diff --git a/.envrc b/.envrc
new file mode 100644
index 0000000..1fe685f
--- /dev/null
+++ b/.envrc
@@ -0,0 +1,3 @@
+use guix
+dotenv
+export C_INCLUDE_PATH="$PWD/include:$HOME/src/mruby/include:$C_INCLUDE_PATH"
diff --git a/.github/workflows/doc.yml b/.github/workflows/doc.yml
new file mode 100644
index 0000000..6e1f0b1
--- /dev/null
+++ b/.github/workflows/doc.yml
@@ -0,0 +1,37 @@
+name: Build and deploy Doxygen to GitHub Pages
+on:
+  push:
+    branches: [ "main" ]
+  pull_request:
+  workflow_dispatch:
+
+jobs:
+  build-and-deploy:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Install Doxygen and Graphviz
+        run: sudo apt-get update && sudo apt-get install -y doxygen graphviz
+
+      - name: Run Doxygen
+        run: doxygen Doxyfile
+
+      - name: Upload Pages artifact
+        uses: actions/upload-pages-artifact@v3
+        with:
+          path: doc/html
+
+  deploy:
+    needs: build-and-deploy
+    runs-on: ubuntu-latest
+    steps:
+      - name: Deploy to GitHub Pages
+        uses: actions/deploy-pages@v4
+    permissions:
+      id-token: write
+      pages: write
+    environment:
+      name: github-pages
+      url: ${{ steps.deployment.outputs.page_url }}
diff --git a/Doxyfile b/Doxyfile
index c0a50ed..e5e00c8 100644
--- a/Doxyfile
+++ b/Doxyfile
@@ -2349,7 +2349,7 @@ ENABLE_PREPROCESSING   = YES
 # The default value is: NO.
 # This tag requires that the tag ENABLE_PREPROCESSING is set to YES.
 
-MACRO_EXPANSION        = NO
+MACRO_EXPANSION        = YES
 
 # If the EXPAND_ONLY_PREDEF and MACRO_EXPANSION tags are both set to YES then
 # the macro expansion is limited to the macros specified with the PREDEFINED and
@@ -2390,7 +2390,7 @@ INCLUDE_FILE_PATTERNS  =
 # recursively expanded use the := operator instead of the = operator.
 # This tag requires that the tag ENABLE_PREPROCESSING is set to YES.
 
-PREDEFINED             =
+PREDEFINED             = HAVE_URI_HAS_HOST
 
 # If the MACRO_EXPANSION and EXPAND_ONLY_PREDEF tags are set to YES then this
 # tag can be used to specify a list of macro names that should be expanded. The
diff --git a/TODO.org b/TODO.org
new file mode 100644
index 0000000..ebb42fe
--- /dev/null
+++ b/TODO.org
@@ -0,0 +1,64 @@
+* URIParserモジュール
+** ClassMethodsモジュール
+*** splitメソッド
+#+begin_src ruby
+      def split(uri)
+        uri = parse(uri)
+      
+        # TODO: Support registry, path, and opaque
+        [uri.scheme, uri.userinfo,
+         nil, # host
+         uri.port,
+         nil, # registry
+         nil, # path
+         nil, # opaque
+         uri.query, uri.fragment]
+      end
+#+end_src
+** URIクラス
+*** hierarchical?メソッド
+#+begin_src ruby
+      def hierarchical?
+        path ? true : false
+      end
+#+end_src
+* Guixパッケージ
+#+begin_src scheme
+  (define-public ruby-yard-mruby
+    (package
+      (name "ruby-yard-mruby")
+      (version "0.3.0")
+      (source
+       (origin
+         (method url-fetch)
+         (uri (rubygems-uri "yard-mruby" version))
+         (sha256
+          (base32 "1vv4s9lv0bif1xcn12yavr05adpj41y0xkrvwzza9rxxr3jz6l7r"))))
+      (build-system ruby-build-system)
+      (arguments (list #:test-target "spec"))
+      (native-inputs (list ruby-rspec))
+      (propagated-inputs (list ruby-yard))
+      (synopsis "Generate Yard documentation for MRuby projects.")
+      (description "Generate Yard documentation for MRuby projects.")
+      (home-page "https://github.com/sagmor/yard-mruby")
+      (license license:expat)))
+
+  (define-public ruby-yard-coderay
+    (package
+      (name "ruby-yard-coderay")
+      (version "0.1.0")
+      (source
+       (origin
+         (method url-fetch)
+         (uri (rubygems-uri "yard-coderay" version))
+         (sha256
+          (base32 "0gqn2m83vxvp579malqi1jhkh0xcwpbz9190qr64zwbiljp5kfrq"))))
+      (build-system ruby-build-system)
+      (arguments (list #:test-target "spec"))
+      (native-inputs (list ruby-rspec))
+      (propagated-inputs (list ruby-coderay ruby-yard))
+      (synopsis "Add's coderay syntax highlighting to YARD docs")
+      (description "Add's coderay syntax highlighting to YARD docs.")
