# PP / PrettyPrint annoyances

**URL:** <https://www.ruby-forum.com/t/pp-prettyprint-annoyances/74085>\
**Category:** Ruby\
**Created:** [October 29, 2006, 10:23pm UTC](https://www.ruby-forum.com/t/pp-prettyprint-annoyances/74085 "2006-10-29T22:23:53Z")\
**Posts on this page:** 6\
**Page:** 1

<div class="post-metadata">

**Author:** ![mcmire](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/f17d59/32.png) [@mcmire](https://www.ruby-forum.com/u/mcmire)\
**Post date:** [October 29, 2006, 10:23pm UTC](https://www.ruby-forum.com/t/pp-prettyprint-annoyances/74085/1 "2006-10-29T22:23:53Z")

</div>

Hello all,

PP/PrettyPrint comes in handy when I’m trying to inspect the contents of  
large arrays, but what if some elements are short length-wise?

irb(main):001:0\> require ‘pp’  
=\> true  
irb(main):002:0\> pp (0…20).to\_a  
[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19,  
20]  
=\> nil  
irb(main):003:0\> pp (0…40).to\_a  
[0,  
1,  
2,  
3,  
4,  
5,  
6,  
7,  
8,  
9,  
10,  
11,  
12,  
13,  
14,  
15,  
16,  
17,  
18,  
19,  
20,  
21,  
22,  
23,  
24,  
25,  
26,  
27,  
28,  
29,  
30,  
31,  
32,  
33,  
34,  
35,  
36,  
37,  
38,  
39,  
40]  
=\> nil

This behavior is sort of ridiculous in my opinion. I’d rather have  
something  
more like:

[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19,  
20,  
21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38,  
39, 40]

I’ve looked at the source code and documentation for PrettyPrint and PP  
but  
I don’t understand how they work, so I’m not really sure how the classes  
could be extended so they work how I want them to work. I also tried  
numerous Google searches and it seems no one has a problem with the  
default  
behavior as I do. Can someone give me a hand here or at least point me  
in  
the right direction?

---

<div class="post-metadata">

**Author:** ![mcmire](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/f17d59/32.png) [@mcmire](https://www.ruby-forum.com/u/mcmire)\
**Post date:** [November 2, 2006, 5:52pm UTC](https://www.ruby-forum.com/t/pp-prettyprint-annoyances/74085/2 "2006-11-02T17:52:43Z")

</div>

Elliot W. wrote:

> This behavior is sort of ridiculous in my opinion. I’d rather have  
> something  
> more like:
> 
> [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19,  
> 20,  
> 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38,  
> 39, 40]

The problem with ‘pp’ in my opinion is the mysterious ‘breakable’. What  
you can do is omit the and handle end of line cases in different manner.  
Someday I may look at changing ‘breakable’, but for now this works.

\<\< START OF CODE

require ‘pp’

class PP  
def comma  
text ‘,’  
end

def comma\_newline  
text “,\n”  
end

def seplist\_with\_limit(list, limit=20, item\_sep=nil, line\_sep=nil,  
iter\_method=:each)  
item\_sep ||= lambda { comma }  
line\_sep ||= lambda { comma\_newline }

```
count = 0
first = true
list. __send__ (iter_method) { |v|
  if count % limit == 0
    if first
      first = false
    else
      line_sep.call
    end
  else
    item_sep.call
  end
  yield(v)
  count += 1
}

```

end  
end

class Array  
def pretty\_print(q)  
q.group(1, ‘[’, ‘]’) {  
q.seplist\_with\_limit(self, 20) { |v|  
q.pp v  
}  
}  
end  
end

pp (0…20).to\_a

pp (0…40).to\_a

> > END OF CODE

---

<div class="post-metadata">

**Author:** ![mcmire](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/f17d59/32.png) [@mcmire](https://www.ruby-forum.com/u/mcmire)\
**Post date:** [November 7, 2006, 10:44am UTC](https://www.ruby-forum.com/t/pp-prettyprint-annoyances/74085/3 "2006-11-07T10:44:44Z")

</div>

Elliot W. wrote:

> =\> nil  
> irb(main):003:0\> pp (0…40).to\_a  
> [0,  
> \<snip long array
> 
> I’ve looked at the source code and documentation for PrettyPrint and  
> PP but  
> I don’t understand how they work, so I’m not really sure how the classes  
> could be extended so they work how I want them to work. I also tried  
> numerous Google searches and it seems no one has a problem with the  
> default  
> behavior as I do. Can someone give me a hand here or at least point me in  
> the right direction?

