[#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:43610] [ruby-trunk - Feature #4264] General type coercion protocol for Ruby

From: "mame (Yusuke Endoh)" <mame@...>
Date: 2012-03-25 05:48:51 UTC
List: ruby-core #43610
Issue #4264 has been updated by mame (Yusuke Endoh).

Assignee changed from matz (Yukihiro Matsumoto) to mame (Yusuke Endoh)


----------------------------------------
Feature #4264: General type coercion protocol for Ruby
https://bugs.ruby-lang.org/issues/4264#change-25107

Author: headius (Charles Nutter)
Status: Assigned
Priority: Normal
Assignee: mame (Yusuke Endoh)
Category: 
Target version: 


=begin
 Justification: Ruby objects variously define to_ary, to_int and others for either explicit (before call) or implicit (during call) coercion. However, the set of methods is limited, and adding more names just clutters namespaces and isn't feasible long-term anyway. This proposal will hopefully start a discussion toward adding a general type-coercion protocol via a #to or #to_any method. To blunt the naming discussion a bit, I will refer to it as #to_x.
 
 Description: The #to_x method will be a "supermethod" of sorts that can be used to coerce a given object to an arbitrary type. Where currently there are specific methods for coercing to specific types (to_ary, to_str), and other more general methods intended not for coercion but for explicitly re-structuring an object's data (to_a, to_s), there's no one protocol for doing general coercion. #to_x would fill the roles of the coercion methods, accepting a target class and responding appropriately.
 
 The response will depend on whether the target object can be coerced to the given type. The result for success should obviously be an instance of the target type. The result for failure could either be "soft": returning nil, or "hard": raising an error. There could also be an optional boolean flag that specifies hard or soft.
 
 Existing coercion methods could (but need not be) implemented in terms of #to_x
 
 def to_ary
   to_x(Array)
 end
 
 def to_str
   to_x(String)
 end
 
 Prior art: JRuby supports coercing Ruby objects to arbitrary Java types in this way. Currently only a set of hard-coded target types are supported for various core Ruby classes, but this is intended to eventually be part of the invocation protocol when calling Java. In other words, if the object being passed is not the exact type of the target parameter, JRuby will invoke to_java(target_param_type) to do the coercion. Performance implications in this are obvious...so there may need to be discussions about modifying this protocol to make it easier to optimize.
=end



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