AK: Add formatter for boolean values.

AK/Format.cpp

@@ -460,6 +460,17 @@ void Formatter<T, typename EnableIf<IsIntegral<T>::value>::Type>::format(StringB
         PrintfImplementation::convert_signed_to_string(value, builder, base, m_alternative_form, upper_case, m_zero_pad, align, width, m_fill, sign_mode);
 }
 
+void Formatter<bool>::format(StringBuilder& builder, bool value, FormatterContext& context)
+{
+    if (m_mode == Mode::Binary || m_mode == Mode::BinaryUppercase || m_mode == Mode::Decimal || m_mode == Mode::Octal || m_mode == Mode::Hexadecimal || m_mode == Mode::HexadecimalUppercase) {
+        Formatter<u8> formatter { *this };
+        return formatter.format(builder, static_cast<u8>(value), context);
+    } else {
+        Formatter<StringView> formatter { *this };
+        formatter.format(builder, value ? "true" : "false", context);
+    }
+}
+
 template struct Formatter<unsigned char, void>;
 template struct Formatter<unsigned short, void>;
 template struct Formatter<unsigned int, void>;

AK/Format.h

@@ -166,6 +166,12 @@ struct StandardFormatter {
 
 template<>
 struct Formatter<StringView> : StandardFormatter {
+    Formatter() { }
+    explicit Formatter(StandardFormatter formatter)
+        : StandardFormatter(formatter)
+    {
+    }
+
     void format(StringBuilder& builder, StringView value, FormatterContext&);
 };
 template<>
@@ -183,9 +189,20 @@ struct Formatter<String> : Formatter<StringView> {
 
 template<typename T>
 struct Formatter<T, typename EnableIf<IsIntegral<T>::value>::Type> : StandardFormatter {
+    Formatter() { }
+    explicit Formatter(StandardFormatter formatter)
+        : StandardFormatter(formatter)
+    {
+    }
+
     void format(StringBuilder&, T value, FormatterContext&);
 };
 
+template<>
+struct Formatter<bool> : StandardFormatter {
+    void format(StringBuilder&, bool value, FormatterContext&);
+};
+
 template<typename... Parameters>
 Array<TypeErasedParameter, sizeof...(Parameters)> make_type_erased_parameters(const Parameters&... parameters)
 {

AK/Tests/TestFormat.cpp

@@ -136,4 +136,15 @@ TEST_CASE(cast_integer_to_character)
     EXPECT_EQ(String::formatted("{:c}", static_cast<unsigned int>('f')), "f");
 }
 
+TEST_CASE(boolean_values)
+{
+    EXPECT_EQ(String::formatted("{}", true), "true");
+    EXPECT_EQ(String::formatted("{}", false), "false");
+    EXPECT_EQ(String::formatted("{:6}", true), "true  ");
+    EXPECT_EQ(String::formatted("{:>4}", false), "false");
+    EXPECT_EQ(String::formatted("{:d}", false), "0");
+    EXPECT_EQ(String::formatted("{:d}", true), "1");
+    EXPECT_EQ(String::formatted("{:#08x}", true), "0x000001");
+}
+
 TEST_MAIN(Format)