kstd/string: simplify comparisons

2 files changed, 69 insertions, 80 deletions

diff --git a/libs/kstd/kstd/string b/libs/kstd/kstd/string
index e228a04..9343b42 100644
--- a/libs/kstd/kstd/string
+++ b/libs/kstd/kstd/string
@@ -9,6 +9,7 @@
 #include <kstd/vector>
 
 #include <algorithm>
+#include <compare>
 #include <concepts>
 #include <cstddef>
 #include <string_view>
@@ -52,7 +53,7 @@ namespace kstd
      * @brief Constructs a string from a string view by copying the characters into owned storage.
      * @param view The string view to copy the characters from.
      */
-    string(std::string_view view)
+    explicit string(std::string_view view)
         : string()
     {
       append(view);
@@ -101,6 +102,26 @@ namespace kstd
      */
     constexpr auto operator=(string const & other) -> string & = default;
 
+    constexpr auto operator=(std::string_view const & other) -> string &
+    {
+      clear();
+      append(other);
+      return *this;
+    }
+
+    constexpr auto operator=(char const * other) -> string &
+    {
+      clear();
+      append(std::string_view{other});
+      return *this;
+    }
+
+    //! Create a string view from this string.
+    constexpr operator std::string_view() const noexcept
+    {
+      return {data(), size()};
+    }
+
     /**
      * @brief Returns the number of characters in this string, not including the null terminator.
      */
@@ -224,6 +245,7 @@ namespace kstd
     {
       if (!view.empty())
       {
+        m_storage.reserve(size() + view.size() + 1);
         std::ranges::for_each(view, [this](auto const ch) { push_back(ch); });
       }
 
@@ -237,7 +259,7 @@ namespace kstd
      */
     constexpr auto append(string const & other) -> string &
     {
-      return append(other.view());
+      return append(static_cast<std::string_view>(other));
     }
 
     /**
@@ -261,12 +283,29 @@ namespace kstd
       return *this;
     }
 
-    /**
-     * @brief Returns a string view of this string, which is a non-owning view into the characters of this string.
-     */
-    [[nodiscard]] constexpr auto view() const noexcept -> std::string_view
+    //! Compare this string lexicographically to another string.
+    //!
+    //! @param other The string to compare to this one.
+    [[nodiscard]] constexpr auto operator<=>(string const & other) const noexcept -> std::strong_ordering = default;
+
+    [[nodiscard]] constexpr auto operator==(string const & other) const noexcept -> bool = default;
+
+    //! Compare this string lexicographically to a C-style string.
+    //!
+    //! @param other The C-style string to compare to this one.
+    //! @return The result of the comparison.
+    [[nodiscard]] constexpr auto operator<=>(char const * other) const noexcept
+    {
+      return static_cast<std::string_view>(*this) <=> other;
+    }
+
+    //! Check if this string compares equal to a C-style string.
+    //!
+    //! @param other The C-style string to compare to this one.
+    //! @return @p true iff. this string compares equal to @p other, @p false otherwise.
+    [[nodiscard]] constexpr auto operator==(char const * other) const noexcept -> bool
     {
-      return std::string_view{data(), size()};
+      return static_cast<std::string_view>(*this) == other;
     }
 
