[ruby-core:69137] [Ruby trunk - Feature #11141] [Rejected] new syntax suggestion for abbreviate definition on block parameters in order

Issue #11141 has been updated by Yukihiro Matsumoto.

Status changed from Open to Rejected

We cannot use $1 etc. as they are already taken for Regexp match.
Short hand notation for block parameter itself is a nice idea though.

Matz.


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Feature #11141:  new syntax suggestion for abbreviate definition on block parameters in order
https://bugs.ruby-lang.org/issues/11141#change-52385

* Author: Arnold Roa
* Status: Rejected
* Priority: Normal
* Assignee: ruby-core
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One of the most commons things I do in Ruby are small block definitions:

~~~
x.each{|a| a}
~~~

One useful syntax introduced was the **&:method** that allows calling a method on a block if only one param is expected. It's a shorcut for** a.each{|x|x.method}**. I think it would be nice if Ruby had a syntax that allows me to not define the params that block would receive, but instead access them in order. For example:

~~~
x.each { $1 }
~~~

Let's suppose the block is waiting for two params, I normally do:

~~~
x.method {|a,b| a - b }
~~~

This syntax will allow us to use:

~~~
 x.method{ $1 - $2 }
~~~ 

So:

~~~
 x.each { p1.stg }
 x.each {|p1| p1.stg}
 x.each &:stg
~~~

would be the same.

Please consider $1 and $2 just as an example. I don't like the fact that they are global variables. It could be _1 or  p1, for example:

~~~
x.method{ p1 - p2 } 
x.each{ p1 - p2 } == x.each {|p1, p2| p1 - p2 }
~~~

Or, as blocks already uses **&:method** it could be ** &:1**. Or any other thing that you may consider more appropriated.

I think this syntax would be very nice for short block definitions, the downside is that it allows for bad practice on longer methods, but in the end, that's a decision that a programer should make.

Maybe this is not a valid reason, but I would like to point out that Regex is actually creating global vars as the results of match: $x vars. (for perl's historical reasons)

So why not introduce this into Ruby's syntax?

Personally I don't like either $1 nor p1. They are just the first quick things that come to my mind.




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