Class: HighLine::Question

Inherits:
Object show all
Includes:
CustomErrors
Defined in:
lib/highline/question.rb,
lib/highline/question/answer_converter.rb

Overview

Question objects contain all the details of a single invocation of HighLine.ask(). The object is initialized by the parameters passed to HighLine.ask() and then queried to make sure each step of the input process is handled according to the users wishes.

Direct Known Subclasses

Menu

Defined Under Namespace

Classes: AnswerConverter

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(template, answer_type) {|_self| ... } ⇒ Question

Create an instance of HighLine::Question. Expects a template to ask (can be "") and an answer_type to convert the answer to. The answer_type parameter must be a type recognized by Question.convert(). If given, a block is yielded the new Question object to allow custom initialization.

Parameters:

  • template (String)

    any String

  • answer_type (Class)

    the type the answer will be converted to it.

Yields:

  • (_self)

Yield Parameters:


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# File 'lib/highline/question.rb', line 52

def initialize(template, answer_type)
  # initialize instance data
  @template    = String(template).dup
  @answer_type = answer_type
  @completion  = @answer_type

  @echo         = true
  @whitespace   = :strip
  @case         = nil
  @in           = nil
  @first_answer = nil
  @glob         = "*"
  @overwrite    = false
  @user_responses = {}
  @internal_responses = default_responses_hash
  @directory = Pathname.new(File.expand_path(File.dirname($PROGRAM_NAME)))

  # allow block to override settings
  yield self if block_given?

  # finalize responses based on settings
  build_responses
end

Instance Attribute Details

#aboveObject

Used to control range checks for answer.


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# File 'lib/highline/question.rb', line 146

def above
  @above
end

#answerObject

The answer, set by HighLine#ask


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# File 'lib/highline/question.rb', line 80

def answer
  @answer
end

#answer_typeObject

The type that will be used to convert this answer.


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# File 'lib/highline/question.rb', line 83

def answer_type
  @answer_type
end

#belowObject

Used to control range checks for answer.


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# File 'lib/highline/question.rb', line 146

def below
  @below
end

#caseObject

Used to control character case processing for the answer to this question. See HighLine::Question.change_case() for acceptable settings.


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# File 'lib/highline/question.rb', line 136

def case
  @case
end

#characterObject

Can be set to true to use HighLine's cross-platform character reader instead of fetching an entire line of input. (Note: HighLine's character reader ONLY supports STDIN on Windows and Unix.) Can also be set to :getc to use that method on the input stream.

WARNING: The echo and overwrite attributes for a question are ignored when using the :getc method.


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

def character
  @character
end

#completionObject

For Auto-completion


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# File 'lib/highline/question.rb', line 85

def completion
  @completion
end

#confirmObject

Asks a yes or no confirmation question, to ensure a user knows what they have just agreed to. The confirm attribute can be set to : true : In this case the question will be, “Are you sure?”. Proc : The Proc is yielded the answer given. The Proc must

output a string which is then used as the confirm
question.

String : The String must use ERB syntax. The String is

evaluated with access to question and answer and
is then used as the confirm question.

When set to false or nil (the default), answers are not confirmed.


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# File 'lib/highline/question.rb', line 160

def confirm
  @confirm
end

#defaultObject

Used to provide a default answer to this question.


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# File 'lib/highline/question.rb', line 138

def default
  @default
end

#directoryObject

The directory from which a user will be allowed to select files, when File or Pathname is specified as an answer_type. Initially set to Pathname.new(File.expand_path(File.dirname($0))).


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# File 'lib/highline/question.rb', line 193

def directory
  @directory
end

#echoObject

Can be set to true or false to control whether or not input will be echoed back to the user. A setting of true will cause echo to match input, but any other true value will be treated as a String to echo for each character typed.

This requires HighLine's character reader. See the character attribute for details.

