From: masafumi.o1988@gmail.com
To: ruby-core@ruby-lang.org
Subject: [ruby-core:96245] [Ruby master Feature#15829] Object#then_if(condition){}
Date: Sun, 15 Dec 2019 08:22:37 +0000 (UTC) [thread overview]
Message-ID: <redmine.journal-83137.20191215082237.635745a2ea93d673@ruby-lang.org> (raw)
In-Reply-To: redmine.issue-15829.20190505182618@ruby-lang.org
Issue #15829 has been updated by okuramasafumi (Masafumi OKURA).
How about `call`ing a condition object if it's callable instead of simply using value as a condition?
```
class Object
def then_if(condition, &block)
if condition
if (condition.respond_to?(:call) && condition.call(self)) || condition
self.then(&block)
end
else
self
end
end
end
```
Then we can do something like this:
```
'str'.then_if(Proc.new {|str| str.downcase == str}) {|str| str.upcase}
```
I know it's complicated and not beautiful, but it's an idea anyway.
----------------------------------------
Feature #15829: Object#then_if(condition){}
https://bugs.ruby-lang.org/issues/15829#change-83137
* Author: foonlyboy (Eike Dierks)
* Status: Rejected
* Priority: Normal
* Assignee:
* Target version:
----------------------------------------
I'd like to propose some sugar to Object#then
There should be `Object#then_if(condition, &block)`
The block should only be applied when the condition is true,
otherwise the object should be returned without applying the block.
Rationale:
I frequently use `Object#then` with Rails to extend queries like this:
```ruby
foo.then {|query|
if(condition)
query.where(zip:zap)
else
query
end
}
```
by using the proposed `Object#then_if` the example could be simplified to:
```ruby
foo.then_if(condition) {|query|
query.where(zip:zap)
}
```
I believe that this also applies to a lot of other use cases,
i.e. only applying some transformation if some condition is true,
but otherwise leaving the result untouched.
--
https://bugs.ruby-lang.org/
prev parent reply other threads:[~2019-12-15 8:22 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <redmine.issue-15829.20190505182618@ruby-lang.org>
2019-05-05 18:26 ` [ruby-core:92559] [Ruby trunk Feature#15829] Object#then_if(condition){} foonlyboy
2019-05-05 18:35 ` [ruby-core:92560] " foonlyboy
2019-05-05 18:48 ` [ruby-core:92561] " foonlyboy
2019-05-05 20:30 ` [ruby-core:92564] " foonlyboy
2019-05-05 20:51 ` [ruby-core:92565] " sawadatsuyoshi
2019-05-11 7:13 ` [ruby-core:92620] " nobu
2019-05-11 12:11 ` [ruby-core:92621] " sawadatsuyoshi
2019-07-29 6:58 ` [ruby-core:93967] [Ruby master " ko1
2019-12-15 8:22 ` masafumi.o1988 [this message]
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