Debug Helper

New in Version 2.1

Handling for instances of class Method. See Method.

About Debug Helper

If (like me), your debugging style is printf debugging, you will have shoved this into your code many times:

show_hash.rb:

hash.each_pair do |key, value|
  p [key, value]
end

And this:

show_array.rb:

array.each_with_index do |item, i|
  p [i, item]
end

This helper assists in debugging by printing an analysis of a given object. The analysis is a yaml structure, and is written to stdout.

For certain classes (see below), the analysis is very detailed.

For the collection classes Array, Hash, Struct, Set, and OpenStruct, the analysis is also recursive; that is, the collection's values are themselves analyzed.

You can control the depth of recursion using option depth. See Options.

Classes treated in detail:

Array
Dir
Exception
File
Hash
IO
MatchData
Method
OpenStruct
Range
Regexp
Set
String
Struct
Symbol

Others are treated as:

Object

But wait, there's more! For your own classes, you can create your own handlers:

Custom

Class Method or Module Method?

Most examples in this documentation show use of the class method:

require 'debug_helper'
DebugHelper.show(obj, message)

You can also choose to use the module method, putd (Thanks, palkan!), which looks a lot like puts.

require 'debug_helper'
include DebugHelper::Putd
putd obj, message

Just be sure to include DebugHelper::Putd.

Array

Simple Array

This example shows a simple array of integers.

show.rb:

require 'debug_helper'

ary = [5, 10, 15]
DebugHelper.show(ary, 'My simple array')

The output shows details of the array.

show.yaml:

---
Array (message='My simple array'):
  Array#size: 3
  Element 0: Integer 5
  Element 1: Integer 10
  Element 2: Integer 15

Mixed Array

This example shows an array of mixed values.

show.rb:

require 'debug_helper'

ary = [0, 'one', :two]
DebugHelper.show(ary, 'My mixed array')

The output shows details of the array.

show.yaml:

---
Array (message='My mixed array'):
  Array#size: 3
  Element 0: Integer 0
  Element 1:
    String:
      String#to_s: one
      String#size: 3
      String#encoding: !ruby/encoding UTF-8
      String#ascii_only?: true
      String#bytesize: 3
  Element 2:
    Symbol:
      Symbol#to_s: two
      Symbol#size: 3
      Symbol#encoding: !ruby/encoding US-ASCII

Nested Arrays

This example shows nested arrays.

show.rb:

require 'debug_helper'

ary = [0, [1, 2], [3, 4]]
DebugHelper.show(ary, 'My nested arrays')

The output shows details of the arrays.

show.yaml:

---
Array (message='My nested arrays'):
  Array#size: 3
  Element 0: Integer 0
  Element 1:
    Array:
      Array#size: 2
      Element 0: Integer 1
      Element 1: Integer 2
  Element 2:
    Array:
      Array#size: 2
      Element 0: Integer 3
      Element 1: Integer 4

Circular Arrays

This example shows arrays that make a circular reference.

show.rb:

require 'debug_helper'

ary_0 = []
ary_1 = []
ary_0.push(ary_1)
ary_1.push(ary_0)
DebugHelper.show(ary_0, 'My circular arrays')

The output shows details of the arrays.

The circular reference is not followed.

show.yaml:

---
Array (message='My circular arrays'):
  Array#size: 1
  Element 0:
    Array:
      Array#size: 1
      Element 0: Array [[[...]]]

Dir

Simple Dir

This example shows a simple Dir.

show.rb:

require 'debug_helper'

dir = Dir.new(File.dirname(__FILE__))
DebugHelper.show(dir, 'My simple dir')

The output shows details of the Dir.

show.yaml:

---
Dir (message='My simple dir'):
  Dir#path: "."
  Dir.entries("."):
  - "."
  - ".."
  - show.md
  - show.rb
  - show.yaml
  - template.md
  Dir.exist?("."): true

Exception

Simple Exception

This example shows a simple Exception.

show.rb:

require 'debug_helper'

def foo
  exception = nil
  begin
    raise Exception.new('Boo!')
  rescue Exception => exception
    # Already saved.
  end
  DebugHelper.show(exception, 'My simple exception')
end

def bar
  foo
end

def baz
  bar
end

baz

The output shows details of the Exception.

show.yaml:

---
Exception (message='My simple exception'):
  Exception#message: Boo!
  Exception#cause: 
  Exception#backtrace:
  - show.rb:6:in `foo'
  - show.rb:14:in `bar'
  - show.rb:18:in `baz'
  - show.rb:21:in `<main>'

File

Simple File

This example shows a simple file.

