Class: Arel::Nodes::Node

Inherits:
Object
  • Object
show all
Includes:
FactoryMethods, Enumerable
Defined in:
lib/arel/nodes/node.rb

Overview

Abstract base class for all AST nodes

Instance Method Summary collapse

Methods included from FactoryMethods

#coalesce, #create_and, #create_false, #create_join, #create_on, #create_string_join, #create_table_alias, #create_true, #grouping, #lower

Instance Method Details

#and(right) ⇒ Object

Factory method to create an Nodes::And node.



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# File 'lib/arel/nodes/node.rb', line 27

def and(right)
  Nodes::And.new [self, right]
end

#each(&block) ⇒ Object

Iterate through AST, nodes will be yielded depth-first



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# File 'lib/arel/nodes/node.rb', line 43

def each(&block)
  return enum_for(:each) unless block_given?

  ::Arel::Visitors::DepthFirst.new(block).accept self
end

#not ⇒ Object

Factory method to create a Nodes::Not node that has the recipient of the caller as a child.



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# File 'lib/arel/nodes/node.rb', line 14

def not
  Nodes::Not.new self
end

#or(right) ⇒ Object

Factory method to create a Nodes::Grouping node that has an Nodes::Or node as a child.



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# File 'lib/arel/nodes/node.rb', line 21

def or(right)
  Nodes::Grouping.new Nodes::Or.new(self, right)
end

#to_sql(engine = Table.engine) ⇒ Object

FIXME: this method should go away. I don’t like people calling to_sql on non-head nodes. This forces us to walk the AST until we can find a node that has a “relation” member.

Maybe we should just use ‘Table.engine`? :’(



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# File 'lib/arel/nodes/node.rb', line 36

def to_sql(engine = Table.engine)
  collector = Arel::Collectors::SQLString.new
  collector = engine.connection.visitor.accept self, collector
  collector.value
end