[ruby-core:86315] [CommonRuby Feature#13581] Syntax sugar for method reference

Issue #13581 has been updated by pvande (Pieter van de Bruggen).


As a blue sky alternative, why not consider something like this:

~~~ ruby
[1, 2, 3].map(&> {Math.sqrt})

# or perhaps more simply

[1, 2, 3].map(&> Math.sqrt)
~~~

Pros:

* It's clean
* It's readable
* It reads like passing a block
  * Specifically, passing a lambda as a block
* It *also* reads something like the Elixir pipe operator

Cons:

* It's only *looks* like Ruby code
  * Is `x.map(&> { a.b.c.d ; Math.sqrt })` valid?  (I hope not.)
  * Is `x.map(&> do; Math.sqrt; end)` valid?  (I hope not.)
  * Is `x.map(&> { begin; rescue; end })` valid?  (I hope not.)
  * Is `x.map(&> { Math.sqrt if x })` valid?  (I hope not.)
  * Is `x.map(&> { Math.sqrt rescue nil })` valid?  (I hope not.)
* It's not actually a shorthand for `Object#method`.
  * The two clearest implementation paths are as a "macro", and as an "atypical evaluation context"
    * The macro approach simply transforms the code into a "proper" block, and passes the argument implicitly (see below for an example)
    * The other approach requires the interpreter to all non-terminal method calls, then produce a block invoking the terminal call with the yielded argument (see below for an example)

Despite the "oddness" of this particular syntax, I think the clarity of expression is very much inline with the Ruby ideals, and is therefore worth discussing.

**Macro Example**

~~~ruby
fn(&> { a.b.c.d })
# => fn() { |__x| a.b.c.d(__x) })
~~~

**Atypical Evaluation Example**

~~~ruby
fn(&> { a.b.c.d })
# => __target = a.b.c; fn() { |__x| __target.d(__x) })
~~~


----------------------------------------
Feature #13581: Syntax sugar for method reference
https://bugs.ruby-lang.org/issues/13581#change-71235

* Author: americodls (Americo Duarte)
* Status: Open
* Priority: Normal
* Assignee: 
* Target version: 
----------------------------------------
Some another programming languages (even Java, in version 8) has a cool way to refer a method as a reference.

I wrote some examples here: https://gist.github.com/americodls/20981b2864d166eee8d231904303f24b

I miss this thing in ruby.

I would thinking if is possible some like this:

~~~
roots = [1, 4, 9].map &Math.method(:sqrt)
~~~

Could be like this:

~~~
roots = [1, 4, 9].map Math->method
~~~

What do you guys thinking about it?



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