   private:
@@ -316,62 +355,12 @@ namespace kstd
     return result;
   }
 
-  [[nodiscard]] constexpr auto inline operator==(string const & lhs, string const & rhs) -> bool
-  {
-    return lhs.view() == rhs.view();
-  }
-
-  [[nodiscard]] constexpr auto inline operator!=(string const & lhs, string const & rhs) -> bool
-  {
-    return !(lhs == rhs);
-  }
-
-  [[nodiscard]] constexpr auto inline operator==(string const & lhs, std::string_view rhs) -> bool
-  {
-    return lhs.view() == rhs;
-  }
-
-  [[nodiscard]] constexpr auto inline operator!=(string const & lhs, std::string_view rhs) -> bool
-  {
-    return !(lhs == rhs);
-  }
-
-  [[nodiscard]] constexpr auto inline operator==(std::string_view lhs, string const & rhs) -> bool
-  {
-    return lhs == rhs.view();
-  }
-
-  [[nodiscard]] constexpr auto inline operator!=(std::string_view lhs, string const & rhs) -> bool
-  {
-    return !(lhs == rhs);
-  }
-
-  [[nodiscard]] constexpr auto inline operator==(string const & lhs, char const * rhs) -> bool
-  {
-    return lhs.view() == std::string_view{rhs};
-  }
-
-  [[nodiscard]] constexpr auto inline operator!=(string const & lhs, char const * rhs) -> bool
-  {
-    return !(lhs == rhs);
-  }
-
-  [[nodiscard]] constexpr auto inline operator==(char const * lhs, string const & rhs) -> bool
-  {
-    return std::string_view{lhs} == rhs.view();
-  }
-
-  [[nodiscard]] constexpr auto inline operator!=(char const * lhs, string const & rhs) -> bool
-  {
-    return !(lhs == rhs);
-  }
-
   template<>
   struct formatter<string> : formatter<std::string_view>
   {
     auto format(string const & str, format_context & context) const -> void
     {
-      formatter<std::string_view>::format(str.view(), context);
+      formatter<std::string_view>::format(static_cast<std::string_view>(str), context);
     }
   };
 
diff --git a/libs/kstd/kstd/string.test.cpp b/libs/kstd/kstd/string.test.cpp
index 9755676..b81cd3a 100644
--- a/libs/kstd/kstd/string.test.cpp
+++ b/libs/kstd/kstd/string.test.cpp
@@ -22,7 +22,7 @@ SCENARIO("String initialization and construction", "[string]")
 
       THEN("the string is empty")
       {
-        REQUIRE(str.view() == std::string_view{});
+        REQUIRE(str == std::string_view{});
       }
     }
   }
@@ -43,7 +43,7 @@ SCENARIO("String initialization and construction", "[string]")
 
       THEN("the string contains the same characters as the view")
       {
-        REQUIRE(str.view() == view);
+        REQUIRE(str == view);
       }
     }
   }
@@ -64,7 +64,7 @@ SCENARIO("String initialization and construction", "[string]")
 
       THEN("the string contains the same characters as the C-style string")
       {
-        REQUIRE(str.view() == c_str);
+        REQUIRE(str == c_str);
       }
     }
   }
@@ -85,7 +85,7 @@ SCENARIO("String initialization and construction", "[string]")
 
       THEN("the string contains the same character as the given character")
       {
-        REQUIRE(str.view() == std::string_view{&ch, 1});
+        REQUIRE(str == std::string_view{&ch, 1});
       }
     }
   }
@@ -100,7 +100,7 @@ SCENARIO("String initialization and construction", "[string]")
 
       THEN("the new string contains the same characters as the original")
       {
-        REQUIRE(str.view() == other.view());
+        REQUIRE(static_cast<std::string_view>(str) == static_cast<std::string_view>(other));
       }
     }
 
@@ -113,7 +113,7 @@ SCENARIO("String initialization and construction", "[string]")
 
       THEN("the string contains the same characters as the assigned string")
       {
-        REQUIRE(str.view() == other.view());
+        REQUIRE(static_cast<std::string_view>(str) == static_cast<std::string_view>(other));
       }
     }
   }
@@ -129,7 +129,7 @@ SCENARIO("String initialization and construction", "[string]")
 
       THEN("the string contains the same characters as the assigned view")
       {
-        REQUIRE(str.view() == view);
+        REQUIRE(str == view);
       }
     }
   }
@@ -145,7 +145,7 @@ SCENARIO("String initialization and construction", "[string]")
 
       THEN("the string contains the same characters as the assigned C-style string")
       {
-        REQUIRE(str.view() == c_str);
+        REQUIRE(str == c_str);
       }
     }
   }
@@ -164,7 +164,7 @@ SCENARIO("String concatenation", "[string]")
 
