From: naruse@...
Date: 2014-11-05T09:45:05+00:00
Subject: [ruby-core:66095] [ruby-trunk - Feature #9179] [Assigned] MatchData#values_at should support named capture

Issue #9179 has been updated by Yui NARUSE.

Status changed from Open to Assigned
Assignee set to Yukihiro Matsumoto

I want to write following code, how do you think matz?

```ruby
reg = %r<\A(?<scheme>[A-Za-z][+\-.0-9A-Za-z]*):(?<hier-part>//(?<authority>[^/\\?#]+)(?<path-absolute>/[^?#]*)|[^/?#][^?#]*|)(?:\?(?<query>[^#]*))?(?:#(?<fragment>.*))?\z>
url = "http://example.com/hoge?foo=Bar#frag"
reg =~ url
p $~.values_at(:scheme, :authority, :"path-absolute", :query, :fragment)
```

----------------------------------------
Feature #9179: MatchData#values_at should support named capture
https://bugs.ruby-lang.org/issues/9179#change-49808

* Author: vzvu3k6k _
* Status: Assigned
* Priority: Normal
* Assignee: Yukihiro Matsumoto
* Category: regexp
* Target version: 
----------------------------------------
=begin
Using (({MatchData#[]})), we can access a named capture by its name.

  /(?<a>...)/.match("foo")[:a]  #=> "foo"
  /(?<a>...)/.match("foo")["a"] #=> "foo"

But (({MatchData#values_at})) accepts only Integer and refuses Symbol or String.

  /(?<a>...)/.match("foo").values_at(:a)
  # I expected it returns ["foo"], but...
  #=> in `values_at': no implicit conversion of Symbol into Integer (TypeError)

  /(?<a>...)/.match("foo").values_at("a")
  #=> in `values_at': no implicit conversion of String into Integer (TypeError)

(These are tested in ruby 2.1.0dev (2013-11-28 trunk 43903) [i686-linux].)

I think (({MatchData#values_at})) should work along with (({MathData#[]})) as follows:

  /(?<a>...)/.match("foo").values_at(:a)  #=> ["foo"]
  /(?<a>...)/.match("foo").values_at("a") #=> ["foo"]

In the patch, (({match_entry})) is removed because it is no longer used. Comments and code are based on (({rb_hash_values_at})) in hash.c. It passes (({make test-all})) except (({TestGc#test_gc_reason})), which fails also on the original version.
=end

---Files--------------------------------
matchdata-values_at-named_capture.diff (1.89 KB)


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