Describe validation rules inside Options::Parser.

Eliminate the Validator class and attatch all the validation rules to
the Options::Record object, on which we can later simply call #validate!
to perform its own validations.

lib/jsduck/options/parser.rb

@@ -47,6 +47,11 @@ def create_parser
           optparser.separator ""
 
           @opts.attribute(:input_files, [])
+          @opts.validator do
+            if @opts.input_files.empty? && !@opts.welcome && !@opts.guides && !@opts.videos && !@opts.examples
+              "Please specify some input files, otherwise there's nothing I can do :("
+            end
+          end
 
           @opts.attribute(:output_dir)
           optparser.on('-o', '--output=PATH',
@@ -62,6 +67,20 @@ def create_parser
               @opts.cache_dir = @opts.output_dir + "/.cache" unless @opts.cache_dir
             end
           end
+          @opts.validator do
+            if @opts.output_dir == :stdout
+              # No output dir needed for export
+              if !@opts.export
+                "Output to STDOUT only works when using --export option"
+              end
+            elsif !@opts.output_dir
+              "Please specify an output directory, where to write all this amazing documentation"
+            elsif File.exists?(@opts.output_dir) && !File.directory?(@opts.output_dir)
+              "The output directory is not really a directory at all :("
+            elsif !File.exists?(File.dirname(@opts.output_dir))
+              "The parent directory for #{@opts.output_dir} doesn't exist"
+            end
+          end
 
           @opts.attribute(:export)
           optparser.on('--export=full/examples',
@@ -74,6 +93,11 @@ def create_parser
             "- examples - inline examples from classes and guides.") do |format|
             @opts.export = format.to_sym
           end
+          @opts.validator do
+            if ![nil, :full, :examples].include?(@opts.export)
+              "Unknown export format: #{@opts.export}"
+            end
+          end
 
           optparser.on('--builtin-classes',
             "Includes docs for JavaScript builtins.",
@@ -261,6 +285,11 @@ def create_parser
             "6 - <H2>,<H3>,<H4>,<H5>,<H6> headings are included.") do |level|
             @opts.guides_toc_level = level.to_i
           end
+          @opts.validator do
+            if !(1..6).include?(@opts.guides_toc_level)
+              "Unsupported --guides-toc-level: '#{@opts.guides_toc_level}'"
+            end
+          end
 
           @opts.attribute(:videos)
           optparser.on('--videos=PATH',
@@ -739,6 +768,25 @@ def create_parser
             "Useful when developing the template files.") do |path|
             @opts.template_dir = canonical(path)
           end
+          @opts.validator do
+            if @opts.export
+              # Don't check these things when exporting
+            elsif !File.exists?(@opts.template_dir + "/extjs")
+              [
+                "Oh noes!  The template directory does not contain extjs/ directory :(",
+                "Please copy ExtJS over to template/extjs or create symlink.",
+                "For example:",
+                "    $ cp -r /path/to/ext-4.0.0 " + @opts.template_dir + "/extjs",
+              ]
+            elsif !File.exists?(@opts.template_dir + "/resources/css")
+              [
+                "Oh noes!  CSS files for custom ExtJS theme missing :(",
+                "Please compile SASS files in template/resources/sass with compass.",
+                "For example:",
+                "    $ compass compile " + @opts.template_dir + "/resources/sass",
+              ]
+            end
+          end
 
           @opts.attribute(:template_links, false)
           optparser.on('--template-links',

lib/jsduck/options/processor.rb

@@ -1,6 +1,5 @@
 require 'jsduck/options/parser'
 require 'jsduck/options/input_files'
-require 'jsduck/options/validator'
 require 'jsduck/logger'
 require 'jsduck/util/json'
 require 'jsduck/util/io'
@@ -22,8 +21,12 @@ def self.process(args)
         # Expand list of input files
         Options::InputFiles.new(opts).expand!
 
-        # Check for fatal problems (possibly exit the program).
-        Options::Validator.new(opts).validate!
+        # Validate the options.
+        # Exit program when there's an error.
+        if err = opts.validate!
+          Array(err).each {|line| Logger.fatal(line) }
+          exit(1)
+        end
 
         # Configure various objects with these options
         Logger.configure(opts)

lib/jsduck/options/record.rb

@@ -10,6 +10,9 @@ module Options
     # ensures that accessing an unexisting option will result in an
     # error.
     class Record
+      def initialize
+        @validators = []
+      end
 
       # Defines accessor for an option,
       # and assigns a default value for it.
@@ -30,6 +33,26 @@ def []=(key, value)
         instance_variable_set("@#{key}", value)
       end
 
+      # Defines a validator function that gets run after all the
+      # options have been parsed.  When validation fails, the function
+      # should return an error message string (or an array of string
+      # for multi-line error message) otherwise nil, to signify
+      # success.
+      def validator(&block)
+        @validators << block
+      end
+
+      # Runs all the validators.  Returns an error message string from
+      # the first failed validation or nil when everything is OK.
+      def validate!
+        @validators.each do |block|
+          if err = block.call()
+            return err
+          end
+        end
+        return nil
+      end
+
     end
 
   end