statesman2mermaid

0_order_state_machine.rb

class OrderStateMachine
  include Statesman::Machine

  state :pending, initial: true
  state :checking_out
  state :purchased
  state :shipped
  state :cancelled
  state :failed
  state :refunded

  transition from: :pending,      to: [:checking_out, :cancelled]
  transition from: :checking_out, to: [:purchased, :cancelled]
  transition from: :purchased,    to: [:shipped, :failed]
  transition from: :shipped,      to: :refunded
end

1_statesman2mermaid.rb

module Statesman
  module Machine
    def self.included(base)
      base.extend(ClassMethods)
      puts "stateDiagram"
    end

    module ClassMethods
      def state(state, initial: false)
        puts "[*] --> #{state.to_s}" if initial
      end

      def transition(from:, to:)
        Array(to).each do |state|
          puts "#{from.to_s} --> #{state.to_s}"
        end
      end
    end
  end
end

load File.join(__dir__, ARGV)

2_result.md

$ ruby 1_statesman2mermaid.rb 0_order_state_machine.rb 
stateDiagram
[*] --> pending
pending --> checking_out
pending --> cancelled
checking_out --> purchased
checking_out --> cancelled
purchased --> shipped
purchased --> failed
shipped --> refunded

stateDiagram
[*] --> pending
pending --> checking_out
pending --> cancelled
checking_out --> purchased
checking_out --> cancelled
purchased --> shipped
purchased --> failed
shipped --> refunded