Refactoring: Refactorings/Move Eval from Runtime to Parse Time

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Calling Kernel#eval is always expensive from a performance standpoint. If performance is necessary, move the eval call to parse-time instead of calling it from run-time

Mechanics

  1. Expand the scope of the string being eval'd
  2. Test


Example

Before

class Person
  def self.attr_with_default(options)
    options.each_pair do |attribute, default_value|
      define_method attribute do
        eval "@#{attribute} ||== #{default_value}"
      end
    end
  end

  attr_with_default :emails => "[]", :employee_number => "EmployeeNumberGenerator.next"
end

After

class Person
  def self.attr_with_default(options)
    options.each_pair do |attribute, default_value|
      eval "define_method attribute do
            @#{attribute} ||== #{default_value}
            end"
    end
  end

  attr_with_default :emails => "[]", :employee_number => "EmployeeNumberGenerator.next"
end
Refactorings
Composing Methods

Extract MethodInline MethodInline TempReplace Temp with QueryReplace Temp with ChainIntroduce Explaining VariableSplit Temporary VariableRemove Assignments to ParametersReplace Method with Method ObjectSubstitute AlgorithmReplace Loop with Collection Closure MethodExtract Surrounding MethodIntroduce Class AnnotationIntroduce Named ParameterRemove Named ParameterRemove Unused Default ParameterDynamic Method DefinitionReplace Dynamic Receptor with Dynamic Method DefinitionIsolate Dynamic ReceptorMove Eval from Runtime to Parse Time

Moving Features Between Objects

Move MethodMove FieldExtract ClassInline ClassHide DelegateRemove Middle Man

Organizing Data

Self Encapsulate FieldReplace Data Value with ObjectChange Value to ReferenceChange Reference to ValueReplace Array with ObjectReplace Hash with ObjectChange Unidirectional Association to BidirectionalChange Bidirectional Association to UnidirectionalReplace Magic Number with Symbolic ContentEncapsulate CollectionReplace Record with Data ClassReplace Type Code with PolymorphismReplace Type Code with Module ExtensionReplace Type Code with State-StrategyReplace Subclass with FieldsLazily Initialized AtributeEagerly Initialized Attribute

Simplifying Conditional Expressions

Decompose ConditionalRecompose ConditionalConsolidate Conditional ExpressionConsolidate Duplicate Conditional FragmentsRemove Control FlagReplace Nested Conditional with Guard ClausesReplace Conditional with PolymorphismIntroduce Null ObjectIntroduce Assertion

Making Method Calls Simpler

Rename MethodAdd ParameterRemove ParameterSeparate Query from ModifierParameterize MethodReplace Parameter with Explicit MethodsPreserve Whole ObjectReplace Parameter with MethodIntroduce Parameter ObjectRemove Setting MethodHide MethodReplace Constructor with Factory MethodReplace Error Code with ExceptionReplace Exception with TestIntroduce GatewayIntroduce Expression Builder

Dealing with Generalization

Pull Up MethodPush Down MethodExtract ModuleInline ModuleExtract SubclassIntroduce InheritanceCollapse HierarchyForm Template MethodReplace Inheritance with DelegationReplace Delegation with HierarchyReplace Abstract Superclass with Module

Big Refactorings

Tease Apart InheritanceConvert Procedural Design to ObjectsSeparate Domain from PresentationExtract Hierarchy