Ruby — Print code and result both at one time Like shell -x option ( One idea )

RUBY.md

Ruby — Print code and result both at one time Like shell -x option ( One idea )

Points

• write codes in Here doc
• each line
• eval

Script

#!/usr/bin/env ruby

commands = <<~COMMANDS
1
1.to_s
nil
1 + 1
2 * 3
[:a, :b, :c]
[1, 2, 3].map { |num| num*3 }
COMMANDS

commands.each_line do |command|
  print command.chomp
  print ' # '
  p (eval command)
end

Result

1 # 1
1.to_s # "1"
nil # nil
1 + 1 # 2
2 * 3 # 6
[:a, :b, :c] # [:a, :b, :c]
[1, 2, 3].map { |num| num*3 } # [3, 6, 9]

Versions

• ruby 2.4.2p198 (2017-09-14 revision 59899) [x86_64-darwin16]

Links

• Medium—Imported

xample-improved.rb

#!/usr/bin/env ruby

codes = <<-CODES
1
1.to_s
nil

1 + 1
2 * 3

[:a, :b, :c]
[1, 2, 3].map { |num| num*3 }

alice = :liddle
alice
CODES

def each_codes(codes)
  b = binding

  codes.each_line do |code|
    code.gsub!(/^\s+|\s+$/, '')
  
    if code.empty?
      print "\n"
      next
    end


    if code =~ /^#/
      puts code
    else
      print code
      print ' # '

      begin
        p (b.eval code)
      rescue => e
        puts e.message
      end
    end
  end
end

each_codes(codes)

## Outputs
# 
# 1 # 1
# 1.to_s # "1"
# nil # nil
# 
# 1 + 1 # 2
# 2 * 3 # 6
# 
# [:a, :b, :c] # [:a, :b, :c]
# [1, 2, 3].map { |num| num*3 } # [3, 6, 9]
# 
# alice = :liddle # :liddle
# alice # :liddle