# class PrettyPrint

- PrettyPrint
- Reference
- Object

##
Overview

This class implements a pretty printing algorithm. It finds line breaks and nice indentations for grouped structure.

###
References

- Ruby's prettyprint.rb
- Christian Lindig, Strictly Pretty, March 2000
- Philip Wadler, A prettier printer, March 1998

##
Defined in:

##
Constructors

- .new(output : IO, maxwidth = 79, newline = "\n", indent = 0)

  Creates a new pretty printer that will write to the given output and be capped at maxwidth.

##
Class Method Summary

- .format(obj, io : IO, width : Int32, newline = "\n", indent = 0)

  Pretty prints obj into io with the given width as a limit and starting with the given indentation.

- .format(io : IO, width : Int32, newline = "\n", indent = 0, &)

  Creates a pretty printer and yields it to the block, appending any output to the given io.

##
Instance Method Summary

- #breakable(sep = " ")

  Appends an element that can turn into a newline if necessary.

- #comma

  Same as:

- #fill_breakable(sep = " ")

  Similar to `#breakable` except the decision to break or not is determined individually.

- #flush

  Outputs any buffered data.

- #group(indent = 0, open_obj = "", close_obj = "", &)

  Creates a group of objects.

- #list(left, elements, right, &) : Nil

  Appends a list of elements surrounded by left and right and separated by commas, yielding each element to the given block.

- #list(left, elements, right) : Nil

  Appends a list of elements surrounded by left and right and separated by commas.

- #nest(indent = 1, &)

  Increases the indentation for breakables inside the current group.

- #surround(left, right, left_break = "", right_break = "", &) : Nil

  Appends a group that is surrounded by the given left and right objects, and optionally is surrounded by the given breakable objects.

- #text(obj)

  Appends a text element.

### Instance methods inherited from class `Reference`

==(other : self)
==(other : JSON::Any)
==(other : YAML::Any)
==(other) ==, dup dup, hash(hasher) hash, inspect(io : IO) : Nil inspect, object_id : UInt64 object_id, pretty_print(pp) : Nil pretty_print, same?(other : Reference)
same?(other : Nil) same?, to_s(io : IO) : Nil to_s

### Constructor methods inherited from class `Reference`

new new

### Instance methods inherited from class `Object`

!=(other) !=, !~(other) !~, ==(other) ==, ===(other : JSON::Any)
===(other : YAML::Any)
===(other) ===, =~(other) =~, __crystal_pseudo_! : Bool __crystal_pseudo_!, __crystal_pseudo_as(type : Class) __crystal_pseudo_as, __crystal_pseudo_as?(type : Class) __crystal_pseudo_as?, __crystal_pseudo_is_a?(type : Class) : Bool __crystal_pseudo_is_a?, __crystal_pseudo_nil? : Bool __crystal_pseudo_nil?, __crystal_pseudo_responds_to?(name : Symbol) : Bool __crystal_pseudo_responds_to?, class class, dup dup, hash(hasher)
hash hash, inspect : String
inspect(io : IO) : Nil inspect, itself itself, not_nil! not_nil!, pretty_inspect(width = 79, newline = "\n", indent = 0) : String pretty_inspect, pretty_print(pp : PrettyPrint) : Nil pretty_print, tap(&) tap, to_json(io : IO)
to_json to_json, to_pretty_json(indent : String = " ")
to_pretty_json(io : IO, indent : String = " ") to_pretty_json, to_s : String
to_s(io : IO) : Nil to_s, to_yaml(io : IO)
to_yaml to_yaml, try(&) try, unsafe_as(type : T.class) forall T unsafe_as

### Class methods inherited from class `Object`

from_json(string_or_io, root : String)
from_json(string_or_io) from_json, from_yaml(string_or_io : String | IO) from_yaml

##
Constructor Detail

def self.new(output : IO, maxwidth = 79, newline = "\n", indent = 0) #

Creates a new pretty printer that will write to the given output and be capped at maxwidth.

##
Class Method Detail

def self.format(obj, io : IO, width : Int32, newline = "\n", indent = 0) #

Pretty prints obj into io with the given width as a limit and starting with the given indentation.

def self.format(io : IO, width : Int32, newline = "\n", indent = 0, &) #

Creates a pretty printer and yields it to the block, appending any output to the given io.

##
Instance Method Detail

def breakable(sep = " ") #

Appends an element that can turn into a newline if necessary.

def comma #

Same as:

    text ","
    breakable

def fill_breakable(sep = " ") #

Similar to `#breakable` except the decision to break or not is determined individually.

def flush #

Outputs any buffered data.

def group(indent = 0, open_obj = "", close_obj = "", &) #

Creates a group of objects. Inside a group all breakable objects are either turned into newlines or are output as is, depending on the available width.

def list(left, elements, right, &) : Nil #

Appends a list of elements surrounded by left and right and separated by commas, yielding each element to the given block.

def list(left, elements, right) : Nil #

Appends a list of elements surrounded by left and right and separated by commas.

def nest(indent = 1, &) #

Increases the indentation for breakables inside the current group.

def surround(left, right, left_break = "", right_break = "", &) : Nil #

Appends a group that is surrounded by the given left and right objects, and optionally is surrounded by the given breakable objects.

def text(obj) #

Appends a text element.