Extract runner callables to factory methods

It was suggested that the callables used in the OptionParser could be defined
as methods on the parser, and set in the options as follows:

    options[:runner] = method(:bisect_and_exit)

Doing this I was unable to capture extra info in the callables, however (for
example, the `#print_help_and_exit` method needs access to the parser and some
invalid options).

Instead, I've tried out adding callable factory methods. This means the
factory methods can each have different signatures, and be passed whatever
information they need, while the resulting callables can all maintain a
consistent interface.

Author: urbanautomaton

lib/rspec/core/option_parser.rb

@@ -68,17 +68,8 @@ def parser(options)
 
         parser.on('--bisect[=verbose]', 'Repeatedly runs the suite in order to isolate the failures to the ',
                   '  smallest reproducible case.') do |argument|
-          options[:runner] = -> (opts, err, out) do
-            RSpec::Support.require_rspec_core "bisect/coordinator"
-
-            success = Bisect::Coordinator.bisect_with(
-              opts.args,
-              RSpec.configuration,
-              bisect_formatter_for(argument)
-            )
-
-            exit(success ? 0 : 1)
-          end
+          options[:bisect] = argument
+          options[:runner] = Callables.bisect_and_exit
         end
 
         parser.on('--[no-]fail-fast[=COUNT]', 'Abort the run after a certain number of failures (1 by default).') do |argument|
@@ -106,28 +97,16 @@ def parser(options)
           options[:dry_run] = true
         end
 
-        parser.on('-X', '--[no-]drb', 'Run examples via DRb.') do |o|
-          if o
-            options[:runner] = -> (opts, err, out) do
-              require 'rspec/core/drb'
-              begin
-                DRbRunner.new(opts).run(err, out)
-                exit
-              rescue DRb::DRbConnError
-                err.puts "No DRb server is running. Running in local process instead ..."
-              end
-            end
-          end
+        parser.on('-X', '--[no-]drb', 'Run examples via DRb.') do |use_drb|
+          options[:runner] = Callables.try_drb_runner if use_drb
         end
 
         parser.on('--drb-port PORT', 'Port to connect to the DRb server.') do |o|
           options[:drb_port] = o.to_i
         end
 
         parser.on('--init', 'Initialize your project with RSpec.') do |_cmd|
-          options[:runner] = -> (*_args) do
-            initialize_project_and_exit
-          end
+          options[:runner] = Callables.initialize_project_and_exit
         end
 
         parser.separator("\n  **** Output ****\n\n")
@@ -264,9 +243,7 @@ def parser(options)
         parser.separator("\n  **** Utility ****\n\n")
 
         parser.on('-v', '--version', 'Display the version.') do
-          options[:runner] = -> (*_args) do
-            print_version_and_exit
-          end
+          options[:runner] = Callables.print_version_and_exit
         end
 
         # These options would otherwise be confusing to users, so we forcibly
@@ -278,9 +255,7 @@ def parser(options)
         invalid_options = %w[-d --I]
 
         parser.on_tail('-h', '--help', "You're looking at it.") do
-          options[:runner] = -> (*_args) do
-            print_help_and_exit(parser, invalid_options)
-          end
+          options[:runner] = Callables.print_help_and_exit(parser, invalid_options)
         end
 
         # This prevents usage of the invalid_options.
@@ -308,26 +283,64 @@ def configure_only_failures(options)
       add_tag_filter(options, :inclusion_filter, :last_run_status, 'failed')
     end
 
-    def initialize_project_and_exit
-      RSpec::Support.require_rspec_core "project_initializer"
-      ProjectInitializer.new.run
-      exit
-    end
+    module Callables
+      class << self
+        def initialize_project_and_exit
+          lambda do |*_args|
+            RSpec::Support.require_rspec_core "project_initializer"
+            ProjectInitializer.new.run
+            exit
+          end
+        end
 
-    def bisect_formatter_for(argument)
-      return Formatters::BisectDebugFormatter if argument == "verbose"
-      Formatters::BisectProgressFormatter
-    end
+        def try_drb_runner
+          lambda do |options, err, out|
+            require 'rspec/core/drb'
+            begin
+              DRbRunner.new(options).run(err, out)
+              exit
+            rescue DRb::DRbConnError
+              err.puts "No DRb server is running. Running in local process instead ..."
+            end
+          end
+        end
 
-    def print_version_and_exit
-      puts RSpec::Core::Version::STRING
-      exit
-    end
+        def bisect_and_exit
+          lambda do |options, _err, _out|
+            RSpec::Support.require_rspec_core "bisect/coordinator"
+
+            success = Bisect::Coordinator.bisect_with(
+              options.args,
+              RSpec.configuration,
+              bisect_formatter_for(options.options[:bisect])
+            )
+
+            exit(success ? 0 : 1)
+          end
+        end
+
+        def print_version_and_exit
+          lambda do |*_args|
+            puts RSpec::Core::Version::STRING
+            exit
+          end
+        end
+
+        def print_help_and_exit(parser, invalid_options)
+          lambda do |*_args|
+            # Removing the blank invalid options from the output.
+            puts parser.to_s.gsub(/^\s+(#{invalid_options.join('|')})\s*$\n/, '')
+            exit
+          end
+        end
+
+        private
 
-    def print_help_and_exit(parser, invalid_options)
-      # Removing the blank invalid options from the output.
-      puts parser.to_s.gsub(/^\s+(#{invalid_options.join('|')})\s*$\n/, '')
-      exit
+        def bisect_formatter_for(argument)
+          return Formatters::BisectDebugFormatter if argument == "verbose"
+          Formatters::BisectProgressFormatter
+        end
+      end
     end
   end
 end