Delphi 2007 was mentioned - no (Win32) generics. And that creates a not insignificant problem with using generics and other new language features in code from (or that may be shared with) existing (i.e. pre-D2009) projects:
- They were introduced in Delphi 2009, along with the unavoidable transition to Unicode - Consequently if you convert existing classes derived from TObjectList to TObjectList<T> or similar then you also have to migrate your code to Unicode - If you find (or fear) that Unicode creates issues for your code that you don't have time to deal with for your next release you have created (generics) code that does not migrate back to Delphi 2007 and the "sanctuary" of ANSIString - Similarly you cannot use these language features if your code has to be shared with other projects that are not migrating to Unicode, although that is perhaps a less likely scenario. The only safe way to deal with this is to deal with Unicode migration as a separate, pre-requisite project before then making any changes that exploit or take advantage of new language features introduced in the Unicode only version(s) of Delphi. Only once you are 100% certain that the Unicode transition has not introduced undesirable side effects can you consider using language features which commit your code to the Unicode compiler/RTL. Sadly successful compilation without errors or warnings is no guarantee against some side effects, so unless you have 100% automated test coverage, achieving that certainty is not necessarily going to be straightforward. From: delphi-boun...@delphi.org.nz [mailto:delphi-boun...@delphi.org.nz] On Behalf Of Sean Cross Sent: Thursday, 15 October 2009 11:41 a.m. To: NZ Borland Developers Group - Delphi List Subject: Re: [DUG] Stupid /easy question If you are using a version of Delphi with generics, you should be able to use a generic list and it'll work fine. eg var myList : TObjectList<TMyObject>; Regards Sean Cross CIO Catalyst Risk Management PO Box 230 Napier 4140 DDI: 06-8340362 Mobile: 021270 3466 Visit us at http://www.catalystrisk.co.nz <http://www.catalystrisk.co.nz/> Offices in Auckland, Hamilton, Napier, Wellington, Christchurch & Dunedin Disclaimer: "The information contained in this document is confidential to the addressee(s) and may be legally privileged. Any view or opinions expressed are those of the author and may not be those of Catalyst Risk Management. No guarantee or representation is made that this communication is free of errors, viruses or interference. If you have received this e-mail message in error please delete it and notify me. Thank you." From: delphi-boun...@delphi.org.nz [mailto:delphi-boun...@delphi.org.nz] On Behalf Of Robert martin Sent: Thursday, 15 October 2009 10:45 a.m. To: NZ Borland Developers Group - Delphi List Subject: Re: [DUG] Stupid /easy question Hi Yeah I read examples of how to add enumerators but since TObjectList already has one I didn't think I needed to. Guess I do. Seems like it is a bit too much work for basic (small) classes not frequently used (such as the one im working on). Will give it a go anyway :) Thanks Rob Jolyon Smith wrote: You will have to implement an enumerator for your TCountryAddressFormats class that returns TCountryAddressFormat references. This isn't a language feature that "just works" - you have to put some infrastructure in place to support it. The feature appears to "just work" for a bunch of VCL types (TStringList etc) because the VCL already contains the necessary infrastructure additions (and which should provide the examplar implementations on which you could base your own). -----Original Message----- From: delphi-boun...@delphi.org.nz [mailto:delphi-boun...@delphi.org.nz] On Behalf Of Robert martin Sent: Thursday, 15 October 2009 10:06 a.m. To: NZ Borland Developers Group - Delphi List Subject: [DUG] Stupid /easy question Hi After the D2010 presentation yesterday I decided I should actually use some of the D2007 features I had not gotten around to using. Specifically the For .. in construct. I am sure I am missing something but here iss what I want to do I have the following 'old school code' (note the base class here inherits from TObjectList) procedure TCountryAddressFormats.LoadStringListWithCompanies(Strings: TStrings); var Counter : Integer; begin for Counter := 0 to Self.Count - 1 do begin Strings.AddObject( TCountryAddressFormat(Self.Items[Counter]).CountryName, Tobject(TCountryAddressFormat(Self.Items[Counter]).CountryRefAsInteger) ); end; end; I wanted to replace it with procedure TCountryAddressFormats.LoadStringListWithCompanies(Strings: TStrings); var CountryAddressFormat : TCountryAddressFormat; begin for CountryAddressFormat in Self do begin Strings.AddObject( CountryAddressFormat.CountryName, TObject(CountryAddressFormat.CountryRefAsInteger) ); end; end; but I get the following error [DCC Error] AddressFormat.pas(157): E2010 Incompatible types: 'TCountryAddressFormat' and 'Pointer' what am I missing ? Cheers Rob _______________________________________________ NZ Borland Developers Group - Delphi mailing list Post: delphi@delphi.org.nz Admin: http://delphi.org.nz/mailman/listinfo/delphi Unsubscribe: send an email to delphi-requ...@delphi.org.nz with Subject: unsubscribe _______________________________________________ NZ Borland Developers Group - Delphi mailing list Post: delphi@delphi.org.nz Admin: http://delphi.org.nz/mailman/listinfo/delphi Unsubscribe: send an email to delphi-requ...@delphi.org.nz with Subject: unsubscribe
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