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 $> in pretty printed format.
It returns obj(s).
Output Customization
To define a customized pretty printing function for your classes, redefine method pretty_print(pp) in the class. Note that require 'pp' is needed before redefining pretty_print(pp).
pretty_print takes the pp argument, which is an instance of the PP class. The method uses text, breakable, nest, group and pp to print the object.
Pretty-Print JSON
To pretty-print JSON refer to JSON#pretty_generate.
Author
Tanaka Akira <akr@fsij.org>
# File tmp/rubies/ruby-3.3.0/lib/pp.rb, line 95
def PP.pp(obj, out=$>, width=width_for(out))
q = PP.new(out, width)
q.guard_inspect_key {q.pp obj}
q.flush
#$pp = q
out << "\n"
end
# File tmp/rubies/ruby-3.3.0/lib/pp.rb, line 124
def sharing_detection
Ractor.current[:pp_sharing_detection]
end
Returns the sharing detection flag as a boolean value. It is false (nil) by default.
# File tmp/rubies/ruby-3.3.0/lib/pp.rb, line 128
def sharing_detection=(b)
Ractor.current[:pp_sharing_detection] = b
end
Sets the sharing detection flag to b.
# File tmp/rubies/ruby-3.3.0/lib/pp.rb, line 107
def PP.singleline_pp(obj, out=$>)
q = SingleLine.new(out)
q.guard_inspect_key {q.pp obj}
q.flush
out
end
Outputs obj to out like PP.pp but with no indent and newline.
PP.singleline_pp returns out.
# File tmp/rubies/ruby-3.3.0/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
Returns the usable width for out. As the width of out:
-
If
outis assigned to a tty device, its width is used. -
Otherwise, or it could not get the value, the
COLUMNenvironment variable is assumed to be set to the width. -
If
COLUMNis 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.