Issue #10930 has been updated by Daniel P. Clark.


Matthew Kerwin wrote:

>  So are you also requesting that  "#{1, 2, 3}" be considered valid? Because
>  that's how I would interpret  "#{*[1,2,3]}"  if I saw it in code.

~~~ruby
"#{1,2,3}"
# SyntaxError: (irb):1: syntax error, unexpected ',', expecting tSTRING_DEND
# "#{1,2,3}"
#      ^
~~~
I see your point.  Comma seperated items themselves don't currently work ininterpolation.  So I guess this suggestion isn't as valid as I thought it was.  I was just thinking of the same behavior "as a string" and not about the step in between.

----------------------------------------
Feature #10930: Allow splat operator to work for string interpolation
https://bugs.ruby-lang.org/issues/10930#change-51768

* Author: Daniel P. Clark
* Status: Feedback
* Priority: Normal
* Assignee: 
----------------------------------------
Currently when you use the splat operator in a method it pulls the items out of the array for method parameters.

~~~ruby
def foo(a,b,c)
  puts "#{a}, #{b}, #{c}"
end

bar = [1,2,3]
foo(*bar)
# => "1, 2, 3"
~~~

So I would expect to be able to do "#{*bar}" and get either "1, 2, 3" or "1,2,3".  But when attempting this I get.

~~~ruby
baz = [1,2,3]

"#{*baz}"

# SyntaxError: (irb):53: syntax error, unexpected tSTRING_DEND, expecting '='
# "#{*baz}"
#         ^
# (irb):53: unterminated string meets end of file

"#{*[1,2,3]}"

# SyntaxError: (irb):54: syntax error, unexpected tSTRING_DEND, expecting :: or '[' or '.'
# "#{*[1,2,3]}"
#             ^
# (irb):54: unterminated string meets end of file
~~~

This doesn't work on any of the Ruby versions available 1.8 through 2.2.1. They each produce the same error.

I propose allowing the splat operator within string interpolation to work the same as [1,2,3].join(',')

~~~ruby
fiz = [1,2,3]

"#{*fiz}"
# => "1,2,3"

"#{*[1,2,3]}"
# => "1,2,3"
~~~



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