Indexing classes/modules/methods

index.rb

#!/usr/bin/env ruby
# frozen_string_literal: true

VM_DEFINECLASS_TYPE_CLASS           = 0x00
VM_DEFINECLASS_TYPE_SINGLETON_CLASS = 0x01
VM_DEFINECLASS_TYPE_MODULE          = 0x02
VM_DEFINECLASS_FLAG_SCOPED          = 0x08
VM_DEFINECLASS_FLAG_HAS_SUPERCLASS  = 0x10

def log(line, event, message)
  puts "%04d %-20s %s" % [line, event, message]
end

def index(iseq, nesting = [:Object])
  line = iseq[9]
  iseq[13].each_with_index do |insn, index|
    case insn
    in Integer
      line = insn
    in [:defineclass, name, class_iseq, ^(VM_DEFINECLASS_TYPE_SINGLETON_CLASS)]
      if iseq[13][index - 2] == [:putself]
        index(class_iseq, nesting + [name])
      else
        raise NotImplementedError, "singleton class with non-self receiver"
      end
    in [:defineclass, name, class_iseq, flags] if flags & VM_DEFINECLASS_TYPE_MODULE > 0
      log(line, :"module-definition", (nesting + [name]).join("::"))
      index(class_iseq, nesting + [name])
    in [:defineclass, name, class_iseq, flags]
      log(line, :"class-definition", (nesting + [name]).join("::"))
      index(class_iseq, nesting + [name])
    in [:definemethod, name, method_iseq]
      log(line, :"method-definition", "#{nesting.join("::")}##{name}")
    in [:definesmethod, name, method_iseq]
      log(line, :"method-definition", (nesting + [name]).join("::"))
    else
      # skip other instructions
    end
  end
end

Dir[ARGV.first].each do |filepath|
  puts "=== #{filepath} ==="
  index(RubyVM::InstructionSequence.compile_file(filepath).to_a)
end