ruby_repl.rb

#!/usr/bin/env ruby

require 'pp'

def ruby_repl processor = nil
  unless (processor && Proc === processor) || block_given?
    warn "Please invoke `ruby_repl` with a block or a proc..."
  else
    in_pry = Kernel.const_defined?("Pry::ColorPrinter")
    cmd_count = 0 # for use in the command prompt
    loop do
      print "repl(%s):%d> " % [
        (in_pry ? Pry.view_clip(self) : self.inspect),
        (cmd_count += 1),
      ]
      input = gets
      ( puts ; break ) unless input
      input = input.chomp
      begin
        result = processor ? processor.call(input) : yield(input)
        print "=> "
        in_pry ? Pry::ColorPrinter.pp(result) : PP.pp(result)
      rescue
        puts "%s: %s" % [$!.class.name, $!.message]
        puts "from (repl):#{cmd_count}:in `__ruby_repl__'"
      end
    end
  end
end

alias :repl :ruby_repl
alias :rr :ruby_repl

if __FILE__ == $0
  require 'pry' rescue LoadError
  ruby_repl do |input| input ; end
end

# That's all Folks!