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

Base class for all SQL expression objects.

Methods

==   attr_reader   eql?   hash   inherited   inspect   inspect   lit   sql_literal  

Attributes

comparison_attrs  [R]  All attributes used for equality and hash methods.

Public Class methods

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 87
87:         def attr_reader(*args)
88:           super
89:           comparison_attrs.concat(args)
90:         end

Copy the comparison_attrs into the subclass.

[Source]

    # File lib/sequel/sql.rb, line 93
93:         def inherited(subclass)
94:           super
95:           subclass.instance_variable_set(:@comparison_attrs, comparison_attrs.dup)
96:         end

Public Instance methods

Alias of eql?

[Source]

     # File lib/sequel/sql.rb, line 112
112:       def ==(other)
113:         eql?(other)
114:       end

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

[Source]

     # File lib/sequel/sql.rb, line 118
118:       def eql?(other)
119:         other.is_a?(self.class) && !self.class.comparison_attrs.find{|a| send(a) != other.send(a)}
120:       end

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

[Source]

     # File lib/sequel/sql.rb, line 123
123:       def hash
124:         ([self.class] + self.class.comparison_attrs.map{|x| send(x)}).hash
125:       end

Show the class name and instance variables for the object, necessary for correct operation on ruby 1.9.2.

[Source]

     # File lib/sequel/sql.rb, line 129
129:       def inspect
130:         "#<#{self.class} #{instance_variables.map{|iv| "#{iv}=>#{instance_variable_get(iv).inspect}"}.join(', ')}>"
131:       end

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

  eval(obj.inspect) == obj

[Source]

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

Returns self, because SQL::Expression already acts like LiteralString.

[Source]

     # File lib/sequel/sql.rb, line 134
134:       def lit
135:         self
136:       end

Alias of to_s

[Source]

     # File lib/sequel/sql.rb, line 139
139:       def sql_literal(ds)
140:         s = ''
141:         to_s_append(ds, s)
142:         s
143:       end

[Validate]