
-    }
-    FUDETAIL_ADVANCE_FORMAT(formatView, index + 1);
-    return formattedSize;
-}
-
-template <typename Arg, typename... Args, size_t Size>
-Result<size_t, FudStatus> formatHelper(
-    CharSpan<Size> buffer,
-    size_t formattedSize,
-    StringView formatView,
-    Arg&& arg,
-    Args&&... args)
-{
-    while (formattedSize < Size) {
-        size_t copyLength = 0;
-        auto found = findBracket(copyLength, formatView);
-        formattedSize = copyRemaining(buffer, formattedSize, formatView, copyLength);
-        fudAssert(formattedSize <= Size);
-        if (!found || formattedSize == Size) {
-            return formattedSize;
-        }
+struct FormatSpec {
+    size_t width;
+    size_t precision;
+    FormatFill fill;
+    FormatSign formatSign;
 
-        bool consumed = false;
-        auto specResult = handleSpec(buffer, formattedSize, formatView, std::forward<Arg>(arg), consumed);
-        formattedSize = M_TakeOrReturn(specResult);
-        fudAssert(formattedSize <= Size);
-        if (formattedSize == Size) {
-            return formattedSize;
-        }
+    FormatType formatType;
 
-        if (consumed) {
-            return formatHelper(buffer, formattedSize, formatView, std::forward<Args>(args)...);
-        }
-    }
+    bool hasWidth;
+    bool takesWidth;
 
-    return formattedSize;
-}
+    bool hasPrecision;
+    bool takesPrecision;
 
-template <typename Arg, typename... Args, size_t Size>
-Result<size_t, FudStatus> formatHelper(
-    CharSpan<Size> buffer,
-    size_t formattedSize,
-    StringView formatView,
-    Arg&& arg)
-{
-    while (formattedSize < Size) {
-        size_t copyLength = 0;
-        auto found = findBracket(copyLength, formatView);
-        formattedSize = copyRemaining(buffer, formattedSize, formatView, copyLength);
-        fudAssert(formattedSize <= Size);
-        if (!found || formattedSize == Size) {
-            return formattedSize;
-        }
+    bool hasFill;
 
-        bool consumed = false;
-        auto specResult = handleSpec(buffer, formattedSize, formatView, std::forward<Arg>(arg), consumed);
-        formattedSize = M_TakeOrReturn(specResult);
-        if (consumed) {
-            return formatHelper(buffer, formattedSize, formatView);
-        }
-    }
-    return formattedSize;
-}
-
-template <size_t Size>
-Result<size_t, FudStatus> formatHelper(
-    CharSpan<Size> buffer,
-    size_t formattedSize,
-    StringView formatView)
-{
-    size_t index = 0;
-    while (formattedSize < Size && formatView.m_length > 0) {
-        while (index < formatView.m_length && formattedSize + index < Size) {
-            if (formatView.m_data[index] == '{') {
-                break;
-            }
-            index++;
-        }
-        bool isBracket{false};
-        if (index + 1 < formatView.m_length && formattedSize + index + 1 < Size) {
-            if (formatView.m_data[index] == '{') {
-                isBracket = true;
-                index++;
-            }
-        }
-        auto copyResult = copyMem(
-            buffer.data() + formattedSize,
-            Size - formattedSize,
-            formatView.m_data,
-            index);
-        formattedSize += index;
-        formatView.m_length -= index;
-        formatView.m_data += index;
-        if (isBracket) {
-            index = 0;
-            if (formatView.m_length > 0) {
-                formatView.m_length--;
-                formatView.m_data++;
-            }
-            if (formattedSize < Size) {
-                buffer.data()[formattedSize] = 'X';
-                formattedSize++;
-            }
-        }
-    }
-    return formattedSize;
-}
+    bool hasFormatSign;
+
+    bool alternateForm;
 
-#undef FUDETAIL_ADVANCE_FORMAT
+    bool leadingZero;
 
-} // namespace detail
+    static Result<FormatSpec, FudStatus> make(StringView& formatView, size_t specIndex);
+};
 
 } // namespace fud
 
diff --git a/include/fud_result.hpp b/include/fud_result.hpp
index 4bfb819..877c49c 100644
--- a/include/fud_result.hpp
+++ b/include/fud_result.hpp
@@ -19,6 +19,7 @@
 #define FUD_RESULT_HPP
 
 #include <variant>
+#include <utility>
 
 namespace fud {
 
@@ -28,62 +29,62 @@ class [[nodiscard]] Result {
   public:
     using ResultType = Result<T, E>;
 
-    Result(const T& value) : m_value{value}
+    constexpr Result(const T& value) : m_value{value}
     {
     }
 
-    Result(const E& value) : m_value{value}
+    constexpr Result(const E& value) : m_value{value}
     {
     }
 
-    Result(T&& value) : m_value{std::move(value)}
+    constexpr Result(T&& value) : m_value{std::move(value)}
     {
     }
 
-    Result(E&& value) : m_value{std::move(value)}
+    constexpr Result(E&& value) : m_value{std::move(value)}
     {
     }
 
-    static ResultType okay(const T& okay)
+    static constexpr ResultType okay(const T& okay)
     {
         return ResultType{okay};
     }
 
-    static ResultType okay(T&& okay)
+    static constexpr ResultType okay(T&& okay)
     {
         return ResultType{std::move(okay)};
     }
 
-    static ResultType error(const E& error)
+    static constexpr ResultType error(const E& error)
     {
         return ResultType{error};
     }
 
-    static ResultType error(E&& error)
+    static constexpr ResultType error(E&& error)
     {
         return ResultType{std::move(error)};
     }
 
     template <typename F>
-    static ResultType okay(const Result<T, F>& okayRes)
+    static constexpr ResultType okay(const Result<T, F>& okayRes)
     {
         return ResultType{okayRes.getOkay()};
     }
 
     template <typename F>
-    static ResultType okay(Result<T, F>&& okayRes)
+    static constexpr ResultType okay(Result<T, F>&& okayRes)
     {
         return ResultType{okayRes.takeOkay()};
     }
 
     template <typename U>
-    static ResultType error(const Result<U, E>& errorRes)
+    static constexpr ResultType error(const Result<U, E>& errorRes)
     {
         return ResultType{errorRes.getError()};
     }
 
     template <typename U>
-    static ResultType error(Result<U, E>&& errorRes)
+    static constexpr ResultType error(Result<U, E>&& errorRes)
     {
         return ResultType{errorRes.takeError()};
     }
@@ -98,28 +99,28 @@ class [[nodiscard]] Result {
         return (m_value.index() == 1);
     }
 
-    [[nodiscard]] const T& getOkay() const&
+    [[nodiscard]] constexpr const T& getOkay() const&
     {
         return std::get<T>(m_value);
     }
 
-    [[nodiscard]] const E& getError() const&
+    [[nodiscard]] constexpr const E& getError() const&
     {
         return std::get<E>(m_value);
     }
 
-    [[nodiscard]] T&& takeOkay()
+    [[nodiscard]] constexpr T&& takeOkay()
     {
         return std::move(std::get<T>(m_value));
     }
 
-    [[nodiscard]] E&& takeError()
+    [[nodiscard]] constexpr E&& takeError()
     {
         return std::move(std::get<E>(m_value));
     }
 
   private:
-    Result() : m_value()
+    constexpr Result() : m_value()
     {
     }
 
diff --git a/include/fud_span.hpp b/include/fud_span.hpp
index cc693f8..5b8497e 100644
--- a/include/fud_span.hpp
+++ b/include/fud_span.hpp
@@ -18,41 +18,71 @@
 #ifndef FUD_SPAN_HPP
 #define FUD_SPAN_HPP
 
-#include <cstdlib>
-
 #include "fud_array.hpp"
+#include "fud_result.hpp"
+#include "fud_status.hpp"
+
+#include <cstddef>
+#include <cstdint>
 
 namespace fud {
 
-template <typename T, size_t Size>
+template <typename T, size_t Size = SIZE_MAX>
 struct Span {
     static_assert(Size > 0);
     using ValueType = T;
 
-    static Span make(Array<T, Size>& array) {
-        Span<T, Size> output{};
-        output.m_data = array.data();
+    static Span make(Array<T, Size>& array)
+    {
+        Span<T, Size> output{array.data(), Size};
         return output;
     }
 
+    static Result<Span, FudStatus> make(Array<T, Size>& array, size_t size)
+    {
+        if (size > Size) {
+            return FudStatus::ArgumentInvalid;
+        }
+        return Span<T, Size>{array.data(), Size};
+    }
+
     template <typename U>
-    static Span make(const Array<U, Size>& array) {
+    static Span make(const Array<U, Size>& array)
+    {
         static_assert(std::convertible_to<U, T>);
-        Span<T, Size> output{};
-        output.m_data = array.data();
-        return output;
+        return Span<T, Size>{array.data(), Size};
     }
 
     template <typename U>
-    static Span make(Array<U, Size>& array) {
+    static Result<Span, FudStatus> make(const Array<U, Size>& array, size_t size)
+    {
         static_assert(std::convertible_to<U, T>);
-        Span<T, Size> output{};
-        output.m_data = array.data();
-        return output;
+        if (size > Size) {
+            return FudStatus::ArgumentInvalid;
+        }
+        return Span<T, Size>{array.data(), Size};
+    }
+
+    template <typename U>
+    static Span make(Array<U, Size>& array)
+    {
+        static_assert(std::convertible_to<U, T>);
+        return Span<T, Size>{array.data(), array.size()};
+    }
+
+    template <typename U>
+    static Result<Span, FudStatus> make(Array<U, Size>& array, size_t size)
+    {
+        static_assert(std::convertible_to<U, T>);
+        if (size > Size) {
+            return FudStatus::ArgumentInvalid;
+        }
+        return Span<T, Size>{array.data(), array.size()};
     }
 
     template <size_t ArraySize>
-    static Span makeCStringBuffer(Array<T, ArraySize>& array) {
+    static Span makeCStringBuffer(Array<T, ArraySize>& array)
+    {
         static_assert(ArraySize > Size);
         Span<T, Size> output{};
         output.m_data = array.data();
@@ -60,10 +90,15 @@ struct Span {
     }
 
     T* m_data;
+    const size_t m_size;
 
     [[nodiscard]] constexpr size_t size() const
     {
-        return Size;
+        if constexpr (Size < SIZE_MAX) {
+            return Size;
+        } else {
+            return m_size;
+        }
     }
 
     constexpr T& front()
@@ -78,12 +113,12 @@ struct Span {
 
     constexpr T& back()
     {
-        return m_data[Size - 1];
+        return m_data[size() - 1];
     }
 
     constexpr const T& back() const
     {
-        return m_data[Size - 1];
+        return m_data[size() - 1];
     }
 
     constexpr T* data() noexcept
@@ -108,12 +143,12 @@ struct Span {
 
     constexpr T* end() noexcept
     {
-        return m_data + Size;
+        return m_data + size();
     }
 
     constexpr const T* end() const noexcept
     {
-        return m_data + Size;
+        return m_data + size();
     }
 
     constexpr T& operator[](size_t index)
diff --git a/include/fud_status.hpp b/include/fud_status.hpp
index bda646b..91048ac 100644
--- a/include/fud_status.hpp
+++ b/include/fud_status.hpp
@@ -40,6 +40,7 @@ enum class [[nodiscard]] FudStatus
     RangeError,
     VariantInvalid,
     BadArrayLength,
+    FormatInvalid,
     NotImplemented,
     NotSupported
 };
@@ -83,6 +84,8 @@ constexpr const char* FudStatusToString(FudStatus status)
         return "VariantInvalid";
     case FudStatus::BadArrayLength:
         return "BadArrayLength";
+    case FudStatus::FormatInvalid:
+        return "FormatInvalid";
     case FudStatus::NotImplemented:
         return "NotImplemented";
     case FudStatus::NotSupported:
diff --git a/include/fud_string.hpp b/include/fud_string.hpp
index ba05450..60a328f 100644
--- a/include/fud_string.hpp
+++ b/include/fud_string.hpp
@@ -23,6 +23,7 @@
 #include "fud_result.hpp"
 #include "fud_status.hpp"
 #include "fud_string_view.hpp"
+#include "fud_c_string.hpp"
 #include "fud_utf8.hpp"
 
 #include <climits>
diff --git a/include/fud_string_view.hpp b/include/fud_string_view.hpp
index 7b4925e..8a47ae5 100644
--- a/include/fud_string_view.hpp
+++ b/include/fud_string_view.hpp
@@ -71,6 +71,14 @@ struct StringView {
 
     Result<size_t, FudStatus> trimWhitespace();
 
+    [[nodiscard]] bool advance();
+
+    void advanceUnsafe();
+
+    [[nodiscard]] bool advance(size_t size);
+
+    void advanceUnsafe(size_t size);
+
     FudStatus toUint8(uint8_t& number, uint8_t specifiedRadix, size_t& strLen) const;
 
     FudStatus toUint16(uint16_t& number, uint8_t specifiedRadix, size_t& strLen) const;
@@ -96,12 +104,6 @@ struct StringView {
     const utf8* m_data{nullptr};
 };
 
-FudStatus skipWhitespace(StringView& view, size_t& skipIndex);
-
-ssize_t cStringLength(const char* str);
-
-ssize_t cStringLength(const char* str, size_t maxLength);
-
 } // namespace fud
 
 #endif
diff --git a/include/fud_utf8.hpp b/include/fud_utf8.hpp
index 539e0f4..3b1a6b7 100644
--- a/include/fud_utf8.hpp
+++ b/include/fud_utf8.hpp
@@ -19,8 +19,8 @@
 #define FUD_UTF8_HPP
 
 #include "fud_array.hpp"
-#include "fud_status.hpp"
 #include "fud_unique_array.hpp"
+#include "fud_c_string.hpp"
 
