Module: Utilrb::Models

Included in:
Module
Defined in:
lib/utilrb/models/registration.rb,
lib/utilrb/models/inherited_enumerable.rb

Defined Under Namespace

Modules: Registration

Instance Method Summary collapse

Instance Method Details

#define_inherited_enumerable(name, attribute_name = name, options = Hash.new, &init) ⇒ Object

Helper method for inherited_enumerable

It is called in the context of the singleton class of the module/class on which inherited_enumerable is called



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# File 'lib/utilrb/models/inherited_enumerable.rb', line 12

def define_inherited_enumerable(name, attribute_name = name, options = Hash.new, &init) # :nodoc:
    # Set up the attribute accessor
  attribute(attribute_name, &init)
  class_eval { private "#{attribute_name}=" }

    promote = method_defined?("promote_#{name}")
  options[:enum_with] ||= :each

    class_eval "    def all_\#{name}; each_\#{name}.to_a end\n    def self_\#{name}; @\#{attribute_name} end\n    EOF\n\n    if options[:map]\n        class_eval <<-EOF, __FILE__, __LINE__+1\n        def find_\#{name}(key)\n            raise ArgumentError, \"nil cannot be used as a key in find_\#{name}\" if !key\n            each_\#{name}(key, true) do |value|\n                return value\n            end\n            nil\n        end\n        def has_\#{name}?(key)\n            ancestors = self.ancestors\n            if ancestors.first != self\n                ancestors.unshift self\n            end\n            for klass in ancestors\n                if klass.instance_variable_defined?(:@\#{attribute_name})\n                    return true if klass.\#{attribute_name}.has_key?(key)\n                end\n            end\n            false\n        end\n        EOF\n    end\n\n    class_eval <<-EOF, __FILE__, __LINE__+1\n    def clear_\#{attribute_name}\n        \#{attribute_name}.clear\n        for klass in ancestors\n            if klass.instance_variable_defined?(:@\#{attribute_name})\n                klass.\#{attribute_name}.clear\n            end\n        end\n    end\n    EOF\n\n    if !promote\n        if options[:map]\n            define_inherited_enumerable_map_without_promotion(name, attribute_name, options)\n        else\n            define_inherited_enumerable_nomap_without_promotion(name, attribute_name, options)\n        end\n    else\n        if options[:map]\n            define_inherited_enumerable_map_with_promotion(name, attribute_name, options)\n        else\n            define_inherited_enumerable_nomap_with_promotion(name, attribute_name, options)\n        end\n    end\nend\n", __FILE__, __LINE__+1

#define_inherited_enumerable_map_with_promotion(name, attribute_name, options) ⇒ Object 



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# File 'lib/utilrb/models/inherited_enumerable.rb', line 143

def define_inherited_enumerable_map_with_promotion(name, attribute_name, options)
    class_eval "    def each_\#{name}(key = nil, uniq = true)\n        if !block_given?\n            return enum_for(:each_\#{name}, key, uniq)\n        end\n\n        ancestors = self.ancestors\n        if ancestors.first != self\n            ancestors.unshift self\n        end\n        if key\n            promotions = []\n            for klass in ancestors\n                if klass.instance_variable_defined?(:@\#{attribute_name})\n                    if klass.\#{attribute_name}.has_key?(key)\n                        value = klass.\#{attribute_name}[key]\n                        for p in promotions\n                            value = p.promote_\#{name}(key, value)\n                        end\n                        yield(value)\n                        return self if uniq\n                    end\n                end\n                promotions.unshift(klass) if klass.respond_to?(\"promote_\#{name}\")\n            end\n        elsif !uniq\n            promotions = []\n            for klass in ancestors\n                if klass.instance_variable_defined?(:@\#{attribute_name})\n                    klass.\#{attribute_name}.\#{options[:enum_with]} do |key, value|\n                        for p in promotions\n                            value = p.promote_\#{name}(key, value)\n                        end\n                        yield(key, value)\n                    end\n                end\n                promotions.unshift(klass) if klass.respond_to?(\"promote_\#{name}\")\n            end\n        else\n            seen = Set.new\n            promotions = []\n            for klass in ancestors\n                if klass.instance_variable_defined?(:@\#{attribute_name})\n                    klass.\#{attribute_name}.\#{options[:enum_with]} do |key, value|\n                        unless seen.include?(key)\n                            for p in promotions\n                                value = p.promote_\#{name}(key, value)\n                            end\n                            seen << key\n                            yield(key, value)\n                        end\n                    end\n                end\n                promotions.unshift(klass) if klass.respond_to?(\"promote_\#{name}\")\n            end\n        end\n        self\n    end\n    EOF\nend\n", __FILE__, __LINE__+1

