[ruby-core:73839] [Ruby trunk Feature#11999] MatchData#to_h to get a Hash from named captures

Issue #11999 has been updated by sorah Shota Fukumori.

Assignee set to sorah Shota Fukumori

Discussed at https://bugs.ruby-lang.org/projects/ruby/wiki/DevelopersMeeting20160216Japan with Matz and several committers:

Log: https://docs.google.com/document/d/1rj7ODOCSfcsQeBd6-p-NiVwqxDUg05G66LwDOkKOGTw/pub

- #to_h is inappropriate name while non-named capture exists:
  1. Return Hash with integer keys? ( `{0 => "a", 1 => "b"}` )
     - there's no use case for this behavior.
     - rejected
  2. `#named_captures` (accepted)
     - matz said acceptable
- Behavior when there are multiple named captures with same name
  - Return last matched value

    ``` ruby
    /(?<a>b)|(?<a>x)/.match("abc").to_h #=> {"a" => "b"}
    ```

- Behavior when named captures didn’t match anything
  - Return nil as value
- Behavior when no named captures
  - `#captures` returns `[]` when a regexp has no capture, so `#named_captures` returns `{}` when a regexp has no named capture

----

@matz Could you confirm this ↑ and say accept here please?

----------------------------------------
Feature #11999: MatchData#to_h to get a Hash from named captures
https://bugs.ruby-lang.org/issues/11999#change-57015

* Author: sorah Shota Fukumori
* Status: Open
* Priority: Normal
* Assignee: sorah Shota Fukumori
----------------------------------------
~~~
class MatchData
  def to_h
    self.names.map { |n| [n, self[n]] }.to_h
  end
end

p '12'.match(/(?<a>.)(?<b>.)(?<c>.)?/).to_h #=> {"a"=>"1", "b"=>"2", "c"=>nil}
~~~

Sometimes I want to get a Hash from named capture, but currently I have to use #names + #captures. How about adding MatchData#to_h for convenience way?



---Files--------------------------------
11999.diff (2.77 KB)


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

Unsubscribe: <mailto:[e-mail]?subject=unsubscribe>
<http://lists.ruby-lang.org/cgi-bin/mailman/options/ruby-core>