show.rb:

require 'debug_helper'

gem_file_path = `gem which debug_helper`.chomp
gem_dir_path = File.dirname(gem_file_path)
gem_file_name = File.basename(gem_file_path)
Dir.chdir(gem_dir_path) do
  file = File.new(gem_file_name)
  DebugHelper.show(file, 'Gem file')
end

The output shows details of the file.

show.yaml:

---
File (message='Gem file'):
  File.absolute_path("debug_helper.rb"): C:/Ruby25-x64/lib/ruby/gems/2.5.0/gems/debug_helper-2.0.0/lib/debug_helper.rb
  File.atime("debug_helper.rb"): 2019-01-25 15:43:42.740298400 -06:00
  File.ctime("debug_helper.rb"): 2019-01-25 15:43:42.740298400 -06:00
  File.executable?("debug_helper.rb"): false
  File.exist?("debug_helper.rb"): true
  File.ftype("debug_helper.rb"): file
  File.mtime("debug_helper.rb"): 2019-01-25 15:43:42.741296200 -06:00
  File.path("debug_helper.rb"): debug_helper.rb
  File.pipe?("debug_helper.rb"): false
  File.readable?("debug_helper.rb"): true
  File.realpath("debug_helper.rb"): C:/Ruby25-x64/lib/ruby/gems/2.5.0/gems/debug_helper-2.0.0/lib/debug_helper.rb
  File.setgid?("debug_helper.rb"): false
  File.setuid?("debug_helper.rb"): false
  File.size("debug_helper.rb"): 3701
  File.socket?("debug_helper.rb"): false
  File.symlink?("debug_helper.rb"): false
  File.writable?("debug_helper.rb"): true

Hash

Simple Hash

This example shows a simple hash.

show.rb:

require 'debug_helper'

hash = {:a => 0, :b => 1, :c => 2}
DebugHelper.show(hash, 'My simple hash')

The output shows details of the hash.

show.yaml:

---
Hash (message='My simple hash'):
  Hash#size: 3
  Hash#default: 
  Hash#default_proc: 
  Pair 0:
    Key:
      Symbol:
        Symbol#to_s: a
        Symbol#size: 1
        Symbol#encoding: !ruby/encoding US-ASCII
    Value: Integer 0
  Pair 1:
    Key:
      Symbol:
        Symbol#to_s: b
        Symbol#size: 1
        Symbol#encoding: !ruby/encoding US-ASCII
    Value: Integer 1
  Pair 2:
    Key:
      Symbol:
        Symbol#to_s: c
        Symbol#size: 1
        Symbol#encoding: !ruby/encoding US-ASCII
    Value: Integer 2

Mixed Hash

This example shows a hash of mixed values.

show.rb:

require 'debug_helper'

hash = {
    :a => 0,
    :b => 'one',
    :c => :two,
}
DebugHelper.show(hash, 'My mixed hash')

The output shows details of the hash.

show.yaml:

---
Hash (message='My mixed hash'):
  Hash#size: 3
  Hash#default: 
  Hash#default_proc: 
  Pair 0:
    Key:
      Symbol:
        Symbol#to_s: a
        Symbol#size: 1
        Symbol#encoding: !ruby/encoding US-ASCII
    Value: Integer 0
  Pair 1:
    Key:
      Symbol:
        Symbol#to_s: b
        Symbol#size: 1
        Symbol#encoding: !ruby/encoding US-ASCII
    Value:
      String:
        String#to_s: one
        String#size: 3
        String#encoding: !ruby/encoding UTF-8
        String#ascii_only?: true
        String#bytesize: 3
  Pair 2:
    Key:
      Symbol:
        Symbol#to_s: c
        Symbol#size: 1
        Symbol#encoding: !ruby/encoding US-ASCII
    Value:
      Symbol:
        Symbol#to_s: two
        Symbol#size: 3
        Symbol#encoding: !ruby/encoding US-ASCII

Nested Hashes

This example shows nested hashes.

show.rb:

require 'debug_helper'

hash = {
    :a => {
        :b => 0,
        :c => 1,
    },
    :d => {
        :e => 2,
        :f => 3,
    }
}
DebugHelper.show(hash, 'My nested hash')

The output shows details of the hashes.

show.yaml:

---
Hash (message='My nested hash'):
  Hash#size: 2
  Hash#default: 
  Hash#default_proc: 
  Pair 0:
    Key:
      Symbol:
        Symbol#to_s: a
        Symbol#size: 1
        Symbol#encoding: !ruby/encoding US-ASCII
    Value:
      Hash:
        Hash#size: 2
        Hash#default: 
        Hash#default_proc: 
        Pair 0:
          Key:
            Symbol:
              Symbol#to_s: b
              Symbol#size: 1
              Symbol#encoding: !ruby/encoding US-ASCII
          Value: Integer 0
        Pair 1:
          Key:
            Symbol:
              Symbol#to_s: c
              Symbol#size: 1
              Symbol#encoding: !ruby/encoding US-ASCII
          Value: Integer 1
  Pair 1:
    Key:
      Symbol:
        Symbol#to_s: d
        Symbol#size: 1
        Symbol#encoding: !ruby/encoding US-ASCII
    Value:
      Hash:
        Hash#size: 2
        Hash#default: 
        Hash#default_proc: 
        Pair 0:
          Key:
            Symbol:
              Symbol#to_s: e
              Symbol#size: 1
              Symbol#encoding: !ruby/encoding US-ASCII
          Value: Integer 2
        Pair 1:
          Key:
            Symbol:
              Symbol#to_s: f
              Symbol#size: 1
              Symbol#encoding: !ruby/encoding US-ASCII
          Value: Integer 3

Circular Hashes

This example shows hashes that make a circular reference.

show.rb:

require 'debug_helper'

hash_0 = {}
hash_1 = {}
hash_0.store(:foo, hash_1)
hash_1.store(:bar, hash_0)
DebugHelper.show(hash_0, 'My circular hashes')

The output shows details of the hashes.

The circular reference is not followed.

show.yaml:

---
Hash (message='My circular hashes'):
  Hash#size: 1
  Hash#default: 
  Hash#default_proc: 
  Pair 0:
    Key:
      Symbol:
        Symbol#to_s: foo
        Symbol#size: 3
        Symbol#encoding: !ruby/encoding US-ASCII
    Value:
      Hash:
        Hash#size: 1
        Hash#default: 
        Hash#default_proc: 
        Pair 0:
          Key:
            Symbol:
              Symbol#to_s: bar
              Symbol#size: 3
              Symbol#encoding: !ruby/encoding US-ASCII
          Value: Hash {:foo=>{:bar=>{...}}}

IO

Simple IO

This example shows a simple IO.

show.rb:

require 'debug_helper'

io = IO.new(IO.sysopen(__FILE__, 'r'), 'r')
DebugHelper.show(io, 'My simple io')

The output shows details of the IO.

show.yaml:

---
IO (message='My simple io'):
  IO#autoclose?: true
  IO#binmode?: false
  IO#closed?: false
  IO#tty?: false

MatchData

Simple MatchData

This example shows a simple MatchData.

show.rb:

require 'debug_helper'

match_data = /[a-z]/.match('abc')
DebugHelper.show(match_data, 'My simple MatchData')

The output shows details of the MatchData.

show.yaml:

---
MatchData (message='My simple MatchData'):
  MatchData#size: 1
  MatchData#regexp: !ruby/regexp /[a-z]/
  MatchData#to_a:
  - a
  MatchData#captures: []
  MatchData#names: []

Multiple Captures

This example shows a MatchData with multiple captures.

show.rb:

require 'debug_helper'

match_data = /(.)(.)(\d+)(\d)/.match('THX1138.')
DebugHelper.show(match_data, 'My MatchData with named captures')

The output shows details of the MatchData.

show.yaml:

---
MatchData (message='My MatchData with named captures'):
  MatchData#size: 5
  MatchData#regexp: !ruby/regexp /(.)(.)(\d+)(\d)/
  MatchData#to_a:
  - HX1138
  - H
  - X
  - '113'
  - '8'
  MatchData#captures:
  - H
  - X
  - '113'
  - '8'
  MatchData#names: []

Named Captures

This example shows a MatchData with named captures.

show.rb:

require 'debug_helper'

match_data = /(?<x>.)(?<y>.)?/.match("a")
DebugHelper.show(match_data, 'My MatchData with named captures')

The output shows details of the MatchData.

show.yaml:

---
MatchData (message='My MatchData with named captures'):
  MatchData#size: 3
  MatchData#regexp: !ruby/regexp /(?<x>.)(?<y>.)?/
  MatchData#to_a:
  - a
  - a
  - 
  MatchData#captures:
  - a
  - 
  MatchData#names:
  - x
  - y

Method

Simple Method

This example shows a simple Method.

show.rb:

require 'debug_helper'

m = method(:puts)
DebugHelper.show(m, 'My simple Method')

The output shows details of the Method.

show.yaml:

---
Method (message='My simple Method'):
  Method#arity: -1
  Method#inspect: "#<Method: main.puts>"
  Method#name: :puts
  Method#original_name: :puts
  Method#owner: !ruby/module 'Kernel'
  Method#parameters:
  - - :rest
  Method#source_location: 
  Method#super_method:

OpenStruct

Simple OpenStruct

This example shows a simple open struct.

show.rb:

require 'ostruct'
require 'debug_helper'

ostruct = OpenStruct.new(:a => 0, :b => 1, :c => 2)
DebugHelper.show(ostruct, 'My simple struct')