+      (home-page "https://github.com/sagmor/yard-coderay")
+      (license license:expat)))
+#+end_src
diff --git a/build/check_uri_copy_uri.c b/build/check_uri_copy_uri.c
new file mode 100644
index 0000000..5bc27a4
--- /dev/null
+++ b/build/check_uri_copy_uri.c
@@ -0,0 +1,2 @@
+#include <uriparser/Uri.h>
+int main(void) { uriCopyUriA(NULL, NULL); }
diff --git a/build/check_uri_equals_uri.c b/build/check_uri_equals_uri.c
new file mode 100644
index 0000000..f31673a
--- /dev/null
+++ b/build/check_uri_equals_uri.c
@@ -0,0 +1,2 @@
+#include <uriparser/Uri.h>
+int main(void) { uriEqualsUriA(NULL, NULL); }
diff --git a/build/check_uri_has_host.c b/build/check_uri_has_host.c
new file mode 100644
index 0000000..354e05f
--- /dev/null
+++ b/build/check_uri_has_host.c
@@ -0,0 +1,2 @@
+#include <uriparser/Uri.h>
+int main(void) { uriHasHostA(NULL); }
diff --git a/build/check_uri_set_fragment.c b/build/check_uri_set_fragment.c
new file mode 100644
index 0000000..404c5c7
--- /dev/null
+++ b/build/check_uri_set_fragment.c
@@ -0,0 +1,2 @@
+#include <uriparser/Uri.h>
+int main(void) { uriSetFragmentA(NULL, NULL, NULL); }
diff --git a/build/check_uri_set_host.c b/build/check_uri_set_host.c
new file mode 100644
index 0000000..37da0bb
--- /dev/null
+++ b/build/check_uri_set_host.c
@@ -0,0 +1,2 @@
+#include <uriparser/Uri.h>
+int main(void) { uriSetHostAutoA(NULL, NULL, NULL); }
diff --git a/build/check_uri_set_path.c b/build/check_uri_set_path.c
new file mode 100644
index 0000000..7aa46df
--- /dev/null
+++ b/build/check_uri_set_path.c
@@ -0,0 +1,2 @@
+#include <uriparser/Uri.h>
+int main(void) { uriSetPathA(NULL, NULL, NULL); }
diff --git a/build/check_uri_set_port.c b/build/check_uri_set_port.c
new file mode 100644
index 0000000..b5901b0
--- /dev/null
+++ b/build/check_uri_set_port.c
@@ -0,0 +1,2 @@
+#include <uriparser/Uri.h>
+int main(void) { uriSetPortTextA(NULL, NULL, NULL); }
diff --git a/build/check_uri_set_query.c b/build/check_uri_set_query.c
new file mode 100644
index 0000000..c3a56fe
--- /dev/null
+++ b/build/check_uri_set_query.c
@@ -0,0 +1,2 @@
+#include <uriparser/Uri.h>
+int main(void) { uriSetQueryA(NULL, NULL, NULL); }
diff --git a/build/check_uri_set_scheme.c b/build/check_uri_set_scheme.c
new file mode 100644
index 0000000..c2953ed
--- /dev/null
+++ b/build/check_uri_set_scheme.c
@@ -0,0 +1,2 @@
+#include <uriparser/Uri.h>
+int main(void) { uriSetSchemeA(NULL, NULL, NULL); }
diff --git a/build/check_uri_set_userinfo.c b/build/check_uri_set_userinfo.c
new file mode 100644
index 0000000..4e31211
--- /dev/null
+++ b/build/check_uri_set_userinfo.c
@@ -0,0 +1,2 @@
+#include <uriparser/Uri.h>
+int main(void) { uriSetUserInfoA(NULL, NULL, NULL); }
diff --git a/build_config.rb b/build_config.rb
index e3f5b0f..528670b 100644
--- a/build_config.rb
+++ b/build_config.rb
@@ -1,3 +1,32 @@
+require "tmpdir"
+require "shellwords"
+require "open3"
+
+def check_function(name:, checker:, macro:, conf:)
+  Dir.mktmpdir("mruby_check_") do |tmpdir|
+    exe = File.join(tmpdir, "check_#{name}")
+    command = [conf.cc.command,
+               *conf.cc.flags.flatten,
+               "-l", "uriparser",
+               '-o', exe,
+               File.join(__dir__, "build/#{checker}")]
+    output, status = Open3.capture2e(ENV, *command)
+    puts "status: #{status}"
+    output.strip!
