Class: Axiom::Optimizer::Algebra::Rename::EmptyOperand

Inherits:
Axiom::Optimizer::Algebra::Rename show all
Defined in:
lib/axiom/optimizer/algebra/rename.rb

Overview

Optimize when the operand is Empty

Constant Summary

Constants inherited from Axiom::Optimizer

Identity, VERSION

Instance Attribute Summary

Attributes inherited from Axiom::Optimizer::Algebra::Rename

#aliases

Attributes inherited from Relation::Operation::Unary

#header

Attributes included from Function::Unary

#operand

Attributes inherited from Axiom::Optimizer

#operation

Instance Method Summary collapse

Methods inherited from Axiom::Optimizer::Algebra::Rename

#initialize

Methods inherited from Relation::Operation::Unary

#initialize

Methods included from Function::Unary

#initialize

Methods inherited from Axiom::Optimizer

chain, #initialize

Constructor Details

This class inherits a constructor from Axiom::Optimizer::Algebra::Rename

Instance Method Details

#optimizable? ⇒ Boolean

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Test if the operand is empty

Returns:

  • (Boolean) 


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# File 'lib/axiom/optimizer/algebra/rename.rb', line 332

def optimizable?
  operand.kind_of?(Axiom::Relation::Empty)
end

#optimize ⇒ Empty

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Return a new Empty relation with the operation’s headers

Returns:

  • (Empty) 


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# File 'lib/axiom/optimizer/algebra/rename.rb', line 341

def optimize
  Axiom::Relation::Empty.new(header)
end