 #include <cstdint>
 #include <optional>
@@ -28,6 +28,8 @@
 
 namespace fud {
 
+
+
 using utf8 = unsigned char;
 
 class String;
@@ -110,6 +112,18 @@ struct Utf82Byte {
     constexpr Utf82Byte(utf8 first, utf8 second) noexcept : characters{{first, second}}
     {
     }
+
+    __attribute__((nonnull))
+    constexpr Utf82Byte(const char* letterStr) noexcept : characters{}
+    {
+        auto length = cStringLength(letterStr, 2);
+        if (length < 2) {
+            return;
+        }
+        characters[0] = static_cast<utf8>(letterStr[0]);
+        characters[1] = static_cast<utf8>(letterStr[1]);
+    }
+
     Array<utf8, 2> characters;
     static constexpr size_t size() noexcept
     {
@@ -145,6 +159,18 @@ struct Utf83Byte {
     {
     }
 
+    __attribute__((nonnull))
+    constexpr Utf83Byte(const char* letterStr) noexcept : characters{}
+    {
+        auto length = cStringLength(letterStr, 3);
+        if (length < 3) {
+            return;
+        }
+        characters[0] = static_cast<utf8>(letterStr[0]);
+        characters[1] = static_cast<utf8>(letterStr[1]);
+        characters[2] = static_cast<utf8>(letterStr[2]);
+    }
+
     Array<utf8, 3> characters;
 
     static constexpr size_t size() noexcept
@@ -187,6 +213,19 @@ struct Utf84Byte {
     {
     }
 
+    __attribute__((nonnull))
+    constexpr Utf84Byte(const char* letterStr) noexcept : characters{}
+    {
+        auto length = cStringLength(letterStr, 4);
+        if (length < 4) {
+            return;
+        }
+        characters[0] = static_cast<utf8>(letterStr[0]);
+        characters[1] = static_cast<utf8>(letterStr[1]);
+        characters[2] = static_cast<utf8>(letterStr[2]);
+        characters[3] = static_cast<utf8>(letterStr[3]);
+    }
+
     Array<utf8, 4> characters;
 
     static constexpr size_t size() noexcept
@@ -250,11 +289,12 @@ struct FudUtf8 {
     Utf8Variant m_variant{Utf8Variant{Ascii{}}};
 
     static constexpr Ascii invalidAsciiCode{Ascii{0xFF}};
-    static FudUtf8 fromString(const String& fudString, size_t index) noexcept;
-    static FudUtf8 fromStringView(StringView view, size_t index) noexcept;
-    // static FudUtf8 fromStringView(const StringView& view, size_t index) noexcept;
 
-    static constexpr FudUtf8 makeUtf8(const Array<utf8, 4>& data)
+    static FudUtf8 from(const String& fudString, size_t index) noexcept;
+
+    static FudUtf8 from(StringView view, size_t index) noexcept;
+
+    static constexpr FudUtf8 make(const Array<utf8, 4>& data)
     {
         FudUtf8 unicode{};
         if (Ascii::valid(data[0])) {
@@ -271,7 +311,12 @@ struct FudUtf8 {
         return unicode;
     }
 
-    static constexpr FudUtf8 makeUtf8(const Ascii& utf8Char)
+    static constexpr FudUtf8 make(utf8 utf8Char)
+    {
+        return make(Ascii{utf8Char});
+    }
+
+    static constexpr FudUtf8 make(Ascii utf8Char)
     {
         FudUtf8 unicode{{Utf8Variant{Ascii{}}}};
         if (utf8Char.valid()) {
@@ -282,6 +327,15 @@ struct FudUtf8 {
         return unicode;
     }
 
+    static constexpr FudUtf8 make(Utf8Variant utf8Variant) {
+        FudUtf8 unicode{};
+        unicode.m_variant = utf8Variant;
+        if (!std::visit([](auto arg) { return arg.valid(); }, utf8Variant)) {
+            unicode.m_variant = invalidAsciiCode;
+        }
+        return unicode;
+    }
+
     static constexpr FudUtf8 invalidAscii()
     {
         FudUtf8 character{};
@@ -460,89 +514,93 @@ struct FudUtf8 {
 };
 
 /** \brief Checks if a character is ascii. */
-bool char_is_ascii(char character);
+[[nodiscard]] bool charIsAscii(char character);
 
-FudStatus utf8_is_ascii(FudUtf8& character, bool& isAscii);
+[[nodiscard]] bool utf8IsAscii(FudUtf8 character);
 
 /** \brief Checks if a character is alphanumeric. */
-bool char_is_alphanumeric(char character);
+[[nodiscard]] bool charIsAlphanumeric(char character);
 
 /** \brief Checks if a character is alphanumeric. */
-FudStatus utf8_is_alphanumeric(FudUtf8* character, bool* pred);
+[[nodiscard]] bool utf8IsAlphanumeric(FudUtf8 character);
 
 /** \brief Checks if a character is alphabetic. */
-bool char_is_alpha(char character);
+[[nodiscard]] bool charIsAlpha(char character);
 
 /** \brief Checks if a character is alphabetic. */
-FudStatus utf8_is_alpha(FudUtf8* character, bool* pred);
+[[nodiscard]] bool utf8IsAlpha(FudUtf8 character);
 
 /** \brief Checks if a character is lowercase. */
-bool char_is_lowercase(char character);
+[[nodiscard]] bool charIsLowercase(char character);
 
 /** \brief Checks if a character is lowercase. */
-FudStatus utf8_is_lowercase(FudUtf8* character, bool* pred);
+[[nodiscard]] bool utf8IsLowercase(FudUtf8 character);
 
 /** \brief Checks if a character is an uppercase character. */
-bool char_is_uppercase(char character);
+[[nodiscard]] bool charIsUppercase(char character);
 
 /** \brief Checks if a character is uppercase. */
-FudStatus utf8_is_uppercase(FudUtf8* character, bool* pred);
+[[nodiscard]] bool utf8IsUppercase(FudUtf8 character);
 
 /** \brief Checks if a character is a digit. */
-bool char_is_digit(char character);
+[[nodiscard]] bool charIsDigit(char character);
 
 /** \brief Checks if a character is a digit. */
-FudStatus utf8_is_digit(FudUtf8* character, bool* pred);
+[[nodiscard]] bool utf8IsDigit(FudUtf8 character);
 
 /** \brief Checks if a character is a hexadecimal character. */
-bool char_is_hex_digit(char character);
+[[nodiscard]] bool charIsHexDigit(char character);
 
 /** \brief Checks if a character is a hexadecimal digit. */
-FudStatus utf8_is_hex_digit(FudUtf8* character, bool* pred);
+[[nodiscard]] bool utf8IsHexDigit(FudUtf8 character);
 
 /** \brief Checks if a character is a control character. */
-bool char_is_control(char character);
+[[nodiscard]] bool charIsControl(char character);
 
 /** \brief Checks if a character is a control character. */
-FudStatus utf8_is_control(FudUtf8* character, bool* pred);
+[[nodiscard]] bool utf8IsControl(FudUtf8 character);
 
 /** \brief Checks if a character is a graphical character. */
-bool char_is_graphical(char character);
+[[nodiscard]] bool charIsGraphical(char character);
 
 /** \brief Checks if a character is a graphical character. */
-FudStatus utf8_is_graphical(FudUtf8* character, bool* pred);
+[[nodiscard]] bool utf8IsGraphical(FudUtf8 character);
 
 /** \brief Checks if a character is a space character. */
-bool char_is_space(char character);
+[[nodiscard]] bool charIsSpace(char character);
 
 /** \brief Checks if a character is a space character. */
-FudStatus utf8_is_space(FudUtf8* character, bool* pred);
+[[nodiscard]] bool utf8IsSpace(FudUtf8 character);
 
 /** \brief Checks if a character is a blank character. */
-bool char_is_blank(char character);
+[[nodiscard]] bool charIsBlank(char character);
 
 /** \brief Checks if a character is a blank character. */
-FudStatus utf8_is_blank(FudUtf8* character, bool* pred);
+[[nodiscard]] bool utf8IsBlank(FudUtf8 character);
 
 /** \brief Checks if a character is a printable character. */
-bool char_is_printable(char character);
+[[nodiscard]] bool charIsPrintable(char character);
 
 /** \brief Checks if a character is a printable character. */
-FudStatus utf8_is_printable(FudUtf8* character, bool* pred);
+[[nodiscard]] bool utf8IsPrintable(FudUtf8 character);
 
 /** \brief Checks if a character is a punctuation character. */
-bool char_is_punctuation(char character);
+[[nodiscard]] bool charIsPunctuation(char character);
 
 /** \brief Checks if a character is a punctuation character. */
-FudStatus utf8_is_punctuation(FudUtf8* character, bool* pred);
+[[nodiscard]] bool utf8IsPunctuation(FudUtf8 character);
 
-uint8_t char_to_lower(uint8_t character);
+/** \brief Converts character to lowercase if valid. */
+uint8_t charToLower(uint8_t character);
 
-FudUtf8* utf8_to_lower(FudUtf8* character);
+/** \brief Converts character to lowercase if valid. */
+FudUtf8 utf8ToLower(FudUtf8 character);
 
-uint8_t char_to_upper(uint8_t character);
+/** \brief Converts character to uppercase if valid. */
+uint8_t charToUpper(uint8_t character);
 
-FudUtf8* utf8_to_upper(FudUtf8* character);
+/** \brief Converts character to uppercase if valid. */
+FudUtf8 utf8ToUpper(FudUtf8 character);
 
 } // namespace fud
 
diff --git a/include/fud_vector.hpp b/include/fud_vector.hpp
new file mode 100644
index 0000000..56e1659
--- /dev/null
+++ b/include/fud_vector.hpp
@@ -0,0 +1,64 @@
+/*
+ * libfud
+ * Copyright 2024 Dominick Allen
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef FUD_VECTOR_HPP
+#define FUD_VECTOR_HPP
+
+#include "fud_allocator.hpp"
+#include "fud_result.hpp"
+#include "fud_status.hpp"
+
+#include <cstddef>
+
+namespace fud {
+
+template <typename T>
+class Vector {
+  public:
+    static Result<Vector<T>, FudStatus> from(const Vector<T>& rhs);
+
+    static Vector<T> move(Vector<T>&& rhs);
+
+    FudStatus copy(const Vector<T>& rhs);
+
+    FudStatus take(Vector<T>&& rhs);
+
+    [[nodiscard]] size_t size() const {
+        return m_length;
+    }
+
+    [[nodiscard]] size_t capacity() const {
+        return m_capacity;
+    }
+
+    FudStatus reserve();
+
+    FudStatus resize();
+
+    FudStatus clear();
+
+    // FudResult at();
+
+  private:
+    Allocator* m_allocator{&globalFudAllocator};
+    size_t m_length{0};
+    size_t m_capacity{0};
+};
+
+} // namespace fud
+
+#endif
diff --git a/source/fud_assert.cpp b/source/fud_assert.cpp
index 98f17d0..3df6734 100644
--- a/source/fud_assert.cpp
+++ b/source/fud_assert.cpp
@@ -1,10 +1,11 @@
 #include "fud_assert.hpp"
 
-#include "fud_array.hpp"
+// #include "fud_array.hpp"
 
 #include <climits>
 #include <cstdio>
-#include <format>
+#include <exception>
+// #include <format>
 
 namespace fud {
 
@@ -20,15 +21,18 @@ constexpr auto MAX_LINE_CHARS = BITS_PER_OCTAL * sizeof(decltype(std::source_loc
         fputs(file_name, stderr);
     }
 
+    /*
     constexpr std::size_t assertMsgSize = MAX_LINE_CHARS + 3;
     Array<char, assertMsgSize> buffer{};
     static_cast<void>(std::format_to_n(buffer.data(), buffer.size() - 1U, ":{}:", sourceLocation.line()));
     buffer[buffer.size() - 1] = '\0';
     fputs(buffer.data(), stderr);
+    */
 
     fputs(sourceLocation.function_name(), stderr);
     fputs(": ", stderr);
     fputs(assertion, stderr);
+    fputc('\n', stderr);
 
     std::terminate();
 }
diff --git a/source/fud_format.cpp b/source/fud_format.cpp
new file mode 100644
index 0000000..ab1bb4f
--- /dev/null
+++ b/source/fud_format.cpp
@@ -0,0 +1,14 @@
+// #include "fud_format.hpp"
+
+namespace fud {
+
+/*
+Result<FormatSpec, FudStatus> FormatSpec::make(StringView view, size_t& length)
+{
+    static_cast<void>(view);
+    static_cast<void>(length);
+    return FudStatus::NotImplemented;
+}
+*/
+
+} // namespace fud
diff --git a/source/fud_string.cpp b/source/fud_string.cpp
index d354fe7..b714dfc 100644
--- a/source/fud_string.cpp
+++ b/source/fud_string.cpp
@@ -23,31 +23,6 @@
 
 namespace fud {
 
-ssize_t cStringLength(const char* str)
-{
-    constexpr auto maxLength = SSIZE_MAX - 1;
-    return cStringLength(str, maxLength);
-}
-
-ssize_t cStringLength(const char* str, size_t maxLength)
-{
-    if (str == nullptr || maxLength > (SSIZE_MAX - 1)) {
-        return -1;
-    }
-
-    ssize_t size = 0;
-
-    while (str[size] != 0 && static_cast<size_t>(size) < maxLength) {
-        size++;
-    }
-
-    if (str[size] != 0 && static_cast<size_t>(size) == maxLength) {
-        return static_cast<ssize_t>(maxLength) + 1;
-    }
-
-    return size;
-}
-
 StringResult String::makeFromCString(const char* cString)
 {
     return makeFromCString(cString, &globalFudAllocator);
diff --git a/source/fud_string_view.cpp b/source/fud_string_view.cpp
index 23a4671..fdb63b3 100644
--- a/source/fud_string_view.cpp
+++ b/source/fud_string_view.cpp
@@ -61,7 +61,7 @@ Result<size_t, FudStatus> StringView::skipWhitespace()
         return RetType::error(FudStatus::NullPointer);
     }
     size_t index = 0;
-    while (m_length > 0 && char_is_space(static_cast<char>(m_data[0]))) {
+    while (m_length > 0 && charIsSpace(static_cast<char>(m_data[0]))) {
         m_data++;
         m_length--;
         index++;
@@ -78,7 +78,7 @@ Result<size_t, FudStatus> StringView::trimWhitespace()
     }
 
     size_t count = 0;
-    while (m_length > 0 && char_is_space(static_cast<char>(m_data[m_length - 1]))) {
+    while (m_length > 0 && charIsSpace(static_cast<char>(m_data[m_length - 1]))) {
         m_length--;
         count++;
     }
@@ -86,6 +86,40 @@ Result<size_t, FudStatus> StringView::trimWhitespace()
     return RetType::okay(count);
 }
 
