Class: Alias::Creator

Inherits:
Object
  • Object
show all
Defined in:
lib/alias/creator.rb

Overview

This is the base creator class. To be a valid subclass, the creator must define Alias::Creator.map and Alias::Creator.generate. Although not required, creators should enforce validation of their aliases with Alias::Creator.valid. Also, the creator should be named in the format Alias::Creators::*Creator where the asterisk stands for any unique string. Since that string is converted to an underscored version when referenced in the console, it’s recommended to make it camel case. For example, Alias::Creators::InstanceMethodCreator is referenced by it’s underscored version :instance_method.

To better understand how a creator works, here’s the steps a creator goes through when creating aliases:

  • map() : Maps the hash from a config file or console input into an array of alias hashes.

  • valid() : Defines a validation that each alias hash must pass.

  • generate() : Given the array of alias hashes, generates the string of ruby code to be evaled for alias creation.

Defined Under Namespace

Classes: AbstractMethodError, FailedAliasCreationError

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(options = {}) ⇒ Creator

:nodoc:



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# File 'lib/alias/creator.rb', line 83

def initialize(options={}) #:nodoc:
  @verbose = false
  @force = false
  @aliases = []
end

Instance Attribute Details

#aliases ⇒ Object

Array of alias hashes that have been created.



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# File 'lib/alias/creator.rb', line 81

def aliases
  @aliases
end

#force ⇒ Object

Same purpose as Alias::Manager.verbose and Alias::Manager.force but unlike them these only take a boolean.



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# File 'lib/alias/creator.rb', line 79

def force
  @force
end

#verbose ⇒ Object

Same purpose as Alias::Manager.verbose and Alias::Manager.force but unlike them these only take a boolean.



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# File 'lib/alias/creator.rb', line 79

def verbose
  @verbose
end

Class Method Details

.class_or_module(klass) ⇒ Object

:nodoc:



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# File 'lib/alias/creator.rb', line 65

def class_or_module(klass) #:nodoc:
  Util.any_const_get(klass).is_a?(Class) ? 'class' : 'module'
end

.creators ⇒ Object

Array of all Creator subclasses.



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# File 'lib/alias/creator.rb', line 75

def creators; @creators; end

.generate(&block) ⇒ Object

Takes a block which converts aliases to a string of ruby code to run through Kernel#eval.



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# File 'lib/alias/creator.rb', line 61

def generate(&block)
  @generate = block
end

.generates_aliases(aliases) ⇒ Object

:nodoc:



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# File 'lib/alias/creator.rb', line 56

def generates_aliases(aliases) #:nodoc:
  @generate ? @generate.call(aliases) : raise(AbstractMethodError, "No generate() defined for #{self}")
end

.inherited(subclass) ⇒ Object

:nodoc:



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# File 'lib/alias/creator.rb', line 69

def inherited(subclass) #:nodoc:
  @creators ||= []
  @creators << subclass
end

.map(&block) ⇒ Object

Takes a block which converts the creator’s config to an array of aliases.



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# File 'lib/alias/creator.rb', line 52

def map(&block)
  @map = block
end

.maps_config(config) ⇒ Object

:nodoc:



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# File 'lib/alias/creator.rb', line 47

def maps_config(config) #:nodoc:
  @map ? @map.call(config) : raise(AbstractMethodError, "No map() defined for #{self}")
end

.valid(key, options = {}) ⇒ Object

Creates a validation expectation for the creator by giving it an Alias::Validator object aka validator. This method must be given an :if or :unless option. If the :if option returns false or :unless option returns true for an alias, the alias is skipped.

Options:

:if

Takes a proc or a symbol referencing a registered validator. This proc must evaluate to true for the validation to pass. See Alias::Validator.validate for what arguments this proc receives by default. See Alias::Validator.default_validators for validators that can be referenced by symbol.

:unless

Same as :if option but the result is negated.

:message

A proc to print a message if the creator’s verbose flag is set. Receives same arguments as :if and :unless procs. If a previous validator is referenced in :unless or :if, then their :message is inherited.

:with

An array of alias attributes/keys which specify the current alias attributes to pass to the validator procs. Overrides default argument a validator proc receives.

:optional

When set to true, this option can be overridden in conjunction with a creator’s force flag. Default is false.



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# File 'lib/alias/creator.rb', line 31

def valid(key, options={})
  begin
    validators[key] = Validator.new(options.merge(:key=>key, :creator=>self))
  rescue Validator::MissingConditionError
    raise ArgumentError, "A :unless or :if option is required."
  rescue Validator::InvalidValidatorError
    $stderr.puts "Validator not set for #{key}"
    @validators.delete(key)
  end
end

.validators ⇒ Object

Stores validators per alias attribute/key.



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# File 'lib/alias/creator.rb', line 43

def validators #:nodoc:
  @validators ||= {}
end

Instance Method Details

#create(aliases_hash, pretend = false) ⇒ Object

Main method used to create aliases. Handles mapping, validation and creation of aliases.



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# File 'lib/alias/creator.rb', line 90

def create(aliases_hash, pretend=false)
  aliases_array = self.class.maps_config(aliases_hash)
  delete_invalid_aliases(aliases_array)
  self.aliases = aliases + aliases_array unless pretend
  begin
    #td: create method for efficiently removing constants/methods in any namespace
    eval_string = Util.silence_warnings { self.class.generates_aliases(aliases_array) }
    pretend ? puts("\n", eval_string) : Kernel.eval(eval_string)
  rescue
    raise FailedAliasCreationError, $!
  end
end

#delete_invalid_aliases(arr) ⇒ Object

Deletes invalid alias hashes that fail defined validators for a creator.



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# File 'lib/alias/creator.rb', line 104

def delete_invalid_aliases(arr)
  arr.delete_if {|alias_hash|
    !self.class.validators.all? {|attribute, validator|
      validator.validate(self, alias_hash, attribute)
    }
  }
end