+    if output
+      puts ">>> output >>>"
+      puts output
+      puts "<<< output <<<"
+    end
+    if status.success?
+      conf.defines << macro
+      puts "found #{name}"
+    else
+      warn "not found #{name}"
+    end
+  end
+end
+
 MRuby::Build.new do |conf|
   toolchain :gcc
   conf.gem File.expand_path(File.dirname(__FILE__))
@@ -5,9 +34,51 @@
 
   conf.linker.libraries << 'uriparser'
 
+  check_function(name: "uriHasHostA",
+                 checker: "check_uri_has_host.c",
+                 macro: "HAVE_URI_HAS_HOST",
+                 conf:)
+  check_function(name: "uriCopyUriA",
+                 checker: "check_uri_copy_uri.c",
+                 macro: "HAVE_URI_COPY_URI",
+                 conf:)
+  check_function(name: "uriEqualsUriA",
+                 checker: "check_uri_equals_uri.c",
+                 macro: "HAVE_URI_EQUALS_URI",
+                 conf:)
+  check_function(name: "uriSetSchemeA",
+                 checker: "check_uri_set_scheme.c",
+                 macro: "HAVE_URI_SET_SCHEME",
+                 conf:)
+  check_function(name: "uriSetUserInfoA",
+                 checker: "check_uri_set_userinfo.c",
+                 macro: "HAVE_URI_SET_USERINFO",
+                 conf:)
+  check_function(name: "uriSetHostAutoA",
+                 checker: "check_uri_set_host.c",
+                 macro: "HAVE_URI_SET_HOST",
+                 conf:)
+  check_function(name: "uriSetPortTextA",
+                 checker: "check_uri_set_port.c",
+                 macro: "HAVE_URI_SET_PORT",
+                 conf:)
+  check_function(name: "uriSetPathA",
+                 checker: "check_uri_set_path.c",
+                 macro: "HAVE_URI_SET_PATH",
+                 conf:)
+  check_function(name: "uriSetQueryA",
+                 checker: "check_uri_set_query.c",
+                 macro: "HAVE_URI_SET_QUERY",
+                 conf:)
+  check_function(name: "uriSetFragmentA",
+                 checker: "check_uri_set_fragment.c",
+                 macro: "HAVE_URI_SET_FRAGMENT",
+                 conf:)
+
   if ENV['DEBUG'] == 'true'
     conf.enable_debug
-    conf.cc.defines = %w(MRB_ENABLE_DEBUG_HOOK)
+    conf.defines << "MRB_ENABLE_DEBUG_HOOK"
     conf.gem core: 'mruby-bin-debugger'
+    conf.gem core: 'mruby-bin-mirb'
   end
 end
diff --git a/manifest.scm b/manifest.scm
new file mode 100644
index 0000000..b9496aa
--- /dev/null
+++ b/manifest.scm
@@ -0,0 +1,8 @@
+(use-modules (guix profiles)
+             (gnu packages commencement)
+             (gnu packages web)
+             (gnu packages documentation))
+
+(packages->manifest (list gcc-toolchain
+                          uriparser
+                          doxygen))
diff --git a/mrblib/mrb_uriparser.rb b/mrblib/mrb_uriparser.rb
index 2591431..1117f42 100644
--- a/mrblib/mrb_uriparser.rb
+++ b/mrblib/mrb_uriparser.rb
@@ -21,20 +21,6 @@ def join(uri_str, *path)
       # TODO: Remove parsing each path after implement accepting URI by merge methods.
       path.reduce(URIParser.parse(uri_str)) { |memo, pat| memo.merge!(URIParser.parse(pat)) }
     end
-
-    # TODO: Implement this.
-    def split(uri)
-      uri = parse(uri)
-
-      # TODO: Support registry, path, and opaque
-      [uri.scheme, uri.userinfo,
-       nil, # host
-       uri.port,
-       nil, # registry
-       nil, # path
-       nil, # opaque
-       uri.query, uri.fragment]
-    end
   end
 
   class << self
@@ -70,11 +56,6 @@ def to_filename(windows: false)
       URIParser.uri_string_to_filename(to_s, windows:)
     end
 
-    # TODO: Implement path.
-    def hierarchical?
-      path ? true : false
-    end
-
     def relative?
