Borland Delphi .NET review

Borland's Delphi has a curious family relationship with Microsoft's .NET platform. The original architect of Delphi, Anders Hejlsberg, moved from Borland to create C#. Although C# is loosely based on C rather than Pascal, there are similarities, especially between the Framework class library and Delphi's VCL (Visual Component Library). Delphi is the leading non-Microsoft development tool for Windows and is superior in several respects to Visual Studio 6 at least.

Even so, Borland's support for .NET wasn't a foregone conclusion. The company has worked hard to reduce its dependence on Microsoft's platform, focusing its energy on JBuilder, its Java tool, and Kylix, a version of Delphi for Linux. A little late in the day, Borland decided it did want a .NET product and has, in fact, already shipped a preview version of Delphi .NET in Delphi 7. However, its ambitions extend beyond merely compiling Object Pascal to Microsoft Intermediate Language. Although product details aren't yet finalised, the company has talked about shipping a suite of tools to include a Delphi-like visual designer and support for C# and VB .NET (see p188) as well as Pascal.

Aside from Borland's well-proven general expertise in development tools, there are a few specific reasons why this might be an attractive alternative to Visual Studio. Microsoft tends to assume use of its entire application suite, including the SQL Server database, SourceSafe code management, COM+ transaction server and IIS web server. Borland is more neutral, so users of Oracle or DB2 databases, or the Apache web server, may find its tools a more comfortable fit. Second, Borland already has compilers for Win32 and for Linux, so it's possible that carefully crafted code might support all three platforms.

Delphi for .NET Preview supplied with Delphi 7 includes a compiler called dccil.exe, a .NET version of the Delphi run-time library and the VCL, tools to let you create ASP .NET applications with Delphi and some brief introductory documentation. When working with Delphi .NET, you can use both the VCL for .NET and the .NET Framework classes. Using the VCL is more comfortable for Delphi developers and maximises code reuse and the possibility of cross-platform compilation, but using the .NET Framework classes may give better performance.

It's interesting that Borland doesn't appear to be implementing CLX for .NET. CLX, which most likely stands for the Component Library for Cross-Platform, is the class library that compiles for both Windows and Linux. You might have thought that CLX would be used for .NET as well, but the GUI part of CLX uses Trolltech's Qt, which doesn't target .NET. There are hints that Borland might move instead towards namespaces as the fundamental technique for cross-platform support.

There are already efforts to make Delphi more .NET friendly. Delphi 7 includes three new compiler settings: Unsafe_Type, Unsafe_Code and Unsafe_Cast. If set, the compiler will warn whenever there is code that can't be verified as type-safe by the .NET JIT compiler. Without type safety, security checks are meaningless and reliability compromised, since the code may write to arbitrary memory locations. Usage of Delphi types such as PChar, which is a pointer to a null-terminated string, breaks type-safety. The idea is that by setting these warnings you can avoid code that will need later modification.

Since Delphi .NET currently has no IDE, its usage is more difficult than standard Delphi. There's also very little documentation. In order to make sense of it, developers need to fall back on three main sources. One is the normal Delphi online help, much of which still applies. Second, there's the Delphi .NET source - although peppered with TODO remarks and commented-out bits of Assembly language, it's the primary source for work with the preview. Finally, there's Microsoft's documentation in the .NET Framework SDK. Since it has access to the Framework, Delphi .NET is already a powerful development tool.