Comments on: Delphi, methods and default values. Convenience or contract enforcement?

By: Yosh

Yosh — Fri, 04 Dec 2009 15:43:52 +0000

I waiting of delphi 64bit

By: Fabricio

Fabricio — Mon, 01 Sep 2008 21:16:39 +0000

(the blog engine eat the comments)
Serge,

[Defaul Parameter vs Overload – not comment the syncronizing]
For me, they different tools for different needs:
Default parameters –
Need: hide optional parameters
Advantages: does not add any implementation code.

Overloading
Need: type translator/cruncher. When you need the class method
to work with new datatypes or simplifying the use of the
existing functionality. Lets do some pseudocode: class A
is a list of
objects of the class b. Class B have the following
properties: Name, Cost, Distance. With overloading you do:
(*…*)
function Add(pClassObj: TClassB):Integer; overload;
function Add(pName:String; pCost:Currency;
pDistance: Integer):Integer;
(*..Implementation..*)
function TClassA.Add(pClassObj:TClassB):Integer;
begin
(* do some house keeping and *)
Result := inherited AddObject(pClassObj.Name,pClassObj);
end;

function TClassA.Add(pName:String; pCost:Currency;
pDistance: Integer):Integer;
var
Aux:TClassB;
begin
Aux := TClassB.Create;
(* Set the properties with the parameter values *)
Result := Add(Aux);
end;

Advantage:
It’s obvious in the above example that overloading gave
result to cleaner and readable code.

[About the syncronization of the declarations
in interface and implementation sections of a unit]
It’s ooooooooooooooooooold bug in Delphi.

By: Serge Dosyukov

Serge Dosyukov — Sun, 31 Aug 2008 19:28:10 +0000

Ops! Yes, you are right about that, except that refactoring in Delphi today is a little bit too much. To compare, you can look at implementation in Refactor! by Developer Express.

By: Brian

Brian — Fri, 29 Aug 2008 17:36:25 +0000

Newer Delphi IDEs have change parameters as a refactoring tool. On the name for a method press CTRL-SHIFT-X. Or right click and select Refactoring, change parameters.

I do miss CodeRush’s delcaration view that I had in Delphi 6 which would show me the declaration and/or implementation for the method I was tryinig to call.

By: Serge Dosyukov

Serge Dosyukov — Fri, 29 Aug 2008 13:44:12 +0000

I think number of spent hours by programmers is much less. Contract once established could be only changed during a new development cycle.
I am not sure though if you are being sarcastic or serious. 🙂 I liked your Delphi 2010 proposal in the past.

I have decided to bring up the subject because of small debate I have few days ago which then lead to “old” C# discussion and Delphi comparison.

Now, would it be good to have an option for synchronization between declaration and implementation? Yes, and there is number of IDE extensions which allow to do just that – be able introduce a new or modify parameters and having code synchronized accordingly.

By: naf

naf — Thu, 28 Aug 2008 23:01:35 +0000

This would all be moot if Delphi was intelligent enough to automatically synchronize the interface and implementation sections (including comments and defaults).

It would probably require less than 1000 manhours on CodeGears end and would save twenty million hours in lost productivity each year (conservatively based on 1,000,000 Delphi users saving five minutes each day). I doubt there is any single change CodeGear could make that would offer that kind of productivity return.

I’m amazed more Delphi users are not annoyed by this blatant contradiction of DRY and shocked that CodeGear have not addressed this remnant of 1980’s programming.