Class | Sequel::SQL::Expression |
In: |
lib/sequel/sql.rb
lib/sequel/extensions/eval_inspect.rb |
Parent: | Object |
Base class for all SQL expression objects.
comparison_attrs | [R] | All attributes used for equality and hash 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.
# 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.
# 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
Returns true if the receiver is the same expression as the the other expression.
# 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
Show the class name and instance variables for the object, necessary for correct operation on ruby 1.9.2.
# 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
# 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.
# File lib/sequel/sql.rb, line 134 134: def lit 135: self 136: end