class PP

A pretty-printer for Ruby objects.

What PP Does ↑

Standard output by p returns this:

#<PP:0x81fedf0 @genspace=#<Proc:0x81feda0>, @group_queue=#<PrettyPrint::GroupQueue:0x81fed3c @queue=[[#<PrettyPrint::Group:0x81fed78 @breakables=[], @depth=0, @break=false>], []]>, @buffer=[], @newline="\n", @group_stack=[#<PrettyPrint::Group:0x81fed78 @breakables=[], @depth=0, @break=false>], @buffer_width=0, @indent=0, @maxwidth=79, @output_width=2, @output=#<IO:0x8114ee4>>

Pretty-printed output returns this:

#<PP:0x81fedf0
 @buffer=[],
 @buffer_width=0,
 @genspace=#<Proc:0x81feda0>,
 @group_queue=
  #<PrettyPrint::GroupQueue:0x81fed3c
   @queue=
    [[#<PrettyPrint::Group:0x81fed78 @break=false, @breakables=[], @depth=0>],
     []]>,
 @group_stack=
  [#<PrettyPrint::Group:0x81fed78 @break=false, @breakables=[], @depth=0>],
 @indent=0,
 @maxwidth=79,
 @newline="\n",
 @output=#<IO:0x8114ee4>,
 @output_width=2>

Usage ↑

pp(obj)             #=> obj
pp obj              #=> obj
pp(obj1, obj2, ...) #=> [obj1, obj2, ...]
pp()                #=> nil

Output obj(s) to $> in pretty printed format.

It returns obj(s).

Output Customization ↑

To define a customized pretty printing function for your classes, redefine method #pretty_print(pp) in the class. Note that require 'pp' is needed before redefining #pretty_print(pp).

#pretty_print takes the pp argument, which is an instance of the PP class. The method uses text, breakable, nest, group and pp to print the object.

Pretty-Print JSON ↑

To pretty-print JSON refer to JSON#pretty_generate.

Author ↑

Tanaka Akira <akr@fsij.org>

Constants

VERSION

Public Class Methods

pp (obj, out=$>, width=width_for(out))

Outputs obj to out in pretty printed format of width columns in width.

If out is omitted, $> is assumed. If width is omitted, the width of out is assumed (see width_for).

PP.pp returns out.

# File lib/pp.rb, line 95
def PP.pp(obj, out=$>, width=width_for(out))
  q = new(out, width)
  q.guard_inspect_key {q.pp obj}
  q.flush
  #$pp = q
  out << "\n"
end
sharing_detection ()

Returns the sharing detection flag as a boolean value. It is false (nil) by default.

# File lib/pp.rb, line 124
def sharing_detection
  Ractor.current[:pp_sharing_detection]
end
sharing_detection= (b)

Sets the sharing detection flag to b.

# File lib/pp.rb, line 128
def sharing_detection=(b)
  Ractor.current[:pp_sharing_detection] = b
end
singleline_pp (obj, out=$>)

Outputs obj to out like PP.pp but with no indent and newline.

PP.singleline_pp returns out.

# File lib/pp.rb, line 107
def PP.singleline_pp(obj, out=$>)
  q = SingleLine.new(out)
  q.guard_inspect_key {q.pp obj}
  q.flush
  out
end
width_for (out)

Returns the usable width for out. As the width of out:

  1. If out is assigned to a tty device, its width is used.

  2. Otherwise, or it could not get the value, the COLUMN environment variable is assumed to be set to the width.

  3. If COLUMN is not set to a non-zero number, 80 is assumed.

And finally, returns the above width value - 1.

  • This -1 is for Windows command prompt, which moves the cursor to the next line if it reaches the last column.

# File lib/pp.rb, line 78
def PP.width_for(out)
  begin
    require 'io/console'
    _, width = out.winsize
  rescue LoadError, NoMethodError, SystemCallError
  end
  (width || ENV['COLUMNS']&.to_i&.nonzero? || 80) - 1
end