The output shows details of the open struct.

show.yaml:

---
OpenStruct (message='My simple struct'):
  Member 0:
    Name:
      Symbol:
        Symbol#to_s: a
        Symbol#size: 1
        Symbol#encoding: !ruby/encoding US-ASCII
    Value: Integer 0
  Member 1:
    Name:
      Symbol:
        Symbol#to_s: b
        Symbol#size: 1
        Symbol#encoding: !ruby/encoding US-ASCII
    Value: Integer 1
  Member 2:
    Name:
      Symbol:
        Symbol#to_s: c
        Symbol#size: 1
        Symbol#encoding: !ruby/encoding US-ASCII
    Value: Integer 2

Mixed OpenStruct

This example shows an open struct of mixed values.

show.rb:

require 'ostruct'
require 'debug_helper'

ostruct = OpenStruct.new(:a => 0, :b => 'one', :c => :two)
DebugHelper.show(ostruct, 'My mixed open struct')

The output shows details of the open struct.

show.yaml:

---
OpenStruct (message='My mixed open struct'):
  Member 0:
    Name:
      Symbol:
        Symbol#to_s: a
        Symbol#size: 1
        Symbol#encoding: !ruby/encoding US-ASCII
    Value: Integer 0
  Member 1:
    Name:
      Symbol:
        Symbol#to_s: b
        Symbol#size: 1
        Symbol#encoding: !ruby/encoding US-ASCII
    Value:
      String:
        String#to_s: one
        String#size: 3
        String#encoding: !ruby/encoding UTF-8
        String#ascii_only?: true
        String#bytesize: 3
  Member 2:
    Name:
      Symbol:
        Symbol#to_s: c
        Symbol#size: 1
        Symbol#encoding: !ruby/encoding US-ASCII
    Value:
      Symbol:
        Symbol#to_s: two
        Symbol#size: 3
        Symbol#encoding: !ruby/encoding US-ASCII

Nested OpenStructs

This example shows nested open structs.

show.rb:

require 'ostruct'
require 'debug_helper'

ostruct = OpenStruct.new(
                        :a => OpenStruct.new(
                                            :b => 0,
                                            :c => 1,
                        ),
                        :d => OpenStruct.new(
                                            :e => 2,
                                            :f => 3,
                        )
)
DebugHelper.show(ostruct, 'My nested struct')

The output shows details of the open structs.

show.yaml:

---
OpenStruct (message='My nested struct'):
  Member 0:
    Name:
      Symbol:
        Symbol#to_s: a
        Symbol#size: 1
        Symbol#encoding: !ruby/encoding US-ASCII
    Value:
      OpenStruct:
        Member 0:
          Name:
            Symbol:
              Symbol#to_s: b
              Symbol#size: 1
              Symbol#encoding: !ruby/encoding US-ASCII
          Value: Integer 0
        Member 1:
          Name:
            Symbol:
              Symbol#to_s: c
              Symbol#size: 1
              Symbol#encoding: !ruby/encoding US-ASCII
          Value: Integer 1
  Member 1:
    Name:
      Symbol:
        Symbol#to_s: d
        Symbol#size: 1
        Symbol#encoding: !ruby/encoding US-ASCII
    Value:
      OpenStruct:
        Member 0:
          Name:
            Symbol:
              Symbol#to_s: e
              Symbol#size: 1
              Symbol#encoding: !ruby/encoding US-ASCII
          Value: Integer 2
        Member 1:
          Name:
            Symbol:
              Symbol#to_s: f
              Symbol#size: 1
              Symbol#encoding: !ruby/encoding US-ASCII
          Value: Integer 3

Circular OpenStructs

This example shows open structs that make a circular reference.

show.rb:

require 'ostruct'
require 'debug_helper'

ostruct_0 = OpenStruct.new
ostruct_1 = OpenStruct.new
ostruct_0.a = ostruct_1
ostruct_1.a = ostruct_0
DebugHelper.show(ostruct_0, 'My circular ostruct')

The output shows details of the open structs.

