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=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
if RUBY_VERSION < '1.9'
require 'active_support/core_ext/string/bytesize'
# 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
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"
)
# % 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) 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
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