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# Copyright (C) 2014 Kouhei Sutou <kou@cozmixng.org>
# This file is based on prettyprint.rb in CRuby.
# This class implements a pretty printing algorithm. It finds line breaks and
# nice indentations for grouped structure.
#
# By default, the class assumes that primitive elements are strings and each
# byte in the strings have single column in width. But it can be used for
# other situations by giving suitable arguments for some methods:
# * newline object and space generation block for PrettyPrint.new
# * optional width argument for PrettyPrint#text
# * PrettyPrint#breakable
#
# There are several candidate uses:
# * text formatting using proportional fonts
# * multibyte characters which has columns different to number of bytes
# * non-string formatting
#
# == Bugs
# * Box based formatting?
# * Other (better) model/algorithm?
#
# Report any bugs at http://bugs.ruby-lang.org
#
# == References
# Christian Lindig, Strictly Pretty, March 2000,
# http://www.st.cs.uni-sb.de/~lindig/papers/#pretty
#
# Philip Wadler, A prettier printer, March 1998,
# http://homepages.inf.ed.ac.uk/wadler/topics/language-design.html#prettier
#
# == Author
# Tanaka Akira <akr@fsij.org>
#
class PrettyPrint
# This is a convenience method which is same as follows:
#
# begin
# q = PrettyPrint.new(output, maxwidth, newline, &genspace)
# ...
# q.flush
# output
# end
#
def PrettyPrint.format(output='', maxwidth=79, newline="\n", genspace=lambda {|n| ' ' * n})
q = PrettyPrint.new(output, maxwidth, newline, &genspace)
yield q
q.flush
output
end
# This is similar to PrettyPrint::format but the result has no breaks.
#
# +maxwidth+, +newline+ and +genspace+ are ignored.
#
# The invocation of +breakable+ in the block doesn't break a line and is
# treated as just an invocation of +text+.
#
def PrettyPrint.singleline_format(output='', maxwidth=nil, newline=nil, genspace=nil)
q = SingleLine.new(output)
yield q
output
end
# Creates a buffer for pretty printing.
#
# +output+ is an output target. If it is not specified, '' is assumed. It
# should have a << method which accepts the first argument +obj+ of
# PrettyPrint#text, the first argument +sep+ of PrettyPrint#breakable, the
# first argument +newline+ of PrettyPrint.new, and the result of a given
# block for PrettyPrint.new.
#
# +maxwidth+ specifies maximum line length. If it is not specified, 79 is
# assumed. However actual outputs may overflow +maxwidth+ if long
# non-breakable texts are provided.
#
# +newline+ is used for line breaks. "\n" is used if it is not specified.
#
# The block is used to generate spaces. {|width| ' ' * width} is used if it
# is not given.
#
def initialize(output='', maxwidth=79, newline="\n", &genspace)
@output = output
@maxwidth = maxwidth
@newline = newline
@genspace = genspace || lambda {|n| ' ' * n}
@output_width = 0
@buffer_width = 0
@buffer = []
root_group = Group.new(0)
@group_stack = [root_group]
@group_queue = GroupQueue.new(root_group)
