Class: HighLine::Menu

Inherits:
Question show all
Defined in:
lib/highline/menu.rb

Overview

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.

Instance Attribute Summary collapse

Attributes inherited from Question

#above, #answer_type, #below, #case, #character, #completion, #confirm, #default, #directory, #echo, #first_answer, #gather, #glob, #in, #limit, #overwrite, #question, #readline, #responses, #validate, #verify_match, #whitespace

Instance Method Summary collapse

Methods inherited from Question

#answer_or_default, #build_responses, #change_case, #convert, #expected_range, #first_answer?, #in_range?, #remove_whitespace, #selection, #valid_answer?

Constructor Details

#initialize {|_self| ... } ⇒ Menu

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.

Yields:

  • (_self)

Yield Parameters:


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# 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

Instance Attribute Details

#flowObject

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


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# File 'lib/highline/menu.rb', line 84

def flow
  @flow
end

#headerObject

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


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# File 'lib/highline/menu.rb', line 95

def header
  @header
end

#indexObject

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


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# File 'lib/highline/menu.rb', line 60

def index
  @index
end

#index_suffixObject

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


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# File 'lib/highline/menu.rb', line 65

def index_suffix
  @index_suffix
end

#layoutObject

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


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# File 'lib/highline/menu.rb', line 105

def layout
  @layout
end

#list_optionObject

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.


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# File 'lib/highline/menu.rb', line 90

def list_option
  @list_option
end

#nil_on_handledObject

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.


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# File 'lib/highline/menu.rb', line 121

def nil_on_handled
  @nil_on_handled
end

#promptObject

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


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# File 'lib/highline/menu.rb', line 100

def prompt
  @prompt
end

#select_byObject

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.


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# File 'lib/highline/menu.rb', line 79

def select_by
  @select_by
end

#shellObject

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.


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# File 'lib/highline/menu.rb', line 113

def shell
  @shell
end

Instance Method Details

#choice(name, help = nil, &action) ⇒ Object

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.


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# 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) ⇒ Object

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.


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# File 'lib/highline/menu.rb', line 149

def choices( *names, &action )
  names.each { |n| choice(n, &action) }
end

#help(topic, help) ⇒ Object

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


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# File 'lib/highline/menu.rb', line 214

def help( topic, help )
  @help[topic] = help
end

#hidden(name, help = nil, &action) ⇒ Object

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


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# 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

#init_helpObject

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


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# 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

#optionsObject

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


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# 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) ⇒ Object

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().


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# 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_aryObject

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


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# 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_strObject

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


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# 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_responsesObject

This method will update the intelligent responses to account for Menu specific differences. This overrides the work done by Question.build_responses().


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# File 'lib/highline/menu.rb', line 374

def update_responses(  )
  append_default unless default.nil?
  @responses = @responses.merge(
                 :ambiguous_completion =>
                   "Ambiguous choice.  " +
                   "Please choose one of #{options.inspect}.",
                 :ask_on_error         =>
                   "?  ",
                 :invalid_type         =>
                   "You must enter a valid #{options}.",
                 :no_completion        =>
                   "You must choose one of " +
                   "#{options.inspect}.",
                 :not_in_range         =>
                   "Your answer isn't within the expected range " +
                   "(#{expected_range}).",
                 :mismatch             =>
                   "Your entries didn't match.",
                 :not_valid            =>
                   "Your answer isn't valid (must match " +
                   "#{@validate.inspect})."
               )
end