       THEN("the first string contains the characters of both strings concatenated")
       {
-        REQUIRE(str1.view() == "Blub Blub");
+        REQUIRE(str1 == "Blub Blub");
       }
 
       THEN("the size of the first string is the sum of the sizes of both strings")
@@ -179,7 +179,7 @@ SCENARIO("String concatenation", "[string]")
 
       THEN("the first string contains the characters of both strings concatenated")
       {
-        REQUIRE(str1.view() == "Blub Blub");
+        REQUIRE(str1 == "Blub Blub");
       }
 
       THEN("the size of the first string is the sum of the sizes of both strings")
@@ -194,7 +194,7 @@ SCENARIO("String concatenation", "[string]")
 
       THEN("the new string contains the characters of both strings concatenated")
       {
-        REQUIRE(str3.view() == "Blub Blub");
+        REQUIRE(str3 == "Blub Blub");
       }
 
       THEN("the size of the new string is the sum of the sizes of both strings")
@@ -215,7 +215,7 @@ SCENARIO("String concatenation", "[string]")
 
       THEN("the string contains the characters of both the original string and the appended view concatenated")
       {
-        REQUIRE(str.view() == "Blub Blub");
+        REQUIRE(str == "Blub Blub");
       }
 
       THEN("the size of the string is the sum of the sizes of the original string and the appended view")
@@ -236,7 +236,7 @@ SCENARIO("String concatenation", "[string]")
 
       THEN("the string contains the original characters followed by the appended character")
       {
-        REQUIRE(str.view() == "Blub!");
+        REQUIRE(str == "Blub!");
       }
 
       THEN("the size of the string is one more than the original size")
@@ -251,7 +251,7 @@ SCENARIO("String concatenation", "[string]")
 
       THEN("the string contains the original characters followed by the appended character")
       {
-        REQUIRE(str.view() == "Blub!");
+        REQUIRE(str == "Blub!");
       }
 
       THEN("the size of the string is one more than the original size")
@@ -276,8 +276,8 @@ SCENARIO("String conversion and comparison", "[string]")
 
       THEN("the string contains the decimal representation of the unsigned integer")
       {
-        REQUIRE(str1.view() == "12345");
-        REQUIRE(str2.view() == "0");
+        REQUIRE(str1 == "12345");
+        REQUIRE(str2 == "0");
       }
     }
   }
@@ -335,7 +335,7 @@ SCENARIO("String clearing", "[string]")
 
       THEN("the string contains no characters")
       {
-        REQUIRE(str.view() == std::string_view{});
+        REQUIRE(str == std::string_view{});
       }
     }
   }
@@ -351,7 +351,7 @@ SCENARIO("String iteration", "[string]")
     {
       kstd::string result;
 
-      for (auto ch : str.view())
+      for (auto ch : static_cast<std::string_view>(str))
       {
         result.push_back(ch);
       }
@@ -396,14 +396,14 @@ SCENARIO("String iteration", "[string]")
     {
       kstd::string result;
 
-      for (auto ch : str.view())
+      for (auto ch : static_cast<std::string_view>(str))
       {
         result.push_back(ch);
       }
 
       THEN("the iterated characters are the same as the characters in the string")
       {
-        REQUIRE(result == str.view());
+        REQUIRE(result == static_cast<std::string_view>(str));
       }
     }
 
@@ -429,7 +429,7 @@ SCENARIO("String iteration", "[string]")
     {
       kstd::string result;
 
-      for (auto ch : str.view())
+      for (auto ch : static_cast<std::string_view>(str))
       {
         result.push_back(ch);
       }
@@ -438,7 +438,7 @@ SCENARIO("String iteration", "[string]")
       {
         REQUIRE(result.empty());
         REQUIRE(result.size() == 0);
-        REQUIRE(result.view() == std::string_view{});
+        REQUIRE(static_cast<std::string_view>(result) == std::string_view{});
       }
     }
   }