       !absolute?
     end
diff --git a/build b/run-all
similarity index 100%
rename from build
rename to run-all
diff --git a/src/mrb_uriparser.c b/src/mrb_uriparser.c
index c6e3a72..2bdbf99 100644
--- a/src/mrb_uriparser.c
+++ b/src/mrb_uriparser.c
@@ -38,12 +38,12 @@
  * it under the terms of the GNU General Public License as published by
  * the Free Software Foundation, either version 3 of the License, or
  * (at your option) any later version.
-
+ *
  * This program is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU General Public License for more details.
-
+ *
  * You should have received a copy of the GNU General Public License
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
@@ -145,7 +145,8 @@ static mrb_value mrb_uriparser_new(mrb_state *const mrb, UriUriA *uri) {
  * URIParser::URI.parse(str)
  * ```
  *
- * @param str URI string to parse.
+ * where `str` is a URI string to parse.
+ *
  * @return `URIParser::URI` instance.
  * @sa mrb_uriparser_recompose
  */
@@ -177,8 +178,9 @@ static mrb_value mrb_uriparser_parse(mrb_state *const mrb,
  * URIParser::URI.from_filename(filename, windows: false)
  * ```
  *
- * @param filename Absolute filename.
- * @param windows  If true, use Windows path conversion.
+ * where `filename` is an absolute filename.  If `windows` is true, use
+ * Windows path conversion.
+ *
  * @return URI string.
  * @sa mrb_uriparser_uri_string_to_filename
  */
@@ -216,13 +218,17 @@ static mrb_value mrb_uriparser_filename_to_uri_string(mrb_state *const mrb,
  *
  * ```ruby
  * URIParser.uri_string_to_filename(uri, windows: false)
+ * ```
+ *
+ * where `uri` is a URI string.  If `windows` is true, use Windows path
+ * conversion.
+ *
+ * ```ruby
  * uri.to_filename(windows: false)
  * ```
  *
  * where `uri` is kind of `URIParser::URI`.
  *
- * @param uri URI string.
- * @param windows If `true`, use Windows path conversion.
  * @return Filename string.
  * @sa mrb_uriparser_filename_to_uri_string
  */
@@ -261,8 +267,8 @@ static mrb_value mrb_uriparser_uri_string_to_filename(mrb_state *const mrb,
  * URIParser.encode_www_form(query_list)
  * ```
  *
- * @param query_list Array of `[key, value]` pairs.  Key is `String`.  Value
- * may be `nil` or `String`.
+ * where `query_list` is `Array` of `[key, value]` pairs.  Key is `String`.
+ * Value may be `nil` or `String`.
  *
  * @return Encoded query string.
  * @sa mrb_uriparser_dissect_query
@@ -302,6 +308,56 @@ static mrb_value mrb_uriparser_compose_query(mrb_state *const mrb,
   return str;
 }
 
+#ifdef HAVE_URI_COPY_URI
+/**
+ * @brief Copy URI.
+ *
+ * ```ruby
+ * uri.dup
+ * uri.clone
+ * ```
+ *
+ * where `uri` is a `URIParser::URI` instance.
+ *
+ * @return New URI.
+ */
+static mrb_value mrb_uriparser_initialize_copy(mrb_state *mrb, mrb_value self) {
+  mrb_value original;
+  mrb_get_args(mrb, "o", &original);
+  UriUriA *uri = MRB_URIPARSER_URI(original);
+  UriUriA *new_uri = mrb_malloc(mrb, sizeof(UriUriA));
+  if (uriCopyUriA(new_uri, uri)) {
+    MRB_URIPARSER_RAISE(mrb, "failed to copy URI");
+  }
+  DATA_TYPE(self) = &mrb_uriparser_data_type;
+  mrb_uriparser_data *data = mrb_malloc(mrb, sizeof(mrb_uriparser_data));
+  data->uri = new_uri;
+  DATA_PTR(self) = data;
+  return self;
+}
+#endif
+
+#ifdef HAVE_URI_EQUALS_URI
+/**
+ * @brief Check two URIs for equivalence.
+ *
+ * ```ruby
+ * uri == another_uri
+ * ```
+ *
+ * where `uri` and `another_uri` are `URIParser::URI` instances.
+ *
+ * @return Boolean.
+ */
+static mrb_value mrb_uriparser_equals(mrb_state *mrb, mrb_value self) {
+  mrb_value another;
+  mrb_get_args(mrb, "o", &another);
+  UriBool result =
+      uriEqualsUriA(MRB_URIPARSER_URI(self), MRB_URIPARSER_URI(another));
+  return mrb_bool_value(result);
+}
+#endif
+
 /**
  * @brief Get the scheme component of the URI.
