Class Sequel::SQL::Expression
In: lib/sequel/extensions/eval_inspect.rb
lib/sequel/sql.rb
Parent: Object

Base class for all SQL expression objects.

Methods

==   attr_reader   clone   dup   eql?   hash   inherited   inspect   inspect  

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.

[Source]

    # File lib/sequel/sql.rb, line 76
76:         def attr_reader(*args)
77:           super
78:           comparison_attrs.concat(args)
79:         end
inherited(subclass)

Copy the comparison_attrs into the subclass.

[Source]

    # File lib/sequel/sql.rb, line 82
82:         def inherited(subclass)
83:           super
84:           subclass.instance_variable_set(:@comparison_attrs, comparison_attrs.dup)
85:         end

Public Instance methods

==(other)

Alias of eql?

[Source]

     # File lib/sequel/sql.rb, line 109
109:       def ==(other)
110:         eql?(other)
111:       end
clone()

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

[Source]

     # File lib/sequel/sql.rb, line 103
103:       def clone
104:         self
105:       end
dup()

Alias for clone

eql?(other)

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

[Source]

     # File lib/sequel/sql.rb, line 115
115:       def eql?(other)
116:         other.is_a?(self.class) && !self.class.comparison_attrs.find{|a| public_send(a) != other.public_send(a)}
117:       end
hash()

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

[Source]

     # File lib/sequel/sql.rb, line 120
120:       def hash
121:         ([self.class] + self.class.comparison_attrs.map{|x| public_send(x)}).hash
122:       end
inspect()

Attempt to produce a string suitable for eval, such that: 

  eval(obj.inspect) == obj

[Source]

    # File lib/sequel/extensions/eval_inspect.rb, line 61
61:       def inspect
62:         # Assume by default that the object can be recreated by calling
63:         # self.class.new with any attr_reader values defined on the class,
64:         # in the order they were defined.
65:         klass = self.class
66:         args = inspect_args.map do |arg|
67:           if arg.is_a?(String) && arg =~ /\A\*/
68:             # Special case string arguments starting with *, indicating that
69:             # they should return an array to be splatted as the remaining arguments.
70:             # Allow calling private methods to get inspect output.
71:             send(arg.sub('*', '')).map{|a| Sequel.eval_inspect(a)}.join(', ')
72:           else
73:             # Allow calling private methods to get inspect output.
74:             Sequel.eval_inspect(send(arg))
75:           end
76:         end
77:         "#{klass}.#{inspect_new_method}(#{args.join(', ')})"
78:       end
inspect()

Show the class name and instance variables for the object.

[Source]

     # File lib/sequel/sql.rb, line 125
125:       def inspect
126:         "#<#{self.class} #{instance_variables.map{|iv| "#{iv}=>#{instance_variable_get(iv).inspect}"}.join(', ')}>"
127:       end

[Validate]