@indent = 0
end
# The output object.
#
# This defaults to '', and should accept the << method
attr_reader :output
# The maximum width of a line, before it is separated in to a newline
#
# This defaults to 79, and should be a Fixnum
attr_reader :maxwidth
# The value that is appended to +output+ to add a new line.
#
# This defaults to "\n", and should be String
attr_reader :newline
# A lambda or Proc, that takes one argument, of a Fixnum, and returns
# the corresponding number of spaces.
#
# By default this is:
# lambda {|n| ' ' * n}
attr_reader :genspace
# The number of spaces to be indented
attr_reader :indent
# The PrettyPrint::GroupQueue of groups in stack to be pretty printed
attr_reader :group_queue
# Returns the group most recently added to the stack.
#
# Contrived example:
# out = ""
# => ""
# q = PrettyPrint.new(out)
# => #<PrettyPrint:0x82f85c0 @output="", @maxwidth=79, @newline="\n", @genspace=#<Proc:0x82f8368@/home/vbatts/.rvm/rubies/ruby-head/lib/ruby/2.0.0/prettyprint.rb:82 (lambda)>, @output_width=0, @buffer_width=0, @buffer=[], @group_stack=[#<PrettyPrint::Group:0x82f8138 @depth=0, @breakables=[], @break=false>], @group_queue=#<PrettyPrint::GroupQueue:0x82fb7c0 @queue=[[#<PrettyPrint::Group:0x82f8138 @depth=0, @breakables=[], @break=false>]]>, @indent=0>
# q.group {
# q.text q.current_group.inspect
# q.text q.newline
# q.group(q.current_group.depth + 1) {
# q.text q.current_group.inspect
# q.text q.newline
# q.group(q.current_group.depth + 1) {
# q.text q.current_group.inspect
# q.text q.newline
# q.group(q.current_group.depth + 1) {
# q.text q.current_group.inspect
# q.text q.newline
# }
# }
# }
# }
# => 284
# puts out
# #<PrettyPrint::Group:0x8354758 @depth=1, @breakables=[], @break=false>
# #<PrettyPrint::Group:0x8354550 @depth=2, @breakables=[], @break=false>
# #<PrettyPrint::Group:0x83541cc @depth=3, @breakables=[], @break=false>
# #<PrettyPrint::Group:0x8347e54 @depth=4, @breakables=[], @break=false>
def current_group
@group_stack.last
end
# Breaks the buffer into lines that are shorter than #maxwidth
def break_outmost_groups
while @maxwidth < @output_width + @buffer_width
return unless group = @group_queue.deq
until group.breakables.empty?
data = @buffer.shift
@output_width = data.output(@output, @output_width)
@buffer_width -= data.width
end
while !@buffer.empty? && Text === @buffer.first
text = @buffer.shift
@output_width = text.output(@output, @output_width)
@buffer_width -= text.width
end
end
end
# This adds +obj+ as a text of +width+ columns in width.
#
# If +width+ is not specified, obj.length is used.
#
def text(obj, width=obj.length)
if @buffer.empty?
@output << obj
@output_width += width
else
text = @buffer.last
unless Text === text
text = Text.new
@buffer << text
end
text.add(obj, width)
@buffer_width += width
break_outmost_groups
end
end
# This is similar to #breakable except
# the decision to break or not is determined individually.
#
# Two #fill_breakable under a group may cause 4 results:
# (break,break), (break,non-break), (non-break,break), (non-break,non-break).
# This is different to #breakable because two #breakable under a group
# may cause 2 results:
# (break,break), (non-break,non-break).
#
# The text +sep+ is inserted if a line is not broken at this point.
#
# If +sep+ is not specified, " " is used.
#
# If +width+ is not specified, +sep.length+ is used. You will have to
# specify this when +sep+ is a multibyte character, for example.
#
def fill_breakable(sep=' ', width=sep.length)
group { breakable sep, width }
end
# This says "you can break a line here if necessary", and a +width+\-column
# text +sep+ is inserted if a line is not broken at the point.
#
# If +sep+ is not specified, " " is used.
#
# If +width+ is not specified, +sep.length+ is used. You will have to
# specify this when +sep+ is a multibyte character, for example.
#
def breakable(sep=' ', width=sep.length)
group = @group_stack.last
if group.break?
flush
@output << @newline
@output << @genspace.call(@indent)
@output_width = @indent
@buffer_width = 0
else
@buffer << Breakable.new(sep, width, self)
@buffer_width += width
break_outmost_groups
end
end
# Groups line break hints added in the block. The line break hints are all
# to be used or not.
#
# If +indent+ is specified, the method call is regarded as nested by
# nest(indent) { ... }.
#
# If +open_obj+ is specified, <tt>text open_obj, open_width</tt> is called
# before grouping. If +close_obj+ is specified, <tt>text close_obj,
# close_width</tt> is called after grouping.
#
def group(indent=0, open_obj='', close_obj='', open_width=open_obj.length, close_width=close_obj.length)
text open_obj, open_width
group_sub {
nest(indent) {
yield
}
}
text close_obj, close_width
end
# Takes a block and queues a new group that is indented 1 level further.
def group_sub
group = Group.new(@group_stack.last.depth + 1)
@group_stack.push group
@group_queue.enq group
begin
yield
ensure
@group_stack.pop
if group.breakables.empty?
