Issue #3591 has been updated by mame (Yusuke Endoh).


marcandre (Marc-Andre Lafortune) wrote:
> I still curious as to actual use cases. Looking at Rails' code, there is one instance of this, and followed immediately by the more general `foo % bar == baz` (when implementing `nth_child`).

With regard to this feature, there is no room for doubt about use cases, I think.  I don't know Rails, but this method would be frequently useful when enjoying mathematical programming.  I can find many actual use cases in my programs for Project Euler:

```
$ egrep "% \w+ == 0" ~/work/peuler/*.rb | wc -l
86
```

Of course, this feature is NOT indispensable, though.

----------------------------------------
Feature #3591: Adding Numeric#divisor? (Have working implementation)
https://bugs.ruby-lang.org/issues/3591#change-67936

* Author: duckinator (Marie Markwell)
* Status: Assigned
* Priority: Normal
* Assignee: matz (Yukihiro Matsumoto)
* Target version: next minor
----------------------------------------
=begin
 On the 'duckinator' branch of my fork of ruby on github, I have added Numeric#divisor?:
   num.divisor?(other)
 is the same as:
   (num % other == 0)
 
 Example usage:
   4.divisor?(2)     #=> true
   1.divisor?(2)     #=> false
   2.4.divisor?(1.2) #=> true
   2.4.divisor?(1.3) #=> false
   126.divisor?(9)   #=> true
 
 I think this would be a very nice feature to add, and would make code using the old (num % other == 0) method much cleaner and easier to understand.
 
 There is a unified diff of it: http://gist.github.com/raw/484144/07b1a6e696cd9301e658ccbc8f90dfcd4d4ef3f1/Numeric_divisor.patch
 
 The original commits can be seen here:
 http://github.com/RockerMONO/ruby/commit/f7959f964cb0bf38418904ccb5643db6b689d29c -- First attempt, only worked with Integers
 http://github.com/RockerMONO/ruby/commit/12376a6bb1c3ffbd4b470850dd758e2dcd783dda -- Second attempt, should work with anything derived from Numeric that can be used as (num % other == 0)
=end




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