Class | HighLine::Menu |
In: |
lib/highline/menu.rb
|
Parent: | Question |
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.
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:
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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. |
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 26 26: def initialize( ) 27: # 28: # Initialize Question objects with ignored values, we'll 29: # adjust ours as needed. 30: # 31: super("Ignored", [ ], &nil) # avoiding passing the block along 32: 33: @items = [ ] 34: @hidden_items = [ ] 35: @help = Hash.new("There's no help for that topic.") 36: 37: @index = :number 38: @index_suffix = ". " 39: @select_by = :index_or_name 40: @flow = :rows 41: @list_option = nil 42: @header = nil 43: @prompt = "? " 44: @layout = :list 45: @shell = false 46: @nil_on_handled = false 47: 48: # Override Questions responses, we'll set our own. 49: @responses = { } 50: # Context for action code. 51: @highline = nil 52: 53: yield self if block_given? 54: 55: init_help if @shell and not @help.empty? 56: update_responses # rebuild responses based on our settings 57: end
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 139 139: def choice( name, help = nil, &action ) 140: @items << [name, action] 141: 142: @help[name.to_s.downcase] = help unless help.nil? 143: 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 151 151: def choices( *names, &action ) 152: names.each { |n| choice(n, &action) } 153: 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 a literal String, also adjusts index_suffix to a single space and select_by to :none. Because of this, you should make a habit of setting the index first.
# File lib/highline/menu.rb, line 177 177: def index=( style ) 178: @index = style 179: 180: # Default settings. 181: if @index == :none or @index.is_a?(String) 182: @index_suffix = " " 183: @select_by = :name 184: end 185: end
Initializes the help system by adding a :help choice, some action code, and the default help listing.
# File lib/highline/menu.rb, line 191 191: def init_help( ) 192: return if @items.include?(:help) 193: 194: topics = @help.keys.sort 195: help_help = @help.include?("help") ? @help["help"] : 196: "This command will display helpful messages about " + 197: "functionality, like this one. To see the help for " + 198: "a specific topic enter:\n\thelp [TOPIC]\nTry asking " + 199: "for help on any of the following:\n\n" + 200: "<%= list(#{topics.inspect}, :columns_across) %>" 201: choice(:help, help_help) do |command, topic| 202: topic.strip! 203: topic.downcase! 204: if topic.empty? 205: @highline.say(@help["help"]) 206: else 207: @highline.say("= #{topic}\n\n#{@help[topic]}") 208: end 209: end 210: 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 250 250: def layout=( new_layout ) 251: @layout = new_layout 252: 253: # Default settings. 254: case @layout 255: when :one_line, :menu_only 256: self.index = :none 257: @flow = :inline 258: end 259: 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 265 265: def options( ) 266: # add in any hidden menu commands 267: @items.concat(@hidden_items) 268: 269: by_index = if @index == :letter 270: l_index = "`" 271: @items.map { "#{l_index.succ!}" } 272: else 273: (1 .. @items.size).collect { |s| String(s) } 274: end 275: by_name = @items.collect { |c| c.first } 276: 277: case @select_by 278: when :index then 279: by_index 280: when :name 281: by_name 282: else 283: by_index + by_name 284: end 285: ensure 286: # make sure the hidden items are removed, before we return 287: @items.slice!(@items.size - @hidden_items.size, @hidden_items.size) 288: 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 Menu.choice().
# File lib/highline/menu.rb, line 295 295: def select( highline_context, selection, details = nil ) 296: # add in any hidden menu commands 297: @items.concat(@hidden_items) 298: 299: # Find the selected action. 300: name, action = if selection =~ /^\d+$/ 301: @items[selection.to_i - 1] 302: else 303: l_index = "`" 304: index = @items.map { "#{l_index.succ!}" }.index(selection) 305: @items.find { |c| c.first == selection } or @items[index] 306: end 307: 308: # Run or return it. 309: if not @nil_on_handled and not action.nil? 310: @highline = highline_context 311: if @shell 312: action.call(name, details) 313: else 314: action.call(name) 315: end 316: elsif action.nil? 317: name 318: else 319: nil 320: end 321: ensure 322: # make sure the hidden items are removed, before we return 323: @items.slice!(@items.size - @hidden_items.size, @hidden_items.size) 324: end
Allows Menu objects to pass as Arrays, for use with HighLine.list(). This method returns all menu items to be displayed, complete with indexes.
# File lib/highline/menu.rb, line 331 331: def to_ary( ) 332: case @index 333: when :number 334: @items.map { |c| "#{@items.index(c) + 1}#{@index_suffix}#{c.first}" } 335: when :letter 336: l_index = "`" 337: @items.map { |c| "#{l_index.succ!}#{@index_suffix}#{c.first}" } 338: when :none 339: @items.map { |c| "#{c.first}" } 340: else 341: @items.map { |c| "#{index}#{@index_suffix}#{c.first}" } 342: end 343: end
Allows Menu to behave as a String, just like Question. Returns the layout to be rendered, which is used by HighLine.say().
# File lib/highline/menu.rb, line 349 349: def to_str( ) 350: case @layout 351: when :list 352: '<%= if @header.nil? then '' else "#{@header}:\n" end %>' + 353: "<%= list( @menu, #{@flow.inspect}, 354: #{@list_option.inspect} ) %>" + 355: "<%= @prompt %>" 356: when :one_line 357: '<%= if @header.nil? then '' else "#{@header}: " end %>' + 358: "<%= @prompt %>" + 359: "(<%= list( @menu, #{@flow.inspect}, 360: #{@list_option.inspect} ) %>)" + 361: "<%= @prompt[/\s*$/] %>" 362: when :menu_only 363: "<%= list( @menu, #{@flow.inspect}, 364: #{@list_option.inspect} ) %><%= @prompt %>" 365: else 366: @layout 367: end 368: end
This method will update the intelligent responses to account for Menu specific differences. This overrides the work done by Question.build_responses().
# File lib/highline/menu.rb, line 375 375: def update_responses( ) 376: append_default unless default.nil? 377: @responses = { :ambiguous_completion => 378: "Ambiguous choice. " + 379: "Please choose one of #{options.inspect}.", 380: :ask_on_error => 381: "? ", 382: :invalid_type => 383: "You must enter a valid #{options}.", 384: :no_completion => 385: "You must choose one of " + 386: "#{options.inspect}.", 387: :not_in_range => 388: "Your answer isn't within the expected range " + 389: "(#{expected_range}).", 390: :not_valid => 391: "Your answer isn't valid (must match " + 392: "#{@validate.inspect})." }.merge(@responses) 393: end