# Strange syntax sugar **URL:** \ **Category:** Ruby\ **Created:** [April 24, 2007, 2:41am UTC](https://www.ruby-forum.com/t/strange-syntax-sugar/92776 "2007-04-24T02:41:15Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![aalfred](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/6a8cbe/32.png) [@aalfred](https://www.ruby-forum.com/u/aalfred)\ **Post date:** [April 24, 2007, 2:41am UTC](https://www.ruby-forum.com/t/strange-syntax-sugar/92776/1 "2007-04-24T02:41:15Z")
I’ve recently had to deal with lots of assignments, where most of them looked like those two lines: foo = bar if !bar.nil? # (case 1) or foo = bar if foo.nil? && !bar.nil? # (case 2) (I know it could be written using ‘unless’, but I strongly dislike ‘unless’) Then, while doing some refactoring of the code (and while searching for more idiomatic form to gain some more clarity in the code) I rewrote those as: foo ??= bar # case 1 foo !!= bar # case 2 At the end it turned out there were only those two cases: - case 1: ‘do-not-assign-nil’, and - case 2: ‘do-not-assign-nil’ for ‘||=’ (similarity with !!=) I thought I ‘discovered’ new fine operators! But I later found out that these cannot be new operators, but are just a possible syntatic sugar. If you cannot understand those two lines quick, they are probably useless. And I admit that after rethinking they were not so simple to understand anymore, and they do not map clearly into: “foo = bar ‘stands for’ foo = foo bar”. But the code still looked ‘cute’ (or at least more ‘clean’) to me! And so I decided to post it just as a question of what others think about it, about how often they would use it, and if anyone likes it at all. This is not a proposal to sweeten the (already sweet) ruby syntax! ---
**Author:** ![aalfred](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/6a8cbe/32.png) [@aalfred](https://www.ruby-forum.com/u/aalfred)\ **Post date:** [April 24, 2007, 5:38am UTC](https://www.ruby-forum.com/t/strange-syntax-sugar/92776/2 "2007-04-24T05:38:25Z")
On Apr 23, 7:40 pm, aalfred [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > I’ve recently had to deal with lots of assignments, where most of them > looked > like those two lines: > > foo = bar if !bar.nil? # (case 1) or > foo = bar if foo.nil? && !bar.nil? # (case 2) > > (I know it could be written using ‘unless’, but I strongly dislike > ‘unless’) I think you won’t need your new sugar if you just rewrite the originals: foo = bar if bar # case 1 foo ||= bar if bar # case 2 That’s the simplest and cleanest, I think. Jeff > **[Hey Daddio!](http://softiesonrails.com)** > > Home of Hey Daddio Software ---
**Author:** ![aalfred](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/6a8cbe/32.png) [@aalfred](https://www.ruby-forum.com/u/aalfred)\ **Post date:** [April 24, 2007, 8:57am UTC](https://www.ruby-forum.com/t/strange-syntax-sugar/92776/3 "2007-04-24T08:57:37Z")
On 4/24/07, Jeff [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > > > > [softiesonrails.com](http://softiesonrails.com) > Note thast when bar == false it won’t work. Jano ---
**Author:** ![aalfred](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/6a8cbe/32.png) [@aalfred](https://www.ruby-forum.com/u/aalfred)\ **Post date:** [April 24, 2007, 9:36am UTC](https://www.ruby-forum.com/t/strange-syntax-sugar/92776/4 "2007-04-24T09:36:43Z")
On 24.04.2007 05:37, Jeff wrote: > > > > I think you won’t need your new sugar if you just rewrite the > originals: > > foo = bar if bar # case 1 > foo ||= bar if bar # case 2 > > That’s the simplest and cleanest, I think. That’s doubling the effort in the second case. Rather do foo &&= bar foo ||= bar As Jano pointed out, this reacts to false in the same way as to nil which might or might not be what you want. Kind regards robert ---
**Author:** ![aalfred](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/6a8cbe/32.png) [@aalfred](https://www.ruby-forum.com/u/aalfred)\ **Post date:** [April 24, 2007, 12:41pm UTC](https://www.ruby-forum.com/t/strange-syntax-sugar/92776/5 "2007-04-24T12:41:11Z")
On Apr 24, 5:37 am, Jeff [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > > ‘unless’) > > I think you won’t need your new sugar if you just rewrite the > originals: > > foo = bar if bar # case 1 > foo ||= bar if bar # case 2 > > That’s the simplest and cleanest, I think. There is a subtelty in the assignment that is hard to see at the first glance: you _never_ assign nil to foo (but assign can false). So your rewrite is not equivalent. ---
**Author:** ![aalfred](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/6a8cbe/32.png) [@aalfred](https://www.ruby-forum.com/u/aalfred)\ **Post date:** [April 26, 2007, 5:24pm UTC](https://www.ruby-forum.com/t/strange-syntax-sugar/92776/6 "2007-04-26T17:24:55Z")
Hi, At Tue, 24 Apr 2007 19:40:06 +0900, aalfred wrote in [ruby-talk:248941]: > > foo = bar if bar # case 1 > > foo ||= bar if bar # case 2 > > > > That’s the simplest and cleanest, I think. > > There is a subtelty in the assignment that is hard to see at the first > glance: you _never_ assign nil to foo (but assign can false). > So your rewrite is not equivalent. Ruby doesn’t distinguish nil and false as boolean, so if ??= were introduced it would not assign false.