Simple Ruby DSL for HTML generation

dsl.rb

# frozen_string_literal: false

# This is the class that implements the DSL.
class Interpreter
  def run(&block)
    # Next line calls the block in the context of the instance.
    instance_eval(&block)
  end

  def method_missing(name, **args, &block)
    tag(name, args, &block)
  end

  def respond_to_missing?(_name)
    true
  end

  def tag(name, args, &block)
    html = ''
    html << "<#{name} #{args_to_string(args)}>"
    html << block.call if block_given?
    html << "</#{name}>"
  end

  def args_to_string(args)
    args.map { |k, v| "#{k}='#{v}'" }.join(' ')
  end
end


# Example usage
val = Interpreter.new.run do
  div class: 'first' do
    div class: 'second' do
      h1 class: 'header'
      a href: 'https://github.com/henvo', target: '_blank' do
        'This is a link'
      end
    end
  end
end

puts val

# Outputs:
# <div class='first'><div class='second'><a href='https://github.com/henvo' target='_blank'>This is a link</a></div></div>