From: "nobu (Nobuyoshi Nakada) via ruby-core" <ruby-core@...>
Date: 2025-02-26T13:55:40+00:00
Subject: [ruby-core:121177] [Ruby master Feature#21157] Comparison operator <>

Issue #21157 has been updated by nobu (Nobuyoshi Nakada).

Description updated

lpogic (��ukasz Pomiet��o) wrote:
> I propose introducing a comparison operator *<>* which would give the following results:
> ```ruby
> 1 <> 2 # => -1
> 2 <> 1 # => 1
> 1 <> 1 # => false
> 1 <> "a" # => true
> ```

I'm not sure what the last example means, maybe incomparable -> true?

> With the help of the new operator, complex ordering expressions could be written explicitly. For example:
> ```ruby
> Point = Struct.new(:x, :y)
> array = [Point.new(1, 2), Point.new(6, 4), Point.new(2, 2), Point.new(5, 2)]
> 
> array.sort{|a, b| a.y <> b.y || b.x <> a.x || 0 } # => [#<struct Point x=5, y=2>, #<struct Point x=2, y=2>, #<struct Point x=1, y=2>, #<struct Point x=6, y=4>]
> ```

```ruby
array.sort{|a, b| (a.y <=> b.y).nonzero? || b.x <> a.x}
```

I agree that it would be a bit shorter/simpler, but I doubt it's worth adding new syntax.

> The `<>` notation may look familiar to sql users, where it means 'not equal'.

Or BASIC users?
Anyway, `<>` in SQL is a boolean operator and not expected returing ��1.



----------------------------------------
Feature #21157: Comparison operator <>
https://bugs.ruby-lang.org/issues/21157#change-112115

* Author: lpogic (��ukasz Pomiet��o)
* Status: Open
----------------------------------------
I propose introducing a comparison operator *<>* which would give the following results:
```ruby
1 <> 2 # => -1
2 <> 1 # => 1
1 <> 1 # => false
1 <> "a" # => true
```

With the help of the new operator, complex ordering expressions could be written explicitly. For example:
```ruby
Point = Struct.new(:x, :y)
array = [Point.new(1, 2), Point.new(6, 4), Point.new(2, 2), Point.new(5, 2)]

array.sort{|a, b| a.y <> b.y || b.x <> a.x || 0 } # => [#<struct Point x=5, y=2>, #<struct Point x=2, y=2>, #<struct Point x=1, y=2>, #<struct Point x=6, y=4>]
```

The `<>` notation may look familiar to sql users, where it means 'not equal'. Defined in the form given it will retain this meaning to some extent:
```ruby
a = b = 1
a_not_equal_b if a <> b
a_equal_b unless a <> b
```



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