Issue #15723 has been updated by jeremyevans0 (Jeremy Evans).


maedi (Maedi Prichard) wrote:
> jeremyevans0, is it possible to have method/property calls that when without an object, reference the "current item" of the block they are in?
> ```
> posts.each { .author = 'Santa Clause' }
> ```

Think about handling:

```ruby
posts.each { puts .author }
```

Currently, that means call the `author` method on the object returned by calling the `puts` method with 0 arguments.  If we added the syntax you are proposing, it would be ambiguous as it could mean calling the puts method with a single argument, which is the object returned by calling the author method on the block argument.

> This stops the range situation (`..`). Then still have the single `.` for non method/property situations.

Unfortunately, it does not address the range situation completely:

```ruby
posts.each { 1...author }
```

This could then mean `(1)..(.author)` or `(1)...(author)`

Or even:

```ruby
posts.each { 1... }
```

This could then mean `(1)..(.)` or `(1)...` (infinite range).

Let's say you want to call a method on the block argument and pass the result as a block to another method:

```ruby
posts.each { foo &.a }
```

Unfortunately, this already is used for the lonely operator, so this would break backwards compatibility.

----------------------------------------
Misc #15723: Reconsider numbered parameters
https://bugs.ruby-lang.org/issues/15723#change-77315

* Author: sos4nt (Stefan Schler)
* Status: Feedback
* Priority: Normal
* Assignee: 
----------------------------------------
I just learned that *numbered parameters* have been merged into Ruby 2.7.0dev.

For readers not familiar with this feature: it allows you to reference block arguments solely by their *index*, e.g.

```ruby
[1, 2, 3].each { |i| puts i }

# can become

[1, 2, 3].each { puts @1 }
```

I have an issue with this new feature: I think **it encourages sloppy programming** and results in **hard to read code**.

---

The [original proposal](https://bugs.ruby-lang.org/issues/4475) was to include a special variable (or keyword) with a **readable name**, something like:

```ruby
[1, 2, 3].each { puts it }

# or

[1, 2, 3].each { puts this }
```

Granted, that looks quite lovely and it actually speaks to me  I can *understand* the code. And it fits Ruby: (quoting the website)

> [Ruby] has an elegant syntax that is natural to read and easy to write.

But the proposed `it` / `this` has limited application. It's only useful when dealing with a single argument. You can't have multiple `it`-s or `this`-es. That's why `@1`, `@2`, `@3` etc. were chosen instead.

However, limiting the usefulness to a single argument isn't bad at at. In fact, a single argument seem to be the limit of what makes sense:
```
h = Hash.new { |hash, key| hash[key] = "Go Fish: #{key}" }

# vs

h = Hash.new { @1[@2] = "Go Fish: #{@2}" }
```
Who wants to read the latter? That looks like an archaic bash program (no offense). We already discourage Perl style `$`-references: (from [The Ruby Style Guide](https://github.com/rubocop-hq/ruby-style-guide#no-perl-regexp-last-matchers))

> Don't use the cryptic Perl-legacy variables denoting last regexp group matches (`$1`, `$2`, etc). Use `Regexp.last_match(n)` instead.

I don't see how our code can benefit from adding `@1` and `@2`.

Naming a parameter isn't useless  it gives context. With more than one parameter, naming is crucial. And yes, naming is hard. But avoiding proper naming by using indices is the wrong way.

So please reconsider numbered parameters.

Use a readable named variable (or keyword) to refer to the first argument or ditch the feature entirely.



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