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 100
100:         def attr_reader(*args)
101:           super
102:           comparison_attrs.concat(args)
103:         end

Copy the comparison_attrs into the subclass.

[Source]

     # File lib/sequel/sql.rb, line 106
106:         def inherited(subclass)
107:           super
108:           subclass.instance_variable_set(:@comparison_attrs, comparison_attrs.dup)
109:         end

Public Instance methods

Alias of eql?

[Source]

     # File lib/sequel/sql.rb, line 125
125:       def ==(other)
126:         eql?(other)
127:       end

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

[Source]

     # File lib/sequel/sql.rb, line 131
131:       def eql?(other)
132:         other.is_a?(self.class) && !self.class.comparison_attrs.find{|a| send(a) != other.send(a)}
133:       end

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

[Source]

     # File lib/sequel/sql.rb, line 136
136:       def hash
137:         ([self.class] + self.class.comparison_attrs.map{|x| send(x)}).hash
138:       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 142
142:       def inspect
143:         "#<#{self.class} #{instance_variables.map{|iv| "#{iv}=>#{instance_variable_get(iv).inspect}"}.join(', ')}>"
144:       end

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

  eval(obj.inspect) == obj

[Source]

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

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

[Source]

     # File lib/sequel/sql.rb, line 147
147:       def lit
148:         self
149:       end

Alias of to_s

[Source]

     # File lib/sequel/sql.rb, line 152
152:       def sql_literal(ds)
153:         s = String.new
154:         to_s_append(ds, s)
155:         s
156:       end

[Validate]