add support for --example-matches -E that allows matching examples with regex syntax

lib/rspec/core/option_parser.rb

@@ -226,6 +226,11 @@ def parser(options)
           (options[:full_description] ||= []) << Regexp.compile(Regexp.escape(o))
         end
 
+        parser.on('-E', '--example-matches STRING', "Run examples whose full nested names match REGEX (may be",
+                  "  used more than once)") do |o|
+          (options[:full_description] ||= []) << Regexp.compile(o)
+        end
+
         parser.on('-t', '--tag TAG[:VALUE]',
                   'Run examples with the specified tag, or exclude examples',
                   'by adding ~ before the tag.',

spec/rspec/core/option_parser_spec.rb

@@ -216,6 +216,16 @@ module RSpec::Core
       end
     end
 
+    %w[--example-matches -E].each do |option|
+      describe option do
+        it "does not escape the arg" do
+          options = Parser.parse([option, 'this (and that)\b'])
+          expect(options[:full_description].length).to eq(1)
+          expect(/this (and that)\b/).to eq(options[:full_description].first)
+        end
+      end
+    end
+
     %w[--pattern -P].each do |option|
       describe option do
         it "sets the filename pattern" do