restore support for IRB <= v1.13.0

[sealocal]

#339 dropped support of IRB older than v1.13.0, which introduced #351

This change restores support for all versions of the irb gem

IRB 1.6.3

require 'bundler/inline'

gemfile do
  ruby '2.7.8'
  source 'https://rubygems.org'
  gem 'irb', '1.6.3'
  gem 'iruby', '0.8.0'
end

puts "The IRB gem is at version #{IRB::VERSION}"
puts "The IRuby gem is at version #{IRuby::VERSION}"

@plainbackend = IRuby::PlainBackend.new
@plainbackend.eval('puts "Hello from plainbackend!"', false)

# => iruby-0.8.0/lib/iruby/backend.rb:60:in `eval': undefined method `build_statement' for #<IRB::Irb:0x000000015bb0ce38> (NoMethodError)

...

gemfile do
  ruby '2.7.8'
  source 'https://rubygems.org'
  gem 'irb', '1.12.0'
  gem 'iruby', '0.8.0'
end

# ...
# => irb-1.12.0/lib/irb/workspace.rb:117:in `eval': no implicit conversion of IRB::Statement::Expression into String (TypeError)

...

gemfile do
  ruby '2.7.8'
  source 'https://rubygems.org'
  gem 'irb', '1.13.0'
  gem 'iruby', '0.8.0'
end

# ...
# => Hello from plainbackend!

[kojix2]

Hello!
Good pull request.
However, I'm concerned about the fact that you're creating an instance of IRB::RegexpCompletor every time.

def initialize
  # ommited
  @completor = defined?(IRB::RegexpCompletor) ? IRB::RegexpCompletor.new : nil
end

def complete(code)
  if @completor
    @completor.completion_candidates('', code, '', bind: @workspace.binding)
  else
    IRB::InputCompletor::CompletionProc.call(code)
  end
end

Wouldn't this be better?

Note: I don't have any professional Ruby/Rails development experience, so I'm not necessarily familiar with the best practices for Ruby web development.

[kojix2]

It seems that an instance of IRB::RegexpCompletor is created each time. This seems inefficient, what do you think?

[sealocal]

Indeed, agree! Added e07b7eb

[sealocal]

Hello! Good pull request. However, I'm concerned about the fact that you're creating an instance of IRB::RegexpCompletor every time.

def initialize
  # ommited
  @completor = defined?(IRB::RegexpCompletor) ? IRB::RegexpCompletor.new : nil
end

def complete(code)
  if @completor
    @completor.completion_candidates('', code, '', bind: @workspace.binding)
  else
    IRB::InputCompletor::CompletionProc.call(code)
  end
end

Wouldn't this be better?

Note: I don't have any professional Ruby/Rails development experience, so I'm not necessarily familiar with the best practices for Ruby web development.

Ah, agree - that was an oversight and changes more than I intended. I've restored the attribute!

[kojix2]

Thank you. Please send another pull request if you find anything else.