Note: When using HighLine to manage echo on Unix based systems, we recommend installing the termios gem. Without it, it's possible to type fast enough to have letters still show up (when reading character by character only).


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# File 'lib/highline/question.rb', line 116

def echo
  @echo
end

#first_answerObject

Returns first_answer, which will be unset following this call.


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# File 'lib/highline/question.rb', line 397

def first_answer
  @first_answer
ensure
  @first_answer = nil
end

#gatherObject

When set, the user will be prompted for multiple answers which will be collected into an Array or Hash and returned as the final answer.

You can set gather to an Integer to have an Array of exactly that many answers collected, or a String/Regexp to match an end input which will not be returned in the Array.

Optionally gather can be set to a Hash. In this case, the question will be asked once for each key and the answers will be returned in a Hash, mapped by key. The @key variable is set before each question is evaluated, so you can use it in your question.


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# File 'lib/highline/question.rb', line 174

def gather
  @gather
end

#globObject

The glob pattern used to limit file selection when File or Pathname is specified as an answer_type. Initially set to "*".


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# File 'lib/highline/question.rb', line 198

def glob
  @glob
end

#inObject

If set, answer must pass an include?() check on this object.


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# File 'lib/highline/question.rb', line 148

def in
  @in
end

#limitObject

Allows you to set a character limit for input.

WARNING: This option forces a character by character read.


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# File 'lib/highline/question.rb', line 101

def limit
  @limit
end

#overwriteObject

When set to true the question is asked, but output does not progress to the next line. The Cursor is moved back to the beginning of the question line and it is cleared so that all the contents of the line disappear from the screen.


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# File 'lib/highline/question.rb', line 232

def overwrite
  @overwrite
end

#readlineObject

Use the Readline library to fetch input. This allows input editing as well as keeping a history. In addition, tab will auto-complete within an Array of choices or a file listing.

WARNING: This option is incompatible with all of HighLine's character reading modes and it causes HighLine to ignore the specified input stream.


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# File 'lib/highline/question.rb', line 126

def readline
  @readline
end

#templateObject

The ERb template of the question to be asked.


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# File 'lib/highline/question.rb', line 77

def template
  @template
end

#validateObject

If set to a Regexp, the answer must match (before type conversion). Can also be set to a Proc which will be called with the provided answer to validate with a true or false return.


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# File 'lib/highline/question.rb', line 144

def validate
  @validate
end

#verify_matchObject

When set to true multiple entries will be collected according to the setting for gather, except they will be required to match each other. Multiple identical entries will return a single answer.


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# File 'lib/highline/question.rb', line 180

def verify_match
  @verify_match
end

#whitespaceObject

Used to control whitespace processing for the answer to this question. See HighLine::Question.remove_whitespace() for acceptable settings.


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# File 'lib/highline/question.rb', line 131

def whitespace
  @whitespace
end

Class Method Details

.build(template_or_question, answer_type = nil, &details) ⇒ Question

If template_or_question is already a Question object just return it. If not, build it.

Parameters:

  • template_or_question (String, Question)

    what to ask

  • answer_type (Class) (defaults to: nil)

    to what class to convert the answer

  • details

    to be passed to Question.new

Returns:


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# File 'lib/highline/question.rb', line 35

def self.build(template_or_question, answer_type = nil, &details)
  if template_or_question.is_a? Question
    template_or_question
  else
    Question.new(template_or_question, answer_type, &details)
  end
end

Instance Method Details

#answer_or_default(answer_string) ⇒ String

Returns the provided answer_string or the default answer for this Question if a default was set and the answer is empty.

Parameters:

Returns:

  • (String)

    the answer itself or a default message.


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# File 'lib/highline/question.rb', line 240

def answer_or_default(answer_string)
  return default if answer_string.empty? && default
  answer_string
end

#ask_on_error_msgself, String

Provides the String to be asked when at an error situation. It may be just the question itself (repeat on error).

