Why is this restriction in place and what are the alternatives if any? Some times I want to just provide a method that sets default values for a record without any parameters but FPC doesn’t let me for some reason.

Regards,
Ryan Joseph

"Ryan Joseph" wrote

Why is this restriction in place and what are the alternatives if any?

Some times I want to just provide a method that sets default values for a record without any parameters but FPC doesn’t let me for some reason.

Delphi compatibility.
As a workaround you could add a constructor with a default parameter.

Regards,
Sven

On Feb 5, 2017, at 3:27 PM, Sven Barth wrote: constructor with a default parameter.

How? never heard of this. Thanks.

Regards,
Ryan Joseph

"Ryan Joseph" wrote

> On Feb 5, 2017, at 3:27 PM, Sven Barth

> > constructor with a default parameter. How? never heard of this. Thanks.

See here at the bottom:
http://freepascal.org/docs-html/current/ref/refsu65.html#x176-19800014.4.1 (it's the same for any kind of routine: function, procedure, method, constructor...)

Regards,
Sven

I never knew Pascal had default parameters, a feature I always use and enjoy in PHP. Once again I learn something new about the language I use. :)

However, the constructor with default params does not work. I get the same error as before. {$modeswitch advancedrecords} is on.

type
	MyRecord = record
		x: integer;
		constructor Foo (_x: integer = 0);
	end;

On Feb 5, 2017, at 8:29 PM, Sven Barth wrote: See here at the bottom: http://freepascal.org/docs-html/current/ref/refsu65.html#x176-19800014.4.1 (it's the same for any kind of routine: function, procedure, method, constructor...)

Regards,
Ryan Joseph

2017-02-05 14:34 GMT+01:00 Ryan Joseph :

AFAIK this is by design. In theory "constructor Create;" is reserved for record "Initializers" (which means initialization for managed fields of record). Parameter less constructor doesn't have much sense for records. Use "class function Foo: MyRecord ;" instead. Probably syntax "constructor Create;" will be used for record initializers in next Delphi releases (around 2018?). In FPC we have implemented this feature (not merged yet : http://bugs.freepascal.org/view.php?id=30687 ) but as "class operator Initialize(var a: MyRecord);".

"Ryan Joseph" wrote

I never knew Pascal had default parameters, a feature I always use and

enjoy in PHP. Once again I learn something new about the language I use. :)

I suggest you to read through the language reference guide then ;)

However, the constructor with default params does not work. I get the

same error as before. {$modeswitch advancedrecords} is on.

Oh, well, it was worth a shot... Alternatively you could declare a class function named Create that returns an instance of the record. Even Delphi is using that for Rtti.TRttiContext.

Regards,
Sven

I tried class functions in records already but I got the error "Class methods must be static in records”. Not sure what that means but I assumed they don’t work either.

Too bad, that would be a nice feature.

On Feb 6, 2017, at 2:29 AM, Sven Barth wrote: Oh, well, it was worth a shot... Alternatively you could declare a class function named Create that returns an instance of the record. Even Delphi is using that for Rtti.TRttiContext.

Regards,
Ryan Joseph

"Ryan Joseph" wrote

I tried class functions in records already but I got the error "Class

methods must be static in records”. Not sure what that means but I assumed they don’t work either.

You need to add the "static" modifier to the method. Class functions in records can't have a self parameter and the "static" disables that. That's why.

Regards,
Sven

Thanks got it now. Not ideal but it works and is a small improvement over a function.

Regards,
Ryan Joseph