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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.

#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>

Public Class Methods

pp(obj, out=$>, width=width_for(out)) click to toggle source

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 pp.rb, line 91
def PP.pp(obj, out=$>, width=width_for(out))
  q = PP.new(out, width)
  q.guard_inspect_key {q.pp obj}
  q.flush
  #$pp = q
  out << "\n"
end
sharing_detection() click to toggle source

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

 
               # File pp.rb, line 120
def sharing_detection
  Ractor.current[:pp_sharing_detection]
end
sharing_detection=(b) click to toggle source

Sets the sharing detection flag to b.

 
               # File pp.rb, line 124
def sharing_detection=(b)
  Ractor.current[:pp_sharing_detection] = b
end
singleline_pp(obj, out=$>) click to toggle source

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

PP.singleline_pp returns out.

 
               # File pp.rb, line 103
def PP.singleline_pp(obj, out=$>)
  q = SingleLine.new(out)
  q.guard_inspect_key {q.pp obj}
  q.flush
  out
end
width_for(out) click to toggle source

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 pp.rb, line 74
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