+bool StringView::advance()
+{
+    if (m_length < 1) {
+        return false;
+    }
+    m_length--;
+    m_data++;
+    return true;
+}
+
+void StringView::advanceUnsafe()
+{
+    fudAssert(m_length > 0);
+    m_length--;
+    m_data++;
+}
+
+bool StringView::advance(size_t size)
+{
+    if (size > m_length) {
+        return false;
+    }
+    m_length -= size;
+    m_data += size;
+    return true;
+}
+
+void StringView::advanceUnsafe(size_t size)
+{
+    fudAssert(size <= m_length);
+    m_length -= size;
+    m_data += size;
+}
+
 #if 0
 
 FudStatus fud_string_truncate(ExtBasicString* source, ssize_t newLength)
diff --git a/source/fud_utf8.cpp b/source/fud_utf8.cpp
index ee8137a..4d617da 100644
--- a/source/fud_utf8.cpp
+++ b/source/fud_utf8.cpp
@@ -19,26 +19,19 @@
 
 #include "fud_string.hpp"
 
-#include <new> // IWYU pragma: keep - this is for placement new overloads.
-
 namespace fud {
 
-FudUtf8 FudUtf8::fromString(const String& fudString, size_t index) noexcept
+FudUtf8 FudUtf8::from(const String& fudString, size_t index) noexcept
 {
     if (!fudString.valid()) {
         return invalidAscii();
     }
 
 
-    return fromStringView(StringView{fudString}, index);
+    return from(StringView{fudString}, index);
 }
 
-// FudUtf8 FudUtf8::fromStringView(const StringView& view, size_t index) noexcept
-// {
-//     return fromStringView(StringView{view}, index);
-// }
-
-FudUtf8 FudUtf8::fromStringView(StringView view, size_t index) noexcept
+FudUtf8 FudUtf8::from(StringView view, size_t index) noexcept
 {
     auto viewLocal{view};
     auto len = viewLocal.length();
@@ -76,126 +69,113 @@ FudUtf8 FudUtf8::fromStringView(StringView view, size_t index) noexcept
     return invalidAscii();
 }
 
-bool char_is_ascii(char character)
+bool charIsAscii(char character)
 {
     return static_cast<uint8_t>(character & ~ASCII_MASK) == 0;
 }
 
-FudStatus utf8_is_ascii(FudUtf8* character, bool* isAscii)
+bool utf8IsAscii(FudUtf8 character)
 {
-    if (anyAreNull(character, isAscii)) {
-        return FudStatus::NullPointer;
-    }
-
-    *isAscii = character->getType() == Utf8Type::Ascii && character->valid();
-
-    return FudStatus::Success;
+    return character.getType() == Utf8Type::Ascii && character.valid();
 }
 
 namespace impl {
 
-/* Assumes that predicate is not a null pointer! */
 template <typename Predicate>
-FudStatus isAsciiPredicate(FudUtf8* character, bool* pred, Predicate&& predicate)
+bool isAsciiPredicate(FudUtf8 character, Predicate&& predicate)
 {
-    if (anyAreNull(character, pred)) {
-        return FudStatus::NullPointer;
-    }
-
-    auto maybeAscii = character->getAscii();
+    auto maybeAscii = character.getAscii();
     if (!maybeAscii.has_value()) {
-        return FudStatus::ArgumentInvalid;
+        return false;
     }
 
     auto asciiChar = *maybeAscii;
-    *pred = std::forward<Predicate>(predicate)(asciiChar.asChar());
-
-    return FudStatus::Success;
+    return std::forward<Predicate>(predicate)(asciiChar.asChar());
 }
 
 } // namespace impl
 
-bool char_is_alphanumeric(char character)
+bool charIsAlphanumeric(char character)
 {
-    if (!char_is_ascii(character)) {
+    if (!charIsAscii(character)) {
         return false;
     }
 
-    if (char_is_alpha(character)) {
+    if (charIsAlpha(character)) {
         return true;
     }
 
-    return char_is_digit(character);
+    return charIsDigit(character);
 }
 
-FudStatus utf8_is_alphanumeric(FudUtf8* character, bool* pred)
+bool utf8IsAlphanumeric(FudUtf8 character)
 {
-    return impl::isAsciiPredicate(character, pred, char_is_alphanumeric);
+    return impl::isAsciiPredicate(character, charIsAlphanumeric);
 }
 
-bool char_is_alpha(char character)
+bool charIsAlpha(char character)
 {
-    if (!char_is_ascii(character)) {
+    if (!charIsAscii(character)) {
         return false;
     }
 
-    if (char_is_uppercase(character)) {
+    if (charIsUppercase(character)) {
         return true;
     }
 
-    return char_is_lowercase(character);
+    return charIsLowercase(character);
 }
 
-FudStatus utf8_is_alpha(FudUtf8* character, bool* pred)
+bool utf8IsAlpha(FudUtf8 character)
 {
-    return impl::isAsciiPredicate(character, pred, char_is_alpha);
+    return impl::isAsciiPredicate(character, charIsAlpha);
 }
 
-bool char_is_lowercase(char character)
+bool charIsLowercase(char character)
 {
-    if (!char_is_ascii(character)) {
+    if (!charIsAscii(character)) {
         return false;
     }
 
     return 'a' <= character && character <= 'z';
 }
 
-FudStatus utf8_is_lowercase(FudUtf8* character, bool* pred)
+bool utf8IsLowercase(FudUtf8 character)
 {
-    return impl::isAsciiPredicate(character, pred, char_is_lowercase);
+    return impl::isAsciiPredicate(character, charIsLowercase);
 }
 
-bool char_is_uppercase(char character)
+bool charIsUppercase(char character)
 {
-    if (!char_is_ascii(character)) {
+    if (!charIsAscii(character)) {
         return false;
     }
 
     return 'A' <= character && character <= 'Z';
 }
 
-FudStatus utf8_is_uppercase(FudUtf8* character, bool* pred)
+bool utf8IsUppercase(FudUtf8 character)
 {
-    return impl::isAsciiPredicate(character, pred, char_is_uppercase);
+    return impl::isAsciiPredicate(character, charIsUppercase);
 }
 
-bool char_is_digit(char character)
+bool charIsDigit(char character)
 {
-    if (!char_is_ascii(character)) {
+    if (!charIsAscii(character)) {
         return false;
     }
 
     return '0' <= character && character <= '9';
 }
 
-FudStatus utf8_is_digit(FudUtf8* character, bool* pred)
+bool utf8IsDigit(FudUtf8 character)
 {
-    return impl::isAsciiPredicate(character, pred, char_is_digit);
+    return impl::isAsciiPredicate(character, charIsDigit);
 }
 
-bool char_is_hex_digit(char character)
+bool charIsHexDigit(char character)
 {
-    if (!char_is_ascii(character)) {
+    if (!charIsAscii(character)) {
         return false;
     }
 
@@ -203,14 +183,14 @@ bool char_is_hex_digit(char character)
         ('A' <= character && character <= 'F');
 }
 
-FudStatus utf8_is_hex_digit(FudUtf8* character, bool* pred)
+bool utf8IsHexDigit(FudUtf8 character)
 {
-    return impl::isAsciiPredicate(character, pred, char_is_hex_digit);
+    return impl::isAsciiPredicate(character, charIsHexDigit);
 }
 
-bool char_is_control(char character)
+bool charIsControl(char character)
 {
-    if (!char_is_ascii(character)) {
+    if (!charIsAscii(character)) {
         return false;
     }
 
@@ -219,70 +199,70 @@ bool char_is_control(char character)
     return ((static_cast<uint8_t>(character) <= maxControlChar)) || character == deleteChar;
 }
 
-FudStatus utf8_is_control(FudUtf8* character, bool* pred)
+bool utf8IsControl(FudUtf8 character)
 {
-    return impl::isAsciiPredicate(character, pred, char_is_control);
+    return impl::isAsciiPredicate(character, charIsControl);
 }
 
-bool char_is_graphical(char character)
+bool charIsGraphical(char character)
 {
-    if (!char_is_ascii(character)) {
+    if (!charIsAscii(character)) {
         return false;
     }
 
-    return char_is_alphanumeric(character) || char_is_punctuation(character);
+    return charIsAlphanumeric(character) || charIsPunctuation(character);
 }
 
-FudStatus utf8_is_graphical(FudUtf8* character, bool* pred)
+bool utf8IsGraphical(FudUtf8 character)
 {
-    return impl::isAsciiPredicate(character, pred, char_is_graphical);
+    return impl::isAsciiPredicate(character, charIsGraphical);
 }
 
-bool char_is_space(char character)
+bool charIsSpace(char character)
 {
-    if (!char_is_ascii(character)) {
+    if (!charIsAscii(character)) {
         return false;
     }
 
     return character == ' ' || character == '\t' || character == '\n' || character == '\r' || character == '\v';
 }
 
-FudStatus utf8_is_space(FudUtf8* character, bool* pred)
+bool utf8IsSpace(FudUtf8 character)
 {
-    return impl::isAsciiPredicate(character, pred, char_is_space);
+    return impl::isAsciiPredicate(character, charIsSpace);
 }
 
-bool char_is_blank(char character)
+bool charIsBlank(char character)
 {
-    if (!char_is_ascii(character)) {
+    if (!charIsAscii(character)) {
         return false;
     }
 
     return character == ' ' || character == '\t';
 }
 
-FudStatus utf8_is_blank(FudUtf8* character, bool* pred)
+bool utf8IsBlank(FudUtf8 character)
 {
-    return impl::isAsciiPredicate(character, pred, char_is_blank);
+    return impl::isAsciiPredicate(character, charIsBlank);
 }
 
-bool char_is_printable(char character)
+bool charIsPrintable(char character)
 {
-    if (!char_is_ascii(character)) {
+    if (!charIsAscii(character)) {
         return false;
     }
 
     return (character >= ' ' && character <= '~');
 }
 
-FudStatus utf8_is_printable(FudUtf8* character, bool* pred)
+bool utf8IsPrintable(FudUtf8 character)
 {
-    return impl::isAsciiPredicate(character, pred, char_is_printable);
+    return impl::isAsciiPredicate(character, charIsPrintable);
 }
 
-bool char_is_punctuation(char character)
+bool charIsPunctuation(char character)
 {
-    if (!char_is_ascii(character)) {
+    if (!charIsAscii(character)) {
         return false;
     }
 
@@ -290,14 +270,14 @@ bool char_is_punctuation(char character)
         (character >= '[' && character <= '`') || (character >= '{' && character <= '~');
 }
 
-FudStatus utf8_is_punctuation(FudUtf8* character, bool* pred)
+bool utf8IsPunctuation(FudUtf8 character)
 {
-    return impl::isAsciiPredicate(character, pred, char_is_punctuation);
+    return impl::isAsciiPredicate(character, charIsPunctuation);
 }
 
-uint8_t char_to_lower(uint8_t character)
+uint8_t charToLower(uint8_t character)
 {
-    if (char_is_uppercase(static_cast<char>(character))) {
+    if (charIsUppercase(static_cast<char>(character))) {
         constexpr uint8_t lowerA = 'a';
         constexpr uint8_t upperA = 'A';
         return static_cast<uint8_t>(character - upperA) + lowerA;
@@ -305,22 +285,18 @@ uint8_t char_to_lower(uint8_t character)
     return character;
 }
 
-FudUtf8* utf8_to_lower(FudUtf8* character)
+FudUtf8 utf8ToLower(FudUtf8 character)
 {
-    if (character == nullptr) {
-        return character;
-    }
-
-    static_cast<void>(character->transformAscii([](Ascii& ascii) {
-        ascii = Ascii{char_to_lower(static_cast<uint8_t>(ascii.asChar()))};
+    static_cast<void>(character.transformAscii([](Ascii& ascii) {
+        ascii = Ascii{charToLower(static_cast<uint8_t>(ascii.asChar()))};
     }));
 
     return character;
 }
 
-uint8_t char_to_upper(uint8_t character)
+uint8_t charToUpper(uint8_t character)
 {
-    if (char_is_lowercase(static_cast<char>(character))) {
+    if (charIsLowercase(static_cast<char>(character))) {
         constexpr uint8_t lowerA = 'a';
         constexpr uint8_t upperA = 'A';
         return static_cast<uint8_t>(character - lowerA) + upperA;
@@ -328,14 +304,10 @@ uint8_t char_to_upper(uint8_t character)
     return character;
 }
 
-FudUtf8* utf8_to_upper(FudUtf8* character)
+FudUtf8 utf8ToUpper(FudUtf8 character)
 {
-    if (character == nullptr) {
-        return character;
-    }
-
-    static_cast<void>(character->transformAscii([](Ascii& ascii) {
-        ascii = Ascii{char_to_upper(static_cast<uint8_t>(ascii.asChar()))};
+    static_cast<void>(character.transformAscii([](Ascii& ascii) {
+        ascii = Ascii{charToUpper(static_cast<uint8_t>(ascii.asChar()))};
     }));
 
     return character;
diff --git a/source/fud_utf8_iterator.cpp b/source/fud_utf8_iterator.cpp
index 2557dc0..a815c64 100644
--- a/source/fud_utf8_iterator.cpp
+++ b/source/fud_utf8_iterator.cpp
@@ -25,7 +25,7 @@ std::optional<FudUtf8> Utf8Iterator::peek() const
         return std::nullopt;
     }
 