  *
@@ -309,7 +365,8 @@ static mrb_value mrb_uriparser_compose_query(mrb_state *const mrb,
  * uri.scheme
  * ```
  *
- * @param self `URIParser::URI` instance.
+ * where `uri` is a `URIParser::URI` instance.
+ *
  * @return Scheme string or `nil`.
  */
 static mrb_value mrb_uriparser_scheme(mrb_state *const mrb,
@@ -317,6 +374,27 @@ static mrb_value mrb_uriparser_scheme(mrb_state *const mrb,
   return MRB_URIPARSER_STR_IN_RANGE(mrb, MRB_URIPARSER_URI(self), scheme);
 }
 
+#ifdef HAVE_URI_SET_SCHEME
+/**
+ * @brief Set the scheme component of the URI.
+ * ```ruby
+ * uri.scheme = ...
+ * ```
+ *
+ * where `uri` is a `URIParser::URI` instance.
+ *
+ * @return `nil`.
+ */
+static mrb_value mrb_uriparser_set_scheme(mrb_state *mrb, mrb_value self) {
+  char *component;
+  mrb_get_args(mrb, "z", &component);
+  if (uriSetSchemeA(MRB_URIPARSER_URI(self), component,
+                    component + strlen(component)))
+    MRB_URIPARSER_RAISE(mrb, "failed to set scheme");
+  return mrb_nil_value();
+}
+#endif
+
 /**
  * @brief Get the userinfo component of the URI.
  *
@@ -324,7 +402,8 @@ static mrb_value mrb_uriparser_scheme(mrb_state *const mrb,
  * uri.userinfo
  * ```
  *
- * @param self `URIParser::URI` instance.
+ * where `uri` is a `URIParser::URI` instance.
+ *
  * @return Userinfo string or `nil`.
  */
 static mrb_value mrb_uriparser_userinfo(mrb_state *const mrb,
@@ -332,6 +411,27 @@ static mrb_value mrb_uriparser_userinfo(mrb_state *const mrb,
   return MRB_URIPARSER_STR_IN_RANGE(mrb, MRB_URIPARSER_URI(self), userInfo);
 }
 
+#ifdef HAVE_URI_SET_USERINFO
+/**
+ * @brief Set the userinfo component of the URI.
+ * ```ruby
+ * uri.userinfo = ...
+ * ```
+ *
+ * where `uri` is a `URIParser::URI` instance.
+ *
+ * @return `nil`.
+ */
+static mrb_value mrb_uriparser_set_userinfo(mrb_state *mrb, mrb_value self) {
+  char *component;
+  mrb_get_args(mrb, "z", &component);
+  if (uriSetUserInfoA(MRB_URIPARSER_URI(self), component,
+                      component + strlen(component)))
+    MRB_URIPARSER_RAISE(mrb, "failed to set userinfo");
+  return mrb_nil_value();
+}
+#endif
+
 /**
  * @brief Get the hostname component of the URI.
  *
@@ -339,7 +439,8 @@ static mrb_value mrb_uriparser_userinfo(mrb_state *const mrb,
  * uri.hostname
  * ```
  *
- * @param self `URIParser::URI` instance.
+ * where `uri` is a `URIParser::URI` instance.
+ *
  * @return Hostname string or `nil`.
  *
  * Note that it returns `::1` for `http://[::1]/bar` so it corresponds to
@@ -350,6 +451,44 @@ static mrb_value mrb_uriparser_hostname(mrb_state *const mrb,
   return MRB_URIPARSER_STR_IN_RANGE(mrb, MRB_URIPARSER_URI(self), hostText);
 }
 
+#ifdef HAVE_URI_SET_HOST
+/**
+ * @brief Set the host component of the URI.
+ * ```ruby
+ * uri.host = ...
+ * ```
+ *
+ * where `uri` is a `URIParser::URI` instance.
+ *
+ * @return `nil`.
+ */
+static mrb_value mrb_uriparser_set_host(mrb_state *mrb, mrb_value self) {
+  char *component;
+  mrb_get_args(mrb, "z", &component);
+  if (uriSetHostAutoA(MRB_URIPARSER_URI(self), component,
+                      component + strlen(component)))
+    MRB_URIPARSER_RAISE(mrb, "failed to set host");
+  return mrb_nil_value();
+}
+#endif
+
+#ifdef HAVE_URI_HAS_HOST
+/**
+ * @brief Check if the URI has host.
+ *
+ * ```ruby
+ * uri.host?
+ * ```
+ *
+ * where `uri` is a `URIParser::URI` instance.
+ *
+ * @return Boolean.