#define_inherited_enumerable_map_without_promotion(name, attribute_name, options) ⇒ Object 



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# File 'lib/utilrb/models/inherited_enumerable.rb', line 75

def define_inherited_enumerable_map_without_promotion(name, attribute_name, options)
    class_eval "    def each_\#{name}(key = nil, uniq = true)\n        if !block_given?\n            return enum_for(:each_\#{name}, key, uniq)\n        end\n\n        ancestors = self.ancestors\n        if ancestors.first != self\n            ancestors.unshift self\n        end\n        if key\n            for klass in ancestors\n                if klass.instance_variable_defined?(:@\#{attribute_name})\n                    if klass.\#{attribute_name}.has_key?(key)\n                        yield(klass.\#{attribute_name}[key])\n                        return self if uniq\n                    end\n                end\n            end\n        elsif !uniq\n            for klass in ancestors\n                if klass.instance_variable_defined?(:@\#{attribute_name})\n                    klass.\#{attribute_name}.\#{options[:enum_with]} do |el|\n                        yield(el)\n                    end\n                end\n            end\n        else\n            seen = Set.new\n            for klass in ancestors\n                if klass.instance_variable_defined?(:@\#{attribute_name})\n                    klass.\#{attribute_name}.\#{options[:enum_with]} do |el| \n                        unless seen.include?(el.first)\n                            seen << el.first\n                            yield(el)\n                        end\n                    end\n                end\n            end\n\n        end\n        self\n    end\n    EOF\nend\n", __FILE__, __LINE__+1

#define_inherited_enumerable_nomap_with_promotion(name, attribute_name, options) ⇒ Object 



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# File 'lib/utilrb/models/inherited_enumerable.rb', line 205

def define_inherited_enumerable_nomap_with_promotion(name, attribute_name, options)
    class_eval "    def each_\#{name}\n        if !block_given?\n            return enum_for(:each_\#{name})\n        end\n\n        ancestors = self.ancestors\n        if ancestors.first != self\n            ancestors.unshift self\n        end\n        promotions = []\n        for klass in ancestors\n            if klass.instance_variable_defined?(:@\#{attribute_name})\n                klass.\#{attribute_name}.\#{options[:enum_with]} do |value|\n                    for p in promotions\n                        value = p.promote_\#{name}(value)\n                    end\n                    yield(value)\n                end\n            end\n            promotions.unshift(klass) if klass.respond_to?(\"promote_\#{name}\")\n        end\n        self\n    end\n    EOF\nend\n", __FILE__, __LINE__+1

#define_inherited_enumerable_nomap_without_promotion(name, attribute_name, options) ⇒ Object 



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# File 'lib/utilrb/models/inherited_enumerable.rb', line 122

def define_inherited_enumerable_nomap_without_promotion(name, attribute_name, options)
    class_eval "    def each_\#{name}\n        if !block_given?\n            return enum_for(:each_\#{name})\n        end\n\n        ancestors = self.ancestors\n        if ancestors.first != self\n            ancestors.unshift self\n        end\n        for klass in ancestors\n            if klass.instance_variable_defined?(:@\#{attribute_name})\n                klass.\#{attribute_name}.\#{options[:enum_with]} { |el| yield(el) }\n            end\n        end\n        self\n    end\n    EOF\nend\n", __FILE__, __LINE__+1