@group_queue.delete group
end
end
end
# Increases left margin after newline with +indent+ for line breaks added in
# the block.
#
def nest(indent)
@indent += indent
begin
yield
ensure
@indent -= indent
end
end
# outputs buffered data.
#
def flush
@buffer.each {|data|
@output_width = data.output(@output, @output_width)
}
@buffer.clear
@buffer_width = 0
end
# The Text class is the means by which to collect strings from objects.
#
# This class is intended for internal use of the PrettyPrint buffers.
class Text # :nodoc:
# Creates a new text object.
#
# This constructor takes no arguments.
#
# The workflow is to append a PrettyPrint::Text object to the buffer, and
# being able to call the buffer.last() to reference it.
#
# As there are objects, use PrettyPrint::Text#add to include the objects
# and the width to utilized by the String version of this object.
def initialize
@objs = []
@width = 0
end
# The total width of the objects included in this Text object.
attr_reader :width
# Render the String text of the objects that have been added to this Text object.
#
# Output the text to +out+, and increment the width to +output_width+
def output(out, output_width)
@objs.each {|obj| out << obj}
output_width + @width
end
# Include +obj+ in the objects to be pretty printed, and increment
# this Text object's total width by +width+
def add(obj, width)
@objs << obj
@width += width
end
end
# The Breakable class is used for breaking up object information
#
# This class is intended for internal use of the PrettyPrint buffers.
class Breakable # :nodoc:
# Create a new Breakable object.
#
# Arguments:
# * +sep+ String of the separator
# * +width+ Fixnum width of the +sep+
# * +q+ parent PrettyPrint object, to base from
def initialize(sep, width, q)
@obj = sep
@width = width
@pp = q
@indent = q.indent
@group = q.current_group
@group.breakables.push self
end
# Holds the separator String
#
# The +sep+ argument from ::new
attr_reader :obj
# The width of +obj+ / +sep+
attr_reader :width
# The number of spaces to indent.
#
# This is inferred from +q+ within PrettyPrint, passed in ::new
attr_reader :indent
# Render the String text of the objects that have been added to this
# Breakable object.
#
# Output the text to +out+, and increment the width to +output_width+
def output(out, output_width)
@group.breakables.shift
if @group.break?
out << @pp.newline
out << @pp.genspace.call(@indent)
@indent
else
@pp.group_queue.delete @group if @group.breakables.empty?
out << @obj
output_width + @width
end
end
end
# The Group class is used for making indentation easier.
#
# While this class does neither the breaking into newlines nor indentation,
# it is used in a stack (as well as a queue) within PrettyPrint, to group
# objects.
#
# For information on using groups, see PrettyPrint#group
#
# This class is intended for internal use of the PrettyPrint buffers.
class Group # :nodoc:
# Create a Group object
#
# Arguments:
# * +depth+ - this group's relation to previous groups
def initialize(depth)
@depth = depth
@breakables = []
@break = false
end
# This group's relation to previous groups
attr_reader :depth
# Array to hold the Breakable objects for this Group
attr_reader :breakables
# Makes a break for this Group, and returns true
def break
@break = true
end
# Boolean of whether this Group has made a break
def break?