The circular reference is not followed.

show.yaml:

---
OpenStruct (message='My circular ostruct'):
  Member 0:
    Name:
      Symbol:
        Symbol#to_s: a
        Symbol#size: 1
        Symbol#encoding: !ruby/encoding US-ASCII
    Value:
      OpenStruct:
        Member 0:
          Name:
            Symbol:
              Symbol#to_s: a
              Symbol#size: 1
              Symbol#encoding: !ruby/encoding US-ASCII
          Value: 'OpenStruct #<OpenStruct a=#<OpenStruct a=#<OpenStruct ...>>>'

Range

Inclusive Range

This example shows a Range that includes its end value.

show.rb:

require 'debug_helper'

range = (0..4)
DebugHelper.show(range, 'My inclusive range')

The output shows details of the Range.

show.yaml:

---
Range (message='My inclusive range'):
  Range#first: 0
  Range#last: 4
  Range#exclude_end?: false

Exclusive Range

This example shows a Range that excludes its end value.

show.rb:

require 'debug_helper'

range = (0...4)
DebugHelper.show(range, 'My exclusive range')

The output shows details of the Range.

show.yaml:

---
Range (message='My exclusive range'):
  Range#first: 0
  Range#last: 4
  Range#exclude_end?: true

Regexp

Simple Regexp

This example shows a simple Regexp.

show.rb:

require 'debug_helper'

regexp = Regexp.new(/\w+/)
DebugHelper.show(regexp, 'My simple regexp')

The output shows details of the Regexp.

show.yaml:

---
Regexp (message='My simple regexp'):
  Regexp#to_s: "(?-mix:\\w+)"
  Regexp#casefold?: false
  Regexp#named_captures: {}
  Regexp#encoding: !ruby/encoding US-ASCII
  Regexp#fixed_encoding?: false

Named Captures

This example shows a Regexp with named captures.

show.rb:

require 'debug_helper'

regexp = Regexp.new(/(?<a>.)(?<b>.)/)
DebugHelper.show(regexp, 'My regexp with named captures')

The output shows details of the Regexp.

show.yaml:

---
Regexp (message='My regexp with named captures'):
  Regexp#to_s: "(?-mix:(?<a>.)(?<b>.))"
  Regexp#casefold?: false
  Regexp#named_captures:
    a:
    - 1
    b:
    - 2
  Regexp#encoding: !ruby/encoding US-ASCII
  Regexp#fixed_encoding?: false

Set

Simple Set

This example shows a simple set of integers.

show.rb:

require 'set'

require 'debug_helper'

set = Set.new([5, 10, 15])
DebugHelper.show(set, 'My simple set')

The output shows details of the set.

show.yaml:

---
Set (message='My simple set'):
  Set#size: 3
  Element 0: Integer 5
  Element 1: Integer 10
  Element 2: Integer 15

Mixed Set

This example shows a set of mixed values.

show.rb:

require 'debug_helper'

require 'set'

set = Set.new([0, 'one', :two])
DebugHelper.show(set, 'My mixed set')

The output shows details of the set.

show.yaml:

---
Set (message='My mixed set'):
  Set#size: 3
  Element 0: Integer 0
  Element 1:
    String:
      String#to_s: one
      String#size: 3
      String#encoding: !ruby/encoding UTF-8
      String#ascii_only?: true
      String#bytesize: 3
  Element 2:
    Symbol:
      Symbol#to_s: two
      Symbol#size: 3
      Symbol#encoding: !ruby/encoding US-ASCII

Nested Sets

This example shows nested sets.

show.rb:

require 'set'

require 'debug_helper'

set = Set.new(
    [0,
     Set.new([1, 2]),
     Set.new([3, 4]),
     ])
DebugHelper.show(set, 'My nested sets')

The output shows details of the sets.

show.yaml:

---
Set (message='My nested sets'):
  Set#size: 3
  Element 0: Integer 0
  Element 1:
    Set:
      Set#size: 2
      Element 0: Integer 1
      Element 1: Integer 2
  Element 2:
    Set:
      Set#size: 2
      Element 0: Integer 3
      Element 1: Integer 4

Circular Sets

This example shows sets that make a circular reference.

show.rb:

require 'set'

require 'debug_helper'

set_0 = Set.new([])
set_1 = Set.new([])
set_0.add(set_1)
set_1.add(set_0)
DebugHelper.show(set_0, 'My circular sets')

The output shows details of the sets.

The circular reference is not followed.

show.yaml:

---
Set (message='My circular sets'):
  Set#size: 1
  Element 0:
    Set:
      Set#size: 1
      Element 0: 'Set #<Set: {#<Set: {#<Set: {...}>}>}>'

String

Simple String

This example shows a simple string.

show.rb:

require 'debug_helper'

s = 'Lorem ipsum'
DebugHelper.show(s, 'My simple string')

The output shows details of the string.

show.yaml:

---
String (message='My simple string'):
  String#to_s: Lorem ipsum
  String#size: 11
  String#encoding: !ruby/encoding UTF-8
  String#ascii_only?: true
  String#bytesize: 11

Multiline String

This example shows a multiline string.

show.rb:

require 'debug_helper'

s = <<EOT
Lorem Ipsum dolor sit amet,consectetur adipisicing elit,
sed doeiusmod tempor incididunt ut laboreet dolore magna aliqua.
EOT
DebugHelper.show(s, 'My multiline string')