+ */
+static mrb_value mrb_uriparser_has_host(mrb_state *mrb, mrb_value self) {
+  return mrb_bool_value(uriHasHostA(MRB_URIPARSER_URI(self)));
+}
+#endif
+
 /**
  * @brief Get the port component of the URI as a string.
  *
@@ -357,7 +496,8 @@ static mrb_value mrb_uriparser_hostname(mrb_state *const mrb,
  * uri.port
  * ```
  *
- * @param self `URIParser::URI` instance.
+ * where `uri` is a `URIParser::URI` instance.
+ *
  * @return Port string or `nil`.
  */
 static mrb_value mrb_uriparser_port(mrb_state *const mrb,
@@ -365,6 +505,27 @@ static mrb_value mrb_uriparser_port(mrb_state *const mrb,
   return MRB_URIPARSER_STR_IN_RANGE(mrb, MRB_URIPARSER_URI(self), portText);
 }
 
+#ifdef HAVE_URI_SET_PORT
+/**
+ * @brief Set the port component of the URI.
+ * ```ruby
+ * uri.port = ...
+ * ```
+ *
+ * where `uri` is a `URIParser::URI` instance.
+ *
+ * @return `nil`.
+ */
+static mrb_value mrb_uriparser_set_port(mrb_state *mrb, mrb_value self) {
+  char *component;
+  mrb_get_args(mrb, "z", &component);
+  if (uriSetPortTextA(MRB_URIPARSER_URI(self), component,
+                      component + strlen(component)))
+    MRB_URIPARSER_RAISE(mrb, "failed to set port");
+  return mrb_nil_value();
+}
+#endif
+
 /**
  * @brief Get the path segments as an array of strings.
  *
@@ -372,7 +533,8 @@ static mrb_value mrb_uriparser_port(mrb_state *const mrb,
  * uri.path_segments
  * ```
  *
- * @param self `URIParser::URI` instance.
+ * where `uri` is a `URIParser::URI` instance.
+ *
  * @return Array of path segment strings.
  */
 static mrb_value mrb_uriparser_path_segments(mrb_state *const mrb,
@@ -386,6 +548,27 @@ static mrb_value mrb_uriparser_path_segments(mrb_state *const mrb,
   return ary;
 }
 
+#ifdef HAVE_URI_SET_PATH
+/**
+ * @brief Set the path component of the URI.
+ * ```ruby
+ * uri.path = ...
+ * ```
+ *
+ * where `uri` is a `URIParser::URI` instance.
+ *
+ * @return `nil`.
+ */
+static mrb_value mrb_uriparser_set_path(mrb_state *mrb, mrb_value self) {
+  char *component;
+  mrb_get_args(mrb, "z", &component);
+  if (uriSetPathA(MRB_URIPARSER_URI(self), component,
+                  component + strlen(component)))
+    MRB_URIPARSER_RAISE(mrb, "failed to set path");
+  return mrb_nil_value();
+}
+#endif
+
 /**
  * @brief Get the query component of the URI.
  *
@@ -393,7 +576,8 @@ static mrb_value mrb_uriparser_path_segments(mrb_state *const mrb,
  * uri.query
  * ```
  *
- * @param self `URIParser::URI` instance.
+ * where `uri` is a `URIParser::URI` instance.
+ *
  * @return Query string or `nil`.
  */
 static mrb_value mrb_uriparser_query(mrb_state *const mrb,
@@ -401,6 +585,27 @@ static mrb_value mrb_uriparser_query(mrb_state *const mrb,
   return MRB_URIPARSER_STR_IN_RANGE(mrb, MRB_URIPARSER_URI(self), query);
 }
 
+#ifdef HAVE_URI_SET_QUERY
+/**
+ * @brief Set the query component of the URI.
+ * ```ruby
+ * uri.query = ...
+ * ```
+ *
+ * where `uri` is a `URIParser::URI` instance.
+ *
+ * @return `nil`.
+ */
+static mrb_value mrb_uriparser_set_query(mrb_state *mrb, mrb_value self) {
+  char *component;
+  mrb_get_args(mrb, "z", &component);
+  if (uriSetQueryA(MRB_URIPARSER_URI(self), component,
+                   component + strlen(component)))
+    MRB_URIPARSER_RAISE(mrb, "failed to set query");
+  return mrb_nil_value();
+}
+#endif
+
 /**
  * @brief Get the fragment component of the URI.
  *
@@ -408,7 +613,8 @@ static mrb_value mrb_uriparser_query(mrb_state *const mrb,
  * uri.fragment
  * ```
  *
- * @param self `URIParser::URI` instance.
+ * where `uri` is a `URIParser::URI` instance.
+ *
  * @return Fragment string or `nil`.
