class Sequel::SQL::Expression

  1. lib/sequel/sql.rb
Superclass: Object

Base class for all SQL expression objects.

Methods

Public Class

  1. attr_reader
  2. comparison_attrs
  3. inherited

Public Instance

  1. ==
  2. clone
  3. eql?
  4. hash
  5. inspect

Public Instance Aliases

dup -> clone

Attributes

comparison_attrs [R]

All attributes used for equality and hash methods.

Public Class methods

attr_reader (*args)

Expression objects are assumed to be value objects, where their attribute values can't change after assignment. In order to make it easy to define equality and hash methods, subclass instances assume that the only values that affect the results of such methods are the values of the object's attributes.

[show source]
# File lib/sequel/sql.rb, line 90
def attr_reader(*args)
  super
  comparison_attrs.concat(args)
end
inherited (subclass)

Copy the ::comparison_attrs into the subclass.

[show source]
# File lib/sequel/sql.rb, line 96
def inherited(subclass)
  super
  subclass.instance_variable_set(:@comparison_attrs, comparison_attrs.dup)
end

Public Instance methods

== (other)

Alias of eql?

[show source]
# File lib/sequel/sql.rb, line 123
def ==(other)
  eql?(other)
end
clone ()

Make clone/dup return self, since Expression objects are supposed to be frozen value objects

[show source]
# File lib/sequel/sql.rb, line 117
def clone
  self
end
eql? (other)

Returns true if the receiver is the same expression as the the other expression.

[show source]
# File lib/sequel/sql.rb, line 129
def eql?(other)
  other.is_a?(self.class) && !self.class.comparison_attrs.find{|a| public_send(a) != other.public_send(a)}
end
hash ()

Make sure that the hash value is the same if the attributes are the same.

[show source]
# File lib/sequel/sql.rb, line 134
def hash
  ([self.class] + self.class.comparison_attrs.map{|x| public_send(x)}).hash
end
inspect ()

Show the class name and instance variables for the object.

[show source]
# File lib/sequel/sql.rb, line 139
def inspect
  "#<#{self.class} #{instance_variables.map{|iv| "#{iv}=>#{instance_variable_get(iv).inspect}"}.join(', ')}>"
end