[ruby-core:106161] [Ruby master Feature#11256] anonymous block forwarding

Issue #11256 has been updated by jeremyevans0 (Jeremy Evans).


bughit (bug hit) wrote in #note-18:
> mame (Yusuke Endoh) wrote in #note-16:
> > @matz accepted this, but said that the formal argument must explicitly receive a anonymous block parameter, i.e.
> > 
> > ```
> > def foo(&) = bar(&) # OK
> > def foo = bar(&)    # NG
> > ```
> > 
> > In the future, matz wants to make it more explicit whether a method accepts a block or not.
> > 
> 
> Where is the naked ampersand in def foo(&) described? 
> 
> Don't see it here: https://docs.ruby-lang.org/en/master/doc/syntax/methods_rdoc.html

This hasn't been committed yet, so you wouldn't see it on the website yet.  The pull request already includes updates to the documentation: https://github.com/ruby/ruby/pull/5051/files#diff-d2caf8d6be0d2ccf90ff06a49bd1b4e4738588b4d5332954d57640e6fce0fd88

> Does it mean the block is required?

No, just as `&block` doesn't mean the block is required.

> What is the reason for the restriction?
> 
> The block may or may not be passed to `def foo`, so what is wrong with forwarding it or its absence with `&`? It reduces the utility of this feature, for what gain?

`In the future, matz wants to make it more explicit whether a method accepts a block or not.`  I assume that means that we could see future changes in Ruby that better align with requiring `&` as a parameter, even if currently it seems reasonable that it would not be required.

In terms of gain currently, if `&` is required, the code to implement the feature is much simpler.  Ruby is already very complex internally.  If we can reduce the amount of complexity added, that is a good reason.

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Feature #11256: anonymous block forwarding
https://bugs.ruby-lang.org/issues/11256#change-94763

* Author: bughit (bug hit)
* Status: Assigned
* Priority: Normal
* Assignee: matz (Yukihiro Matsumoto)
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since capturing a block into a proc is slow: foo(&block)
and creating chains of blocks is kind of ugly and ultimately also inefficient: foo{yield}
why not allow block forwarding without capturing: foo(&) foo(1, 2, &)



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