### Home Classes Methods

### In Files

- lib/highline/menu.rb

### Parent

Question

### Methods

- ::new
- #choice
- #choices
- #help
- #hidden
- #index=
- #init_help
- #layout=
- #options
- #select
- #to_ary
- #to_str
- #update_responses

### Files

- CHANGELOG
- INSTALL
- LICENSE
- README.rdoc
- TODO

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# HighLine::Menu

Menu objects encapsulate all the details of a call to HighLine.choose(). Using the accessors and Menu.choice() and Menu.choices(), the block passed to HighLine.choose() can detail all aspects of menu display and control.

### Attributes

flow[RW]

This attribute is passed directly on as the mode to HighLine.list() by all the preset layouts. See that method for appropriate settings.

header[RW]

Used by all the preset layouts to display title and/or introductory information, when set. Defaults to `nil`.

index[R]

An index to append to each menu item in display. See Menu.index=() for details.

index_suffix[RW]

The String placed between an index and a menu item. Defaults to ". ". Switches to " ", when index is set to a String (like "-").

layout[R]

An ERb layout to use when displaying this Menu object. See Menu.layout=() for details.

list_option[RW]

This setting is passed on as the third parameter to HighLine.list() by all the preset layouts. See that method for details of its effects. Defaults to `nil`.

nil_on_handled[RW]

When `true`, any selected item handled by provided action code will return `nil`, instead of the results to the action code. This may prove handy when dealing with mixed menus where only the names of items without any code (and `nil`, of course) will be returned. Defaults to `false`.

prompt[RW]

Used by all the preset layouts to ask the actual question to fetch a menu selection from the user. Defaults to "? ".

select_by[RW]

The select_by attribute controls how the user is allowed to pick a menu item. The available choices are:

`:index` | The user is allowed to type the numerical or alphabetical index for their selection.
`:index_or_name` | Allows both methods from the `:index` option and the `:name` option.
`:name` | Menu items are selected by typing a portion of the item name that will be auto-completed.

shell[RW]

When set to `true`, responses are allowed to be an entire line of input, including details beyond the command itself. Only the first "word" of input will be matched against the menu choices, but both the command selected and the rest of the line will be passed to provided action blocks. Defaults to `false`.

### Public Class Methods

new( ) click to toggle source

Create an instance of HighLine::Menu. All customization is done through the passed block, which should call accessors and choice() and choices() as needed to define the Menu. Note that Menus are also Questions, so all that functionality is available to the block as well.

    # File lib/highline/menu.rb, line 24
    def initialize(  )
      #
      # Initialize Question objects with ignored values, we'll
      # adjust ours as needed.
      #
      super("Ignored", [ ], &nil)    # avoiding passing the block along

      @items           = [ ]
      @hidden_items    = [ ]
      @help            = Hash.new("There's no help for that topic.")

      @index           = :number
      @index_suffix    = ". "
      @select_by       = :index_or_name
      @flow            = :rows
      @list_option     = nil
      @header          = nil
      @prompt          = "?  "
      @layout          = :list
      @shell           = false
      @nil_on_handled  = false

      # Override Questions responses, we'll set our own.
      @responses       = { }
      # Context for action code.
      @highline        = nil

      yield self if block_given?

      init_help if @shell and not @help.empty?
    end

### Public Instance Methods

choice( name, help = nil, &action ) click to toggle source

Adds name to the list of available menu items. Menu items will be displayed in the order they are added.

An optional action can be associated with this name and if provided, it will be called if the item is selected. The result of the method will be returned, unless nil_on_handled is set (when you would get `nil` instead). In shell mode, a provided block will be passed the command chosen and any details that followed the command. Otherwise, just the command is passed. The `@highline` variable is set to the current HighLine context before the action code is called and can thus be used for adding output and the like.

    # File lib/highline/menu.rb, line 136
    def choice( name, help = nil, &action )
      @items << [name, action]

      @help[name.to_s.downcase] = help unless help.nil?
      update_responses  # rebuild responses based on our settings
    end

choices( *names, &action ) click to toggle source

A shortcut for multiple calls to the sister method choice(). Be warned: An action set here will apply to all provided names. This is considered to be a feature, so you can easily hand-off interface processing to a different chunk of code.

    # File lib/highline/menu.rb, line 149
    def choices( *names, &action )
      names.each { |n| choice(n, &action) }
    end

help( topic, help ) click to toggle source

Used to set help for arbitrary topics. Use the topic `"help"` to override the default message.

    # File lib/highline/menu.rb, line 214
    def help( topic, help )
      @help[topic] = help
    end

hidden( name, help = nil, &action ) click to toggle source

Identical to choice(), but the item will not be listed for the user.

    # File lib/highline/menu.rb, line 154
    def hidden( name, help = nil, &action )
      @hidden_items << [name, action]

      @help[name.to_s.downcase] = help unless help.nil?
    end

index=( style ) click to toggle source

Sets the indexing style for this Menu object. Indexes are appended to menu items, when displayed in list form. The available settings are:

`:number` | Menu items will be indexed numerically, starting with 1. This is the default method of indexing.
`:letter` | Items will be indexed alphabetically, starting with a.
`:none` | No index will be appended to menu items.
any String | Will be used as the literal index.

Setting the index to `:none` or a literal String also adjusts index_suffix to a single space and select_by to `:name`. Because of this, you should make a habit of setting the index first.

    # File lib/highline/menu.rb, line 175
    def index=( style )
      @index = style

      # Default settings.
      if @index == :none or @index.is_a?(::String)
        @index_suffix = " "
        @select_by    = :name
      end
    end

init_help( ) click to toggle source

Initializes the help system by adding a `:help` choice, some action code, and the default help listing.

