Improved YARD cheatsheet

yardoc_cheatsheet.md

NOTE: This is outdated. Check the comments below for more up-to-date forks of this gist.

Improved YARD CHEATSHEET http://yardoc.org

forked from https://gist.github.com/chetan/1827484 which is from early 2012 and contains outdated information.

• Official Getting Started Guide
• Official Tags documentation
• Type naming examples

Templates to remind you of the options and formatting for the different types of objects you might want to document using YARD.

Linking Objects {...}

To link another "object" (class, method, module, etc.), use the format:

{ObjectName#method OPTIONAL_TITLE}
{Class::CONSTANT My constant's title}
{#method_inside_current_namespace}

Methods

# An alias to {Parser::SourceParser}'s parsing method
# 
# @author Donovan Bray
#
# @see http://example.com Description of URL
# @see SomeOtherClass#method
#
# @deprecated Use {#my_new_method} instead of this method because
#   it uses a library that is no longer supported in Ruby 1.9. 
#   The new method accepts the same parameters.
#
# @abstract
# @private

Method parameters

# @param [Hash] opts the options to create a message with.
# @option opts [String] :subject The subject
# @option opts [String] :from ('nobody') From address
# @option opts [String] :to Recipient email
# @option opts [String] :body ('') The email's body 
#
# @param (see User#initialize)
# @param [OptionParser] opts the option parser object
# @param [Array<String>] args the arguments passed from input. This
#   array will be modified.
# @param [Array<String, Symbol>] list the list of strings and symbols.
# @param [Hash<Symbol, String>] a hash with symbol keys and string values
#
# The options parsed out of the commandline.
# Default options are:
#   :format => :dot

Examples

# @example Reverse a string
#   "mystring".reverse #=> "gnirtsym"
#
# @example Parse a glob of files
#   YARD.parse('lib/**/*.rb')

Modules

# Namespace for classes and modules that handle serving documentation over HTTP
# @since 0.6.0

Classes

# Abstract base class for CLI utilities. Provides some helper methods for
# the option parser
# 
# @author Full Name
# @abstract
# @since 0.6.0
# @deprecated Describe the reason or provide alt. references here
#
# # Attributes can be documented directly like this
# attr_reader :hello
#
# If you generate attributes via meta programming, use
# @!attribute [r | w | rw] attribute_name

See https://www.rubydoc.info/gems/yard/file/docs/Tags.md#attribute for more information on documenting attributes.

Exceptions

# @raise [ExceptionClass] description

Return values

# @return [optional, types, ...] description
# @return [true] always returns true
# @return [void]
# @return [String, nil] the contents of our object or nil
#   if the object has not been filled with data.
#
# We don't care about the "type" here:
# @return the object
#
# @return [String, #read] a string or object that responds to #read
# @return description here with no types

Anywhere

# @todo Add support for Jabberwocky service
#   There is an open source Jabberwocky library available 
#   at http://somesite.com that can be integrated easily
#   into the project.

Blocks

# for block {|a, b, c| ... }
# @yield [a, b, c] Description of block
#
# @yieldparam [optional, types, ...] argname description
# @yieldreturn [optional, types, ...] description

@chriscz thanks, updated!

I'm curious:

# @return [String, nil] returns a nullable string

so how do I represent a hash of symbol to nullable string; like this?

# @param [Hash<Symbol, [String, nil]>] a hash with symbol keys and nullable string values

@sleekweasel The type field can be quite free form, but you can check the current conventions on https://yardoc.org/types.

In your case, it would be

# @param [Hash{Symbol => String, nil}] a hash with symbol keys and nullable string values

How to repr return multiple values?

# @return [Hash{Number => PartnerLocationIdMap}, Array(LocationMultiple)]

@dmitchell That looks correct. When you say Array(LocationMultiple) then its a list with single element 1-tuple, i.e. return [LocationMultiple.new]
If you want multiple items in the array you have to use Array<LocationMultiple> which will work for return [LocationMultiple.new, LocationMultiple.new, ...]

Need this in PDF badly :)

Also doesn't document the fact that parameter name can precede the type

 # @param request [Request] the request object

from https://www.rubydoc.info/gems/yard/file/docs/GettingStarted.md

PRs welcome here: https://github.com/chriscz/cheatsheets (alsoe @dolzenko check the output folder for a PDF)

@phansch, would you consider updating @param to match to the documentation indicated by yardoc.org?

I see https://yardoc.org/guides/ links "Getting Started" to https://rubydoc.info/gems/yard/file/docs/GettingStarted.md, and that page gives the following, with the name of the param (format) coming before the type of the param ([Symbol]):

@param format [Symbol] the format type, `:text` or `:html`

The present version of this gist has the type of the param ([Hash]) coming after the name of the param (opts) :

@param [Hash] opts the options to create a message with.