-    auto character = FudUtf8::fromStringView(m_view, m_index);
+    auto character = FudUtf8::from(m_view, m_index);
 
     if (!character.valid()) {
         return std::nullopt;
@@ -41,7 +41,7 @@ std::optional<FudUtf8> Utf8Iterator::next()
         return std::nullopt;
     }
 
-    auto character = FudUtf8::fromStringView(m_view, m_index);
+    auto character = FudUtf8::from(m_view, m_index);
 
     if (!character.valid()) {
         m_index = m_view.length();
diff --git a/test/CMakeLists.txt b/test/CMakeLists.txt
index 0860c0d..c4d957b 100644
--- a/test/CMakeLists.txt
+++ b/test/CMakeLists.txt
@@ -59,23 +59,17 @@ endfunction()
 fud_add_test(test_fud SOURCES test_fud.cpp)
 fud_add_test(test_allocator SOURCES test_allocator.cpp)
 fud_add_test(test_assert SOURCES test_assert.cpp)
+# fud_add_test(test_c_file SOURCES test_c_file.cpp)
 fud_add_test(test_directory SOURCES test_directory.cpp)
 fud_add_test(test_format SOURCES test_format.cpp)
 fud_add_test(test_result SOURCES test_result.cpp)
 fud_add_test(test_span SOURCES test_span.cpp)
 fud_add_test(test_sqlite SOURCES test_sqlite.cpp)
 fud_add_test(test_string SOURCES test_string.cpp)
+fud_add_test(test_utf8 SOURCES test_utf8.cpp)
+
 # fud_add_test(test_deserialize_number SOURCES test_deserialize_number.cpp)
 # fud_add_test(test_ext_algorithm SOURCES test_algorithm.cpp)
 # fud_add_test(test_ext_array SOURCES
 #     test_ext_array.cpp
 #     test_ext_unique_array.cpp)
-# fud_add_test(test_ext_utf8 SOURCES
-#     test_ext_utf8.cpp)
-# fud_add_test(test_ext_string SOURCES
-#     test_ext_string.cpp
-#     test_ext_string_cxx.cpp)
-# fud_add_test(test_ext_string_format SOURCES
-#     test_ext_string_format.cpp)
-
-# fud_add_test(test_c_file SOURCES test_c_file.cpp)
diff --git a/test/test_common.hpp b/test/test_common.hpp
index 05f86db..0ca8eb4 100644
--- a/test/test_common.hpp
+++ b/test/test_common.hpp
@@ -34,7 +34,16 @@ static_assert(sizeof(THREE_BYTE) == 3 + 1);
 static_assert(sizeof(FOUR_BYTE) == 4 + 1);
 
 #define CHQUOTE "why waste time learning, when ignorance is instantaneous?"
-#define CHARACTER_SET "abcdefghijklmnopqrstuvwxyz ABCDEFGHIJKLMNOPQRSTUVWXYZ"
+
+#define LOWERCASE_CHARS "abcdefghijklmnopqrstuvwxyz"
+#define UPPERCASE_CHARS "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
+#define DECIMAL_CHARS "0123456789"
+#define ALPHA_CHARS LOWERCASE_CHARS UPPERCASE_CHARS
+#define ALPHA_NUMERIC_CHARS ALPHA_CHARS DECIMAL_CHARS
+#define PUNCTUATION_CHARS "!\"#$%&'()*+,-./:;<=>?@[\\]^_`{|}~"
+#define GRAPHICAL_CHARS ALPHA_NUMERIC_CHARS PUNCTUATION_CHARS
+#define CHARACTER_SET LOWERCASE_CHARS " " UPPERCASE_CHARS
+
 // NOLINTEND(cppcoreguidelines-macro-usage)
 constexpr size_t charSetSize = sizeof(CHARACTER_SET) - 1;
 
diff --git a/test/test_format.cpp b/test/test_format.cpp
index a373fec..319ed22 100644
--- a/test/test_format.cpp
+++ b/test/test_format.cpp
@@ -15,21 +15,17 @@
  * limitations under the License.
  */
 
-#include "fud_array.hpp"
-#include "fud_format.hpp"
-#include "fud_span.hpp"
+// #include "fud_array.hpp"
+// #include "fud_format.hpp"
+// #include "fud_span.hpp"
 
 #include "gtest/gtest.h"
 
 namespace fud {
 
-TEST(FormatTest, BasicTest)
+TEST(FormatTest, FormatSpecTest)
 {
-    auto buffer{Array<char, 64>::constFill('\0')};
-    auto span = Span<char, buffer.size() - 1U>::makeCStringBuffer(buffer);
 
-    auto formatResult = format(span, "Hello, {}! {}", "world", 42);
-    printf("%s\n", buffer.data());
 }
 
