'Blocky' ERB syntax

inline-erb.rb

require 'erb'

class UserTemplate
  def initialize(user)
    @user = user
  end

  def to_s
    # In the ERB template, we can refer to all instance variables, etc. due to
    # the binding being passed.
    #
    # Note how 'blocky' this looks!
    ERB.new(<<~'EOB').result(binding)
      To: <%= @user.name %>

      Dear <%= @user.firstname %>, this is for you.
    EOB
  end
end

User = Struct.new(:lastname, :firstname, keyword_init: true) do
  def name
    [self.firstname, self.lastname].join(' ')
  end
end

marge = User.new(firstname: 'Marge', lastname: 'Simpson')
puts UserTemplate.new(marge)
# To: Marge Simpson
#
# Dear Marge, this is for you.