class HighLine::Menu

Menu objects encapsulate all the details of a call to HighLine.choose(). Using the accessors and #choice and #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 #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 #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( ) { |self| ... } 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.

Calls superclass method
# 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 #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_s( ) 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_s(  )
  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