Implement MatchData#named_captures.

PullRequest: truffleruby/488

Author: eregon

CHANGELOG.md

@@ -2,20 +2,24 @@
 
 New features:
 
-* Implemented `Dir.each_child`.
 * macOS clocks `CLOCK_MONOTONIC_RAW`, `_MONOTONIC_RAW_APPROX`, `_UPTIME_RAW`,
   `_UPTIME_RAW_APPROX`, and `_PROCESS_CPUTIME_ID` have been implemented (#1480).
 
 Bug fixes:
 
-* Adding missing support for the `close_others` option to `exec` and `spawn`.
 * FFI::Pointer now does the correct range checks for signed and unsigned values.
 * Allow signal `0` to be used with `Process.kill` (#1474).
 * `IO#dup` now properly sets the new `IO` instance to be close-on-exec.
 * `IO#reopen` now properly resets the receiver to be close-on-exec.
 * `StringIO#set_encoding` no longer raises an exception if the underlying
   `String` is frozen (#1473).
 
+Compatibility:
+
+* Implemented `Dir.each_child`.
+* Adding missing support for the `close_others` option to `exec` and `spawn`.
+* Implemented the missing `MatchData#named_captures` method (#1512).
+
 Changes:
 
 * `Process::CLOCK_` constants have been given the same value as in standard

spec/ruby/core/matchdata/named_captures_spec.rb

@@ -9,5 +9,9 @@
     it 'prefers later captures' do
       /\A(?<a>.)(?<b>.)(?<b>.)(?<a>.)\z/.match('0123').named_captures.should == { 'a' => '3', 'b' => '2' }
     end
+
+    it 'returns the latest matched capture, even if a later one that does not match exists' do
+      /\A(?<a>.)(?<b>.)(?<b>.)(?<a>.)?\z/.match('012').named_captures.should == { 'a' => '0', 'b' => '2' }
+    end
   end
 end

spec/tags/core/matchdata/named_captures_tags.txt

@@ -365,6 +365,10 @@ def names
     regexp.names
   end
 
+  def named_captures
+    names.collect { |name| [name, self[name]] }.to_h
+  end
+
   def pre_match_from(idx)
     source = Truffle.invoke_primitive(:match_data_get_source, self)
     return source.byteslice(0, 0) if self.byte_begin(0) == 0