You've demonstrated that it is trivially replaced by 'if' and negation. I think that's almost the definition of inelegant.
The truth is there is a balance in all languages. Nearly every word was invented to prevent having to say a string of other words to mean the same thing.
"Unless" is a single word to mean "If not". I consider that elegant.
However, some languages take this too far, in my opinion. German famously has a word for nearly everything. I'm not sure that's elegant, in that it requires learning a far greater number of words.
English has many words that I wouldn't consider elegant, simply because they're uncommon or convoluted. Never use a 10 dollar word when a 5 cent word will do.
So, if, like me and the ruby community, you prefer to optimize for developer happiness, "unless" is an elegant choice.
If you prefer to optimize for peak computing performance, if may be more computationally efficient use "if not".
But, _unless_ you're saying that you never use the word "unless" in everyday language, I think we can agree it's a good word that has good applications. I don't see why that wouldn't be true in programming.
That's not quite how it works though, right? Compound words are exactly that, combining two or more words to narrow down the meaning, without having to invent a new word. It's almost like "if not" vs "unless"...
Side note: ancient Greek didn't use spaces, and many other languages (Thai and Written Chinese are the ones with which I'm most familiar) either don't use spaces or make spaces optional. The distinction between a phrase and a word gets a bit blurry at times, and I find the distinction is seldom useful, particularly when making comparisons across languages.
Ruby inherits the Perl philosophy of "There's more than one way to do it". Compare with Python, and its "There should be one — and preferably only one — obvious way to do it."
It's true that it makes the compiler less elegant, but Ruby optimizes for the programmer at the expense of the compiler.
"count" is only equivalent to "length" and "size" when called with no argument and no block, and should be slower for that case (it includes a comparison of arity and a call to rb_block_given_p() in MRI before it returns the array length).
IMHO, something ‶elegant″ in programming is not something that can't be built form something else (or we will all end up in writing only CMOVs), but something that conveys the meaning of its author precisely and concisely – which makes it inherently subjective. I'm in the `unless` team, I can perfectly understand if you are in the `no unless` team, but this argument does not make a lot of sense.
The very ergonomic solution to map a computation to every element of a sequence is `map`. In this case, `for` is filled with bookkeeping that does not matter.
Also, the `for` operator definitely predates the `map` function. Some people also prefer `map` to be more or less pure and expect it to return a usable list; `for ` has no such expectation, it e.g. may consist solely in printing elements.
And `CAS/Compare Accumulator with Storage` definitely predates `if`, still you are most probably using the latter.
But there are enough people on this thread who feel differently that it makes me wonder if maybe we're wrong. If code is meant to be read and understood by all, and if "unless" is confusing to a large number of people, maybe those of us who like it should knock it off.
I do find it more elegant and easier to read, but maybe you and I can process double negatives easier than the anti-unless crowd are able to process "unless" logic.
If that's the case, I'd be willing to sacrifice my preference for "unless" for the greater good.
Could you give an example of a double negative in this case?
I ask because using "if" does not lend itself to double negatives in my experience, but just thinking about "unless" I see double negatives being an issue (since unless is already negating the operand).
I would likely not be a programmer if it weren’t for Ruby and it doing things different.
I had tried to learn programming for years (JavaScript, Python, Java, C#), none of it stuck or progressed beyond following tutorials and one of the things I had serious issues with was negation.
Then I came across Ruby and it just kinda clicked into place like no other language had. With Ruby I was able to do my own things within a month.
Now I don’t really have a problem picking up other languages anymore. But there’s others out there right now struggling to learn programming and there should be as many programming languages doing things different as possible to increase the chance that they come across one that is obvious for the way they think.
This idea of there should only be one way of doing things is poison in my opinion.
Which is why unless is such a hard concept for people to grasp, not just in code, but also in regular English.
At least the "if not" makes the negation explicit, which can then be easily eliminated using several different techniques (early return, swap with the else condition) if the negation is confusing enough.
However, "unless" necessarily includes negation because that's how the word is defined.
This is the first I've heard about this confusion over the word "unless" in English.
In spoken English I do notice that most often the "unless" comes after a statement. Example: "I'll be there on time, unless the bus is late." That is more clear (to me) than "I'll be there on time, if the bus is not late." Maybe not by coincidence, I tend to like "unless" when it follows the action in in Ruby code, too.
Go to the store and get milk, if not we already have some.