The output shows details of the string.

show.yaml:

---
String (message='My multiline string'):
  String#to_s: |
    Lorem Ipsum dolor sit amet,consectetur adipisicing elit,
    sed doeiusmod tempor incididunt ut laboreet dolore magna aliqua.
  String#size: 122
  String#encoding: !ruby/encoding UTF-8
  String#ascii_only?: true
  String#bytesize: 122

Struct

Simple Struct

This example shows a simple struct.

show.rb:

require 'debug_helper'

MyStruct = Struct.new(:a, :b, :c)
struct = MyStruct.new(0, 1, 2)
DebugHelper.show(struct, 'My simple struct')

The output shows details of the struct.

show.yaml:

---
MyStruct (message='My simple struct'):
  MyStruct#size: 3
  Member 0:
    Name:
      Symbol:
        Symbol#to_s: a
        Symbol#size: 1
        Symbol#encoding: !ruby/encoding US-ASCII
    Value: Integer 0
  Member 1:
    Name:
      Symbol:
        Symbol#to_s: b
        Symbol#size: 1
        Symbol#encoding: !ruby/encoding US-ASCII
    Value: Integer 1
  Member 2:
    Name:
      Symbol:
        Symbol#to_s: c
        Symbol#size: 1
        Symbol#encoding: !ruby/encoding US-ASCII
    Value: Integer 2

Mixed Struct

This example shows a struct of mixed values.

show.rb:

require 'debug_helper'

MyStruct = Struct.new(:a, :b, :c)
struct = MyStruct.new(0, 'one', :two)
DebugHelper.show(struct, 'My mixed struct')

The output shows details of the struct.

show.yaml:

---
MyStruct (message='My mixed struct'):
  MyStruct#size: 3
  Member 0:
    Name:
      Symbol:
        Symbol#to_s: a
        Symbol#size: 1
        Symbol#encoding: !ruby/encoding US-ASCII
    Value: Integer 0
  Member 1:
    Name:
      Symbol:
        Symbol#to_s: b
        Symbol#size: 1
        Symbol#encoding: !ruby/encoding US-ASCII
    Value:
      String:
        String#to_s: one
        String#size: 3
        String#encoding: !ruby/encoding UTF-8
        String#ascii_only?: true
        String#bytesize: 3
  Member 2:
    Name:
      Symbol:
        Symbol#to_s: c
        Symbol#size: 1
        Symbol#encoding: !ruby/encoding US-ASCII
    Value:
      Symbol:
        Symbol#to_s: two
        Symbol#size: 3
        Symbol#encoding: !ruby/encoding US-ASCII

Nested Structs

This example shows nested structs.

show.rb:

require 'debug_helper'

MyStruct_0 = Struct.new(:a, :b)
MyStruct_1 = Struct.new(:c, :d)
struct_1a = MyStruct_1.new(2, 3)
struct_1b = MyStruct_1.new(4, 5)
struct_0 = MyStruct_0.new(struct_1a, struct_1b)
DebugHelper.show(struct_0, 'My nested struct')

The output shows details of the structs.

show.yaml:

---
MyStruct_0 (message='My nested struct'):
  MyStruct_0#size: 2
  Member 0:
    Name:
      Symbol:
        Symbol#to_s: a
        Symbol#size: 1
        Symbol#encoding: !ruby/encoding US-ASCII
    Value:
      MyStruct_1:
        MyStruct_1#size: 2
        Member 0:
          Name:
            Symbol:
              Symbol#to_s: c
              Symbol#size: 1
              Symbol#encoding: !ruby/encoding US-ASCII
          Value: Integer 2
        Member 1:
          Name:
            Symbol:
              Symbol#to_s: d
              Symbol#size: 1
              Symbol#encoding: !ruby/encoding US-ASCII
          Value: Integer 3
  Member 1:
    Name:
      Symbol:
        Symbol#to_s: b
        Symbol#size: 1
        Symbol#encoding: !ruby/encoding US-ASCII
    Value:
      MyStruct_1:
        MyStruct_1#size: 2
        Member 0:
          Name:
            Symbol:
              Symbol#to_s: c
              Symbol#size: 1
              Symbol#encoding: !ruby/encoding US-ASCII
          Value: Integer 4
        Member 1:
          Name:
            Symbol:
              Symbol#to_s: d
              Symbol#size: 1
              Symbol#encoding: !ruby/encoding US-ASCII
          Value: Integer 5

Circular Structs

This example shows structs that make a circular reference.

show.rb:

require 'debug_helper'

MyStruct = Struct.new(:a, :b, :c)
struct_0 = MyStruct.new(0, 1, 2)
struct_1 = MyStruct.new(3, 4, 5)
struct_0.a = struct_1
struct_1.a = struct_0
DebugHelper.show(struct_0, 'My circular struct')

The output shows details of the structs.

