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YARD::Options

Generalized options class for passing around large amounts of options between objects.

The options class exists for better visibility and documentability of options being passed through to other objects. Because YARD has parser and template architectures that are heavily reliant on options, it is necessary to make these option keys easily visible and understood by developers. Since the options class is more than just a basic Hash, the subclass can provide aliasing and convenience methods to simplify option property access, and, if needed, support backward-compatibility for deprecated key names.

Hash and OpenStruct-like Access

Although the options class allows for Hash-like access (opts[:key]), the recommended mechanism for accessing an option key will be via standard method calls on attributes

The options class can also act as an open ended key value storage structure (like a Hash or OpenStruct), and allows for setting and getting of unregistered option keys. This methodology is not recommended, however, and is only supported for backward compatibility inside YARD. Whenever possible, developers should define all keys used by an options class.

Declaring Default Values

Note that the options class can contain default value definitions for certain options, but to initialize these defaults, {reset_defaults} must be called manually after initialization; the options object is always created empty until defaults are applied.

@abstract Subclasses should define (and document) custom attributes that are expected

to be made available as option keys.

@example Defining an Options class with custom option keys

class TemplateOptions < YARD::Options
  # @return [Symbol] the output format to generate templates in
  attr_accessor :format

  # @return [Symbol] the template to use when generating output
  attr_accessor :template
end

@example Initializing default option values

class TemplateOptions < YARD::Options
  def reset_defaults
    super
    self.format = :html
    self.template = :default
    self.highlight = true
    # ...
  end
end

@example Using default_attr to create default attributes

class TemplateOptions < YARD::Options
  default_attr :format, :html
  default_attr :template, :default
  default_attr :highlight, true
end

@example Deprecating an option while still supporting it

class TemplateOptions < YARD::Options
  # @return [Boolean] if syntax highlighting should be performed on code blocks.
  #   Defaults to true.
  attr_accessor :highlight

  # @deprecated Use {#highlight} instead.
  # @return [Boolean] if no syntax highlighting should be performs on code blocks.
  #   Defaults to false.
  attr_accessor :no_highlight
  def no_highlight=(value) @highlight = !value end
  def no_highlight; !highlight end
end

Public Class Methods

default_attr(key, default) click to toggle source

@!macro [attach] yard.default_attr

@!attribute $1

Defines an attribute named key and sets a default value for it

@example Defining a default option key

default_attr :name, 'Default Name'
default_attr :time, lambda { Time.now }

@param [Symbol] key the option key name @param [Object, Proc] default the default object value. If the default

value is a proc, it is executed upon initialization.
# File lib/yard/options.rb, line 79
def self.default_attr(key, default)
  (@defaults ||= {})[key] = default
  attr_accessor(key)
end

Public Instance Methods

==(other) click to toggle source

@return [Boolean] whether another Options object equals the

keys and values of this options object
# File lib/yard/options.rb, line 156
def ==(other)
  case other
  when Options; to_hash == other.to_hash
  when Hash; to_hash == other
  else false
  end
end
[](key) click to toggle source

Delegates calls with Hash syntax to actual method with key name

@example Calling on an option key with Hash syntax

options[:format] # equivalent to: options.format

@param [Symbol, String] key the option name to access @return the value of the option named key

# File lib/yard/options.rb, line 90
def [](key) send(key) end
[]=(key, value) click to toggle source

Delegates setter calls with Hash syntax to the attribute setter with the key name

@example Setting an option with Hash syntax

options[:format] = :html # equivalent to: options.format = :html

@param [Symbol, String] key the optin to set @param [Object] value the value to set for the option @return [Object] the value being set

# File lib/yard/options.rb, line 99
def []=(key, value) send("#{key}=", value) end
delete(key) click to toggle source

Deletes an option value for key

@param [Symbol, String] key the key to delete a value for @return [Object] the value that was deleted

# File lib/yard/options.rb, line 204
def delete(key)
  val = self[key]
  if instance_variable_defined?("@#{key}")
    remove_instance_variable("@#{key}")
  end
  val
end
each(&block) click to toggle source

Yields over every option key and value @yield [key, value] every option key and value @yieldparam [Symbol] key the option key @yieldparam [Object] value the option value @return [void]

# File lib/yard/options.rb, line 142
def each(&block)
  instance_variables.each do |ivar|
    name = ivar.to_s.sub(/^@/, '')
    yield(name.to_sym, send(name))
  end
end
inspect() click to toggle source

Inspects the object

# File lib/yard/options.rb, line 150
def inspect
  "<#{self.class}: #{to_hash.inspect}>"
end
merge(opts) click to toggle source

Creates a new options object and sets options hash or object value onto that object.

@param [Options, Hash] opts @return [Options] the newly created options object @see update

# File lib/yard/options.rb, line 122
def merge(opts)
  dup.update(opts)
end
method_missing(meth, *args, &block) click to toggle source

Handles setting and accessing of unregistered keys similar to an OpenStruct object.

@note It is not recommended to set and access unregistered keys on

an Options object. Instead, register the attribute before using it.
# File lib/yard/options.rb, line 169
def method_missing(meth, *args, &block)
  if meth.to_s =~ /^(.+)=$/
    log.debug "Attempting to set unregistered key #{$1} on #{self.class}"
    instance_variable_set("@#{$1}", args.first)
  elsif args.size == 0
    log.debug "Attempting to access unregistered key #{meth} on #{self.class}"
    instance_variable_get("@#{meth}")
  else
    super
  end
end
reset_defaults() click to toggle source

Resets all values to their defaults.

@abstract Subclasses should override this method to perform custom

value initialization if not using {default_attr}. Be sure to call
+super+ so that default initialization can take place.

@return [void]

# File lib/yard/options.rb, line 187
def reset_defaults
  names_set = {}
  self.class.ancestors.each do |klass| # look at all ancestors
    defaults = klass.instance_variable_get("@defaults")
    next unless defaults
    defaults.each do |key, value|
      next if names_set[key]
      names_set[key] = true
      self[key] = Proc === value ? value.call : value
    end
  end
end
tap(&block) click to toggle source
# File lib/yard/options.rb, line 213
def tap(&block) yield(self); self end
to_hash() click to toggle source

@return [Hash] Converts options object to an options hash. All keys

will be symbolized.
# File lib/yard/options.rb, line 128
def to_hash
  opts = {}
  instance_variables.each do |ivar|
    name = ivar.to_s.sub(/^@/, '')
    opts[name.to_sym] = send(name)
  end
  opts
end
update(opts) click to toggle source

Updates values from an options hash or options object on this object. All keys passed should be key names defined by attributes on the class.

@example Updating a set of options on an Options object

opts.update(:template => :guide, :type => :fulldoc)

@param [Hash, Options] opts @return [self]

# File lib/yard/options.rb, line 108
def update(opts)
  opts = opts.to_hash if Options === opts
  opts.each do |key, value|
    self[key] = value
  end
  self
end

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