Examples of how Ruby 2.6 is more functional than ever! 👏🎉🚀

fp_01.rb

raise 'Wrong Ruby version!' unless RUBY_VERSION >= '2.6.0'

module Strings
  Trim = -> str { String(str).strip }
  Replace = -> (sub, new_sub, str) { String(str).gsub(sub, new_sub) }
  LowerCase = -> str { String(str).downcase }
end

                                         # -- Alternative syntax --
Slugify =                                # Slugify =
  Strings::Trim                          #   Strings::Trim           \
    .>> Strings::LowerCase               #     >> Strings::LowerCase \
    .>> Strings::Replace.curry[' ', '-'] #     >> Strings::Replace.curry[' ', '-']

                                            # -- Alternative syntax --
slug = Slugify.(' I WILL be a url slug   ') # Slugify.call(' I WILL be a url slug   ')
                                            # Slugify[' I WILL be a url slug   ']
p slug # => "i-will-be-a-url-slug"

def slugify(value)
  String(value)
    .then(&Strings::Trim)
    .then(&Strings::LowerCase)
    .then(&Strings::Replace.curry[' ', '-'])
end

p slugify('    I will be a url SLUG ') # => "i-will-be-a-url-slug"

#####################
# Fuctional Objects #
#####################

#
# -- Static/Singleton methods --
#
module Slugify2
  extend self

  def call(value)
    String(value)
      .then(&method(:trim))
      .then(&method(:lower_case))
      .then(&method(:replace_spaces_by_dashes))
  end

  private

  def trim(str)
    str.strip
  end

  def lower_case(str)
    str.downcase
  end

  def replace_spaces_by_dashes(str)
    str.gsub(' ', '-')
  end
end
                                        # -- Alternative syntax --
p Slugify2.(' I will BE a url slug   ') # Slugify2.call(' I will BE a url slug   ')

#
# -- Instances --
#
class Slugifier
  def initialize(sub, new_sub)
    @sub = sub
    @new_sub = new_sub
  end

  def call(value)
    String(value)
      .then(&method(:trim))
      .then(&method(:lower_case))
      .then(&method(:replace))
  end

  private

  def trim(str)
    str.strip
  end

  def lower_case(str)
    str.downcase
  end

  def replace(str)
    str.gsub(@sub, @new_sub)
  end
end

Slugify3 = Slugifier.new(' ', '-')

                                        # -- Alternative syntax --
p Slugify3.(' I will be a URL slug   ') # Slugify3.call(' I will be a URL slug   ')

#
# -- Instances and Lambdas --
#
class Slugifier2
  Trim = -> str { String(str).strip }
  Replace = -> (sub, new_sub, str) { String(str).gsub(sub, new_sub) }
  LowerCase = -> str { String(str).downcase }

  def initialize(sub, new_sub)
    @sub = sub
    @new_sub = new_sub
  end

  def call(value)
    String(value)
      .then(&Trim)
      .then(&LowerCase)
      .then(&Replace.curry[' ', '-'])
  end
end

Slugify4 = Slugifier2.new(' ', '-')

                                        # -- Alternative syntax --
p Slugify4.(' I will Be a urL slug   ') # Slugify4.call(' I will Be a urL slug   ')