Regexp Union

gistfile1.txt

diff --git a/kernel/common/regexp19.rb b/kernel/common/regexp19.rb
index 8496d78..4459921 100644
--- a/kernel/common/regexp19.rb
+++ b/kernel/common/regexp19.rb
@@ -116,26 +116,6 @@ class Regexp
     source.encoding
   end
 
-  def self.compatible_encodings(*patterns)
-    ascii = []
-    non_ascii = []
-    first_pattern = patterns.first
-    encoding = convert(first_pattern).encoding
-
-    patterns.each do |pattern|
-      pattern = convert(pattern)
-      if pattern.encoding.ascii_compatible?
-        ascii << pattern.encoding
-      else
-        non_ascii << pattern.encoding
-      end
-    end 
-
-    raise ArgumentError, "incompatible encodings: #{non_ascii.first} and #{ascii.first}" if !ascii.empty? && !non_ascii.empty?
-    compatible?(ascii + non_ascii) 
-    encoding
-  end
-
   def self.convert(pattern)
     return pattern if pattern.kind_of? Regexp
     if pattern.kind_of? Array
@@ -145,7 +125,8 @@ class Regexp
     end
   end
 
-  def self.compatible?(encodings)
+  def self.compatible?(*patterns)
+    encodings = patterns.collect{ |r| convert(r).encoding } 
     last_enc = encodings.pop
     encodings.each do |encoding|
       raise ArgumentError, "incompatible encodings: #{encoding} and #{last_enc}" unless Encoding.compatible?(last_enc, encoding)
@@ -168,7 +149,8 @@ class Regexp
         return Regexp.new(Regexp.quote(StringValue(pat)))
       end
     else
-      enc = compatible_encodings(*patterns)
+      compatible?(*patterns)
+      enc = convert(patterns.first).encoding
     end
 
     str = "".encode(enc)
@@ -183,6 +165,8 @@ class Regexp
     end
 
     Regexp.new(str)
+  rescue Encoding::CompatibilityError => e
+    raise ArgumentError, e.message
   end
 
   def self.escape(str)