Ruby » Ruby master

Feature #15381

Updated by Eregon (Benoit Daloze) about 5 years ago

The single splat calls `to_a` implicitly on the object (if it is not an array already) so that, for example, we have the convenience of writing conditions in an array literal: 

 ```ruby 
 a = [ 
   *(:foo if some_condition), 
   *(:bar if another_condition), 
 ] 
 ``` 

 And the ampersand implicitly calls `to_proc` on the object (if it is not a proc already) so that we can substitute a block with an ampersand followed by a symbol: 

 ```ruby 
 some_method(&:some_method_name) 
 ``` 

 Unlike the single splat and ampersand, the double splat does not seem to implicitly call a corresponding method. I propose that the double splat should call `to_h` `to_hash` implicitly on the object if it not already a Hash hash so that we can, for example, write a condition in a hash literal as follows: 

 ```ruby 
 h = { 
   **({a: 1} if some_condition), 
   **({b: 2) if another_condition), 
 } 
 ``` 

 There may be some other benefits of this feature that I have not noticed yet.

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