@break
end
# Boolean of whether this Group has been queried for being first
#
# This is used as a predicate, and ought to be called first.
def first?
if defined? @first
false
else
@first = false
true
end
end
end
# The GroupQueue class is used for managing the queue of Group to be pretty
# printed.
#
# This queue groups the Group objects, based on their depth.
#
# This class is intended for internal use of the PrettyPrint buffers.
class GroupQueue # :nodoc:
# Create a GroupQueue object
#
# Arguments:
# * +groups+ - one or more PrettyPrint::Group objects
def initialize(*groups)
@queue = []
groups.each {|g| enq g}
end
# Enqueue +group+
#
# This does not strictly append the group to the end of the queue,
# but instead adds it in line, base on the +group.depth+
def enq(group)
depth = group.depth
@queue << [] until depth < @queue.length
@queue[depth] << group
end
# Returns the outer group of the queue
def deq
@queue.each {|gs|
(gs.length-1).downto(0) {|i|
unless gs[i].breakables.empty?
gs = gs[i, 1]
group = gs.first
group.break
return group
end
}
gs.each {|group| group.break}
gs.clear
}
return nil
end
# Remote +group+ from this queue
def delete(group)
@queue[group.depth].delete(group)
end
end
# PrettyPrint::SingleLine is used by PrettyPrint.singleline_format
#
# It is passed to be similar to a PrettyPrint object itself, by responding to:
# * #text
# * #breakable
# * #nest
# * #group
# * #flush
# * #first?
#
# but instead, the output has no line breaks
#
class SingleLine
# Create a PrettyPrint::SingleLine object
#
# Arguments:
# * +output+ - String (or similar) to store rendered text. Needs to respond to '<<'
# * +maxwidth+ - Argument position expected to be here for compatibility.
# This argument is a noop.
# * +newline+ - Argument position expected to be here for compatibility.
# This argument is a noop.
def initialize(output, maxwidth=nil, newline=nil)
@output = output
@first = [true]
end
# Add +obj+ to the text to be output.
#
# +width+ argument is here for compatibility. It is a noop argument.
def text(obj, width=nil)
@output << obj
end
# Appends +sep+ to the text to be output. By default +sep+ is ' '
#
# +width+ argument is here for compatibility. It is a noop argument.
def breakable(sep=' ', width=nil)
@output << sep
end
# Takes +indent+ arg, but does nothing with it.
#
# Yields to a block.
def nest(indent) # :nodoc:
yield
end
# Opens a block for grouping objects to be pretty printed.
#
# Arguments:
# * +indent+ - noop argument. Present for compatibility.
# * +open_obj+ - text appended before the &blok. Default is ''
# * +close_obj+ - text appended after the &blok. Default is ''
# * +open_width+ - noop argument. Present for compatibility.
# * +close_width+ - noop argument. Present for compatibility.
def group(indent=nil, open_obj='', close_obj='', open_width=nil, close_width=nil)
@first.push true
@output << open_obj
yield
@output << close_obj
@first.pop
end
# Method present for compatibility, but is a noop
def flush # :nodoc:
end
# This is used as a predicate, and ought to be called first.
def first?
result = @first[-1]
@first[-1] = false
result
end
end
end
# Copyright (C) 2014-2020 Sutou Kouhei <kou@cozmixng.org>
# This file is based on pp.rb in CRuby.
module Kernel
# Returns a pretty printed object as a string.
#
# In order to use this method you must first require the PP module:
#
# require 'pp'
#
# See the PP module for more information.
def pretty_inspect
PP.pp(self, '')
end
private
# prints arguments in pretty form.
#
# pp returns argument(s).
def pp(*objs) # :nodoc:
objs.each {|obj|
PP.pp(obj)
}
objs.size <= 1 ? objs.first : objs
end
module_function :pp # :nodoc:
