Lazarus is a completely open source project that aims to provide class libraries for Free Pascal that emulate Delphi. Lazarus is completely API independent meaning that once you write your own code, you can just link it against the API widget set of your choice. The developers describe the program as follows...
If you are creating a product on Windows using the standard Windows widgets, first you decide what widget set you want to use. Then you copy the code over to your Linux development machine, compile, and link against the gtk+ interface unit. Hey presto - you've just created a Linux version of the Windows product on Lazarus without any additional coding.
For those working on cross-platform coding, Lazarus is an exciting project that promises to make widget creation a lot easier.
Enables you to create Linux/Windows programs easily
Limited on instructions for those with no coding experience
Lazarus is the class libraries for Free Pascal that emulate Delphi. Free Pascal is a GPL'ed compiler that runs on Linux, Win32, OS/2, 68K and more. Free Pascal is designed to be able to understand and compile Delphi syntax, which is of course OOP.
Lazarus is the part of the missing puzzle that will allow you to develop Delphi like programs in all of the above platforms. Unlike Java which strives to be a write once run anywhere, Lazarus and Free Pascal strives for write once compile anywhere.
"First choice for most programming tasks."
Lazarus is excellent for platform-sensitive development. Additionally, it is easy to use and generates efficient machine code.