RefactorIntroduceWith

Code with many references attributes or methods of another object can be simplifed by introducing a "With ... End With" block. This can be particularly effective if a complex expression is repeated with every reference.

Languages:

• VbClassic
• PascalLanguage

Alternatives:

• Consider IntroduceLocalVariable to evaluate a complex expression in only one place.
• FeatureEnvy: Consider ExtractMethod and MoveMethod to put the code in the object where the attributes lie. IntroduceForeignMethod if the target object can't be changed.

Related Refactorings:

• RefactorEliminateWith if it's too sparsely used, or to remedy the FeatureEnvy smell "With" blocks often emit.

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[Examples]

In VbClassic: from...

	rsObject.Open ...
	If rsObject.RecordCount = 0 Then
	  rsObject.AddNew
	  rsObject!PK = value
	End If
	rsObject!Attr = value

to...

	With rsObject
	  .Open ...
	  If .RecordCount = 0 Then
	    .AddNew
	    !PK = value
	  End If
	  !Attr = value
	End With

PascalLanguage: from...

	emp.name       := "Joe";
	emp.status     := "X";
	emp.bday.month :=    6;
	emp.bday.day   :=   27;
	emp.bday.year  := 1958;

to...

	with emp do
	begin
	  name   := "Joe";
	  status := "X";
	  with bday do
	  begin
	    month :=    6;
	    day   :=   27;
	    year  := 1958;
	  end
	end

Applicability to other languages: Applies to any language supporting the "with" shorthand. Examples: Pascal

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The refactoring can be done one step further, by removing the variable completely:

(Example in VbClassic) from...

	set rst = dbs.TableDefs("tblWhatEver").OpenRecordset(dbOpenTable)
	If not rst.EOF() Then
	  rst.AddNew
	  rst!PK = value
	  rst.Update
	  rst.Close
	End If
	Set rst = Nothing

to...

	With dbs.TableDefs("tblWhatEver").OpenRecordset(dbOpenTable)
	  If not .EOF() Then
	    .AddNew
	    !PK = value
	    .Update
	    .Close
	  End If
	End With

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ContributorsList: JeffGrigg, (name of Pascal example author missing)

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[CategoryRefactoring/RefactoringLanguage]