Hi,

Where can I find some information about the [] procedure modifier of FPC?
For example:

procedure fpc_check_object(_vmt : pointer);
[public,alias:'FPC_CHECK_OBJECT'];  compilerproc;

What $modes support this?
The reason I ask is I'm trying to distinguish them from Delphi Attributes in pparser.

Btw, 'compilerproc' is not listed here:
https://www.freepascal.org/docs-html/ref/refse97.html#x187-20900014.10

Mattias

2017-11-16 11:39 GMT+01:00 Mattias Gaertner :

What $modes support this? The reason I ask is I'm trying to distinguish them from Delphi Attributes in pparser.

for Delphi like attributes FPC will have new modeswitch "prefixedattributes" . The implicit usage for $prefixedattributes in DELPHI/DELPHIUNICODE mode is not decided yet (but IMO this is probable scenario).

Good to know. Thanks.

So, how will FPC distinguish the two []?

Mattias

Am 16.11.2017 14:01 schrieb "Mattias Gaertner" :

"prefixedattributes" .

The implicit usage for $prefixedattributes in DELPHI/DELPHIUNICODE mode

is

not decided yet (but IMO this is probable scenario).

Good to know. Thanks.

So, how will FPC distinguish the two []?

The only idea I have is to check whether the first identifier is a attribute and if not handle it as a modifier (or if a comma is following the first identifier).

Regards,
Sven

2017-11-16 14:01 GMT+01:00 Mattias Gaertner :

Good to know. Thanks. So, how will FPC distinguish the two []?

for now the idea is very simple: for active prefixedattributes "procedure modifier []" will be inaccessible (which means breaking for backward compatibility). This is the reason why $prefixedattributes in DELPHI/DELPHIUNICODE may be not enabled by default. In Delphi mode "procedure modifier []" is used very rare (if ever?) so I see no real problem (even if the problem exist can be simple eliminated by switching off prefixedattributes).

anyway maybe is possible to use both "[]" at the same time, but that need to be checked.

pparser can't do that.

And I fear that this heuristic will lead to confusing error messages. I hope there is a better way.

Delphi does not support it. It thinks it is an undefined attribute. So IMO FPC's [] modifier should be disabled in mode delphi+delphiunicode. So the problem will only happen in mode objfpc or when the user enable the modeswitch prefixedattributes.

Maybe pparser can use a heuristic. What is the syntax and keywords of fpc's [] modifier?

If it is correct that FPC's modifier was never documented and is hardly used, perhaps a $modeswitch procmodifierbrackets can be added?

Mattias

I think that prefixedattributes should simply disable the use of proc modifier []. The probability of having code that needs both is almost zero, the [] syntax is very old and almost not used.

Mode Delphi(Unicode) enables prefixedattributes, all other modes need an explicit modeswitch to enable it.

Let's keep it clear, simple and unambiguous.

Michael.

2017-11-16 15:21 GMT+01:00 Michael Van Canneyt :

+1 . so I think that we have clear situation.

Keywords are all supported modifiers.

"[" <MODIFIER> [,<MODIFIER>[,...]] "]"

And this can be mixed and matched with non-bracketed modifiers, so the following is valid:

=== code begin ===

procedure Bla; cdecl; [public, overload]; iocheck;
begin
end;

=== code end ===

If it is correct that FPC's modifier was never documented and is hardly used, perhaps a $modeswitch procmodifierbrackets can be added?

It is at least not totally undocumented:
https://www.freepascal.org/docs-html/current/ref/refsu81.html#x199-22100014.10.12

It's a feature that FPC supports and thus there are probably users out there that use it no matter whether it's in Delphi mode or not.

Regards,
Sven

One other point to differentiate them: the modifier one always ends with a semicolon after the closing bracket, Delphi's attributes never do that.

Regards,
Sven

2017-11-16 20:17 GMT+01:00 Sven Barth via fpc-pascal <

sadly this is not true at all :(

see:

https://svn.freepascal.org/cgi-bin/viewvc.cgi?view=revision&revision=35000

in above example it works without semicolon without any problems

Okay, that might be true in the middle of the modifier list, but not if it's the last one:

=== code begin ===

unit tprocmod;
interface
procedure Bla; cdecl; [public, overload]
var
  test: LongInt;
implementation
procedure Bla;
begin
end;
end.

=== code end ===

This results in "Syntax error, ";" expected but "VAR" found".

In how far that can be used to handle the modifiers and attributes together in parallel needs to be seen...

Regards,
Sven

I like clear, simple and unambiguous.

+1 . so I think that we have clear situation.

Mattias