Returns:

  • (self)

    if :ask_on_error on responses Hash is set to :question

  • (String)

    if :ask_on_error on responses Hash is set to something else


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# File 'lib/highline/question.rb', line 566

def ask_on_error_msg
  if final_responses[:ask_on_error] == :question
    self
  elsif final_responses[:ask_on_error]
    final_responses[:ask_on_error]
  end
end

#build_responses(message_source = answer_type) ⇒ Hash

Called late in the initialization process to build intelligent responses based on the details of this Question object. Also used by Menu#update_responses.

Parameters:

  • message_source (Class) (defaults to: answer_type)

    Array or String for example. Same as #answer_type.

Returns:

  • (Hash)

    responses Hash winner (new and old merge).


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# File 'lib/highline/question.rb', line 254

def build_responses(message_source = answer_type)
  append_default if [::String, Symbol].include? default.class

  new_hash = build_responses_new_hash(message_source)
  # Update our internal responses with the new hash
  # generated from the message source
  @internal_responses = @internal_responses.merge(new_hash)
end

#build_responses_new_hash(message_source) ⇒ Hash

When updating the responses hash, it generates the new one.

Parameters:

  • message_source (Class)

    Array or String for example. Same as #answer_type.

Returns:

  • (Hash)

    responses hash


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# File 'lib/highline/question.rb', line 273

def build_responses_new_hash(message_source)
  { ambiguous_completion: "Ambiguous choice.  Please choose one of " +
    choice_error_str(message_source) + ".",
    invalid_type: "You must enter a valid #{message_source}.",
    no_completion: "You must choose one of " +
      choice_error_str(message_source) + ".",
    not_in_range: "Your answer isn't within the expected range " \
      "(#{expected_range}).",
    not_valid: "Your answer isn't valid (must match " \
      "#{validate.inspect})." }
end

#change_case(answer_string) ⇒ String

Returns the provided answer_string after changing character case by the rules of this Question. Valid settings for whitespace are:

nil

Do not alter character case. (Default.)

:up

Calls upcase().

:upcase

Calls upcase().

:down

Calls downcase().

:downcase

Calls downcase().

:capitalize

Calls capitalize().

An unrecognized choice (like :none) is treated as nil.

Parameters:

Returns:

  • (String)

    upcased, downcased, capitalized or unchanged answer String.


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# File 'lib/highline/question.rb', line 318

def change_case(answer_string)
  if [:up, :upcase].include?(@case)
    answer_string.upcase
  elsif [:down, :downcase].include?(@case)
    answer_string.downcase
  elsif @case == :capitalize
    answer_string.capitalize
  else
    answer_string
  end
end

#check_rangeObject

Run #in_range? and raise an error if not succesful


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# File 'lib/highline/question.rb', line 364

def check_range
  raise NotInRangeQuestionError unless in_range?
end

#choices_complete(answer_string) ⇒ String

Try to auto complete answer_string

Parameters:

Returns:

Raises:


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# File 'lib/highline/question.rb', line 371

def choices_complete(answer_string)
  # cheating, using OptionParser's Completion module
  choices = selection
  choices.extend(OptionParser::Completion)
  answer = choices.complete(answer_string)
  raise NoAutoCompleteMatch unless answer
  answer
end

#confirm_question(highline) ⇒ String

Returns the String to be shown when asking for an answer confirmation.

Parameters:

Returns:


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# File 'lib/highline/question.rb', line 543

def confirm_question(highline)
  if confirm == true
    "Are you sure?  "
  elsif confirm.is_a?(Proc)
    confirm.call(answer)
  else
    # evaluate ERb under initial scope, so it will have
    # access to question and answer
    template = if ERB.instance_method(:initialize).parameters.assoc(:key) # Ruby 2.6+
      ERB.new(confirm, trim_mode: "%")
    else
      ERB.new(confirm, nil, "%")
    end
    template_renderer = TemplateRenderer.new(template, self, highline)
    template_renderer.render
  end
end

#convertObject

Transforms the given answer_string into the expected type for this Question. Currently supported conversions are:

[...]

