Feature #10426: A predicate to express congruence

• Status: Open
• Assignee: -
• Target version: -

[sawa (Tsuyoshi Sawada)]

I occasionally felt the necessity of a predicate that checks congruence with respect to some operations:

class Object
	def equal_by? other, &pr
		pr.call(self) == pr.call(other)
	end
	alias congruent? equal_by?
end

5.congruent?(2){|e| e % 3} #=> true
"HELLO".equal_by?("Hello", &:downcase) #=> true

[gogotanaka (Kazuki Tanaka)]

@Tsuyoshi Sawada san
I like it.

One thing I'm a little worried about is congruent? might be too specified word.
I mean, I'm not sure congruent can be used in except modulo or geometry context.

[nobu (Nobuyoshi Nakada)]

How about similar? or analog? ?