Hi,?

Is there "record literal in FPC? e.g. normally, you do:

var
? ?cp : TPoint;
cp.X := 0;
cp.Y := 0;
Edit1.CaretPos := cp;

I would like to use literal directly, such as:

Edit1.CaretPos := (X: 0, Y: 0);?

But the above syntax is wrong. Is there such thing exists?

Thanks,
Shannon
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no, but try the point function

xrfang wrote

I would like to use literal directly, such as: Edit1.CaretPos := (X: 0, Y: 0);

You can use a typed constant thus:

const Origin: TPoint = (x:0; y:0);
begin
...
  Edit1.CaretPos := Origin;
...

Thanks, but what I want is to AVOID any kind of declarations. So I will use the Point() function suggested by ik.

? ?, 1? 9, 2013 at 12:26 ???Howard Page-Clark ???

xrfang wrote

I would like to use literal directly, such as: Edit1.CaretPos := (X: 0, Y: 0);

You can use a typed constant thus:

const Origin: TPoint = (x:0; y:0);
begin
..
Edit1.CaretPos := Origin;
..

If you declare an inline function producing the record, the effect would be the same with that literal record.

Hi leledumbo,

As far as I know pascal inline directive only affect the compiler, not how you write code. Could you please give an example how inline function helps in my question?

Thanks

2013/1/9 leledumbo

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Hi,

you could also use the with-statement, that is pretty handy in such cases:

|with Edit1.CaretPos do
begin
  X := 0;
  Y := 0;
end;|

Best Regards,
Andreas

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As far as I know pascal inline directive only affect the compiler, not how

you write code. Could you please give an example how inline function helps in my question?

Yes it does, what I mean is to create something that Point() function does and using inline directive it's nearly the same as assigning record via literal. Well, if you know how it's done by other compilers, record literal assignment is actually broken down into field by field assignment. So if you make a function that returns the record with given arguments as record fields, with inline directive the final code would be the same. Well... maybe you'll need some other directives as well, but it's just my thought. I never really compare the generated code...

Well, my purpose is to make the source code look comfortable, not how the binary code is generated :)

Well, again, I got a good idea from Andreas.

Thanks to all of you.

? ?, 1? 9, 2013 at 7:45 ???leledumbo ???

As far as I know pascal inline directive only affect the compiler, not how

you write code. Could you please give an example how inline function helps in my question?

Yes it does, what I mean is to create something that Point() function does and using inline directive it's nearly the same as assigning record via literal. Well, if you know how it's done by other compilers, record literal assignment is actually broken down into field by field assignment. So if you make a function that returns the record with given arguments as record fields, with inline directive the final code would be the same. Well... maybe you'll need some other directives as well, but it's just my thought. I never really compare the generated code...

Hi Adreas,

I just tried, your method did not work as expected. ?It compiled ok, but didn't put the cursor at the end of the line as I wanted. ?However, assign CaretPos a new TPoint worked.

Regards,

? ?, 1? 9, 2013 at 4:47 ???Andreas Schneider ???
Hi,

you could also use the with-statement, that is pretty handy in such cases:

with Edit1.CaretPos do
begin
  X := 0;
  Y := 0;
end;
Best Regards,
Andreas

On 08.01.2013 16:30, xrfang wrote:
Hi,?

Is there "record literal in FPC? e.g. normally, you do:

var
? ?cp : TPoint;
cp.X := 0;
cp.Y := 0;
Edit1.CaretPos := cp;

I would like to use literal directly, such as:

Edit1.CaretPos := (X: 0, Y: 0);?

But the above syntax is wrong. Is there such thing exists?

Thanks,
Shannon

"With" does not work with record properties.

Mattias

Interesting. IIRC that worked correctly in Delphi 2010 (it's been a while ...). This /might /be a bug in FPC.

The root of the problem is how properties are handled. Afaics however, the use of /with/ should cause it to assign the final record afterwards. Apparently it doesn't - at least not always. Could be by design, could be a bug. I'll check the bug tracker later and may report that. (You can do that yourself, if you want, but sooner or later I would like that functionality to work too, so I've a personal interest in this and therefore would not mind to report it :-))

Greetings,
Andreas

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I don't know if it's related to the fact that TEdit.CaretPos.X (or Y) is read only, or as Mattias said, the with syntax cannot work with record anyway... :-)

This should be a problem (if any) with lazarus not fpc.

Shannon

? ?, 1? 9, 2013 at 8:27 ???Andreas Schneider ???
Interesting. IIRC that worked correctly in Delphi 2010 (it's been a while ...). This might be a bug in FPC.

The root of the problem is how properties are handled. Afaics however, the use of with should cause it to assign the final record afterwards. Apparently it doesn't - at least not always. Could be by design, could be a bug. I'll check the bug tracker later and may report that. (You can do that yourself, if you want, but sooner or later I would like that functionality to work too, so I've a personal interest in this and therefore would not mind to report it :-))

Greetings,
Andreas

On 09.01.2013 13:19, xrfang wrote:
Hi Adreas,

I just tried, your method did not work as expected. ?It compiled ok, but didn't put the cursor at the end of the line as I wanted. ?However, assign CaretPos a new TPoint worked.

Regards,

? ?, 1? 9, 2013 at 4:47 ???Andreas Schneider ???
Hi,

you could also use the with-statement, that is pretty handy in such cases:

with Edit1.CaretPos do
begin
  X := 0;
  Y := 0;
end;
Best Regards,
Andreas

On 08.01.2013 16:30, xrfang wrote:
Hi,?

Is there "record literal in FPC? e.g. normally, you do:

var
? ?cp : TPoint;
cp.X := 0;
cp.Y := 0;
Edit1.CaretPos := cp;

I would like to use literal directly, such as:

Edit1.CaretPos := (X: 0, Y: 0);?

But the above syntax is wrong. Is there such thing exists?

Thanks,
Shannon

That would be nice. At the moment fpc does not do that.

Feel free to submit a feature request to the fpc bug tracker.

Mattias

09.01.13, 20:34, Mattias Gaertner ?????:

First check whether it works delphi mode.

Best regards,
Paul Ishenin

First check whether it works delphi mode.

Apparently, it even works in mode objfpc. But only when the property directly reads/writes a member. If there is a setter method, it will still compile but NOT actually change the record. Neither in mode objfpc nor in mode delphi.

Example attached. I will also open a bug report.

I don't know if it's related to the fact that TEdit.CaretPos.X (or Y) is read only, or as Mattias said, the with syntax cannot work with record anyway... :-)

A "with" should evaluate to an address, but a Delphi compatible *property* doesn't have an address.

DoDi

Hans-Peter Diettrich wrote

A "with" should evaluate to an address

IMHO this is an "implementation detail", that any compiler can handle as it likes to. It also could just work as if in the source the appropriate record elements code are prefixed by the "with" argument. That does not prevent that during compilation as well a code using "with" as a fully expanded code can be optimized to use a pointer to the record.

(I in fact never use "with" as with Delphi 7 - which I last tested on that behalf - the debugger does not easily show record elements that are defined in a "with" clause. Moreover more often than not the code with (nested) with can get rather ambiguous and confusing.)

-Michael