[ruby-dev:45452] [ruby-trunk - Feature #5735][Feedback] Extending the use of splat operator to when it is inside a hash

Issue #5735 has been updated by mame (Yusuke Endoh).

Status changed from Open to Feedback
Assignee set to matz (Yukihiro Matsumoto)

Marc-Andre proposed a similar idea at [ruby-core:41772], and Matz commented a little at [ruby-core:41822].
It would be good to investigate how many use cases occur in real world.


matz wrote:
> I am still not sure if we need hash splat nor hash decomposition, it
> might be useful in some cases, but also makes syntax more complex.
> So we need more discussion before picking it.
>
> But if we could made consensus I'd make small changes to proposed
> syntax.
>
> For hash splat, I'd rather use ** instead of *, because splat in array
> and splat in hash are different.  Using same operator could cause
> confusion.  Besides that, I would also restrict hash splat position to
> the end, since hashes do not have order.

-- 
Yusuke Endoh <[e-mail]>
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Feature #5735: Extending the use of splat operator to when it is inside a hash
https://bugs.ruby-lang.org/issues/5735#change-25303

Author: sawa (Tsuyoshi Sawada)
Status: Feedback
Priority: Normal
Assignee: matz (Yukihiro Matsumoto)
Category: 
Target version: 


Ruby convention of allowing omittion of the curly brackets for the last argument is convenient:

foo(arg1, arg2, 1 => :a, 2 => :b)

Sometimes, I want to pass a hash with some modifications. For example, suppose `h = {3 => :c, 4 => :d, 5 => :e}` is a hash already defined and that I want to add some key-value pairs as well as overwrite some values of `h`, such as {3 => :c, 4 => :f, 5 => :e, 6 => :g}, and pass that. The current convention only allows:

foo(arg1, arg2, h.merge(4 => :f, 6 => :g))

but it would be more convenient if a hash preceded by the splat operator is placed in a hash, it is interpreted as part of the hash, allowing notations like:

foo(arg1, arg2, *h, 4 => :f, 6 => :g)

or, if I want to overwrite the hash `{4 => :f, 6 => :g}` with `h`, then:

foo(arg1, arg2, 4 => :f, 6 => :g, *h)

Or besides the argument position, in general, usages like the following:

{3 => :h, *h, 4 => :f, 6 => :g}

This is an analogy from the splat operator used within an array:

[1, 2, *[4, 5, 6], 7, 8]




-- 
http://bugs.ruby-lang.org/