Synchronize Declaration / Implementation

A very common programmers task is to adjust an existing method’s signature.
For example add or remove a parameter, change a procedure into a function, or change the function’s result type.
After you changed a method’s signature in the implementation (or declaration),
the “Synchronize Declaration / Implementation” refactoring updates the corresponding signature
in the declaration(or implementation) depending on the editor cursor position.

An example

Suppose you have a class TSample with a method DoSomething like this:

type
  TSample = class (TObject)
  public
    procedure DoSomething;
  end;

implementation

procedure TSample.DoSomething;
begin
  // actual code here
end;

type

TSample = class (TObject)

public

procedure DoSomething;

end;

implementation

procedure TSample.DoSomething;

begin

// actual code here

end;

Suppose now that you want to change this method to a function, returning a Boolean. It also should have a parameter “Level: Integer”.

After changing the implementation header to the new signature…

type
  TSample = class (TObject)
  public
    procedure DoSomething;
  end;

implementation

function TSample.DoSomething(Level: Integer): Boolean;
begin
  // actual code here
end;

type

TSample = class (TObject)

public

procedure DoSomething;

end;

implementation

function TSample.DoSomething(Level: Integer): Boolean;

begin

// actual code here

end;

…rather than manually adjusting the method declaration in the class interface, now press Ctrl+Alt+Y (default keyboard shortcut) to invoke the Synchronize Declaration / Implementation refactoring:

type
  TSample = class (TObject)
  public
    // declaration signature updated based on implementation
    function DoSomething(Level: Integer): Boolean;
  end;

implementation

function TSample.DoSomething(Level: Integer): Boolean;
begin
  // actual code here
end;

type

TSample = class (TObject)

public

// declaration signature updated based on implementation

function DoSomething(Level: Integer): Boolean;

end;

implementation

function TSample.DoSomething(Level: Integer): Boolean;

begin

// actual code here

end;

..that updates the declaration with the changes you made in the implementation.

Similar, if you modify the method signature in the class definition and press Ctrl+Alt+Y
in the declaration, the implementation signature – method type, parameter list and result type – are updated.

Note that the keyboard shortcut Ctrl+Alt+Y is a default and can be adjusted to your preferences.