  */
 static mrb_value mrb_uriparser_fragment(mrb_state *const mrb,
@@ -416,6 +622,27 @@ static mrb_value mrb_uriparser_fragment(mrb_state *const mrb,
   return MRB_URIPARSER_STR_IN_RANGE(mrb, MRB_URIPARSER_URI(self), fragment);
 }
 
+#ifdef HAVE_URI_SET_FRAGMENT
+/**
+ * @brief Set the fragment component of the URI.
+ * ```ruby
+ * uri.fragment = ...
+ * ```
+ *
+ * where `uri` is a `URIParser::URI` instance.
+ *
+ * @return `nil`.
+ */
+static mrb_value mrb_uriparser_set_fragment(mrb_state *mrb, mrb_value self) {
+  char *component;
+  mrb_get_args(mrb, "z", &component);
+  if (uriSetFragmentA(MRB_URIPARSER_URI(self), component,
+                      component + strlen(component)))
+    MRB_URIPARSER_RAISE(mrb, "failed to set fragment");
+  return mrb_nil_value();
+}
+#endif
+
 /**
  * @brief Check if the URI has an absolute path.
  *
@@ -426,7 +653,8 @@ static mrb_value mrb_uriparser_fragment(mrb_state *const mrb,
  * uri.relative?
  * ```
  *
- * @param self `URIParser::URI` instance.
+ * where `uri` is a `URIParser::URI` instance.
+ *
  * @return Boolean.
  */
 static mrb_value mrb_uriparser_absolute_path(mrb_state *const mrb,
@@ -441,7 +669,8 @@ static mrb_value mrb_uriparser_absolute_path(mrb_state *const mrb,
  * uri.to_s
  * ```
  *
- * @param self `URIParser::URI` instance.
+ * where `uri` is a `URIParser::URI` instance.
+ *
  * @return URI string.
  * @sa mrb_uriparser_parse
  *
@@ -469,8 +698,9 @@ static mrb_value mrb_uriparser_recompose(mrb_state *const mrb,
  * uri.merge!(rel)
  * ```
  *
- * @param self `URIParser::URI` instance.
- * @param rel Relative URI (`URIParser::URI`).
+ * where `uri` is a `URIParser::URI` instance, and `rel` is relative URI
+ * (`URIParser::URI`).
+ *
  * @return Modified `URIParser::URI` instance.
  * @sa mrb_uriparser_merge
  */
@@ -501,8 +731,9 @@ static mrb_value mrb_uriparser_merge_mutably(mrb_state *const mrb,
  * uri + rel
  * ```
  *
- * @param self `URIParser::URI` instance.
- * @param rel Relative URI (`URIParser::URI`).
+ * where `uri` is a `URIParser::URI` instance, and `rel` is relative URI
+ * (`URIParser::URI`).
+ *
  * @return New resolved `URIParser::URI` instance.
  * @sa mrb_uriparser_merge_mutably
  * @sa mrb_uriparser_create_reference
@@ -533,8 +764,9 @@ static mrb_value mrb_uriparser_merge(mrb_state *const mrb,
  * uri.route_to(dest, domain_root: false)
  * ```
  *
- * @param base Base URI (`URIParser::URI`).
- * @param domain_root If true, reference is from domain root.
+ * where `base` is a base URI (`URIParser::URI`).  If `domain_root` is true,
+ * reference is from domain root.
+ *
  * @return New relative `URIParser::URI` instance.
  * @sa mrb_uriparser_merge
  */
@@ -574,9 +806,10 @@ static mrb_value mrb_uriparser_create_reference(mrb_state *const mrb,
  *                fragment: true)
  * ```
  *
- * @param self `URIParser::URI` instance.
- * @param scheme, userinfo, host, path, query, fragment: Enable normalization
- * for each component.
+ * where `uri` is kind of `URIParser::URI`.  `scheme`, `userinfo`, `host`,
+ * `path`, `query`, `fragment` are for enabling normalization for each
+ * component.
+ *
  * @return Modified `URIParser::URI` instance.
  *
  * By default all parts are normalized.  If path is empty, this
@@ -622,7 +855,8 @@ static mrb_value mrb_uriparser_normalize(mrb_state *const mrb,
  * uri.decode_www_form
  * ```
  *
- * @param self `URIParser::URI` instance.
+ * where `uri` is a `URIParser::URI` instance.
+ *
  * @return Array of `[key, value]` pairs.
