Lazarus (IDE)

Lazarus

Lazarus IDE 0.9.26 running on Mac OS X
Developer(s)	Volunteers
Stable release	1.0.6 / February 3, 2013; 39 days ago (2013-02-03)
Operating system	Cross-platform
Type	RAD tool for Pascal and Object Pascal
License	GNU General Public License, GNU Lesser General Public License, and others
Website	http://www.lazarus.freepascal.org/

Lazarus is a free cross-platform IDE which provides a Delphi-like development experience for Pascal and Object Pascal developers. It is developed for, and supported by, the Free Pascal compiler. Since early 2008, Lazarus has been available for Microsoft Windows, several Linux distributions, FreeBSD, and Mac OS X. The earliest versions were created before that, and Lazarus is a front end for the much older Free Pascal.

Cross-platform development

Lazarus uses Free Pascal as its back-end compiler. Therefore Lazarus can, theoretically, be used to develop applications for all platforms supported by Free Pascal.

Similar to Free Pascal’s run-time library, Lazarus provides a cross-platform application framework called the Lazarus Component Library (LCL), which provides a single, unified interface for programmers, with different platform-specific implementations. Using LCL, one can create applications in a write once, compile anywhere manner, unless system-dependent features are used explicitly.

Cross-compiling

As Free Pascal supports cross-compiling, Lazarus applications can be cross-compiled from Windows to Linux and FreeBSD, and vice versa. Compiling from Mac OS X to Windows, Linux and FreeBSD is possible. Cross-compiling to Mac OS X could be done for older (PowerPC) versions, but not for newer Intel versions, since Apple doesn't release the assembler and linker sources anymore.

Applications for embedded devices (Phones, PDA's, routers, game consoles) are cross-compiled from a *nix or Windows.

Lazarus Component Library

Architecture of the Lazarus Component Library

The standard application framework, Lazarus Component Library (LCL) was modeled after the Visual Component Library (VCL) in Delphi 6, but it is available for operating systems other than Windows. This is done by separating the definition of common widget classes and their widgetset-specific implementation. Support for each widget set is done by providing an interface which interacts directly with the widget set.^[1]

Currently (early 2011), the development status of widget toolkit interfaces is roughly as follows.

The plan is to write a new GTK3 backend from scratch, because the GTK2 backend was no clean implementation and inherits GTK1 traits.

Database development

Developers can install packages that allow Lazarus to support several databases. Programs can interact with databases through code or by components dropped on a form. The data-aware components represent fields and are connected by the correct setting of properties to a TDataSource, which represents a table, and to the database components, which may be TPSQLDatabase, TSQLiteDataSet, or equivalent.

The following databases are supported out of the box using the built in database components:

• dBase and FoxPro can be supported without the need for an external server or library through the TDbf component
• InterBase / Firebird. See [1]
• MySQL. See [2]
• ODBC databases. See [3]
• Oracle. See [4]
• PostgreSQL. See [5]
• SQLite. See [6]

Other components, such as Zeoslib, can also be used

• MSSQL works with Zeoslib. FPC versions 2.6.2 and higher have built-in support for MSSQL access (using the FreeTDS client library).

Differences from Delphi

While resembling Delphi in many ways, there are a few limitations regarding the performance and feature set.

• Under Windows executable, by default, file size is somewhat larger than the Delphi (6/7) equivalent because debug information is included within Lazarus executables, instead of as separate files like Delphi. However, the 0.9.30 release introduces an external debug symbols feature. Lazarus program file size can be significantly reduced by using an external symbols file (it can be set in Compiler options), and also by using Strip
• Components for Delphi can be installed in Lazarus, but they must be converted, which can be complex. (2.4.x based 0.9.30 should make this easier)
• Missing important media libraries and widgets:
  • Microsoft Office connectivity (popping up Excel with a simple table filled out works fine in 2.5.x trunk)
  • Datasnap (not a publicly documented system, Borland proprietary enterprise functionality)
• Networking is mostly available
• No support to directly call .NET libraries. On the other hand, it is possible to call Object Pascal code from .NET software. ^[2]
• COM support was missing from the 2.0.x series, but it was initially working in 2.2.0, and has matured since.
• Missing dynamically loadable packages support.
• Not 100 percent compatible with VCL. As mentioned previously this is by design, although the current LCL widget set should suffice for most applications. But this makes the deep repository of available VCL widgets inaccessible without conversion. The conversion effort mostly involves some editing, although there are a few fundamental differences. When porting, missing units in the libraries and COM support are a considerably bigger problem than incompatibilities between LCL and VCL.

Distribution and licensing

Like Free Pascal, Lazarus is free software. Different portions are distributed under different free software licenses, including GPL, LGPL, MPL, and a modified version of LGPL.^[3]

Specifically, the LCL, which is statically built into the produced executables, is licensed under a modified version of the LGPL, granting extra permissions to allow it to be statically built into the produced software, including proprietary ones.

Note that installing a design-time package is equivalent to linking to the IDE. Thus, distributing the Lazarus IDE with a GPL-incompatible design-time package (e.g. the JEDI packages, which are licensed under the Mozilla Public License) pre-installed would cause a license violation. This does not prohibit proprietary packages from being developed with Lazarus, though.

Lazarus is officially distributed via Sourceforge.

Versions

Applications produced with Lazarus

• Cartes du Ciel is a free planetarium program for Linux, Mac OS X and Windows. The software maps out and labels most of the constellations, planets, and objects you can see with a telescope. It's fully written in Lazarus/FPC and released under GPL.
• Cheat Engine is an open source memory scanner/hex editor/debugger. It is useful for cheating in computer games. Since version 6.0 it is compiled with Lazarus/FPC.
• MyNotex is a free software for Gnu/Linux useful to take and to manage textual notes.
• Peazip is an open source archiver, made with Lazarus/FPC
• TorChat is moving away from Python, and is being rewritten in Lazarus + Free Pascal.

Libraries compatible with Lazarus

• GLScene is a free OpenGL-based library that provides visual components and objects allowing description and rendering of 3D scenes.
• OpenWire is an Open Source library that allows pin type properties to make connections between LCL components similar to LabVIEW or Agilent VEE.

See also

Free software portal

• Free Pascal Compiler
• Perbandingan -- Pascal IDEs

References

External links

• About Lazarus
• Project Homepage at SourceForge.net
• The Lazarus Documentation Project

Pascal programming language family   Dialects Pascal Object Pascal Oxygene Clascal Concurrent Pascal SuperPascal   Compilers Current Delphi Oxygene PocketStudio HP Pascal IP Pascal Prospero Pascal Free Pascal (Lazarus) GNU Pascal Turbo51 MIDletPascal Pic Micro Pascal ACK   Historical Virtual Pascal Apple Pascal Turbo Pascal Microsoft Pascal UCSD Pascal JRT Pascal/MT+   API CLX FireMonkey LCL Object Windows Library OpenWire Turbo Vision Visual Component Library   Perbandingan -- Pascal and C Perbandingan -- Pascal and Delphi Related to: ALGOL (1958) Modula-2 (1977) Ada (1983) Oberon (1986) Modula-3 (1988) Oberon-2 (1991) Component Pascal (1991)