You could just use inspect (not sure if that’s what you really want,  
though):

irb(main):001:0\> (0…100).to\_a.inspect  
=\> “[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18,  
19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36,  
37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54,  
55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72,  
73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90,  
91, 92, 93, 94, 95, 96, 97, 98, 99, 100]”

-Justin

---

<div class="post-metadata">

**Author:** ![mcmire](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/f17d59/32.png) [@mcmire](https://www.ruby-forum.com/u/mcmire)\
**Post date:** [November 3, 2006, 1:06am UTC](https://www.ruby-forum.com/t/pp-prettyprint-annoyances/74085/4 "2006-11-03T01:06:22Z")

</div>

1. 

irb(main):011:0\> a=(0…20).to\_a  
=\> [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18,  
19, 20]  
irb(main):012:0\> print a.inspect  
[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19,  
20]  
=\> nil

2)irb(main):013:0\> a=(0…20).to\_a  
=\> [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18,  
19, 20]  
irb(main):014:0\> a.each{|e| print “#{e}\t”}  
0 1 2 3 4 5 6 7 8  
9 10 11 12 13 14 15 16 17  
18 19 20  
=\> [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18,  
19, 20]

Which one do you really want 1) or 2)?

Li

---

<div class="post-metadata">

**Author:** ![mcmire](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/f17d59/32.png) [@mcmire](https://www.ruby-forum.com/u/mcmire)\
**Post date:** [November 7, 2006, 10:46am UTC](https://www.ruby-forum.com/t/pp-prettyprint-annoyances/74085/5 "2006-11-07T10:46:25Z")

</div>

#inspect would work if the array were simple, but the array I want to  
pretty  
print is not. I would give you the real case but it’s really long, so a  
better example is:

#!/usr/bin/ruby  
require ‘pp’  
array = [  
{ :key1 =\> ‘value1’, :key2 =\> ‘value2’, :key3 =\> ‘value3’ },  
1, 2, 3,  
[  
‘foo’, ‘bar’,  
[  
{ :key1 =\> ‘value1’, :key2 =\> ‘value2’ },  
‘baz’, ‘quux’  
]  
]  
]  
array2 = array.dup  
array2[4][2].push(‘a longer string’, ‘an even longer string’)

p array  
puts  
pp array  
puts  
p array2  
puts  
pp array2

==OUTPUT==

[{:key1=\>“value1”, :key2=\>“value2”, :key3=\>“value3”}, 1, 2, 3, [“foo”,  
“bar”, [{:key1=\>“value1”, :key2=\>“value2”}, “baz”, “quux”]]]

[{:key1=\>“value1”, :key2=\>“value2”, :key3=\>“value3”},  
1,  
2,  
3,  
[“foo”, “bar”, [{:key1=\>“value1”, :key2=\>“value2”}, “baz”, “quux”]]]

[{:key1=\>“value1”, :key2=\>“value2”, :key3=\>“value3”}, 1, 2, 3, [“foo”,  
“bar”, [{:key1=\>“value1”, :key2=\>“value2”}, “baz”, “quux”, “longer  
string”,  
“even longer string”]]]

[{:key1=\>“value1”, :key2=\>“value2”, :key3=\>“value3”},  
1,  
2,  
3,  
[“foo”,  
“bar”,  
[{:key1=\>“value1”, :key2=\>“value2”},  
“baz”,  
“quux”,  
“longer string”,  
“even longer string”]]]

For array2, I want 1, 2, and 3 to be on one line, “foo” and “bar” to be  
one  
line, and “baz”, “quux” and “longer string” to be one line. PP isn’t  
doing  
that, obviously.

Perhaps someone knows of another pretty print library?

– Elliot

---

<div class="post-metadata">

**Author:** ![mcmire](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/f17d59/32.png) [@mcmire](https://www.ruby-forum.com/u/mcmire)\
**Post date:** [November 7, 2006, 10:47am UTC](https://www.ruby-forum.com/t/pp-prettyprint-annoyances/74085/6 "2006-11-07T10:47:24Z")

</div>

On 10/30/06, Elliot W. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote:

> ```
> 'foo', 'bar',
> 
> ```
> 
> puts
> 
> [{:key1=\>“value1”, :key2=\>“value2”, :key3=\>“value3”},
> 
> For array2, I want 1, 2, and 3 to be on one line, “foo” and “bar” to be one  
> line, and “baz”, “quux” and “longer string” to be one line. PP isn’t doing  
> that, obviously.
> 
> Perhaps someone knows of another pretty print library?

I thought that changing Array#pretty\_print would be sufficient, after  
deeper look it seems that the problem is in the prettyprint module -  
somewhere in the breaking routines - if the whole group (=array,  
hash,…) is short enough to fit within the desired width (default  
=79) then it’s not split into line. Otherwise _every_ line is split.  
So it’s a kind of take all or nothing deal.

The solution would be (better, harder) patching prettyprint.rb to  
check the individual fields for overflow or (hack, posissibly easier)  
to patch Array#pretty\_print from pp.rb to add breakable just in the  
desired places.