Class: Sequel::SQL::Expression

Inherits:

Object

• Object
• Sequel::SQL::Expression

show all

Defined in:

lib/sequel/sql.rb

Overview

Class Method Summary (collapse)

• + (Object) attr_reader(*args)

  Expression objects are assumed to be value objects, where their attribute values can't change after assignment.

• + (Object) comparison_attrs

  All attributes used for equality and hash methods.

• + (Object) to_s_method(meth, args = :self)

  Create a to_s instance method that takes a dataset, and calls the method provided on the dataset with args as the argument (self by default).

Instance Method Summary (collapse)

• - (Object) ==(other)

  Alias of eql?.

• - (Boolean) eql?(other)

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

• - (Object) hash

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

• - (Object) inspect

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

• - (Object) lit

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

• - (Object) sql_literal(ds)

  Alias of to_s.

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# File 'lib/sequel/sql.rb', line 68

def self.attr_reader(*args)
  super
  comparison_attrs.concat args
end

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# File 'lib/sequel/sql.rb', line 74

def self.comparison_attrs
  @comparison_attrs ||= self == Expression ? [] : superclass.comparison_attrs.clone
end

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# File 'lib/sequel/sql.rb', line 81

def self.to_s_method(meth, args=:self) # :nodoc:
  class_eval("def to_s(ds) ds.#{meth}(#{args}) end", __FILE__, __LINE__)
  class_eval("def to_s_append(ds, sql) ds.#{meth}_append(sql, #{args}) end", __FILE__, __LINE__)
end

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# File 'lib/sequel/sql.rb', line 88

def ==(other)
  eql?(other)
end

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# File 'lib/sequel/sql.rb', line 94

def eql?(other)
  other.is_a?(self.class) && !self.class.comparison_attrs.find{|a| send(a) != other.send(a)}
end

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# File 'lib/sequel/sql.rb', line 99

def hash
  ([self.class] + self.class.comparison_attrs.map{|x| send(x)}).hash
end

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# File 'lib/sequel/sql.rb', line 105

def inspect
  "#<#{self.class} #{instance_variables.map{|iv| "#{iv}=>#{instance_variable_get(iv).inspect}"}.join(', ')}>"
end

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# File 'lib/sequel/sql.rb', line 110

def lit
  self
end

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# File 'lib/sequel/sql.rb', line 115

def sql_literal(ds)
  to_s(ds)
end