  * @sa mrb_uriparser_compose_query
  *
@@ -666,17 +900,52 @@ void mrb_mruby_uriparser_gem_init(mrb_state *const mrb) {
                              mrb_uriparser_compose_query, MRB_ARGS_REQ(1));
   struct RClass *const uri = mrb_define_class_under(
       mrb, uriparser, MRB_URIPARSER_URI_MODULE_NAME, mrb->object_class);
+#ifdef HAVE_URI_COPY_URI
+  mrb_define_method(mrb, uri, "initialize_copy", mrb_uriparser_initialize_copy,
+                    MRB_ARGS_REQ(1));
+#endif
+#ifdef HAVE_URI_EQUALS_URI
+  mrb_define_method(mrb, uri, "==", mrb_uriparser_equals, MRB_ARGS_REQ(1));
+#endif
   mrb_define_method(mrb, uri, "scheme", mrb_uriparser_scheme, MRB_ARGS_NONE());
+#ifdef HAVE_URI_SET_SCHEME
+  mrb_define_method(mrb, uri, "scheme=", mrb_uriparser_set_scheme,
+                    MRB_ARGS_REQ(1));
+#endif
   mrb_define_method(mrb, uri, "userinfo", mrb_uriparser_userinfo,
                     MRB_ARGS_NONE());
+#ifdef HAVE_URI_SET_USERINFO
+  mrb_define_method(mrb, uri, "userinfo=", mrb_uriparser_set_userinfo,
+                    MRB_ARGS_REQ(1));
+#endif
   mrb_define_method(mrb, uri, "hostname", mrb_uriparser_hostname,
                     MRB_ARGS_NONE());
+#ifdef HAVE_URI_SET_HOST
+  mrb_define_method(mrb, uri, "host=", mrb_uriparser_set_host, MRB_ARGS_REQ(1));
+#endif
+#ifdef HAVE_URI_HAS_HOST
+  mrb_define_method(mrb, uri, "host?", mrb_uriparser_has_host, MRB_ARGS_NONE());
+#endif
   mrb_define_method(mrb, uri, "port", mrb_uriparser_port, MRB_ARGS_NONE());
+#ifdef HAVE_URI_SET_PORT
+  mrb_define_method(mrb, uri, "port=", mrb_uriparser_set_port, MRB_ARGS_REQ(1));
+#endif
   mrb_define_method(mrb, uri, "path_segments", mrb_uriparser_path_segments,
                     MRB_ARGS_NONE());
+#ifdef HAVE_URI_SET_PATH
+  mrb_define_method(mrb, uri, "path=", mrb_uriparser_set_path, MRB_ARGS_REQ(1));
+#endif
   mrb_define_method(mrb, uri, "query", mrb_uriparser_query, MRB_ARGS_NONE());
+#ifdef HAVE_URI_SET_QUERY
+  mrb_define_method(mrb, uri, "query=", mrb_uriparser_set_query,
+                    MRB_ARGS_REQ(1));
+#endif
   mrb_define_method(mrb, uri, "fragment", mrb_uriparser_fragment,
                     MRB_ARGS_NONE());
+#ifdef HAVE_URI_SET_FRAGMENT
+  mrb_define_method(mrb, uri, "fragment=", mrb_uriparser_set_fragment,
+                    MRB_ARGS_REQ(1));
+#endif
   mrb_define_method(mrb, uri, "absolute_path?", mrb_uriparser_absolute_path,
                     MRB_ARGS_NONE());
   mrb_define_method(mrb, uri, "to_s", mrb_uriparser_recompose, MRB_ARGS_NONE());
diff --git a/test/mrb_uriparser.rb b/test/mrb_uriparser.rb
index 6fba87a..cc06a48 100644
--- a/test/mrb_uriparser.rb
+++ b/test/mrb_uriparser.rb
@@ -195,3 +195,28 @@
   assert_true(URIParser.parse("http://example.com/").absolute?)
   assert_false(URIParser.parse("./").absolute?)
 end
+
+assert("URIParser::URI#host?") do
+  assert_true(URIParser.parse("http://example.com").host?)
+end
+
+assert("URIParser::URI#dup") do
+  uri = URIParser.parse("http://example.com")
+  new_uri = uri.dup
+  assert_equal("example.com", new_uri.hostname)
+  assert_not_same(uri, new_uri)
+end
+
+assert("URIParser::URI#==") do
+  source = "http://example.com:12345/some/path?query"
+  uri = URIParser.parse(source)
+  assert_true(uri == URIParser.parse(source))
+  another_source = "http://foo.example.com:12345/some/path?query"
+  assert_false(uri == URIParser.parse(another_source))
+end
+
+assert("URIParser::URI#scheme=") do
+  uri = URIParser.parse("http://example.com")
+  uri.scheme = "https"
+  assert_equal("https://example.com", uri.to_s)
+end