 } // namespace fud
diff --git a/test/test_utf8.cpp b/test/test_utf8.cpp
new file mode 100644
index 0000000..8f1d655
--- /dev/null
+++ b/test/test_utf8.cpp
@@ -0,0 +1,1163 @@
+/*
+ * libfud
+ * Copyright 2024 Dominick Allen
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "fud_algorithm.hpp"
+#include "fud_allocator.hpp"
+#include "fud_array.hpp"
+#include "fud_string.hpp"
+#include "fud_utf8.hpp"
+#include "fud_utf8_iterator.hpp"
+#include "fud_vector.hpp"
+#include "test_common.hpp"
+// #include "fud_format.hpp"
+// #include "fud_span.hpp"
+
+#include "gtest/gtest.h"
+
+namespace fud {
+
+constexpr size_t validAsciiSize = INT8_MAX + 1;
+constexpr size_t invalidAsciiSize = UINT8_MAX + 1 - validAsciiSize;
+
+constexpr size_t numControlChars = 33;
+constexpr char printableCharOffset = 0x20;
+
+constexpr auto invalidAscii = FudUtf8::invalidAsciiCode.character();
+
+auto generateInvalidAsciiChars()
+{
+    Iota<utf8> iota{};
+    return generate([]() { return Array<utf8, invalidAsciiSize>{}; }, [&]() { return iota().value(); });
+}
+
+TEST(Utf8Test, Utf8Creation)
+{
+    const Array<utf8, 4> threeByte = {THREE_BYTE};
+
+    FudUtf8 utf8Point{FudUtf8::make(threeByte)};
+    ASSERT_NE(utf8Point.data(), nullptr);
+    ASSERT_EQ(utf8Point.size(), 3);
+    ASSERT_NE(utf8Point.hash(), -1);
+
+    const Array<utf8, 4> asciiLetter = {'A'};
+    utf8Point = FudUtf8::make(asciiLetter);
+    ASSERT_NE(utf8Point.data(), nullptr);
+    ASSERT_EQ(utf8Point.size(), 1);
+
+    const Array<utf8, 4> twoByte = {TWO_BYTE};
+    utf8Point = FudUtf8::make(twoByte);
+    ASSERT_NE(utf8Point.data(), nullptr);
+    ASSERT_EQ(utf8Point.size(), 2);
+    ASSERT_NE(utf8Point.hash(), -1);
+
+    Array<utf8, 4> fourByte = {
+        static_cast<utf8>(FOUR_BYTE[0]),
+        static_cast<utf8>(FOUR_BYTE[1]),
+        static_cast<utf8>(FOUR_BYTE[2]),
+        static_cast<utf8>(FOUR_BYTE[3])};
+    utf8Point = FudUtf8::make(fourByte);
+    ASSERT_NE(utf8Point.data(), nullptr);
+    ASSERT_EQ(utf8Point.size(), 4);
+    ASSERT_NE(utf8Point.hash(), -1);
+
+    const Array<utf8, 4> invalidBytes = {0xFF, 0xFF, 0xFF, 0xFF};
+    utf8Point = FudUtf8::make(invalidBytes);
+    ASSERT_EQ(utf8Point.data(), nullptr);
+    ASSERT_EQ(utf8Point.size(), 0);
+    ASSERT_EQ(utf8Point.hash(), -1);
+}
+
+TEST(Utf8Test, Utf8MultiByte)
+{
+    Array<utf8, sizeof(MULTI_BYTE_LITERAL)> data{MULTI_BYTE_LITERAL};
+    constexpr size_t bufSize = data.size();
+    EXPECT_EQ(data[bufSize - 1], '\0');
+
+    class FixedAllocator final : public Allocator {
+      private:
+        Array<utf8, bufSize> m_memory{};
+        size_t m_allocated{0};
+
+      public:
+        virtual ~FixedAllocator() override final = default;
+
+        virtual Result<void*, FudStatus> allocate(size_t bytes, size_t alignment) override final
+        {
+            static_cast<void>(alignment);
+            if (bytes > m_memory.size() - m_allocated) {
+                return FudStatus::AllocFailure;
+            }
+            auto* data = m_memory.data() + m_allocated;
+            m_allocated += bytes;
+            return data;
+        }
+
+        virtual FudStatus deallocate(void* pointer, size_t bytes) override final
+        {
+            static_cast<void>(pointer);
+            static_cast<void>(bytes);
+            return FudStatus::Success;
+        }
+
+        virtual bool isEqual(const Allocator& rhs) const override final
+        {
+            return &rhs == this;
+        }
+    };
+    FixedAllocator fixedAllocator;
+
+    auto stringBufferRes{String::makeFromCString(MULTI_BYTE_LITERAL, &fixedAllocator)};
+
+    ASSERT_TRUE(stringBufferRes.isOkay());
+    auto stringBuffer{stringBufferRes.takeOkay()};
+    EXPECT_EQ(stringBuffer.size(), bufSize);
+    EXPECT_EQ(stringBuffer.size(), sizeof(data));
+    EXPECT_EQ(stringBuffer.length(), bufSize - 1);
+    EXPECT_TRUE(stringBuffer.nullTerminated());
+    EXPECT_TRUE(stringBuffer.valid());
+    ASSERT_TRUE(stringBuffer.utf8Valid());
+
+    Utf8Iterator utf8Iter{stringBuffer};
+    auto characterOpt = utf8Iter.next();
+    ASSERT_TRUE(characterOpt.has_value());
+
+    // MULTI_BYTE_LITERAL "test今日素敵はですねƩ®😀z"
+    const Array<FudUtf8, 16> multiByteCharacters{
+        FudUtf8::make(Utf8Variant{Ascii{'t'}}),
+        FudUtf8::make(Utf8Variant{Ascii{'e'}}),
+        FudUtf8::make(Utf8Variant{Ascii{'s'}}),
+        FudUtf8::make(Utf8Variant{Ascii{'t'}}),
+        FudUtf8::from(StringView{sizeof("今"), "今"}, 0),
+        FudUtf8::from(StringView{sizeof("日"), "日"}, 0),
+        FudUtf8::from(StringView{sizeof("素"), "素"}, 0),
+        FudUtf8::from(StringView{sizeof("敵"), "敵"}, 0),
+        FudUtf8::from(StringView{sizeof("は"), "は"}, 0),
+        FudUtf8::from(StringView{sizeof("で"), "で"}, 0),
+        FudUtf8::from(StringView{sizeof("す"), "す"}, 0),
+        FudUtf8::from(StringView{sizeof("ね"), "ね"}, 0),
+        FudUtf8::from(StringView{sizeof("Ʃ"), "Ʃ"}, 0),
+        FudUtf8::from(StringView{sizeof("®"), "®"}, 0),
+        FudUtf8::from(StringView{sizeof("😀"), "😀"}, 0),
+        FudUtf8::make(Utf8Variant{Ascii{'z'}}),
+    };
+
+    size_t idx = 0;
+    while (characterOpt.has_value()) {
+        auto character = *characterOpt;
+        if (character != FudUtf8{Utf8Variant{Ascii{'\0'}}}) {
+            EXPECT_TRUE(character.size() >= 1);
+            ASSERT_LT(idx, multiByteCharacters.size());
+            EXPECT_EQ(character.size(), multiByteCharacters[idx].size());
+            EXPECT_EQ(character, multiByteCharacters[idx]);
+            EXPECT_TRUE(multiByteCharacters[idx].valid());
+            if (character != multiByteCharacters[idx]) {
+                printf("idx = %zu, %.*s\n", idx, static_cast<int>(character.size()), character.data());
+            }
+            idx++;
+        }
+        characterOpt = utf8Iter.next();
+    }
+    utf8Iter.reset();
+    ASSERT_TRUE(utf8Iter.next().has_value());
+
+    FudUtf8 invalid = FudUtf8::invalidAscii();
+    ASSERT_FALSE(invalid.valid());
+    ASSERT_EQ(invalid.size(), 0);
+    ASSERT_EQ(invalid.data(), nullptr);
+    ASSERT_EQ(invalid.hash(), -1);
+}
+
+TEST(Utf8Test, Utf8IsAscii)
+{
+    ASSERT_FALSE(charIsAscii(invalidAscii));
+
+    Iota<int16_t> charIota{0, 1, validAsciiSize};
+
+    ASSERT_TRUE(allOf(
+        [&]() -> std::optional<char> {
+            auto value = charIota();
+            return value ? std::optional<char>(static_cast<char>(*value)) : std::nullopt;
+        },
+        charIsAscii));
+
+    Iota<int16_t> invalidCharIota{validAsciiSize, 1, invalidAsciiSize};
+
+    ASSERT_FALSE(anyOf(
+        [&]() -> std::optional<char> {
+            auto value = invalidCharIota();
+            return value ? std::optional<char>(static_cast<char>(*value)) : std::nullopt;
+        },
+        charIsAscii));
+
+    FudUtf8 unicode{FudUtf8::invalidAscii()};
+    ASSERT_FALSE(utf8IsAscii(unicode));
+
+    charIota.set(0);
+    ASSERT_TRUE(allOf(
+        [&]() -> std::optional<FudUtf8> {
+            auto value = charIota();
+            return value ? std::optional<FudUtf8>(FudUtf8::make(static_cast<utf8>(*value))) : std::nullopt;
+        },
+        utf8IsAscii));
+
+    invalidCharIota.set(invalidAsciiSize);
+    ASSERT_FALSE(anyOf(
+        [&]() -> std::optional<FudUtf8> {
+            auto value = invalidCharIota();
+            return value ? std::optional<FudUtf8>(FudUtf8::make(static_cast<utf8>(*value))) : std::nullopt;
+        },
+        utf8IsAscii));
+}
+
+TEST(Utf8Test, Utf8IsAlphaNumeric)
+{
+    constexpr size_t numAlphaNumericChars = 26 * 2 + 10;
+    Array<char, numAlphaNumericChars + 1> alphaNumericCharLiteral{ALPHA_NUMERIC_CHARS};
+    Array<char, numAlphaNumericChars> alphaNumericChars{};
+    copyMem<numAlphaNumericChars>(alphaNumericChars, alphaNumericCharLiteral);
+#if 0
+    ASSERT_TRUE(allOf(alphaNumericChars, charIsAlphanumeric));
+
+    auto alphaNumericSetResult{StaticSet<char, numAlphaNumericChars>::makeFromArray(alphaNumericChars)};
+    ASSERT_TRUE(alphaNumericSetResult.isOkay());
+    auto alphaNumericSet{std::move(alphaNumericSetResult.getOkay())};
+
+    constexpr size_t numNonAlphaNumericChars = validAsciiSize - numAlphaNumericChars;
+    FixedVector<char, numNonAlphaNumericChars> nonAlphaNumericChars{};
+    for (char idx = 0; idx < INT8_MAX; ++idx) {
+        if (!alphaNumericSet.isKey(idx)) {
+            ASSERT_TRUE(nonAlphaNumericChars.pushBack(idx));
+        }
+    }
+    ASSERT_FALSE(anyOf(nonAlphaNumericChars, charIsAlphanumeric));
+
+    auto invalidAsciiChars = generateInvalidAsciiChars();
+    ASSERT_FALSE(anyOf(invalidAsciiChars, charIsAlphanumeric));
+
+    ASSERT_TRUE(allOf(
+        map(alphaNumericChars, [](auto input) { return ExtUtf8Char4{static_cast<utf8>(input)}; }),
+        ext_lib_char4_is_alphanumeric));
+    ASSERT_FALSE(anyOf(
+        map(nonAlphaNumericChars, [](auto input) { return ExtUtf8Char4{static_cast<utf8>(input)}; }),
+        ext_lib_char4_is_alphanumeric));
+    ASSERT_FALSE(anyOf(
+        map(invalidAsciiChars, [](auto input) { return ExtUtf8Char4{static_cast<utf8>(input)}; }),
+        ext_lib_char4_is_alphanumeric));
+
+    ASSERT_TRUE(allOf(
+        map(alphaNumericChars, [](auto input) { return ExtUtf8Char4{static_cast<utf8>(input)}; }),
+        ext_lib_char4_is_alphanumeric));
+    ASSERT_FALSE(anyOf(
+        map(nonAlphaNumericChars, [](auto input) { return ExtUtf8Char4{static_cast<utf8>(input)}; }),
+        ext_lib_char4_is_alphanumeric));
+    ASSERT_FALSE(anyOf(
+        map(invalidAsciiChars, [](auto input) { return ExtUtf8Char4{static_cast<utf8>(input)}; }),
+        ext_lib_char4_is_alphanumeric));
+
+    Utf8 utf8{invalidAscii};
+    bool isAscii = false;
+    ASSERT_EQ(ext_lib_utf8_is_alphanumeric(nullptr, nullptr), ExtNullPointer);
+    ASSERT_EQ(ext_lib_utf8_is_alphanumeric(&utf8, nullptr), ExtNullPointer);
+    ASSERT_EQ(ext_lib_utf8_is_alphanumeric(nullptr, &isAscii), ExtNullPointer);
+    ASSERT_EQ(ext_lib_utf8_is_alphanumeric(&utf8, &isAscii), ExtInvalidInput);
+    ASSERT_FALSE(isAscii);
+
+    ASSERT_TRUE(allOf(
+        map(alphaNumericChars,
+            [](char letter) { return FudUtf8::makeUtf8(ExtUtf8Char4{static_cast<utf8>(letter)}); }),
+        [](auto& utf8Letter) {
+            bool predicate = false;
+            auto isPredicateStatus = ext_lib_utf8_is_alphanumeric(&utf8Letter, &predicate);
+            return isPredicateStatus == ExtSuccess && predicate;
+        }));
+    ASSERT_FALSE(anyOf(
+        map(nonAlphaNumericChars,
+            [](char letter) { return FudUtf8::makeUtf8(ExtUtf8Char4{static_cast<utf8>(letter)}); }),
+        [](auto& utf8Letter) {
+            bool predicate = false;
+            auto isPredicateStatus = ext_lib_utf8_is_alphanumeric(&utf8Letter, &predicate);
+            return isPredicateStatus != ExtSuccess || predicate;
+        }));
+    ASSERT_FALSE(allOf(
+        map(nonAlphaNumericChars,
+            [](char letter) { return FudUtf8::makeUtf8(ExtUtf8Char4{static_cast<utf8>(letter)}); }),
+        [](auto& utf8Letter) {
+            bool predicate = false;
+            auto isPredicateStatus = ext_lib_utf8_is_alphanumeric(&utf8Letter, &predicate);
+            return isPredicateStatus == ExtInvalidInput && !predicate;
+        }));
+#endif
+}
+
+#if 0
+TEST(Utf8Test, Utf8IsAlpha)
+{
+    constexpr size_t numAlphaChars = sizeof(ALPHA_CHARS) - 1;
+    Array<char, numAlphaChars + 1> alphaCharLiteral{ALPHA_CHARS};
+    Array<char, numAlphaChars> alphaChars{};
+    copyMem<numAlphaChars>(alphaChars, alphaCharLiteral);
+
+    ASSERT_TRUE(allOf(alphaChars, ext_lib_char_is_alpha));
+
+    auto alphaSetResult{StaticSet<char, numAlphaChars>::makeFromArray(alphaChars)};
+    ASSERT_TRUE(alphaSetResult.isOkay());
+    auto alphaSet{std::move(alphaSetResult.getOkay())};
+
+    constexpr size_t numNonAlphaChars = validAsciiSize - numAlphaChars;
+    FixedVector<char, numNonAlphaChars> nonAlphaChars{};
+    for (char idx = 0; idx < INT8_MAX; ++idx) {
+        if (!alphaSet.isKey(idx)) {
+            ASSERT_TRUE(nonAlphaChars.pushBack(idx));
+        }
+    }
+    ASSERT_FALSE(anyOf(nonAlphaChars, ext_lib_char_is_alpha));
+
+    auto invalidAsciiChars = generateInvalidAsciiChars();
+    ASSERT_FALSE(anyOf(invalidAsciiChars, ext_lib_char_is_alpha));
+
+    ASSERT_TRUE(allOf(
+        map(alphaChars, [](auto input) { return ExtUtf8Char4{static_cast<utf8>(input)}; }),
+        ext_lib_char4_is_alpha));
+    ASSERT_FALSE(anyOf(
+        map(nonAlphaChars, [](auto input) { return ExtUtf8Char4{static_cast<utf8>(input)}; }),
+        ext_lib_char4_is_alpha));
+    ASSERT_FALSE(anyOf(