Answer must be a member of the passed Array. Auto-completion is used to expand partial answers.

lambda {...}

Answer is passed to lambda for conversion.

Date

Date.parse() is called with answer.

DateTime

DateTime.parse() is called with answer.

File

The entered file name is auto-completed in terms of directory + glob, opened, and returned.

Float

Answer is converted with Kernel.Float().

Integer

Answer is converted with Kernel.Integer().

nil

Answer is left in String format. (Default.)

Pathname

Same as File, save that a Pathname object is returned.

String

Answer is converted with Kernel.String().

HighLine::String

Answer is converted with HighLine::String()

Regexp

Answer is fed to Regexp.new().

Symbol

The method to_sym() is called on answer and the result returned.

any other Class

The answer is passed on to Class.parse().

This method throws ArgumentError, if the conversion cannot be completed for any reason.


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# File 'lib/highline/question.rb', line 359

def convert
  AnswerConverter.new(self).convert
end

#default_responses_hashObject


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# File 'lib/highline/question.rb', line 263

def default_responses_hash
  {
    ask_on_error: "?  ",
    mismatch: "Your entries didn't match."
  }
end

#expected_rangeObject

Returns an English explanation of the current range settings.


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# File 'lib/highline/question.rb', line 381

def expected_range
  expected = []

  expected << "above #{above}" if above
  expected << "below #{below}" if below
  expected << "included in #{@in.inspect}" if @in

  case expected.size
  when 0 then ""
  when 1 then expected.first
  when 2 then expected.join(" and ")
  else        expected[0..-2].join(", ") + ", and #{expected.last}"
  end
end

#final_response(error) ⇒ Object


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# File 'lib/highline/question.rb', line 292

def final_response(error)
  response = final_responses[error]
  if response.respond_to?(:call)
    response.call(answer)
  else
    response
  end
end

#final_responsesObject

This is the actual responses hash that gets used in determining output Notice that we give @user_responses precedence over the responses generated internally via build_response


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# File 'lib/highline/question.rb', line 288

def final_responses
  @internal_responses.merge(@user_responses)
end

#first_answer?Boolean

Returns true if first_answer is set.

Returns:

  • (Boolean)

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# File 'lib/highline/question.rb', line 404

def first_answer?
  true if @first_answer
end

#format_answer(answer_string) ⇒ String

Convert to String, remove whitespace and change case when necessary

Parameters:

Returns:

  • (String)

    converted String


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# File 'lib/highline/question.rb', line 462

def format_answer(answer_string)
  answer_string = String(answer_string)
  answer_string = remove_whitespace(answer_string)
  change_case(answer_string)
end

#get_echo_for_response(response) ⇒ String

Returns an echo string that is adequate for this Question settings.

Parameters:

Returns:


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# File 'lib/highline/question.rb', line 590

def get_echo_for_response(response)
  # actually true, not only truethy value
  if echo == true
    response
  # any truethy value, probably a String
  elsif echo
    echo
  # any falsy value, false or nil
  else
    ""
  end
end

#get_response(highline) ⇒ String

Return a line or character of input, as requested for this question. Character input will be returned as a single character String, not an Integer.

This question's first_answer will be returned instead of input, if set.

Raises EOFError if input is exhausted.

Parameters:

Returns:

  • (String)

    a character or line


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# File 'lib/highline/question.rb', line 515

def get_response(highline)
  return first_answer if first_answer?

  case character
  when :getc
    highline.get_response_getc_mode(self)
  when true
    highline.get_response_character_mode(self)
  else
    highline.get_response_line_mode(self)
  end
end

#get_response_or_default(highline) ⇒ String

Uses #get_response but returns a default answer using #answer_or_default in case no answers was returned.