The circular reference is not followed.

show.yaml:

---
MyStruct (message='My circular struct'):
  MyStruct#size: 3
  Member 0:
    Name:
      Symbol:
        Symbol#to_s: a
        Symbol#size: 1
        Symbol#encoding: !ruby/encoding US-ASCII
    Value:
      MyStruct:
        MyStruct#size: 3
        Member 0:
          Name:
            Symbol:
              Symbol#to_s: a
              Symbol#size: 1
              Symbol#encoding: !ruby/encoding US-ASCII
          Value: 'MyStruct #<struct MyStruct a=#<struct MyStruct a=#<struct MyStruct:...>,
            b=4, c=5>, b=1, c=2>'
        Member 1:
          Name:
            Symbol:
              Symbol#to_s: b
              Symbol#size: 1
              Symbol#encoding: !ruby/encoding US-ASCII
          Value: Integer 4
        Member 2:
          Name:
            Symbol:
              Symbol#to_s: c
              Symbol#size: 1
              Symbol#encoding: !ruby/encoding US-ASCII
          Value: Integer 5
  Member 1:
    Name:
      Symbol:
        Symbol#to_s: b
        Symbol#size: 1
        Symbol#encoding: !ruby/encoding US-ASCII
    Value: Integer 1
  Member 2:
    Name:
      Symbol:
        Symbol#to_s: c
        Symbol#size: 1
        Symbol#encoding: !ruby/encoding US-ASCII
    Value: Integer 2

Symbol

Simple Symbol

This example shows a simple symbol.

show.rb:

require 'debug_helper'

DebugHelper.show(:lorem_ipsum, 'My symbol')

The output shows details of the symbol.

show.yaml:

---
Symbol (message='My symbol'):
  Symbol#to_s: lorem_ipsum
  Symbol#size: 11
  Symbol#encoding: !ruby/encoding US-ASCII

Object

Classes not mentioned above are not analyzed, but are treated more simply.

Unanalyzed Object

This example shows an object that will not be analyzed.

show.rb:

require 'debug_helper'

class MyClass
  def inspect
    'My class inspection'
  end
end
DebugHelper.show(MyClass.new, 'My class')

The output shows details of the object.

show.yaml:

--- MyClass (message='My class') My class inspection

Custom

You can create custom handlers for your own classes.

Instance Methods

This example shows a custom handler that explicates via instance methods.

Here's a class Foo that has some instance methods:

foo.rb:

require 'debug_helper'

class Foo

  def my_array
    %w/foo bar baz/
  end

  def my_hash
    {:a => 0, :b => 1}
  end

end

Here's its custom debug handler class FooHandler. The array returned by method calls_for_instance tells the base class Handler which methods to call for the explication, and what arguments to pass, if any.

foo_handler.rb:

require 'debug_helper'

class DebugHelper

  class FooHandler < Handler

    def calls_for_instance
      [
          [:my_array],
          [:my_hash],
          [:respond_to?, :your_array],
          [:respond_to?, :your_hash],
      ]
    end

  end

end

Here's a program that uses the custom handler.

show.rb:

require 'debug_helper'
require_relative 'foo'
require_relative 'foo_handler'

DebugHelper.show(Foo.new, 'My class Foo')

The output shows details of the object.

show.yaml:

---
Foo (message='My class Foo'):
  Foo#my_array:
  - foo
  - bar
  - baz
  Foo#my_hash:
    :a: 0
    :b: 1
  Foo#respond_to?(:your_array): false
  Foo#respond_to?(:your_hash): false

Singleton Methods

This example shows a custom handler that explicates via singleton methods.

Here's a class Foo that has some singleton methods:

foo.rb:

require 'debug_helper'

class Foo

  def self.my_array
    %w/bat bam bad/
  end

  def self.my_hash
    {:c => 2, :d => 3}
  end

end

Here's its custom debug handler class FooHandler. The array returned in method calls_for_class tells the base class Handler which methods to call for the explication.

foo_handler.rb:

require 'debug_helper'

class DebugHelper

  class FooHandler < Handler

    def calls_for_class
      [
          [:my_array],
          [:my_hash],
          [:respond_to?, :your_array],
          [:respond_to?, :your_hash],
      ]
    end

  end

end

Here's a program that uses the custom handler.

show.rb:

require 'debug_helper'
require_relative 'foo'
require_relative 'foo_handler'

DebugHelper.show(Foo.new, 'My class Foo')

The output shows details of the object.

show.yaml:

---
Foo (message='My class Foo'):
  Foo.my_array:
  - bat
  - bam
  - bad
  Foo.my_hash:
    :c: 2
    :d: 3
  Foo.respond_to?(:your_array): false
  Foo.respond_to?(:your_hash): false

Instance and Singleton Methods

This example shows a custom handler that explicates via both kinds of methods.