+        map(invalidAsciiChars, [](auto input) { return ExtUtf8Char4{static_cast<utf8>(input)}; }),
+        ext_lib_char4_is_alpha));
+
+    ASSERT_TRUE(allOf(
+        map(alphaChars, [](auto input) { return ExtUtf8Char4{static_cast<utf8>(input)}; }),
+        ext_lib_char4_is_alpha));
+    ASSERT_FALSE(anyOf(
+        map(nonAlphaChars, [](auto input) { return ExtUtf8Char4{static_cast<utf8>(input)}; }),
+        ext_lib_char4_is_alpha));
+    ASSERT_FALSE(anyOf(
+        map(invalidAsciiChars, [](auto input) { return ExtUtf8Char4{static_cast<utf8>(input)}; }),
+        ext_lib_char4_is_alpha));
+
+    Utf8 utf8{invalidAscii};
+    bool isAscii = false;
+    ASSERT_EQ(ext_lib_utf8_is_alpha(nullptr, nullptr), ExtNullPointer);
+    ASSERT_EQ(ext_lib_utf8_is_alpha(&utf8, nullptr), ExtNullPointer);
+    ASSERT_EQ(ext_lib_utf8_is_alpha(nullptr, &isAscii), ExtNullPointer);
+    ASSERT_EQ(ext_lib_utf8_is_alpha(&utf8, &isAscii), ExtInvalidInput);
+    ASSERT_FALSE(isAscii);
+
+    ASSERT_TRUE(allOf(
+        map(alphaChars, [](char letter) { return FudUtf8::makeUtf8(ExtUtf8Char4{static_cast<utf8>(letter)}); }),
+        [](auto& utf8Letter) {
+            bool predicate = false;
+            auto isPredicateStatus = ext_lib_utf8_is_alpha(&utf8Letter, &predicate);
+            return isPredicateStatus == ExtSuccess && predicate;
+        }));
+    ASSERT_FALSE(anyOf(
+        map(nonAlphaChars,
+            [](char letter) { return FudUtf8::makeUtf8(ExtUtf8Char4{static_cast<utf8>(letter)}); }),
+        [](auto& utf8Letter) {
+            bool predicate = false;
+            auto isPredicateStatus = ext_lib_utf8_is_alpha(&utf8Letter, &predicate);
+            return isPredicateStatus != ExtSuccess || predicate;
+        }));
+    ASSERT_FALSE(allOf(
+        map(nonAlphaChars,
+            [](char letter) { return FudUtf8::makeUtf8(ExtUtf8Char4{static_cast<utf8>(letter)}); }),
+        [](auto& utf8Letter) {
+            bool predicate = false;
+            auto isPredicateStatus = ext_lib_utf8_is_alpha(&utf8Letter, &predicate);
+            return isPredicateStatus == ExtInvalidInput && !predicate;
+        }));
+}
+
+TEST(Utf8Test, Utf8IsLower)
+{
+    constexpr size_t numLowerChars = 26;
+    Array<char, numLowerChars + 1> lowerCharLiteral{LOWERCASE_CHARS};
+    Array<char, numLowerChars> lowerChars{};
+    copyMem<numLowerChars>(lowerChars, lowerCharLiteral);
+
+    ASSERT_TRUE(allOf(lowerChars, ext_lib_char_is_lowercase));
+
+    auto lowerSetResult{StaticSet<char, numLowerChars>::makeFromArray(lowerChars)};
+    ASSERT_TRUE(lowerSetResult.isOkay());
+    auto lowerSet{std::move(lowerSetResult.getOkay())};
+
+    constexpr size_t numNonLowerChars = validAsciiSize - numLowerChars;
+    FixedVector<char, numNonLowerChars> nonLowerChars{};
+    for (char idx = 0; idx < INT8_MAX; ++idx) {
+        if (!lowerSet.isKey(idx)) {
+            ASSERT_TRUE(nonLowerChars.pushBack(idx));
+        }
+    }
+    ASSERT_FALSE(anyOf(nonLowerChars, ext_lib_char_is_lowercase));
+
+    auto invalidAsciiChars = generateInvalidAsciiChars();
+    ASSERT_FALSE(anyOf(invalidAsciiChars, ext_lib_char_is_lowercase));
+
+    ASSERT_TRUE(allOf(
+        map(lowerChars, [](auto input) { return ExtUtf8Char4{static_cast<utf8>(input)}; }),
+        ext_lib_char4_is_lowercase));
+    ASSERT_FALSE(anyOf(
+        map(nonLowerChars, [](auto input) { return ExtUtf8Char4{static_cast<utf8>(input)}; }),
+        ext_lib_char4_is_lowercase));
+    ASSERT_FALSE(anyOf(
+        map(invalidAsciiChars, [](auto input) { return ExtUtf8Char4{static_cast<utf8>(input)}; }),
+        ext_lib_char4_is_lowercase));
+
+    ASSERT_TRUE(allOf(
+        map(lowerChars, [](auto input) { return ExtUtf8Char4{static_cast<utf8>(input)}; }),
+        ext_lib_char4_is_lowercase));
+    ASSERT_FALSE(anyOf(
+        map(nonLowerChars, [](auto input) { return ExtUtf8Char4{static_cast<utf8>(input)}; }),
+        ext_lib_char4_is_lowercase));
+    ASSERT_FALSE(anyOf(
+        map(invalidAsciiChars, [](auto input) { return ExtUtf8Char4{static_cast<utf8>(input)}; }),
+        ext_lib_char4_is_lowercase));
+
+    Utf8 utf8{invalidAscii};
+    bool isAscii = false;
+    ASSERT_EQ(ext_lib_utf8_is_lowercase(nullptr, nullptr), ExtNullPointer);
+    ASSERT_EQ(ext_lib_utf8_is_lowercase(&utf8, nullptr), ExtNullPointer);
+    ASSERT_EQ(ext_lib_utf8_is_lowercase(nullptr, &isAscii), ExtNullPointer);
+    ASSERT_EQ(ext_lib_utf8_is_lowercase(&utf8, &isAscii), ExtInvalidInput);
+    ASSERT_FALSE(isAscii);
+
+    ASSERT_TRUE(allOf(
+        map(lowerChars, [](char letter) { return FudUtf8::makeUtf8(ExtUtf8Char4{static_cast<utf8>(letter)}); }),
+        [](auto& utf8Letter) {
+            bool predicate = false;
+            auto isPredicateStatus = ext_lib_utf8_is_lowercase(&utf8Letter, &predicate);
+            return isPredicateStatus == ExtSuccess && predicate;
+        }));
+    ASSERT_FALSE(anyOf(
+        map(nonLowerChars,
+            [](char letter) { return FudUtf8::makeUtf8(ExtUtf8Char4{static_cast<utf8>(letter)}); }),
+        [](auto& utf8Letter) {
+            bool predicate = false;
+            auto isPredicateStatus = ext_lib_utf8_is_lowercase(&utf8Letter, &predicate);
+            return isPredicateStatus != ExtSuccess || predicate;
+        }));
+    ASSERT_FALSE(allOf(
+        map(nonLowerChars,
+            [](char letter) { return FudUtf8::makeUtf8(ExtUtf8Char4{static_cast<utf8>(letter)}); }),
+        [](auto& utf8Letter) {
+            bool predicate = false;
+            auto isPredicateStatus = ext_lib_utf8_is_lowercase(&utf8Letter, &predicate);
+            return isPredicateStatus == ExtInvalidInput && !predicate;
+        }));
+}
+
+TEST(Utf8Test, Utf8IsUpper)
+{
+    constexpr size_t numUpperChars = 26;
+    Array<char, numUpperChars + 1> upperCharLiteral{UPPERCASE_CHARS};
+    Array<char, numUpperChars> upperChars{};
+    copyMem<numUpperChars>(upperChars, upperCharLiteral);
+
+    ASSERT_TRUE(allOf(upperChars, ext_lib_char_is_uppercase));
+
+    auto upperSetResult{StaticSet<char, numUpperChars>::makeFromArray(upperChars)};
+    ASSERT_TRUE(upperSetResult.isOkay());
+    auto upperSet{std::move(upperSetResult.getOkay())};
+
+    constexpr size_t numNonUpperChars = validAsciiSize - numUpperChars;
+    FixedVector<char, numNonUpperChars> nonUpperChars{};
+    for (char idx = 0; idx < INT8_MAX; ++idx) {
+        if (!upperSet.isKey(idx)) {
+            ASSERT_TRUE(nonUpperChars.pushBack(idx));
+        }
+    }
+    ASSERT_FALSE(anyOf(nonUpperChars, ext_lib_char_is_uppercase));
+
+    auto invalidAsciiChars = generateInvalidAsciiChars();
+    ASSERT_FALSE(anyOf(invalidAsciiChars, ext_lib_char_is_uppercase));
+
+    ASSERT_TRUE(allOf(
+        map(upperChars, [](auto input) { return ExtUtf8Char4{static_cast<utf8>(input)}; }),
+        ext_lib_char4_is_uppercase));
+    ASSERT_FALSE(anyOf(
+        map(nonUpperChars, [](auto input) { return ExtUtf8Char4{static_cast<utf8>(input)}; }),
+        ext_lib_char4_is_uppercase));
+    ASSERT_FALSE(anyOf(
+        map(invalidAsciiChars, [](auto input) { return ExtUtf8Char4{static_cast<utf8>(input)}; }),
+        ext_lib_char4_is_uppercase));
+
+    ASSERT_TRUE(allOf(
+        map(upperChars, [](auto input) { return ExtUtf8Char4{static_cast<utf8>(input)}; }),
+        ext_lib_char4_is_uppercase));
+    ASSERT_FALSE(anyOf(
+        map(nonUpperChars, [](auto input) { return ExtUtf8Char4{static_cast<utf8>(input)}; }),
+        ext_lib_char4_is_uppercase));
+    ASSERT_FALSE(anyOf(
+        map(invalidAsciiChars, [](auto input) { return ExtUtf8Char4{static_cast<utf8>(input)}; }),
+        ext_lib_char4_is_uppercase));
+
+    Utf8 utf8{invalidAscii};
+    bool isAscii = false;
+    ASSERT_EQ(ext_lib_utf8_is_uppercase(nullptr, nullptr), ExtNullPointer);
+    ASSERT_EQ(ext_lib_utf8_is_uppercase(&utf8, nullptr), ExtNullPointer);
+    ASSERT_EQ(ext_lib_utf8_is_uppercase(nullptr, &isAscii), ExtNullPointer);
+    ASSERT_EQ(ext_lib_utf8_is_uppercase(&utf8, &isAscii), ExtInvalidInput);
+    ASSERT_FALSE(isAscii);
+
+    ASSERT_TRUE(allOf(
+        map(upperChars, [](char letter) { return FudUtf8::makeUtf8(ExtUtf8Char4{static_cast<utf8>(letter)}); }),
+        [](auto& utf8Letter) {
+            bool predicate = false;
+            auto isPredicateStatus = ext_lib_utf8_is_uppercase(&utf8Letter, &predicate);
+            return isPredicateStatus == ExtSuccess && predicate;
+        }));
+    ASSERT_FALSE(anyOf(
+        map(nonUpperChars,
+            [](char letter) { return FudUtf8::makeUtf8(ExtUtf8Char4{static_cast<utf8>(letter)}); }),
+        [](auto& utf8Letter) {
+            bool predicate = false;
+            auto isPredicateStatus = ext_lib_utf8_is_uppercase(&utf8Letter, &predicate);
+            return isPredicateStatus != ExtSuccess || predicate;
+        }));
+    ASSERT_FALSE(allOf(
+        map(nonUpperChars,
+            [](char letter) { return FudUtf8::makeUtf8(ExtUtf8Char4{static_cast<utf8>(letter)}); }),
+        [](auto& utf8Letter) {
+            bool predicate = false;
+            auto isPredicateStatus = ext_lib_utf8_is_uppercase(&utf8Letter, &predicate);
+            return isPredicateStatus == ExtInvalidInput && !predicate;
+        }));
+}
+
+TEST(Utf8Test, Utf8IsDigit)
+{
+    constexpr size_t numDigitChars = 10;
+    Array<char, numDigitChars + 1> digitCharLiteral{"0123456789"};
+    Array<char, numDigitChars> digitChars{};
+    copyMem<numDigitChars>(digitChars, digitCharLiteral);
+
+    ASSERT_TRUE(allOf(digitChars, ext_lib_char_is_digit));
+
+    auto digitSetResult{StaticSet<char, numDigitChars>::makeFromArray(digitChars)};
+    ASSERT_TRUE(digitSetResult.isOkay());
+    auto digitSet{std::move(digitSetResult.getOkay())};
+
+    constexpr size_t numNonDigitChars = validAsciiSize - numDigitChars;
+    FixedVector<char, numNonDigitChars> nonDigitChars{};
+    for (char idx = 0; idx < INT8_MAX; ++idx) {
+        if (!digitSet.isKey(idx)) {
+            ASSERT_TRUE(nonDigitChars.pushBack(idx));
+        }
+    }
+    ASSERT_FALSE(anyOf(nonDigitChars, ext_lib_char_is_digit));
+
+    auto invalidAsciiChars = generateInvalidAsciiChars();
+    ASSERT_FALSE(anyOf(invalidAsciiChars, ext_lib_char_is_digit));
+
+    ASSERT_TRUE(allOf(
+        map(digitChars, [](auto input) { return ExtUtf8Char4{static_cast<utf8>(input)}; }),
+        ext_lib_char4_is_digit));
+    ASSERT_FALSE(anyOf(
+        map(nonDigitChars, [](auto input) { return ExtUtf8Char4{static_cast<utf8>(input)}; }),
+        ext_lib_char4_is_digit));
+    ASSERT_FALSE(anyOf(
+        map(invalidAsciiChars, [](auto input) { return ExtUtf8Char4{static_cast<utf8>(input)}; }),
+        ext_lib_char4_is_digit));
+
+    ASSERT_TRUE(allOf(
+        map(digitChars, [](auto input) { return ExtUtf8Char4{static_cast<utf8>(input)}; }),
+        ext_lib_char4_is_digit));
+    ASSERT_FALSE(anyOf(
+        map(nonDigitChars, [](auto input) { return ExtUtf8Char4{static_cast<utf8>(input)}; }),
+        ext_lib_char4_is_digit));
+    ASSERT_FALSE(anyOf(
+        map(invalidAsciiChars, [](auto input) { return ExtUtf8Char4{static_cast<utf8>(input)}; }),
+        ext_lib_char4_is_digit));
+
+    Utf8 utf8{invalidAscii};
+    bool isAscii = false;
+    ASSERT_EQ(ext_lib_utf8_is_digit(nullptr, nullptr), ExtNullPointer);
+    ASSERT_EQ(ext_lib_utf8_is_digit(&utf8, nullptr), ExtNullPointer);
+    ASSERT_EQ(ext_lib_utf8_is_digit(nullptr, &isAscii), ExtNullPointer);
+    ASSERT_EQ(ext_lib_utf8_is_digit(&utf8, &isAscii), ExtInvalidInput);
+    ASSERT_FALSE(isAscii);
+
+    ASSERT_TRUE(allOf(
+        map(digitChars, [](char letter) { return FudUtf8::makeUtf8(ExtUtf8Char4{static_cast<utf8>(letter)}); }),
+        [](auto& utf8Letter) {
+            bool predicate = false;
+            auto isPredicateStatus = ext_lib_utf8_is_digit(&utf8Letter, &predicate);
+            return isPredicateStatus == ExtSuccess && predicate;
+        }));
+    ASSERT_FALSE(anyOf(
+        map(nonDigitChars,
+            [](char letter) { return FudUtf8::makeUtf8(ExtUtf8Char4{static_cast<utf8>(letter)}); }),
+        [](auto& utf8Letter) {
+            bool predicate = false;
+            auto isPredicateStatus = ext_lib_utf8_is_digit(&utf8Letter, &predicate);
+            return isPredicateStatus != ExtSuccess || predicate;
+        }));
+    ASSERT_FALSE(allOf(
+        map(nonDigitChars,
+            [](char letter) { return FudUtf8::makeUtf8(ExtUtf8Char4{static_cast<utf8>(letter)}); }),
+        [](auto& utf8Letter) {
+            bool predicate = false;
+            auto isPredicateStatus = ext_lib_utf8_is_digit(&utf8Letter, &predicate);
