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
This attribute is passed directly on as the mode to HighLine.list() by all the preset layouts. See that method for appropriate settings.
Used by all the preset layouts to display title and/or introductory
information, when set. Defaults to nil
.
An index to append to each menu item in display. See #index= for details.
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
.
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
.
Used by all the preset layouts to ask the actual question to fetch a menu selection from the user. Defaults to “? ”.
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.
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
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
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
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
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
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
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
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
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
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+$/ @items[selection.to_i - 1] else l_index = "`" index = @items.map { "#{l_index.succ!}" }.index(selection) @items.find { |c| c.first == selection } or @items[index] end # Run or return it. if not action.nil? @highline = highline_context if @shell result = action.call(name, details) else result = action.call(name) end @nil_on_handled ? nil : result elsif action.nil? name else nil end ensure # make sure the hidden items are removed, before we return @items.slice!(@items.size - @hidden_items.size, @hidden_items.size) end
Allows Menu objects to pass as Arrays, for use with HighLine.list(). This method returns all menu items to be displayed, complete with indexes.
# File lib/highline/menu.rb, line 330 def to_ary( ) case @index when :number @items.map { |c| "#{@items.index(c) + 1}#{@index_suffix}#{c.first}" } when :letter l_index = "`" @items.map { |c| "#{l_index.succ!}#{@index_suffix}#{c.first}" } when :none @items.map { |c| "#{c.first}" } else @items.map { |c| "#{index}#{@index_suffix}#{c.first}" } end end
Allows Menu to behave as a String, just like Question. Returns the layout to be rendered, which is used by HighLine.say().
# File lib/highline/menu.rb, line 348 def to_s( ) case @layout when :list '<%= if @header.nil? then '' else "#{@header}:\n" end %>' + "<%= list( @menu, #{@flow.inspect}, #{@list_option.inspect} ) %>" + "<%= @prompt %>" when :one_line '<%= if @header.nil? then '' else "#{@header}: " end %>' + "<%= @prompt %>" + "(<%= list( @menu, #{@flow.inspect}, #{@list_option.inspect} ) %>)" + "<%= @prompt[/\s*$/] %>" when :menu_only "<%= list( @menu, #{@flow.inspect}, #{@list_option.inspect} ) %><%= @prompt %>" else @layout end end
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