[#43120] [ruby-trunk - Bug #6124][Open] What is the purpose of "fake" gems in Ruby — Vit Ondruch <v.ondruch@...>

27 messages 2012/03/07

[#43142] Questions about thread performance (with benchmark included) — Rodrigo Rosenfeld Rosas <rr.rosas@...>

A while ago I've written an article entitled "How Nokogiri and JRuby

10 messages 2012/03/08

[#43148] [ruby-trunk - Feature #6126][Open] Introduce yes/no constants aliases for true/false — Egor Homakov <homakov@...>

16 messages 2012/03/09

[#43238] [ruby-trunk - Feature #6130][Open] inspect using to_s is pain — Thomas Sawyer <transfire@...>

21 messages 2012/03/11

[#43313] [ruby-trunk - Feature #6150][Open] add Enumerable#grep_v — Suraj Kurapati <sunaku@...>

17 messages 2012/03/15

[#43325] [ruby-trunk - Bug #6154][Open] Eliminate extending WaitReadable/Writable at runtime — Charles Nutter <headius@...>

25 messages 2012/03/16

[#43334] [ruby-trunk - Bug #6155][Open] Enumerable::Lazy#flat_map raises an exception when an element does not respond to #each — Dan Kubb <dan.kubb@...>

9 messages 2012/03/16

[#43370] [ruby-trunk - Feature #6166][Open] Enumerator::Lazy#pinch — Thomas Sawyer <transfire@...>

15 messages 2012/03/17

[#43373] [ruby-trunk - Bug #6168][Open] Segfault in OpenSSL bindings — Nguma Abojo <git.email.address@...>

14 messages 2012/03/17

[#43454] [ruby-trunk - Bug #6174][Open] Fix collision of ConditionVariable#wait timeout and #signal (+ other cosmetic changes) — "funny_falcon (Yura Sokolov)" <funny.falcon@...>

10 messages 2012/03/18

[#43497] [ruby-trunk - Bug #6179][Open] File::pos broken in Windows 1.9.3p125 — "jmthomas (Jason Thomas)" <jmthomas@...>

24 messages 2012/03/20

[#43502] [ruby-trunk - Feature #6180][Open] to_b for converting objects to a boolean value — "AaronLasseigne (Aaron Lasseigne)" <aaron.lasseigne@...>

17 messages 2012/03/20

[#43529] [ruby-trunk - Bug #6183][Open] Enumerator::Lazy performance issue — "gregolsen (Innokenty Mikhailov)" <anotheroneman@...>

36 messages 2012/03/21

[#43543] [ruby-trunk - Bug #6184][Open] [BUG] Segmentation fault ruby 1.9.3p165 (2012-03-18 revision 35078) [x86_64-darwin11.3.0] — "Gebor (Pierre-Henry Frohring)" <frohring.pierrehenry@...>

8 messages 2012/03/21

[#43672] [ruby-trunk - Feature #6201][Open] do_something then return :special_case (include "then" operator) — "rosenfeld (Rodrigo Rosenfeld Rosas)" <rr.rosas@...>

12 messages 2012/03/26

[#43678] [ruby-trunk - Bug #6203][Open] Array#values_at does not handle ranges with end index past the end of the array — "ferrous26 (Mark Rada)" <markrada26@...>

15 messages 2012/03/26

[#43794] [ruby-trunk - Feature #6216][Open] SystemStackError backtraces should not be reduced to one line — "postmodern (Hal Brodigan)" <postmodern.mod3@...>

15 messages 2012/03/28

[#43814] [ruby-trunk - Feature #6219][Open] Return value of Hash#store — "MartinBosslet (Martin Bosslet)" <Martin.Bosslet@...>

20 messages 2012/03/28

[#43858] [ruby-trunk - Feature #6222][Open] Use ++ to connect statements — "gcao (Guoliang Cao)" <gcao99@...>

12 messages 2012/03/29

[#43904] [ruby-trunk - Feature #6225][Open] Hash#+ — "trans (Thomas Sawyer)" <transfire@...>

36 messages 2012/03/29

[#43951] [ruby-trunk - Bug #6228][Open] [mingw] Errno::EBADF in ruby/test_io.rb on ruby_1_9_3 — "jonforums (Jon Forums)" <redmine@...>

28 messages 2012/03/30

[#43996] [ruby-trunk - Bug #6236][Open] WEBrick::HTTPServer swallows Exception — "regularfry (Alex Young)" <alex@...>

13 messages 2012/03/31

[ruby-core:43547] [ruby-trunk - Feature #6180] to_b for converting objects to a boolean value

From: "aef (Alexander E. Fischer)" <aef@...>
Date: 2012-03-21 22:32:44 UTC
List: ruby-core #43547
Issue #6180 has been updated by aef (Alexander E. Fischer).


I too would very much like to see a #to_bool method on every object.

In my opinion, if you define a public API, you should be as strict as possible about what each method returns, so that your users can rely on it, but also to minimize the possible usage scenarios of the API. The latter one helps me as developer to keep the API working for a maximum amount of users after I changed internal aspects. Because of this I always cast return values of question mark methods into true or false (some languages would call it Boolean for simplicity) with the double ! operator, which I think is ugly because its not so obvious what the operator does at first.

I do this because I imagine people using the output in ways that I surely didn't intend nor that I will support after changes. In some cases they could even circumvent my public API. I think that an object should protect its encapsulation so that, if you want to break the encapsulation (circumvent the public API) by force (which is possible most of the times in Ruby), you have to do it knowingly.

A small example:

object.value = "valid string"
object.value?
# => "valid string"

object.value?.insert(0, "in")
object.value?
# => "invalid string"

This works if the returned object is a String, Array, Hash, Set or any oder mutable object. To prohibit such usage I could use #freeze, which does not protect deep structures perfectly out of the box and may be unhandy for further usage of the returned object or I could #dup or #clone the object before giving it out, which will probably need more processing power than simply returning a boolean casted value, either through !! or #to_bool.
----------------------------------------
Feature #6180: to_b for converting objects to a boolean value
https://bugs.ruby-lang.org/issues/6180#change-25026

Author: AaronLasseigne (Aaron Lasseigne)
Status: Open
Priority: Normal
Assignee: 
Category: 
Target version: 


When a boolean return value is required it has become common practice is to use "!!" to convert the object. It would be more consistent to provide a "to_b" method on Object.


-- 
http://bugs.ruby-lang.org/

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