+            return isPredicateStatus == ExtInvalidInput && !predicate;
+        }));
+}
+
+TEST(Utf8Test, Utf8IsHexDigit)
+{
+    constexpr size_t numHexDigitChars = 6 * 2 + 10;
+    Array<char, numHexDigitChars + 1> hexDigitCharLiteral{"abcdefABCDEF0123456789"};
+    Array<char, numHexDigitChars> hexDigitChars{};
+    copyMem<numHexDigitChars>(hexDigitChars, hexDigitCharLiteral);
+
+    ASSERT_TRUE(allOf(hexDigitChars, ext_lib_char_is_hex_digit));
+
+    auto hexDigitSetResult{StaticSet<char, numHexDigitChars>::makeFromArray(hexDigitChars)};
+    ASSERT_TRUE(hexDigitSetResult.isOkay());
+    auto hexDigitSet{std::move(hexDigitSetResult.getOkay())};
+
+    constexpr size_t numNonHexDigitChars = validAsciiSize - numHexDigitChars;
+    FixedVector<char, numNonHexDigitChars> nonHexDigitChars{};
+    for (char idx = 0; idx < INT8_MAX; ++idx) {
+        if (!hexDigitSet.isKey(idx)) {
+            ASSERT_TRUE(nonHexDigitChars.pushBack(idx));
+        }
+    }
+    ASSERT_FALSE(anyOf(nonHexDigitChars, ext_lib_char_is_hex_digit));
+
+    auto invalidAsciiChars = generateInvalidAsciiChars();
+    ASSERT_FALSE(anyOf(invalidAsciiChars, ext_lib_char_is_hex_digit));
+
+    ASSERT_TRUE(allOf(
+        map(hexDigitChars, [](auto input) { return ExtUtf8Char4{static_cast<utf8>(input)}; }),
+        ext_lib_char4_is_hex_digit));
+    ASSERT_FALSE(anyOf(
+        map(nonHexDigitChars, [](auto input) { return ExtUtf8Char4{static_cast<utf8>(input)}; }),
+        ext_lib_char4_is_hex_digit));
+    ASSERT_FALSE(anyOf(
+        map(invalidAsciiChars, [](auto input) { return ExtUtf8Char4{static_cast<utf8>(input)}; }),
+        ext_lib_char4_is_hex_digit));
+
+    ASSERT_TRUE(allOf(
+        map(hexDigitChars, [](auto input) { return ExtUtf8Char4{static_cast<utf8>(input)}; }),
+        ext_lib_char4_is_hex_digit));
+    ASSERT_FALSE(anyOf(
+        map(nonHexDigitChars, [](auto input) { return ExtUtf8Char4{static_cast<utf8>(input)}; }),
+        ext_lib_char4_is_hex_digit));
+    ASSERT_FALSE(anyOf(
+        map(invalidAsciiChars, [](auto input) { return ExtUtf8Char4{static_cast<utf8>(input)}; }),
+        ext_lib_char4_is_hex_digit));
+
+    Utf8 utf8{invalidAscii};
+    bool isAscii = false;
+    ASSERT_EQ(ext_lib_utf8_is_hex_digit(nullptr, nullptr), ExtNullPointer);
+    ASSERT_EQ(ext_lib_utf8_is_hex_digit(&utf8, nullptr), ExtNullPointer);
+    ASSERT_EQ(ext_lib_utf8_is_hex_digit(nullptr, &isAscii), ExtNullPointer);
+    ASSERT_EQ(ext_lib_utf8_is_hex_digit(&utf8, &isAscii), ExtInvalidInput);
+    ASSERT_FALSE(isAscii);
+
+    ASSERT_TRUE(allOf(
+        map(hexDigitChars,
+            [](char letter) { return FudUtf8::makeUtf8(ExtUtf8Char4{static_cast<utf8>(letter)}); }),
+        [](auto& utf8Letter) {
+            bool predicate = false;
+            auto isPredicateStatus = ext_lib_utf8_is_hex_digit(&utf8Letter, &predicate);
+            return isPredicateStatus == ExtSuccess && predicate;
+        }));
+    ASSERT_FALSE(anyOf(
+        map(nonHexDigitChars,
+            [](char letter) { return FudUtf8::makeUtf8(ExtUtf8Char4{static_cast<utf8>(letter)}); }),
+        [](auto& utf8Letter) {
+            bool predicate = false;
+            auto isPredicateStatus = ext_lib_utf8_is_hex_digit(&utf8Letter, &predicate);
+            return isPredicateStatus != ExtSuccess || predicate;
+        }));
+    ASSERT_FALSE(allOf(
+        map(nonHexDigitChars,
+            [](char letter) { return FudUtf8::makeUtf8(ExtUtf8Char4{static_cast<utf8>(letter)}); }),
+        [](auto& utf8Letter) {
+            bool predicate = false;
+            auto isPredicateStatus = ext_lib_utf8_is_hex_digit(&utf8Letter, &predicate);
+            return isPredicateStatus == ExtInvalidInput && !predicate;
+        }));
+}
+
+TEST(Utf8Test, Utf8IsControl)
+{
+    auto controlChars = generateIndexArray<Array, char, numControlChars>([](int idx) { return static_cast<char>(idx); });
+    constexpr const char deleteChar = 0x7F;
+    controlChars.back() = deleteChar;
+
+    ASSERT_TRUE(allOf(controlChars, ext_lib_char_is_control));
+
+    constexpr size_t numNonControlChars = 256 - numControlChars;
+    auto nonControlChars = generateIndexArray<Array, char, numControlChars>([](int idx) {
+        return static_cast<char>(idx + printableCharOffset);
+    });
+    ASSERT_FALSE(anyOf(nonControlChars, ext_lib_char_is_control));
+
+    auto invalidAsciiChars = generateInvalidAsciiChars();
+    ASSERT_FALSE(anyOf(invalidAsciiChars, ext_lib_char_is_control));
+
+    ASSERT_TRUE(allOf(
+        map(controlChars, [](auto input) { return ExtUtf8Char4{static_cast<utf8>(input)}; }),
+        ext_lib_char4_is_control));
+    ASSERT_FALSE(anyOf(
+        map(nonControlChars, [](auto input) { return ExtUtf8Char4{static_cast<utf8>(input)}; }),
+        ext_lib_char4_is_control));
+    ASSERT_FALSE(anyOf(
+        map(invalidAsciiChars, [](auto input) { return ExtUtf8Char4{static_cast<utf8>(input)}; }),
+        ext_lib_char4_is_control));
+
+    ASSERT_TRUE(allOf(
+        map(controlChars, [](auto input) { return ExtUtf8Char4{static_cast<utf8>(input)}; }),
+        ext_lib_char4_is_control));
+    ASSERT_FALSE(anyOf(
+        map(nonControlChars, [](auto input) { return ExtUtf8Char4{static_cast<utf8>(input)}; }),
+        ext_lib_char4_is_control));
+    ASSERT_FALSE(anyOf(
+        map(invalidAsciiChars, [](auto input) { return ExtUtf8Char4{static_cast<utf8>(input)}; }),
+        ext_lib_char4_is_control));
+
+    Utf8 utf8{invalidAscii};
+    bool isAscii = false;
+    ASSERT_EQ(ext_lib_utf8_is_control(nullptr, nullptr), ExtNullPointer);
+    ASSERT_EQ(ext_lib_utf8_is_control(&utf8, nullptr), ExtNullPointer);
+    ASSERT_EQ(ext_lib_utf8_is_control(nullptr, &isAscii), ExtNullPointer);
+    ASSERT_EQ(ext_lib_utf8_is_control(&utf8, &isAscii), ExtInvalidInput);
+    ASSERT_FALSE(isAscii);
+
+    ASSERT_TRUE(allOf(
+        map(controlChars,
+            [](char letter) { return FudUtf8::makeUtf8(ExtUtf8Char4{static_cast<utf8>(letter)}); }),
+        [](auto& utf8Letter) {
+            bool predicate = false;
+            auto isPredicateStatus = ext_lib_utf8_is_control(&utf8Letter, &predicate);
+            return isPredicateStatus == ExtSuccess && predicate;
+        }));
+    ASSERT_FALSE(anyOf(
+        map(nonControlChars,
+            [](char letter) { return FudUtf8::makeUtf8(ExtUtf8Char4{static_cast<utf8>(letter)}); }),
+        [](auto& utf8Letter) {
+            bool predicate = false;
+            auto isPredicateStatus = ext_lib_utf8_is_control(&utf8Letter, &predicate);
+            return isPredicateStatus != ExtSuccess || predicate;
+        }));
+    ASSERT_FALSE(allOf(
+        map(nonControlChars,
+            [](char letter) { return FudUtf8::makeUtf8(ExtUtf8Char4{static_cast<utf8>(letter)}); }),
+        [](auto& utf8Letter) {
+            bool predicate = false;
+            auto isPredicateStatus = ext_lib_utf8_is_control(&utf8Letter, &predicate);
+            return isPredicateStatus == ExtInvalidInput && !predicate;
+        }));
+}
+
+TEST(Utf8Test, Utf8IsGraphical)
+{
+    constexpr size_t numGraphicalChars = sizeof(GRAPHICAL_CHARS) - 1;
+    Array<char, numGraphicalChars + 1> graphicalCharLiteral{GRAPHICAL_CHARS};
+    Array<char, numGraphicalChars> graphicalChars{};
+    copyMem<numGraphicalChars>(graphicalChars, graphicalCharLiteral);
+
+    ASSERT_TRUE(allOf(graphicalChars, ext_lib_char_is_graphical));
+
+    auto graphicalSetResult{StaticSet<char, numGraphicalChars>::makeFromArray(graphicalChars)};
+    ASSERT_TRUE(graphicalSetResult.isOkay());
+    auto graphicalSet{std::move(graphicalSetResult.getOkay())};
+
+    constexpr size_t numNonGraphicalChars = validAsciiSize - numGraphicalChars;
+    FixedVector<char, numNonGraphicalChars> nonGraphicalChars{};
+    for (char idx = 0; idx < INT8_MAX; ++idx) {
+        if (!graphicalSet.isKey(idx)) {
+            ASSERT_TRUE(nonGraphicalChars.pushBack(idx));
+        }
+    }
+    ASSERT_FALSE(anyOf(nonGraphicalChars, ext_lib_char_is_graphical));
+
+    auto invalidAsciiChars = generateInvalidAsciiChars();
+    ASSERT_FALSE(anyOf(invalidAsciiChars, ext_lib_char_is_graphical));
+
+    ASSERT_TRUE(allOf(
+        map(graphicalChars, [](auto input) { return ExtUtf8Char4{static_cast<utf8>(input)}; }),
+        ext_lib_char4_is_graphical));
+    ASSERT_FALSE(anyOf(
+        map(nonGraphicalChars, [](auto input) { return ExtUtf8Char4{static_cast<utf8>(input)}; }),
+        ext_lib_char4_is_graphical));
+    ASSERT_FALSE(anyOf(
+        map(invalidAsciiChars, [](auto input) { return ExtUtf8Char4{static_cast<utf8>(input)}; }),
+        ext_lib_char4_is_graphical));
+
+    ASSERT_TRUE(allOf(
+        map(graphicalChars, [](auto input) { return ExtUtf8Char4{static_cast<utf8>(input)}; }),
+        ext_lib_char4_is_graphical));
+    ASSERT_FALSE(anyOf(
+        map(nonGraphicalChars, [](auto input) { return ExtUtf8Char4{static_cast<utf8>(input)}; }),
+        ext_lib_char4_is_graphical));
+    ASSERT_FALSE(anyOf(
+        map(invalidAsciiChars, [](auto input) { return ExtUtf8Char4{static_cast<utf8>(input)}; }),
+        ext_lib_char4_is_graphical));
+
+    Utf8 utf8{invalidAscii};
+    bool isAscii = false;
+    ASSERT_EQ(ext_lib_utf8_is_graphical(nullptr, nullptr), ExtNullPointer);
+    ASSERT_EQ(ext_lib_utf8_is_graphical(&utf8, nullptr), ExtNullPointer);
+    ASSERT_EQ(ext_lib_utf8_is_graphical(nullptr, &isAscii), ExtNullPointer);
+    ASSERT_EQ(ext_lib_utf8_is_graphical(&utf8, &isAscii), ExtInvalidInput);
+    ASSERT_FALSE(isAscii);
+
+    ASSERT_TRUE(allOf(
+        map(graphicalChars,
+            [](char letter) { return FudUtf8::makeUtf8(ExtUtf8Char4{static_cast<utf8>(letter)}); }),
+        [](auto& utf8Letter) {
+            bool predicate = false;
+            auto isPredicateStatus = ext_lib_utf8_is_graphical(&utf8Letter, &predicate);
+            return isPredicateStatus == ExtSuccess && predicate;
+        }));
+    ASSERT_FALSE(anyOf(
+        map(nonGraphicalChars,
+            [](char letter) { return FudUtf8::makeUtf8(ExtUtf8Char4{static_cast<utf8>(letter)}); }),
+        [](auto& utf8Letter) {
+            bool predicate = false;
+            auto isPredicateStatus = ext_lib_utf8_is_graphical(&utf8Letter, &predicate);
+            return isPredicateStatus != ExtSuccess || predicate;
+        }));
+    ASSERT_FALSE(allOf(
+        map(nonGraphicalChars,
+            [](char letter) { return FudUtf8::makeUtf8(ExtUtf8Char4{static_cast<utf8>(letter)}); }),
+        [](auto& utf8Letter) {
+            bool predicate = false;
+            auto isPredicateStatus = ext_lib_utf8_is_graphical(&utf8Letter, &predicate);
+            return isPredicateStatus == ExtInvalidInput && !predicate;
+        }));
+}
+
+TEST(Utf8Test, Utf8IsSpace)
+{
+    constexpr size_t numSpaceChars = sizeof(" \t\v\r\n") - 1;
+    Array<char, numSpaceChars + 1> spaceCharLiteral{" \t\v\r\n"};
+    Array<char, numSpaceChars> spaceChars{};
+    copyMem<numSpaceChars>(spaceChars, spaceCharLiteral);
+
+    ASSERT_TRUE(allOf(spaceChars, ext_lib_char_is_space));
+
+    auto spaceSetResult{StaticSet<char, numSpaceChars>::makeFromArray(spaceChars)};
+    ASSERT_TRUE(spaceSetResult.isOkay());
+    auto spaceSet{std::move(spaceSetResult.getOkay())};
+
+    constexpr size_t numNonSpaceChars = validAsciiSize - numSpaceChars;
+    FixedVector<char, numNonSpaceChars> nonSpaceChars{};
+    for (char idx = 0; idx < INT8_MAX; ++idx) {
+        if (!spaceSet.isKey(idx)) {
+            ASSERT_TRUE(nonSpaceChars.pushBack(idx));
+        }
+    }
+    ASSERT_FALSE(anyOf(nonSpaceChars, ext_lib_char_is_space));
+
+    auto invalidAsciiChars = generateInvalidAsciiChars();
+    ASSERT_FALSE(anyOf(invalidAsciiChars, ext_lib_char_is_space));
+
+    ASSERT_TRUE(allOf(
+        map(spaceChars, [](auto input) { return ExtUtf8Char4{static_cast<utf8>(input)}; }),
+        ext_lib_char4_is_space));
+    ASSERT_FALSE(anyOf(
+        map(nonSpaceChars, [](auto input) { return ExtUtf8Char4{static_cast<utf8>(input)}; }),
+        ext_lib_char4_is_space));
+    ASSERT_FALSE(anyOf(
+        map(invalidAsciiChars, [](auto input) { return ExtUtf8Char4{static_cast<utf8>(input)}; }),
+        ext_lib_char4_is_space));
+
+    ASSERT_TRUE(allOf(
+        map(spaceChars, [](auto input) { return ExtUtf8Char4{static_cast<utf8>(input)}; }),
+        ext_lib_char4_is_space));
+    ASSERT_FALSE(anyOf(
+        map(nonSpaceChars, [](auto input) { return ExtUtf8Char4{static_cast<utf8>(input)}; }),
+        ext_lib_char4_is_space));
+    ASSERT_FALSE(anyOf(
