Driving IRB with Crystal

drive_irb.cr

#!/usr/bin/env crystal

reader, writer = IO.pipe

# Write your script to drive IRB here
spawn do
  sleep 1.second
  writer.puts "1+1"

  sleep 1.second
  writer.puts "Object.new"

  sleep 1.second
ensure
  writer.close
end

File.open("output.txt", "w") do |output_txt|
  output = IO::MultiWriter.new(
    STDOUT,
    output_txt,
  )

  irb = Process.new(
    "irb",
    args: %w[--prompt classic],
    input: reader, # When we write to the writer, it will read from the reader
    output: output,
    error: output,
  )

  irb.wait
end

output

➜  driving_irb cat output.txt
Switch to inspect mode.
irb(main):001:0> 1+1
2
irb(main):002:0> Object.new
#<Object:0x000000011be87918>
irb(main):003:0>