diff --git a/ChangeLog b/ChangeLog
index 9c41c6f400..33bb1489af 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+Mon Dec  8 13:02:11 2003  Minero Aoki  <aamine@loveruby.net>
+
+	* lib/uri/common.rb: new method URI.regexp. [ruby-dev:22121]
+
+	* test/uri/test_common.rb: add test for URI.regexp.
+
 Mon Dec  8 12:44:14 2003  Yukihiro Matsumoto  <matz@ruby-lang.org>
 
 	* pack.c: define swap16 and swap32 only if they are not
diff --git a/lib/uri/common.rb b/lib/uri/common.rb
index 5d6a3b5519..fbb3558a32 100644
--- a/lib/uri/common.rb
+++ b/lib/uri/common.rb
@@ -396,28 +396,46 @@ module URI
 --- URI::extract(str[, schemes])
 
 =end
-  def self.extract(str, schemes = [])
-    urls = []
-    regexp = ABS_URI_REF
-    unless schemes.empty?
-      regexp = Regexp.new('(?=' + schemes.collect{|s| 
-			    Regexp.quote(s + ':')
-			  }.join('|') + ')' + PATTERN::X_ABS_URI, 
-			  Regexp::EXTENDED, 'N')
-    end
-
-    str.scan(regexp) {
-      if block_given?
-	yield($&)
-      else
-	urls << $&
-      end
-    }
-
+  def self.extract(str, schemes = nil, &block)
     if block_given?
-      return nil
+      str.scan(regexp(schemes)) { yield $& }
+      nil
     else
-      return urls
+      result = []
+      str.scan(regexp(schemes)) { result.push $& }
+      result
+    end
+  end
+
+=begin
+
+--- URI::regexp([match_schemes])
+
+    Returns a Regexp object which matches to URI-like strings.
+    If MATCH_SCHEMES given, resulting regexp matches to URIs
+    whose scheme is one of the MATCH_SCHEMES.
+
+    The Regexp object returned by this method includes arbitrary
+    number of capture group (parentheses).  Never rely on its
+    number.
+
+      # extract first URI from html_string
+      html_string.slice(URI.regexp)
+
+      # remove ftp URIs
+      html_string.sub(URI.regexp(['ftp'])
+
+      # You should not rely on the number of parentheses
+      html_string.scan(URI.regexp) do |*matches|
+        p $&
+      end
+
+=end
+  def self.regexp(schemes = nil)
+    unless schemes
+      ABS_URI_REF
+    else
+      /(?=#{Regexp.union(*schemes)}:)#{PATTERN::X_ABS_URI}/xn
     end
   end