+        map(invalidAsciiChars, [](auto input) { return ExtUtf8Char4{static_cast<utf8>(input)}; }),
+        ext_lib_char4_is_space));
+
+    Utf8 utf8{invalidAscii};
+    bool isAscii = false;
+    ASSERT_EQ(ext_lib_utf8_is_space(nullptr, nullptr), ExtNullPointer);
+    ASSERT_EQ(ext_lib_utf8_is_space(&utf8, nullptr), ExtNullPointer);
+    ASSERT_EQ(ext_lib_utf8_is_space(nullptr, &isAscii), ExtNullPointer);
+    ASSERT_EQ(ext_lib_utf8_is_space(&utf8, &isAscii), ExtInvalidInput);
+    ASSERT_FALSE(isAscii);
+
+    ASSERT_TRUE(allOf(
+        map(spaceChars, [](char letter) { return FudUtf8::makeUtf8(ExtUtf8Char4{static_cast<utf8>(letter)}); }),
+        [](auto& utf8Letter) {
+            bool predicate = false;
+            auto isPredicateStatus = ext_lib_utf8_is_space(&utf8Letter, &predicate);
+            return isPredicateStatus == ExtSuccess && predicate;
+        }));
+    ASSERT_FALSE(anyOf(
+        map(nonSpaceChars,
+            [](char letter) { return FudUtf8::makeUtf8(ExtUtf8Char4{static_cast<utf8>(letter)}); }),
+        [](auto& utf8Letter) {
+            bool predicate = false;
+            auto isPredicateStatus = ext_lib_utf8_is_space(&utf8Letter, &predicate);
+            return isPredicateStatus != ExtSuccess || predicate;
+        }));
+    ASSERT_FALSE(allOf(
+        map(nonSpaceChars,
+            [](char letter) { return FudUtf8::makeUtf8(ExtUtf8Char4{static_cast<utf8>(letter)}); }),
+        [](auto& utf8Letter) {
+            bool predicate = false;
+            auto isPredicateStatus = ext_lib_utf8_is_space(&utf8Letter, &predicate);
+            return isPredicateStatus == ExtInvalidInput && !predicate;
+        }));
+}
+
+TEST(Utf8Test, Utf8IsBlank)
+{
+    constexpr size_t numBlankChars = sizeof(" \t") - 1;
+    Array<char, numBlankChars + 1> blankCharLiteral{" \t"};
+    Array<char, numBlankChars> blankChars{};
+    copyMem<numBlankChars>(blankChars, blankCharLiteral);
+
+    ASSERT_TRUE(allOf(blankChars, ext_lib_char_is_blank));
+
+    auto blankSetResult{StaticSet<char, numBlankChars>::makeFromArray(blankChars)};
+    ASSERT_TRUE(blankSetResult.isOkay());
+    auto blankSet{std::move(blankSetResult.getOkay())};
+
+    constexpr size_t numNonBlankChars = validAsciiSize - numBlankChars;
+    FixedVector<char, numNonBlankChars> nonBlankChars{};
+    for (char idx = 0; idx < INT8_MAX; ++idx) {
+        if (!blankSet.isKey(idx)) {
+            ASSERT_TRUE(nonBlankChars.pushBack(idx));
+        }
+    }
+    ASSERT_FALSE(anyOf(nonBlankChars, ext_lib_char_is_blank));
+
+    auto invalidAsciiChars = generateInvalidAsciiChars();
+    ASSERT_FALSE(anyOf(invalidAsciiChars, ext_lib_char_is_blank));
+
+    ASSERT_TRUE(allOf(
+        map(blankChars, [](auto input) { return ExtUtf8Char4{static_cast<utf8>(input)}; }),
+        ext_lib_char4_is_blank));
+    ASSERT_FALSE(anyOf(
+        map(nonBlankChars, [](auto input) { return ExtUtf8Char4{static_cast<utf8>(input)}; }),
+        ext_lib_char4_is_blank));
+    ASSERT_FALSE(anyOf(
+        map(invalidAsciiChars, [](auto input) { return ExtUtf8Char4{static_cast<utf8>(input)}; }),
+        ext_lib_char4_is_blank));
+
+    ASSERT_TRUE(allOf(
+        map(blankChars, [](auto input) { return ExtUtf8Char4{static_cast<utf8>(input)}; }),
+        ext_lib_char4_is_blank));
+    ASSERT_FALSE(anyOf(
+        map(nonBlankChars, [](auto input) { return ExtUtf8Char4{static_cast<utf8>(input)}; }),
+        ext_lib_char4_is_blank));
+    ASSERT_FALSE(anyOf(
+        map(invalidAsciiChars, [](auto input) { return ExtUtf8Char4{static_cast<utf8>(input)}; }),
+        ext_lib_char4_is_blank));
+
+    Utf8 utf8{invalidAscii};
+    bool isAscii = false;
+    ASSERT_EQ(ext_lib_utf8_is_blank(nullptr, nullptr), ExtNullPointer);
+    ASSERT_EQ(ext_lib_utf8_is_blank(&utf8, nullptr), ExtNullPointer);
+    ASSERT_EQ(ext_lib_utf8_is_blank(nullptr, &isAscii), ExtNullPointer);
+    ASSERT_EQ(ext_lib_utf8_is_blank(&utf8, &isAscii), ExtInvalidInput);
+    ASSERT_FALSE(isAscii);
+
+    ASSERT_TRUE(allOf(
+        map(blankChars, [](char letter) { return FudUtf8::makeUtf8(ExtUtf8Char4{static_cast<utf8>(letter)}); }),
+        [](auto& utf8Letter) {
+            bool predicate = false;
+            auto isPredicateStatus = ext_lib_utf8_is_blank(&utf8Letter, &predicate);
+            return isPredicateStatus == ExtSuccess && predicate;
+        }));
+    ASSERT_FALSE(anyOf(
+        map(nonBlankChars,
+            [](char letter) { return FudUtf8::makeUtf8(ExtUtf8Char4{static_cast<utf8>(letter)}); }),
+        [](auto& utf8Letter) {
+            bool predicate = false;
+            auto isPredicateStatus = ext_lib_utf8_is_blank(&utf8Letter, &predicate);
+            return isPredicateStatus != ExtSuccess || predicate;
+        }));
+    ASSERT_FALSE(allOf(
+        map(nonBlankChars,
+            [](char letter) { return FudUtf8::makeUtf8(ExtUtf8Char4{static_cast<utf8>(letter)}); }),
+        [](auto& utf8Letter) {
+            bool predicate = false;
+            auto isPredicateStatus = ext_lib_utf8_is_blank(&utf8Letter, &predicate);
+            return isPredicateStatus == ExtInvalidInput && !predicate;
+        }));
+}
+
+TEST(Utf8Test, Utf8IsPrintable)
+{
+    constexpr size_t numPrintableChars = validAsciiSize - numControlChars;
+    auto printableChars = generateIndexArray<Array, char, numPrintableChars>([](int idx) {
+        return static_cast<char>(idx + printableCharOffset);
+    });
+
+    ASSERT_TRUE(allOf(printableChars, ext_lib_char_is_printable));
+
+    auto printableSetResult{StaticSet<char, numPrintableChars>::makeFromArray(printableChars)};
+    ASSERT_TRUE(printableSetResult.isOkay());
+    auto printableSet{std::move(printableSetResult.getOkay())};
+
+    constexpr size_t numNonPrintableChars = validAsciiSize - numPrintableChars;
+    FixedVector<char, numNonPrintableChars> nonPrintableChars{};
+    for (char idx = 0; idx < INT8_MAX; ++idx) {
+        if (!printableSet.isKey(idx)) {
+            ASSERT_TRUE(nonPrintableChars.pushBack(idx));
+        }
+    }
+    ASSERT_FALSE(anyOf(nonPrintableChars, ext_lib_char_is_printable));
+
+    auto invalidAsciiChars = generateInvalidAsciiChars();
+    ASSERT_FALSE(anyOf(invalidAsciiChars, ext_lib_char_is_printable));
+
+    ASSERT_TRUE(allOf(
+        map(printableChars, [](auto input) { return ExtUtf8Char4{static_cast<utf8>(input)}; }),
+        ext_lib_char4_is_printable));
+    ASSERT_FALSE(anyOf(
+        map(nonPrintableChars, [](auto input) { return ExtUtf8Char4{static_cast<utf8>(input)}; }),
+        ext_lib_char4_is_printable));
+    ASSERT_FALSE(anyOf(
+        map(invalidAsciiChars, [](auto input) { return ExtUtf8Char4{static_cast<utf8>(input)}; }),
+        ext_lib_char4_is_printable));
+
+    ASSERT_TRUE(allOf(
+        map(printableChars, [](auto input) { return ExtUtf8Char4{static_cast<utf8>(input)}; }),
+        ext_lib_char4_is_printable));
+    ASSERT_FALSE(anyOf(
+        map(nonPrintableChars, [](auto input) { return ExtUtf8Char4{static_cast<utf8>(input)}; }),
+        ext_lib_char4_is_printable));
+    ASSERT_FALSE(anyOf(
+        map(invalidAsciiChars, [](auto input) { return ExtUtf8Char4{static_cast<utf8>(input)}; }),
+        ext_lib_char4_is_printable));
+
+    Utf8 utf8{invalidAscii};
+    bool isAscii = false;
+    ASSERT_EQ(ext_lib_utf8_is_printable(nullptr, nullptr), ExtNullPointer);
+    ASSERT_EQ(ext_lib_utf8_is_printable(&utf8, nullptr), ExtNullPointer);
+    ASSERT_EQ(ext_lib_utf8_is_printable(nullptr, &isAscii), ExtNullPointer);
+    ASSERT_EQ(ext_lib_utf8_is_printable(&utf8, &isAscii), ExtInvalidInput);
+    ASSERT_FALSE(isAscii);
+
+    ASSERT_TRUE(allOf(
+        map(printableChars,
+            [](char letter) { return FudUtf8::makeUtf8(ExtUtf8Char4{static_cast<utf8>(letter)}); }),
+        [](auto& utf8Letter) {
+            bool predicate = false;
+            auto isPredicateStatus = ext_lib_utf8_is_printable(&utf8Letter, &predicate);
+            return isPredicateStatus == ExtSuccess && predicate;
+        }));
+    ASSERT_FALSE(anyOf(
+        map(nonPrintableChars,
+            [](char letter) { return FudUtf8::makeUtf8(ExtUtf8Char4{static_cast<utf8>(letter)}); }),
+        [](auto& utf8Letter) {
+            bool predicate = false;
+            auto isPredicateStatus = ext_lib_utf8_is_printable(&utf8Letter, &predicate);
+            return isPredicateStatus != ExtSuccess || predicate;
+        }));
+    ASSERT_FALSE(allOf(
+        map(nonPrintableChars,
+            [](char letter) { return FudUtf8::makeUtf8(ExtUtf8Char4{static_cast<utf8>(letter)}); }),
+        [](auto& utf8Letter) {
+            bool predicate = false;
+            auto isPredicateStatus = ext_lib_utf8_is_printable(&utf8Letter, &predicate);
+            return isPredicateStatus == ExtInvalidInput && !predicate;
+        }));
+}
+
+TEST(Utf8Test, Utf8IsPunctuation)
+{
+    constexpr size_t numPunctuationChars = sizeof(PUNCTUATION_CHARS) - 1;
+    Array<char, numPunctuationChars + 1> punctuationCharLiteral{PUNCTUATION_CHARS};
+    Array<char, numPunctuationChars> punctuationChars{};
+    copyMem<numPunctuationChars>(punctuationChars, punctuationCharLiteral);
+
+    ASSERT_TRUE(allOf(punctuationChars, ext_lib_char_is_punctuation));
+
+    auto punctuationSetResult{StaticSet<char, numPunctuationChars>::makeFromArray(punctuationChars)};
+    ASSERT_TRUE(punctuationSetResult.isOkay());
+    auto punctuationSet{std::move(punctuationSetResult.getOkay())};
+
+    constexpr size_t numNonPunctuationChars = validAsciiSize - numPunctuationChars;
+    FixedVector<char, numNonPunctuationChars> nonPunctuationChars{};
+    for (char idx = 0; idx < INT8_MAX; ++idx) {
+        if (!punctuationSet.isKey(idx)) {
+            ASSERT_TRUE(nonPunctuationChars.pushBack(idx));
+        }
+    }
+    ASSERT_FALSE(anyOf(nonPunctuationChars, ext_lib_char_is_punctuation));
+
+    auto invalidAsciiChars = generateInvalidAsciiChars();
+    ASSERT_FALSE(anyOf(invalidAsciiChars, ext_lib_char_is_punctuation));
+
+    ASSERT_TRUE(allOf(
+        map(punctuationChars, [](auto input) { return ExtUtf8Char4{static_cast<utf8>(input)}; }),
+        ext_lib_char4_is_punctuation));
+    ASSERT_FALSE(anyOf(
+        map(nonPunctuationChars, [](auto input) { return ExtUtf8Char4{static_cast<utf8>(input)}; }),
+        ext_lib_char4_is_punctuation));
+    ASSERT_FALSE(anyOf(
+        map(invalidAsciiChars, [](auto input) { return ExtUtf8Char4{static_cast<utf8>(input)}; }),
+        ext_lib_char4_is_punctuation));
+
+    ASSERT_TRUE(allOf(
+        map(punctuationChars, [](auto input) { return ExtUtf8Char4{static_cast<utf8>(input)}; }),
+        ext_lib_char4_is_punctuation));
+    ASSERT_FALSE(anyOf(
+        map(nonPunctuationChars, [](auto input) { return ExtUtf8Char4{static_cast<utf8>(input)}; }),
+        ext_lib_char4_is_punctuation));
+    ASSERT_FALSE(anyOf(
+        map(invalidAsciiChars, [](auto input) { return ExtUtf8Char4{static_cast<utf8>(input)}; }),
+        ext_lib_char4_is_punctuation));
+
+    Utf8 utf8{invalidAscii};
+    bool isAscii = false;
+    ASSERT_EQ(ext_lib_utf8_is_punctuation(nullptr, nullptr), ExtNullPointer);
+    ASSERT_EQ(ext_lib_utf8_is_punctuation(&utf8, nullptr), ExtNullPointer);
+    ASSERT_EQ(ext_lib_utf8_is_punctuation(nullptr, &isAscii), ExtNullPointer);
+    ASSERT_EQ(ext_lib_utf8_is_punctuation(&utf8, &isAscii), ExtInvalidInput);
+    ASSERT_FALSE(isAscii);
+
+    ASSERT_TRUE(allOf(
+        map(punctuationChars,
+            [](char letter) { return FudUtf8::makeUtf8(ExtUtf8Char4{static_cast<utf8>(letter)}); }),
+        [](auto& utf8Letter) {
+            bool predicate = false;
+            auto isPredicateStatus = ext_lib_utf8_is_punctuation(&utf8Letter, &predicate);
+            return isPredicateStatus == ExtSuccess && predicate;
+        }));
+    ASSERT_FALSE(anyOf(
+        map(nonPunctuationChars,
+            [](char letter) { return FudUtf8::makeUtf8(ExtUtf8Char4{static_cast<utf8>(letter)}); }),
+        [](auto& utf8Letter) {
+            bool predicate = false;
+            auto isPredicateStatus = ext_lib_utf8_is_punctuation(&utf8Letter, &predicate);
+            return isPredicateStatus != ExtSuccess || predicate;
+        }));
+    ASSERT_FALSE(allOf(
+        map(nonPunctuationChars,
+            [](char letter) { return FudUtf8::makeUtf8(ExtUtf8Char4{static_cast<utf8>(letter)}); }),
+        [](auto& utf8Letter) {
+            bool predicate = false;
+            auto isPredicateStatus = ext_lib_utf8_is_punctuation(&utf8Letter, &predicate);
+            return isPredicateStatus == ExtInvalidInput && !predicate;
+        }));
+}
+#endif
+
+} // namespace fud