Here's a class Foo that has instance methods and singleton methods:

foo.rb:

require 'debug_helper'

class Foo

  def my_array
    %w/foo bar baz/
  end

  def my_hash
    {:a => 0, :b => 1}
  end

  def self.my_array
    %w/bat bam bad/
  end

  def self.my_hash
    {:c => 2, :d => 3}
  end

end

Here's its custom debug handler class FooHandler.

foo_handler.rb:

require 'debug_helper'

class DebugHelper

  class FooHandler < Handler

    def calls_for_instance
      [
          [:my_array],
          [:my_hash],
          [:respond_to?, :your_array],
          [:respond_to?, :your_hash],
      ]
    end

    def calls_for_class
      [
          [:my_array],
          [:my_hash],
          [:respond_to?, :your_array],
          [:respond_to?, :your_hash],
      ]
    end

  end

end

Here's a program that uses the custom handler.

show.rb:

require 'debug_helper'
require_relative 'foo'
require_relative 'foo_handler'

DebugHelper.show(Foo.new, 'My class Foo')

The output shows details of the object.

show.yaml:

---
Foo (message='My class Foo'):
  Foo#my_array:
  - foo
  - bar
  - baz
  Foo#my_hash:
    :a: 0
    :b: 1
  Foo#respond_to?(:your_array): false
  Foo#respond_to?(:your_hash): false
  Foo.my_array:
  - bat
  - bam
  - bad
  Foo.my_hash:
    :c: 2
    :d: 3
  Foo.respond_to?(:your_array): false
  Foo.respond_to?(:your_hash): false

Options

Option `depth`

This example shows how option depth affects output.

show.rb:

require 'debug_helper'

ary = [0,
       [1,
        [2,
         [3,
          [4]
         ]
        ]
       ]
]
(1..5).each do |depth|
  message = "Show depth #{depth}"
  DebugHelper.show(ary, message, {:depth => depth})
end

The output shows output for various depths.

show.yaml:

---
Array (message='Show depth 1'):
  Array#size: 2
  Element 0: Integer 0
  Element 1: Array [1, [2, [3, [4]]]]
---
Array (message='Show depth 2'):
  Array#size: 2
  Element 0: Integer 0
  Element 1:
    Array:
      Array#size: 2
      Element 0: Integer 1
      Element 1: Array [2, [3, [4]]]
---
Array (message='Show depth 3'):
  Array#size: 2
  Element 0: Integer 0
  Element 1:
    Array:
      Array#size: 2
      Element 0: Integer 1
      Element 1:
        Array:
          Array#size: 2
          Element 0: Integer 2
          Element 1: Array [3, [4]]
---
Array (message='Show depth 4'):
  Array#size: 2
  Element 0: Integer 0
  Element 1:
    Array:
      Array#size: 2
      Element 0: Integer 1
      Element 1:
        Array:
          Array#size: 2
          Element 0: Integer 2
          Element 1:
            Array:
              Array#size: 2
              Element 0: Integer 3
              Element 1: Array [4]
---
Array (message='Show depth 5'):
  Array#size: 2
  Element 0: Integer 0
  Element 1:
    Array:
      Array#size: 2
      Element 0: Integer 1
      Element 1:
        Array:
          Array#size: 2
          Element 0: Integer 2
          Element 1:
            Array:
              Array#size: 2
              Element 0: Integer 3
              Element 1:
                Array:
                  Array#size: 1
                  Element 0: Integer 4

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Metadata

Debug Helper

New in Version 2.1

About Debug Helper

Class Method or Module Method?

Array

Simple Array

Mixed Array

Nested Arrays

Circular Arrays

Dir

Simple Dir

Exception

Simple Exception

File

Simple File

Hash

Simple Hash

Mixed Hash

Nested Hashes

Circular Hashes

IO

Simple IO

MatchData

Simple MatchData

Multiple Captures

Named Captures

Method

Simple Method

OpenStruct

Simple OpenStruct

Mixed OpenStruct

Nested OpenStructs

Circular OpenStructs

Range

Inclusive Range

Exclusive Range

Regexp

Simple Regexp

Named Captures

Set

Simple Set

Mixed Set

Nested Sets

Circular Sets

String

Simple String

Multiline String

Struct

Simple Struct

Mixed Struct

Nested Structs

Circular Structs

Symbol

Simple Symbol

Object

Unanalyzed Object

Custom

Instance Methods

Singleton Methods

Instance and Singleton Methods

Options

Option depth

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Option `depth`