is it possible to undeclare an identifier?

[dummzeuch 1517]

The unit Windows declares quite a few rather generic identifiers, e.g.

const ERROR = 0

which is annoying when you want to use that identifier for a local variable (e.g. a string):

var
  Value: Double;
begin
// function TryGetSomeValue(const _Name: string; out _Value: Double; out _Error: string): boolean;
  if not TryGetSomeValue('WrongName', Value, Error) then begin
    LogError(Error);
    Value := -1;
  end;

This will not compile because Error is a constant and not a string variable. So I want to declare it as a local string variable using Shift+Ctrl+V but that fails (does nothing *1) because there is already such an identifier.

 

This is no problem when it occurs once, but it becomes a bloody nuisance when you have to write several similar function calls.

I would really like to use "Error" as a variable name here, rather than "Err" or "lError" or "ErrorStr".

 

Is there any way to undeclare an identifier, so  Shift+Ctrl+V (and probably others) work again?

I doubt it but I have been wrong before.

 

(*1: Yes, one could regard this as a bug in the refactoring functionality. I haven't checked whether there already is a bug report.)

[David Heffernan 2353]

30 minutes ago, dummzeuch said:

Is there any way to undeclare an identifier, so  Shift+Ctrl+V (and probably others) work again?

No

[Arnaud Bouchez 407]

I guess the only way is to use a "free" name like "ErrorMsg" instead of "Error"...

Edited December 4, 2020 by Arnaud Bouchez

[Guest]

not talk about that "Error" is procedure in System.pas, line 5759.

• RAD Studio 10.3.3 Arch!

 

if using a .INC for easy hide "original type"?

 

A FranksteinBuilders presents:  😂

 

INCLUDE FILE

{$DEFINE ERRORasSTRING}
//
{$IFDEF ERRORasSTRING}

var
  Error: string;
{$ELSE}
// Else, stay the original "Const"
{$ENDIF}

 

in USE:

unit Unit1;

interface

// uses
// ...;

{$I incRedeclareErrorForMyProject.inc } // var Error:string;

// type
// ...
// var
// Error: string;

procedure prcTestUnit2;

implementation

{ ..$I incRedeclareErrorForMyProject.inc }
// var
// Error: string;

procedure prcTestUnit2;
var
  lText: string;
begin
  lText := Error;
  //
  // System.Error( errorCode:TRuntimeError );
end;

end.

of course, if "ERRORasSTRING" not defined, then, the compile help you with many "Error"s 

hug

 

Edited December 4, 2020 by Guest

[Guest]

look this when asking "help" for Ctrl+Shif+V procedure:

[Rollo62 539]

I know its modern nowadays to use all kind of bare names for anything.

But those names are very likely to conflict with identifiers, keywords, etc., with a whole bunch of possible hard.-to-find sideeffects.

 

Thats why I still like consequently use the decoration of names:
L - for local instance: LError

F - for field instance:  FError

G - for a global instance: GError (nevertheless: global variables are not recommended)

 

This little extra char gives me a lot of extra-info

- its not a function or procedure, if you use it with discipline

- its not a global, intrinsic function, if you use it with discipline

- its a local or field instance, or even global

 

All this just because of the tiny character, I think its still very much worth it.

 

Edited December 5, 2020 by Rollo62

[Guest]

I like: "lMyXXXXXX"  l=L  because ALL is "local" on the end!

 

Global = local for my app (or project)

Local = local for my unit/proc/func

 

 When "XXXX" have a reference with type of var, ex.:  lMyFDClient = FDQuery/Table client

 

then, "l" on the start it's good for me!

Edited December 5, 2020 by Guest

[Guest]

another way, as was said in another post, is possible use "&" char before names on vars, like:

 

var
  &Error: string;

procedure TForm1.FormCreate(Sender: TObject);
begin
  Caption := &Error;
end;

NOTE: verify since when it's possible in Delphi editions!

[Rollo62 539]

On 12/5/2020 at 4:58 PM, emailx45 said:

another way, as was said in another post, is possible use "&" char before names on vars, like:

 

var
  &Error: string;

procedure TForm1.FormCreate(Sender: TObject);
begin
  Caption := &Error;
end;

 

 

Yes, thats possible too, and I always wonder why on earth I should ever do it like that ?

Oh yeah: Its so much advanced over FError, to have a fancy pig-tail in front

Edited December 7, 2020 by Rollo62

[Guest]

"F" is for private "Field" on Class/Record/Interfaces etc... definitions, not for common "var" on unit-body by default.

each other use a "fancy pig-tail" that like it

Edited December 7, 2020 by Guest