Trap interrupt during option input

* Extract OptionFetcher
  This class handles fetching the options from the user, and manages the
  various interrupt signals during input

Fixes #81

lib/liftoff.rb

@@ -16,6 +16,7 @@
 require 'liftoff/git_setup'
 require 'liftoff/launchpad'
 require 'liftoff/object_picker'
+require 'liftoff/option_fetcher'
 require 'liftoff/project'
 require 'liftoff/project_builder'
 require 'liftoff/project_configuration'

lib/liftoff/launchpad.rb

@@ -23,10 +23,7 @@ def liftoff
     private
 
     def fetch_options
-      @config.project_name = ask('Project name? ') { |q| q.default = @config.project_name }
-      @config.company = ask('Company name? ') { |q| q.default = @config.company }
-      @config.author = ask('Author name? ') { |q| q.default = @config.author }
-      @config.prefix = ask('Prefix? ') { |q| q.default = @config.prefix }.upcase
+      OptionFetcher.new(@config).fetch_options
     end
 
     def perform_project_actions
@@ -69,7 +66,7 @@ def enable_warnings
     def enable_static_analyzer
       xcode_helper.enable_static_analyzer(@config.enable_static_analyzer)
     end
-    
+
     def open_project
       `open -a "Xcode" .`
     end

lib/liftoff/option_fetcher.rb

@@ -0,0 +1,26 @@
+module Liftoff
+  class OptionFetcher
+    def initialize(configuration)
+      @configuration = configuration
+    end
+
+    def fetch_options
+      fetch_option_for(:project_name, 'Project name')
+      fetch_option_for(:company, 'Company name')
+      fetch_option_for(:author, 'Author name')
+      fetch_option_for(:prefix, 'Prefix')
+    end
+
+    private
+
+    def fetch_option_for(attribute, prompt)
+      value = ask("#{prompt}? ") { |q| q.default = @configuration.public_send(attribute) }
+      @configuration.public_send("#{attribute}=", value)
+    rescue EOFError
+      puts
+      fetch_option_for(attribute, prompt)
+    rescue Interrupt
+      exit 1
+    end
+  end
+end