1  # encoding: utf-8
   2 
   3  =begin
   4    heavily based on Masao Mutoh's gettext String interpolation extension
   5    http://github.com/mutoh/gettext/blob/f6566738b981fe0952548c421042ad1e0cdfb31e/lib/gettext/core_ext/string.rb
   6    Copyright (C) 2005-2009 Masao Mutoh
   7    You may redistribute it and/or modify it under the same license terms as Ruby.
   8  =end
   9 
  10  begin
  11    raise ArgumentError if ("a %{x}" % {:x=>'b'}) != 'a b'
  12  rescue ArgumentError
  13    # KeyError is raised by String#% when the string contains a named placeholder
  14    # that is not contained in the given arguments hash. Ruby 1.9 includes and
  15    # raises this exception natively. We define it to mimic Ruby 1.9's behaviour
  16    # in Ruby 1.8.x
  17    class KeyError < IndexError
  18      def initialize(message = nil)
  19        super(message || "key not found")
  20      end
  21    end unless defined?(KeyError)
  22 
  23    # Extension for String class. This feature is included in Ruby 1.9 or later but not occur TypeError.
  24    #
  25    # String#% method which accept "named argument". The translator can know
  26    # the meaning of the msgids using "named argument" instead of %s/%d style.
  27    class String
  28      # For older ruby versions, such as ruby-1.8.5
  29      alias :bytesize :size unless instance_methods.find {|m| m.to_s == 'bytesize'}
  30      alias :interpolate_without_ruby_19_syntax :% # :nodoc:
  31 
  32      INTERPOLATION_PATTERN = Regexp.union(
  33        /%\{(\w+)\}/,                               # matches placeholders like "%{foo}"
  34        /%<(\w+)>(.*?\d*\.?\d*[bBdiouxXeEfgGcps])/  # matches placeholders like "%<foo>.d"
  35      )
  36 
  37      INTERPOLATION_PATTERN_WITH_ESCAPE = Regexp.union(
  38        /%%/,
  39        INTERPOLATION_PATTERN
  40      )
  41 
  42      # % uses self (i.e. the String) as a format specification and returns the
  43      # result of applying it to the given arguments. In other words it interpolates
  44      # the given arguments to the string according to the formats the string
  45      # defines.
  46      #
  47      # There are three ways to use it:
  48      #
  49      # * Using a single argument or Array of arguments.
  50      #
  51      #   This is the default behaviour of the String class. See Kernel#sprintf for
  52      #   more details about the format string.
  53      #
  54      #   Example:
  55      #
  56      #     "%d %s" % [1, "message"]
  57      #     # => "1 message"
  58      #
  59      # * Using a Hash as an argument and unformatted, named placeholders.
  60      #
  61      #   When you pass a Hash as an argument and specify placeholders with %{foo}
  62      #   it will interpret the hash values as named arguments.
  63      #
  64      #   Example:
  65      #
  66      #     "%{firstname}, %{lastname}" % {:firstname => "Masao", :lastname => "Mutoh"}
  67      #     # => "Masao Mutoh"
  68      #
  69      # * Using a Hash as an argument and formatted, named placeholders.
  70      #
  71      #   When you pass a Hash as an argument and specify placeholders with %<foo>d
  72      #   it will interpret the hash values as named arguments and format the value
  73      #   according to the formatting instruction appended to the closing >.
  74      #
  75      #   Example:
  76      #
  77      #     "%<integer>d, %<float>.1f" % { :integer => 10, :float => 43.4 }
  78      #     # => "10, 43.3"
  79      def %(args)
  80        if args.kind_of?(Hash)
  81          dup.gsub(INTERPOLATION_PATTERN_WITH_ESCAPE) do |match|
  82            if match == '%%'
  83              '%'
  84            else
  85              key = ($1 || $2).to_sym
  86              raise KeyError unless args.has_key?(key)
  87              $3 ? sprintf("%#{$3}", args[key]) : args[key]
  88            end
  89          end
  90        elsif self =~ INTERPOLATION_PATTERN
  91          raise ArgumentError.new('one hash required')
  92        else
  93          result = gsub(/%([{<])/, '%%\1')
  94          result.send :'interpolate_without_ruby_19_syntax', args
  95        end
  96      end
  97    end
  98  en