This library provides external validations for any Ruby class.

It originates from emmanuels aequitas repository with the following changes:

• Only support for external validators
• Use composable algebra for internals
• Will allow serialization to javascript for client side validation (not implemented)
• No contextual validators anymore (use additional external validators)
• 100% code rewrite
• Use equalizer and adamantium where possible.

require 'vanguard'

class ProgrammingLanguage
  attr_reader :name

  def initialize(name)
    @name = name
  end
end

VALIDATOR = Vanguard::Validator.build do
  validates_presence_of :name
end

ruby = ProgrammingLanguage.new('ruby')

result = VALIDATOR.call(ruby)
result.valid? # => true
result.violations # => #<Set: {}>

other = ProgrammingLanguage.new('')

result = VALIDATOR.call(other)
result.valid? # => false
result.violations # => #<Set: {<Vanguard:::Violation ....>}>

See Vanguard::Macros to learn about the complete collection of validation rules available.

• Markus Schirp mbj
• Emmanuel Gomez emmanuel

If an instance fails one or more validation rules, Vanguard::Violation instances will populate the Vanguard::ViolationSet object that is available through the Vanguard::Result#violations method.

Vanguard currently has no support for generating human readable violation messages!

For example:

result = YOUR_VALIDATOR.call(Account.new(:name => "Jose"))
if result.valid?
  # my_account is valid and can be saved
else
  result.violations.each do |e|
    do_something_with(e)
  end
end

##Contextual Validation

Vanguard does not provide a means of grouping your validations into contexts. Define a validator per context for this.