module DidYouMean

The DidYouMean gem adds functionality to suggest possible method/class names upon errors such as NameError and NoMethodError. In Ruby 2.3 or later, it is automatically activated during startup.

@example

methosd
# => NameError: undefined local variable or method `methosd' for main:Object
#   Did you mean?  methods
#                  method

OBject
# => NameError: uninitialized constant OBject
#    Did you mean?  Object

@full_name = "Yuki Nishijima"
first_name, last_name = full_name.split(" ")
# => NameError: undefined local variable or method `full_name' for main:Object
#    Did you mean?  @full_name

@@full_name = "Yuki Nishijima"
@@full_anme
# => NameError: uninitialized class variable @@full_anme in Object
#    Did you mean?  @@full_name

full_name = "Yuki Nishijima"
full_name.starts_with?("Y")
# => NoMethodError: undefined method `starts_with?' for "Yuki Nishijima":String
#    Did you mean?  start_with?

hash = {foo: 1, bar: 2, baz: 3}
hash.fetch(:fooo)
# => KeyError: key not found: :fooo
#    Did you mean?  :foo

Disabling did_you_mean

Occasionally, you may want to disable the did_you_mean gem for e.g. debugging issues in the error object itself. You can disable it entirely by specifying --disable-did_you_mean option to the ruby command:

$ ruby --disable-did_you_mean -e "1.zeor?"
-e:1:in `<main>': undefined method `zeor?' for 1:Integer (NameError)

When you do not have direct access to the ruby command (e.g. +rails console+, irb), you could applyoptions using the RUBYOPT environment variable:

$ RUBYOPT='--disable-did_you_mean' irb
irb:0> 1.zeor?
# => NoMethodError (undefined method `zeor?' for 1:Integer)

Getting the original error message

Sometimes, you do not want to disable the gem entirely, but need to get the original error message without suggestions (e.g. testing). In this case, you could use the #original_message method on the error object:

no_method_error = begin
                    1.zeor?
                  rescue NoMethodError => error
                    error
                  end

no_method_error.message
# => NoMethodError (undefined method `zeor?' for 1:Integer)
#    Did you mean?  zero?

no_method_error.original_message
# => NoMethodError (undefined method `zeor?' for 1:Integer)

Constants

PlainFormatter

The DidYouMean::Formatter is the basic, default formatter for the gem. The formatter responds to the message_for method and it returns a human readable string.

VERSION
VerboseFormatter

The DidYouMean::Formatter is the basic, default formatter for the gem. The formatter responds to the message_for method and it returns a human readable string.

Public Class Methods

correct_error(error_class, spell_checker) click to toggle source

Adds DidYouMean functionality to an error using a given spell checker

# File did_you_mean.rb, line 97
def self.correct_error(error_class, spell_checker)
  if defined?(Ractor)
    new_mapping = { **@spell_checkers, error_class.to_s => spell_checker }
    new_mapping.default = NullChecker

    @spell_checkers = Ractor.make_shareable(new_mapping)
  else
    spell_checkers[error_class.to_s] = spell_checker
  end

  error_class.prepend(Correctable) if error_class.is_a?(Class) && !(error_class < Correctable)
end
formatter() click to toggle source

Returns the currently set formatter. By default, it is set to DidYouMean::Formatter.

# File did_you_mean.rb, line 117
def self.formatter
  if defined?(Ractor)
    Ractor.current[:__did_you_mean_formatter__] || Formatter
  else
    Formatter
  end
end
formatter=(formatter) click to toggle source

Updates the primary formatter used to format the suggestions.

# File did_you_mean.rb, line 126
def self.formatter=(formatter)
  if defined?(Ractor)
    Ractor.current[:__did_you_mean_formatter__] = formatter
  end
end
spell_checkers() click to toggle source

Returns a sharable hash map of error types and spell checker objects.

# File did_you_mean.rb, line 92
def self.spell_checkers
  @spell_checkers
end