module ActiveSupport::Inflector

the configured I18n.locale.
By default, this parameter is set to nil and it will use
the word will be parameterized as a word of that language.
If the optional parameter +locale+ is specified,

parameterize("^très_Jolie-- ", separator: ".") # => "tres_jolie--"
parameterize("^très|Jolie-- ", separator: "_") # => "tres_jolie--"
parameterize("^très|Jolie__ ") # => "tres-jolie__"

It preserves dashes and underscores unless they are used as separators:

parameterize("^très|Jolie-- ", preserve_case: true) # => "tres-Jolie"
parameterize("Donald E. Knuth", preserve_case: true) # => "Donald-E-Knuth"

To preserve the case of the characters in a string, use the +preserve_case+ argument.

parameterize("^très|Jolie__ ", separator: '_') # => "tres_jolie"
parameterize("Donald E. Knuth", separator: '_') # => "donald_e_knuth"

To use a custom separator, override the +separator+ argument.

parameterize("^très|Jolie-- ") # => "tres-jolie"
parameterize("Donald E. Knuth") # => "donald-e-knuth"

a 'pretty' URL.
Replaces special characters in a string so that it may be used as part of

def parameterize(string, separator: "-", preserve_case: false, locale: nil)
  # Replace accented chars with their ASCII equivalents.
  parameterized_string = transliterate(string, locale: locale)
  # Turn unwanted chars into the separator.
  parameterized_string.gsub!(/[^a-z0-9\-_]+/i, separator)
  unless separator.nil? || separator.empty?
    if separator == "-"
      re_duplicate_separator        = /-{2,}/
      re_leading_trailing_separator = /^-|-$/i
    else
      re_sep = Regexp.escape(separator)
      re_duplicate_separator        = /#{re_sep}{2,}/
      re_leading_trailing_separator = /^#{re_sep}|#{re_sep}$/i
    end
    # No more than one of the separator in a row.
    parameterized_string.gsub!(re_duplicate_separator, separator)
    # Remove leading/trailing separator.
    parameterized_string.gsub!(re_leading_trailing_separator, "")
  end
  parameterized_string.downcase! unless preserve_case
  parameterized_string
end