#inherited_enumerable(name, attribute_name = name, options = Hash.new, &init) ⇒ Object

Defines an attribute as being enumerable in the class instance and in the whole class inheritance hierarchy. More specifically, it defines a each_#{name}(&iterator) instance method and a each_#{name}(&iterator) class method which iterates (in order) on

  • the instance #name attribute

  • the singleton class #name attribute

  • the class #name attribute

  • the superclass #name attribute

  • the superclass’ superclass #name attribute

…

This method can be used on modules, in which case the module is used as if it was part of the inheritance hierarchy.

The name option defines the enumeration method name (value will define a each_value method). attribute_name defines the attribute name. init is a block called to initialize the attribute. Valid options in options are:

map

If true, the attribute should respond to []. In that case, the enumeration method is each_value(key = nil, uniq = false) If key is given, we iterate on the values given by attribute[key]. If uniq is true, the enumeration will yield at most one value for each key found (so, if both key and uniq are given, the enumeration yields at most one value). See the examples below

enum_with

the enumeration method of the enumerable, if it is not each

Example

Let’s define some classes and look at the ancestor chain

class A;  end
module M; end
class B < A; include M end
A.ancestors # => [A, Object, Kernel]
B.ancestors # => [B, M, A, Object, Kernel]

Attributes for which ‘map’ is not set

class A
  inherited_enumerable("value", "values") do
      Array.new
  end
end
module M
  inherited_enumerable("mod") do
      Array.new
  end
end

A.values << 1 # => [1]
B.values << 2 # => [2]
M.mod << 1 # => [1]
b = B.new 
class << b
    self.values << 3 # => [3]
    self.mod << 4 # => [4]
end
M.mod << 2 # => [1, 2]

A.enum_for(:each_value).to_a # => [1]
B.enum_for(:each_value).to_a # => [2, 1]
b.singleton_class.enum_for(:each_value).to_a # => [3, 2, 1]
b.singleton_class.enum_for(:each_mod).to_a # => [4, 1, 2]

Attributes for which ‘map’ is set

class A
  inherited_enumerable("mapped", "map", :map => true) do
      Hash.new { |h, k| h[k] = Array.new }
  end
end

A.map['name'] = 'A' # => "A"
A.map['universe'] = 42
B.map['name'] = 'B' # => "B"
B.map['half_of_it'] = 21

Let’s see what happens if we don’t specify the key option.

A.enum_for(:each_mapped).to_a # => [["name", "A"], ["universe", 42]]

If the uniq option is set (the default), we see only B’s value for ‘name’

B.enum_for(:each_mapped).to_a # => [["half_of_it", 21], ["name", "B"], ["universe", 42]]

If the uniq option is not set, we see both values for ‘name’. Note that since ‘map’ is a Hash, the order of keys in one class is not guaranteed. Nonetheless, we have the guarantee that values from B appear before those from A

B.enum_for(:each_mapped, nil, false).to_a # => [["half_of_it", 21], ["name", "B"], ["name", "A"], ["universe", 42]]

Now, let’s see how ‘key’ behaves

A.enum_for(:each_mapped, 'name').to_a # => ["A"]
B.enum_for(:each_mapped, 'name').to_a # => ["B"]
B.enum_for(:each_mapped, 'name', false).to_a # => ["B", "A"]



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# File 'lib/utilrb/models/inherited_enumerable.rb', line 326

def inherited_enumerable(name, attribute_name = name, options = Hash.new, &init)
  singleton_class.class_eval { define_inherited_enumerable(name, attribute_name, options, &init) }

  if is_a?(Module) && !is_a?(Class)
 unless const_defined_here?(:ClassExtension)
    const_set(:ClassExtension, Module.new)
 end
 class_extension = const_get(:ClassExtension)
 class_extension.class_eval do
    define_inherited_enumerable(name, attribute_name, options, &init)
 end
  end
end