Delphi language features missing from the Free Pascal Compiler

Note: some new Delphi features are already implemented in FPC trunk.

New since D4

Exporting of overloaded functions

(version not entirely sure, but came in with overloading, so definitely pre-D6)

In library packages select an overloaded variant to export. Assume we have some overloaded methods:

function doSomeThing(a:type1):type2;stdcall; function doSomeThing(a:type3):type4;stdcall;

and in the library (for building the dll using the unit above) we want to export them:

exports

   doSomeThing(a:type1) name 'doSomeThingTYPE1',
   doSomeThing(a:type3) name 'doSomeThingTYPE3';

implements delegation of interfaces

Delegating interfaces to classes is not always supported,

• Mantis 16531
• Mantis 8591
• Mantis 23403

New since Delphi 2007

New since Delphi 2009

Anonymous Methods

1. http://docs.embarcadero.com/products/rad_studio/delphiAndcpp2009/HelpUpdate2/EN/html/devcommon/anonymousmethods_xml.html
2. http://delphi.about.com/od/objectpascalide/a/understanding-anonymous-methods-in-delphi.htm

Supported since 3.3.1: Support for Function References and Anonymous Functions

New since Delphi 2010

Custom Attributes

Custom Attributes are a language feature in Delphi that allow annotating types and type members with special objects that carry additional information. Attributes extend the object-oriented model with aspect-oriented elements.

http://delphi.about.com/od/oopindelphi/a/delphi-attributes-understanding-using-attributes-in-delphi.htm

Supported since 3.3.1: Custom Attributes

Enhanced RTTI

http://docwiki.embarcadero.com/RADStudio/en/RTTI_directive_(Delphi)

Delayed directive

Info is here: http://docwiki.embarcadero.com/RADStudio/en/Libraries_and_Packages#Delayed_Loading Some info about internals:

1. http://blogs.embarcadero.com/abauer/2009/08/25/38894
2. http://blogs.embarcadero.com/abauer/2009/08/29/38896
3. http://blogs.embarcadero.com/chrishesik/2009/11/02/35056

fpc wiki about that topic: http://wiki.freepascal.org/Dynamically_loading_headers

Originally I thought that delayed is similar to weakexternal which FPC has for some platforms but after reading this: http://docwiki.embarcadero.com/CodeExamples/XE3/en/DelayedLoading_(Delphi) I understand that this is simply a wrapper around LoadLibrary and GetProcessAdress with automatic loading and unloading.--Paul Ishenin 13:45, 18 January 2013 (UTC)

Misc

1. (Library) packages
2. "automated" keyword, which is like "public", but generates COM specific RTTI. Afaik this kind of COM usage is deprecated though.

Already implemented

FPC 3.0.4

Advanced records

http://docwiki.embarcadero.com/RADStudio/en/Structured_Types#Records_.28advanced.29

FPC 2.6.0

AS and IS extended for interfaces

New since Delphi 2010. Info is here:

1. http://docwiki.embarcadero.com/RADStudio/en/Interface_References#Casting_Interface_References_to_Objects
2. http://blogs.embarcadero.com/abauer/2009/08/21/38893

Implemented in FPC 2.6.0.

Reference

1. http://edn.embarcadero.com/article/34324
2. http://edn.embarcadero.com/article/images/39076/New_Delphi_Coding_Styles_and_Architectures.pdf
3. http://docwiki.embarcadero.com/RADStudio/en/What's_New_in_Delphi_and_C%2B%2BBuilder_2010

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From the Free Pascal wiki, page "Delphi language features missing from the Free Pascal Compiler", as it stood on 2023-08-08 after a change by Mattias2, out of the wiki's dump of 2024-05-26. Copyright stays with the author who wrote it, according to the old wiki's Licensing page. If you have concerns about this material, message the admin.