+# This backports the Ruby 1.9 String interpolation syntax to Ruby 1.8.
+#
+# This backport has been shipped with I18n for a number of versions. Meanwhile
+# Rails has started to rely on it and we are going to move it to ActiveSupport.
+# See https://rails.lighthouseapp.com/projects/8994/tickets/6013-move-19-string-interpolation-syntax-backport-from-i18n-to-activesupport
+#
+# Once the above patch has been applied to Rails the following code will be
+# removed from I18n.
+
+=begin
+ heavily based on Masao Mutoh's gettext String interpolation extension
+ http://github.com/mutoh/gettext/blob/f6566738b981fe0952548c421042ad1e0cdfb31e/lib/gettext/core_ext/string.rb
+ Copyright (C) 2005-2009 Masao Mutoh
+ You may redistribute it and/or modify it under the same license terms as Ruby.
+=end
+
+begin
+ raise ArgumentError if ("a %{x}" % {:x=>'b'}) != 'a b'
+rescue ArgumentError
+ # KeyError is raised by String#% when the string contains a named placeholder
+ # that is not contained in the given arguments hash. Ruby 1.9 includes and
+ # raises this exception natively. We define it to mimic Ruby 1.9's behaviour
+ # in Ruby 1.8.x
+ class KeyError < IndexError
+ def initialize(message = nil)
+ super(message || "key not found")
+ end
+ end unless defined?(KeyError)
+
+ # Extension for String class. This feature is included in Ruby 1.9 or later but not occur TypeError.
+ #
+ # String#% method which accept "named argument". The translator can know
+ # the meaning of the msgids using "named argument" instead of %s/%d style.
+ class String
+ # For older ruby versions, such as ruby-1.8.5
+ alias :bytesize :size unless instance_methods.find {|m| m.to_s == 'bytesize'}
+ alias :interpolate_without_ruby_19_syntax :% # :nodoc:
+
+ INTERPOLATION_PATTERN = Regexp.union(
+ /%\{(\w+)\}/, # matches placeholders like "%{foo}"
+ /%<(\w+)>(.*?\d*\.?\d*[bBdiouxXeEfgGcps])/ # matches placeholders like "%<foo>.d"
+ )
+
+ INTERPOLATION_PATTERN_WITH_ESCAPE = Regexp.union(
+ /%%/,
+ INTERPOLATION_PATTERN
+ )
+
+ # % uses self (i.e. the String) as a format specification and returns the
+ # result of applying it to the given arguments. In other words it interpolates
+ # the given arguments to the string according to the formats the string
+ # defines.
+ #
+ # There are three ways to use it:
+ #
+ # * Using a single argument or Array of arguments.
+ #
+ # This is the default behaviour of the String class. See Kernel#sprintf for
+ # more details about the format string.
+ #
+ # Example:
+ #
+ # "%d %s" % [1, "message"]
+ # # => "1 message"
+ #
+ # * Using a Hash as an argument and unformatted, named placeholders.
+ #
+ # When you pass a Hash as an argument and specify placeholders with %{foo}
+ # it will interpret the hash values as named arguments.
+ #
+ # Example:
+ #
+ # "%{firstname}, %{lastname}" % {:firstname => "Masao", :lastname => "Mutoh"}
+ # # => "Masao Mutoh"
+ #
+ # * Using a Hash as an argument and formatted, named placeholders.
+ #
+ # When you pass a Hash as an argument and specify placeholders with %<foo>d
+ # it will interpret the hash values as named arguments and format the value
+ # according to the formatting instruction appended to the closing >.
+ #
+ # Example:
+ #
+ # "%<integer>d, %<float>.1f" % { :integer => 10, :float => 43.4 }
+ # # => "10, 43.3"
+ def %(args)
+ if args.kind_of?(Hash)
+ dup.gsub(INTERPOLATION_PATTERN_WITH_ESCAPE) do |match|
+ if match == '%%'
+ '%'
+ else
+ key = ($1 || $2).to_sym
+ raise KeyError unless args.has_key?(key)
+ $3 ? sprintf("%#{$3}", args[key]) : args[key]
+ end
+ end
+ elsif self =~ INTERPOLATION_PATTERN
+ raise ArgumentError.new('one hash required')
+ else
+ result = gsub(/%([{<])/, '%%\1')
+ result.send :'interpolate_without_ruby_19_syntax', args
+ end
+ end
+ end
+end