Put colors in Tty class

Changed format of Errors and Warnings slightly.

Library/Homebrew/utils.rb

@@ -21,21 +21,44 @@
 #  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 #  THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
+class Tty
+  class <<self
+    def blue; bold 34; end
+    def white; bold 39; end
+    def red; underline 31; end
+    def yellow; underline 33 ; end
+    def reset; escape 0; end
+    
+  private
+    def color n
+      escape "0;#{n}"
+    end
+    def bold n
+      escape "1;#{n}"
+    end
+    def underline n
+      escape "4;#{n}"
+    end
+    def escape n
+      "\033[#{n}m" if $stdout.tty?
+    end
+  end
+end
+
 # args are additional inputs to puts until a nil arg is encountered
 def ohai title, *sput
   title = title[0, `/usr/bin/tput cols`.strip.to_i-4] unless ARGV.verbose?
-  puts "\033[0;34m==>\033[0;0;1m #{title}\033[0;0m"
+  puts "#{Tty.blue}==>#{Tty.white} #{title}#{Tty.reset}"
   puts *sput unless sput.empty?
 end
 
-# shows a warning in delicious pink
 def opoo warning
-  puts "\033[1;35m==>\033[0;0;1m Warning!\033[0;0m #{warning}"
+  puts "#{Tty.red}Warning#{Tty.reset}: #{warning}"
 end
 
 def onoe error
   lines = error.to_s.split'\n'
-  puts "\033[1;31m==>\033[0;0;1m Error\033[0;0m: #{lines.shift}"
+  puts "#{Tty.red}Error#{Tty.reset}: #{lines.shift}"
   puts *lines unless lines.empty?
 end