end
##
# A pretty-printer for Ruby objects.
#
# All examples assume you have loaded the PP class with:
# require 'pp'
#
##
# == 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 <tt>obj(s)</tt> to <tt>$></tt> in pretty printed format.
#
# It returns <tt>obj(s)</tt>.
#
##
# == Output Customization
#
# To define a customized pretty printing function for your classes,
# redefine method <code>#pretty_print(pp)</code> in the class.
#
# <code>#pretty_print</code> takes the +pp+ argument, which is an instance of the PP class.
# The method uses #text, #breakable, #nest, #group and #pp to print the
# object.
#
##
# == Pretty-Print JSON
#
# To pretty-print JSON refer to JSON#pretty_generate.
#
##
# == Author
# Tanaka Akira <akr@fsij.org>
class PP < PrettyPrint
class StandardOutput
def <<(string)
print(string)
self
end
end
# Outputs +obj+ to +out+ in pretty printed format of
# +width+ columns in width.
#
# If +out+ is omitted, <code>$></code> is assumed.
# If +width+ is omitted, 79 is assumed.
#
# PP.pp returns +out+.
def PP.pp(obj, out=nil, width=79)
out ||= StandardOutput.new
q = PP.new(out, width)
q.guard_inspect_key {q.pp obj}
q.flush
#$pp = q
out << "\n"
end
# Outputs +obj+ to +out+ like PP.pp but with no indent and
# newline.
#
# PP.singleline_pp returns +out+.
def PP.singleline_pp(obj, out=$>)
q = SingleLine.new(out)
q.guard_inspect_key {q.pp obj}
q.flush
out
end
@sharing_detection = false
class << self
# Returns the sharing detection flag as a boolean value.
# It is false by default.
attr_accessor :sharing_detection
end
module PPMethods
def initialize(*args)
super
@inspecting = {}
end
# Yields to a block
# and preserves the previous set of objects being printed.
def guard_inspect_key
save = @inspecting
begin
@inspecting = {}
yield
ensure
@inspecting = save
end
end
# Check whether the object_id +id+ is in the current buffer of objects
# to be pretty printed. Used to break cycles in chains of objects to be
# pretty printed.
def check_inspect_key(id)
@inspecting.include?(id)
end
# Adds the object_id +id+ to the set of objects being pretty printed, so
# as to not repeat objects.
def push_inspect_key(id)
@inspecting[id] = true
end
# Removes an object from the set of objects being pretty printed.
def pop_inspect_key(id)
@inspecting.delete id
end
# Adds +obj+ to the pretty printing buffer
# using Object#pretty_print or Object#pretty_print_cycle.
#
# Object#pretty_print_cycle is used when +obj+ is already
# printed, a.k.a the object reference chain has a cycle.
def pp(obj)
id = obj.object_id
if check_inspect_key(id)
group {obj.pretty_print_cycle self}
return
end
begin
push_inspect_key(id)
group {obj.pretty_print self}
ensure
pop_inspect_key(id) unless PP.sharing_detection
end
end
# A convenience method which is same as follows:
#
# group(1, '#<' + obj.class.name, '>') { ... }
def object_group(obj, &block) # :yield:
group(1, '#<' + obj.class.name, '>', &block)
end
# A convenience method, like object_group, but also reformats the Object's
# object_id.
def object_address_group(obj, &block)
str = obj.to_s
str.chomp!('>')
group(1, str, '>', &block)
end
# A convenience method which is same as follows:
#
# text ','
# breakable
def comma_breakable
text ','
breakable
end
# Adds a separated list.
# The list is separated by comma with breakable space, by default.
#
# #seplist iterates the +list+ using +iter_method+.
# It yields each object to the block given for #seplist.
# The procedure +separator_proc+ is called between each yields.
#
# If the iteration is zero times, +separator_proc+ is not called at all.
#
# If +separator_proc+ is nil or not given,
# +lambda { comma_breakable }+ is used.
# If +iter_method+ is not given, :each is used.
#
# For example, following 3 code fragments has similar effect.
#
# q.seplist([1,2,3]) {|v| xxx v }
#
# q.seplist([1,2,3], lambda { q.comma_breakable }, :each) {|v| xxx v }
#
# xxx 1
# q.comma_breakable
# xxx 2
# q.comma_breakable
# xxx 3
def seplist(list, sep=nil, iter_method=:each) # :yield: element
sep ||= lambda { comma_breakable }
first = true
list.__send__(iter_method) {|*v|
if first
first = false
else
sep.call
end
yield(*v)
}
end
# A present standard failsafe for pretty printing any given Object
def pp_object(obj)
object_address_group(obj) {
seplist(obj.pretty_print_instance_variables, lambda { text ',' }) {|v|
breakable
v = v.to_s if Symbol === v
text v
text '='
group(1) {
breakable ''
pp(obj.instance_variable_get(v))
}
}
}
end
# A pretty print for a Hash
def pp_hash(obj)
group(1, '{', '}') {
seplist(obj, nil, :each) {|k, v|
group {
pp k
text '=>'
group(1) {
breakable ''
pp v
}
}
}
}
end
end
include PPMethods
class SingleLine < PrettyPrint::SingleLine # :nodoc:
include PPMethods
end
module ObjectMixin # :nodoc:
# 1. specific pretty_print
# 2. specific inspect
# 3. generic pretty_print
# A default pretty printing method for general objects.
# It calls #pretty_print_instance_variables to list instance variables.
#
# If +self+ has a customized (redefined) #inspect method,
# the result of self.inspect is used but it obviously has no
# line break hints.
#
# This module provides predefined #pretty_print methods for some of
# the most commonly used built-in classes for convenience.
def pretty_print(q)
if methods(false).include?(:inspect)
q.text self.inspect
else
q.pp_object(self)
end
end
# A default pretty printing method for general objects that are
# detected as part of a cycle.
def pretty_print_cycle(q)
q.object_address_group(self) {
q.breakable
q.text '...'
}
end
# Returns a sorted array of instance variable names.
#
# This method should return an array of names of instance variables as symbols or strings as:
# +[:@a, :@b]+.
def pretty_print_instance_variables
instance_variables.sort
end
# Is #inspect implementation using #pretty_print.
# If you implement #pretty_print, it can be used as follows.
#
# alias inspect pretty_print_inspect
#
# However, doing this requires that every class that #inspect is called on
# implement #pretty_print, or a RuntimeError will be raised.
def pretty_print_inspect
PP.singleline_pp(self, '')
end
end
end
class String # :nodoc:
def pretty_print(q) # :nodoc:
q.text inspect
end
def pretty_print_cycle(q) # :nodoc:
q.text inspect
end
end
class Array # :nodoc:
def pretty_print(q) # :nodoc:
q.group(1, '[', ']') {
q.seplist(self) {|v|
q.pp v
}
}
end
def pretty_print_cycle(q) # :nodoc:
q.text(empty? ? '[]' : '[...]')
end
end
class Hash # :nodoc:
def pretty_print(q) # :nodoc:
q.pp_hash self
end
def pretty_print_cycle(q) # :nodoc:
q.text(empty? ? '{}' : '{...}')
end
end
class Struct # :nodoc:
def pretty_print(q) # :nodoc:
q.group(1, sprintf("#<struct %s", self.class), '>') {
q.seplist(members, lambda { q.text "," }) {|member|
q.breakable
q.text member.to_s
q.text '='
q.group(1) {
q.breakable ''
q.pp self[member]
}
}
}
end
def pretty_print_cycle(q) # :nodoc:
q.text sprintf("#<struct %s:...>", self.class)
end
end
class Range # :nodoc:
def pretty_print(q) # :nodoc:
q.pp self.begin
q.breakable ''
q.text(self.exclude_end? ? '...' : '..')
q.breakable ''
q.pp self.end
end
end
class MatchData # :nodoc:
def pretty_print(q) # :nodoc:
nc = []
self.regexp.named_captures.each {|name, indexes|
indexes.each {|i| nc[i] = name }
}
q.object_group(self) {
q.breakable
q.seplist(0...self.size, lambda { q.breakable }) {|i|
if i == 0
q.pp self[i]
else
if nc[i]
q.text nc[i]
else
q.pp i
end
q.text ':'
q.pp self[i]
end
}
}
end
end
class Object < BasicObject # :nodoc:
include PP::ObjectMixin
[Numeric, Symbol, FalseClass, TrueClass, NilClass, Module].each {|c|
c.class_eval {
def pretty_print_cycle(q)
q.text inspect
end
}
}
[Numeric, FalseClass, TrueClass, NilClass, Module].each {|c|
c.class_eval {
def pretty_print(q)
q.text inspect
end
}
}
end