    # File lib/highline/menu.rb, line 189
    def init_help(  )
      return if @items.include?(:help)

      topics    = @help.keys.sort
      help_help = @help.include?("help") ? @help["help"] :
                  "This command will display helpful messages about " +
                  "functionality, like this one.  To see the help for " +
                  "a specific topic enter:\n\thelp [TOPIC]\nTry asking " +
                  "for help on any of the following:\n\n" +
                  "<%= list(#{topics.inspect}, :columns_across) %>"
      choice(:help, help_help) do |command, topic|
        topic.strip!
        topic.downcase!
        if topic.empty?
          @highline.say(@help["help"])
        else
          @highline.say("= #{topic}\n\n#{@help[topic]}")
        end
      end
    end

layout=( new_layout ) click to toggle source

Setting a layout with this method also adjusts some other attributes of the Menu object, to ideal defaults for the chosen layout. To account for that, you probably want to set a layout first in your configuration block, if needed.

Accepted settings for layout are:

`:list` | The default layout. The header if set will appear at the top on its own line with a trailing colon. Then the list of menu items will follow. Finally, the prompt will be used as the ask()-like question.
`:one_line` | A shorter layout that fits on one line. The header comes first followed by a colon and spaces, then the prompt with menu items between trailing parenthesis.
`:menu_only` | Just the menu items, followed up by a likely short prompt.
any ERb String | Will be taken as the literal layout. This String can access `@header`, `@menu` and `@prompt`, but is otherwise evaluated in the typical HighLine context, to provide access to utilities like HighLine.list() primarily.

If set to either `:one_line`, or `:menu_only`, index will default to `:none` and flow will default to `:inline`.

    # File lib/highline/menu.rb, line 248
    def layout=( new_layout )
      @layout = new_layout

      # Default settings.
      case @layout
      when :one_line, :menu_only
        self.index = :none
        @flow  = :inline
      end
    end

options( ) click to toggle source

This method returns all possible options for auto-completion, based on the settings of index and select_by.

    # File lib/highline/menu.rb, line 263
    def options(  )
      # add in any hidden menu commands
      @items.concat(@hidden_items)

      by_index = if @index == :letter
        l_index = "`"
        @items.map { "#{l_index.succ!}" }
      else
        (1 .. @items.size).collect { |s| String(s) }
      end
      by_name = @items.collect { |c| c.first }

      case @select_by
      when :index then
        by_index
      when :name
        by_name
      else
        by_index + by_name
      end
    ensure
      # make sure the hidden items are removed, before we return
      @items.slice!(@items.size - @hidden_items.size, @hidden_items.size)
    end

select( highline_context, selection, details = nil ) click to toggle source

This method processes the auto-completed user selection, based on the rules for this Menu object. If an action was provided for the selection, it will be executed as described in Menu.choice().

    # File lib/highline/menu.rb, line 293
    def select( highline_context, selection, details = nil )
      # add in any hidden menu commands
      @items.concat(@hidden_items)

      # Find the selected action.
      name, action = if selection =~ /^\d+$/
        @items[selection.to_i - 1]
      else
        l_index = "`"
        index = @items.map { "#{l_index.succ!}" }.index(selection)
        @items.find { |c| c.first == selection } or @items[index]
      end

      # Run or return it.
      if not action.nil?
        @highline = highline_context
        if @shell
          result = action.call(name, details)
        else
          result = action.call(name)
        end
        @nil_on_handled ? nil : result
      elsif action.nil?
        name
      else
        nil
      end
    ensure
      # make sure the hidden items are removed, before we return
      @items.slice!(@items.size - @hidden_items.size, @hidden_items.size)
    end

to_ary( ) click to toggle source

Allows Menu objects to pass as Arrays, for use with HighLine.list(). This method returns all menu items to be displayed, complete with indexes.

    # File lib/highline/menu.rb, line 330
    def to_ary(  )
      case @index
      when :number
        @items.map { |c| "#{@items.index(c) + 1}#{@index_suffix}#{c.first}" }
      when :letter
        l_index = "`"
        @items.map { |c| "#{l_index.succ!}#{@index_suffix}#{c.first}" }
      when :none
        @items.map { |c| "#{c.first}" }
      else
        @items.map { |c| "#{index}#{@index_suffix}#{c.first}" }
      end
    end

to_str( ) click to toggle source

Allows Menu to behave as a String, just like Question. Returns the layout to be rendered, which is used by HighLine.say().

    # File lib/highline/menu.rb, line 348
    def to_str(  )
      case @layout
      when :list
        '<%= if @header.nil? then '' else "#{@header}:\n" end %>' +
        "<%= list( @menu, #{@flow.inspect},
                          #{@list_option.inspect} ) %>" +
        "<%= @prompt %>"
      when :one_line
        '<%= if @header.nil? then '' else "#{@header}:  " end %>' +
        "<%= @prompt %>" +
        "(<%= list( @menu, #{@flow.inspect},
                           #{@list_option.inspect} ) %>)" +
        "<%= @prompt[/\s*$/] %>"
      when :menu_only
        "<%= list( @menu, #{@flow.inspect},
                          #{@list_option.inspect} ) %><%= @prompt %>"
      else
        @layout
      end
    end

update_responses( ) click to toggle source

This method will update the intelligent responses to account for Menu specific differences. Calls the superclass' (Question's) build_responses method, overriding its default arguments to specify 'options' will be used to populate choice lists, and that the newly built hash will predominate over the preexisting hash for any keys that are the same.

    # File lib/highline/menu.rb, line 377
    def update_responses(  )
      build_responses(options, true)
    end

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