Parameters:

Returns:


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# File 'lib/highline/question.rb', line 535

def get_response_or_default(highline)
  self.answer = answer_or_default(get_response(highline))
end

#in_range?Boolean

Returns true if the answer_object is greater than the above attribute, less than the below attribute and include?()ed in the in attribute. Otherwise, false is returned. Any nil attributes are not checked.

Returns:

  • (Boolean)

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# File 'lib/highline/question.rb', line 414

def in_range?
  (!above || answer > above) &&
    (!below || answer < below) &&
    (!@in || @in.include?(answer))
end

#remove_whitespace(answer_string) ⇒ String

Returns the provided answer_string after processing whitespace by the rules of this Question. Valid settings for whitespace are:

nil

Do not alter whitespace.

:strip

Calls strip(). (Default.)

:chomp

Calls chomp().

:collapse

Collapses all whitespace runs to a single space.

:strip_and_collapse

Calls strip(), then collapses all whitespace runs to a single space.

:chomp_and_collapse

Calls chomp(), then collapses all whitespace runs to a single space.

:remove

Removes all whitespace.

An unrecognized choice (like :none) is treated as nil.

This process is skipped for single character input.

Parameters:

Returns:

  • (String)

    answer string with whitespaces removed


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# File 'lib/highline/question.rb', line 441

def remove_whitespace(answer_string)
  if !whitespace
    answer_string
  elsif [:strip, :chomp].include?(whitespace)
    answer_string.send(whitespace)
  elsif whitespace == :collapse
    answer_string.gsub(/\s+/, " ")
  elsif [:strip_and_collapse, :chomp_and_collapse].include?(whitespace)
    result = answer_string.send(whitespace.to_s[/^[a-z]+/])
    result.gsub(/\s+/, " ")
  elsif whitespace == :remove
    answer_string.gsub(/\s+/, "")
  else
    answer_string
  end
end

#responsesObject

A Hash that stores the various responses used by HighLine to notify the user. The currently used responses and their purpose are as follows:

:ambiguous_completion

Used to notify the user of an ambiguous answer the auto-completion system cannot resolve.

:ask_on_error

This is the question that will be redisplayed to the user in the event of an error. Can be set to :question to repeat the original question.

:invalid_type

The error message shown when a type conversion fails.

:no_completion

Used to notify the user that their selection does not have a valid auto-completion match.

:not_in_range

Used to notify the user that a provided answer did not satisfy the range requirement tests.

:not_valid

The error message shown when validation checks fail.


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# File 'lib/highline/question.rb', line 223

def responses
  @user_responses
end

#selectionObject

Returns an Array of valid answers to this question. These answers are only known when answer_type is set to an Array of choices, File, or Pathname. Any other time, this method will return an empty Array.


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# File 'lib/highline/question.rb', line 473

def selection
  if completion.is_a?(Array)
    completion
  elsif [File, Pathname].include?(completion)
    Dir[File.join(directory.to_s, glob)].map do |file|
      File.basename(file)
    end
  else
    []
  end
end

#show_question(highline) ⇒ void

This method returns an undefined value.

readline() needs to handle its own output, but readline only supports full line reading. Therefore if question.echo is anything but true, the prompt will not be issued. And we have to account for that now. Also, JRuby-1.7's ConsoleReader.readLine() needs to be passed the prompt to handle line editing properly.

Parameters:


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# File 'lib/highline/question.rb', line 581

def show_question(highline)
  highline.say(self)
end

#to_sObject

Stringifies the template to be asked.


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# File 'lib/highline/question.rb', line 486

def to_s
  template
end

#valid_answer?Boolean

Returns true if the provided answer_string is accepted by the validate attribute or false if it's not.

It's important to realize that an answer is validated after whitespace and case handling.

Returns:

  • (Boolean)

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# File 'lib/highline/question.rb', line 497

def valid_answer?
  !validate ||
    (validate.is_a?(Regexp) && answer =~ validate) ||
    (validate.is_a?(Proc)   && validate[answer])
end