add support for +help

part of #26

bin/jobrnr

@@ -6,6 +6,9 @@ require_relative '../lib/jobrnr'
 
 begin
   exit Jobrnr::Application.new(ARGV).run
+rescue Jobrnr::HelpException => e
+  puts e.message
+  exit 0
 rescue Jobrnr::Error => e
   Jobrnr::Log.error e
 end

lib/jobrnr/error.rb

@@ -6,4 +6,6 @@ class OptionsError < Error; end
   class ImportError < Error; end
   class ArgumentError < Error; end
   class TypeError < Error; end
+
+  class HelpException < StandardError; end
 end

lib/jobrnr/plus_option_parser.rb

@@ -86,6 +86,8 @@ def parse(specs, plus_option_strings)
       option_definitions = transform_specs(specs.clone)
       plus_options = plus_options_to_hash(plus_option_strings)
 
+      raise Jobrnr::HelpException, help(option_definitions) if plus_options.keys.include?(:help)
+
       unless Jobrnr::Util.array_subset_of?(plus_options.keys, option_definitions.keys)
         raise Jobrnr::ArgumentError, "The following options are not valid options: #{unsupported_options(plus_options, option_definitions)}\n\n#{help(option_definitions)}"
       end

test/plus_option_parser_test.rb

@@ -112,6 +112,26 @@
                          ))
         assert_equal(exp, act)
       end
+
+      it 'supports +help' do
+        e = assert_raises(Jobrnr::HelpException) { @obj.parse(@specs, %w(+help)) }
+
+        assert_equal(Jobrnr::Util.strip_heredoc(<<-EOF).strip, e.message)
+          OPTIONS
+
+            +default-true[=<value>]
+              An option with a default true value. Default: true
+
+            +default-inferred[=<value>]
+              An option with an inferred default value. Default: false
+
+            +fix-num=<value>
+              A fixnum option. Default: 1
+
+            +string=<value>
+              A string option. Default: hello world
+        EOF
+      end
     end
 
     describe 'errors' do