Replace Bond with IRB

iruby.gemspec

@@ -17,7 +17,6 @@ Gem::Specification.new do |s|
 
   s.required_ruby_version = '>= 2.3.0'
 
-  s.add_dependency 'bond', '~> 0.5'
   s.add_dependency 'data_uri', '~> 0.1'
   s.add_dependency 'ffi-rzmq'
   s.add_dependency 'mimemagic', '~> 0.3'

lib/iruby/backend.rb

@@ -36,17 +36,20 @@ class PlainBackend
     prepend History
 
     def initialize
-      require 'bond'
-      Bond.start(debug: true)
-      @eval_path = '(iruby)'
+      require 'irb'
+      require 'irb/completion'
+      IRB.setup(nil)
+      @irb = IRB::Irb.new
+      IRB.conf[:MAIN_CONTEXT] = @irb.context
     end
 
     def eval(code, store_history)
-      TOPLEVEL_BINDING.eval(code, @eval_path, 1)
+      @irb.context.evaluate(code, 0)
+      @irb.context.last_value
     end
 
     def complete(code)
-      Bond.agent.call(code, code)
+      IRB::InputCompletor::CompletionProc.call(code)
     end
   end
 

lib/iruby/ostream.rb

@@ -46,6 +46,11 @@ def writelines(lines)
       lines.each { |s| write(s) }
     end
 
+    # Called by irb
+    def set_encoding(extern, intern)
+      a = extern
+    end
+
     private
 
     def build_string