guard predicates are rake tasks, not functions

rakefile

@@ -510,51 +510,21 @@ end
 
 # --- Internationalization tasks
 
-# Make sure config file with username/password exists
-# Returns boolean: returns true if file exists and is nonzero length
-def validate_transifex_config()
-  config_file = "#{Dir.home}/.transifexrc"
-  if !File.file?(config_file) or File.size(config_file)==0
-    raise "Cannot connect to Transifex, config file is missing or empty: #{config_file}\n" +
-      "See http://help.transifex.com/features/client/#transifexrc\n"
-    return false
-  end
-  return true
-end
-
-# Make sure GNU gettext utilities are available
-# Returns boolean: returns true if utilities are available, else returns false
-def validate_gnu_gettext()
-    begin
-      select_executable('xgettext')
-      return true
-    rescue
-      puts "Error:".red
-      puts "Cannot locate GNU gettext utilities, which are required by django for internationalization.".red
-      puts "(see https://docs.djangoproject.com/en/dev/topics/i18n/translation/#message-files)".red
-      puts "Try downloading them from http://www.gnu.org/software/gettext/".red
-      return false
-    end
-end
-
-
 namespace :i18n do
 
   desc "Extract localizable strings from sources"
   task :extract do
-    if validate_gnu_gettext()
-      sh(File.join(REPO_ROOT, "i18n", "extract.py"))
-    end
+    Rake::Task["i18n:validate:gettext"].execute
+    sh(File.join(REPO_ROOT, "i18n", "extract.py"))
   end
 
   desc "Compile localizable strings from sources. With optional flag 'extract', will extract strings first."
   task :generate do
-    if validate_gnu_gettext()
-      if ARGV.last.downcase == 'extract'
-        Rake::Task["i18n:extract"].execute
-      end
-      sh(File.join(REPO_ROOT, "i18n", "generate.py"))
+    Rake::Task["i18n:validate:gettext"].execute
+    if ARGV.last.downcase == 'extract'
+      Rake::Task["i18n:extract"].execute
     end
+    sh(File.join(REPO_ROOT, "i18n", "generate.py"))
   end
 
   desc "Simulate international translation by generating dummy strings corresponding to source strings."
@@ -567,30 +537,52 @@ namespace :i18n do
     end
   end
 
+  namespace :validate do
+
+    desc "Make sure GNU gettext utilities are available"
+    task :gettext do
+      begin
+        select_executable('xgettext')
+      rescue
+        msg = "Cannot locate GNU gettext utilities, which are required by django for internationalization.\n"
+        msg += "(see https://docs.djangoproject.com/en/dev/topics/i18n/translation/#message-files)\n"
+        msg += "Try downloading them from http://www.gnu.org/software/gettext/"
+        abort(msg.red)
+      end
+    end
+
+    desc "Make sure config file with username/password exists"
+    task :transifex_config do
+      config_file = "#{Dir.home}/.transifexrc"
+      if !File.file?(config_file) or File.size(config_file)==0
+        msg ="Cannot connect to Transifex, config file is missing or empty: #{config_file}\n" 
+        msg += "See http://help.transifex.com/features/client/#transifexrc"
+        abort(msg.red)
+      end
+    end
+  end
+
   namespace :transifex do
     desc "Push source strings to Transifex for translation"
     task :push do
-      if validate_transifex_config()
-        cmd = File.join(REPO_ROOT, "i18n", "transifex.py")
-        sh("#{cmd} push")
-      end
+      Rake::Task["i18n:validate:transifex_config"].execute
+      cmd = File.join(REPO_ROOT, "i18n", "transifex.py")
+      sh("#{cmd} push")
     end
 
     desc "Pull translated strings from Transifex"
     task :pull do
-      if validate_transifex_config()
-        cmd = File.join(REPO_ROOT, "i18n", "transifex.py")
-        sh("#{cmd} pull")
-      end
+      Rake::Task["i18n:validate:transifex_config"].execute
+      cmd = File.join(REPO_ROOT, "i18n", "transifex.py")
+      sh("#{cmd} pull")
     end
   end
 
   desc "Run tests for the internationalization library"
   task :test do
-    if validate_gnu_gettext()
-      test = File.join(REPO_ROOT, "i18n", "tests")
-      sh("nosetests #{test}")
-    end
+    Rake::Task["i18n:validate:gettext"].execute
+    test = File.join(REPO_ROOT, "i18n", "tests")
+    sh("nosetests #{test}")
   end
 
 end