Lazarus on RPi

Lazarus is a cross-platform IDE for Free Pascal, a professional 32 bit / 64 bit Pascal Compiler. Lazarus supports a wide variety of processors and Linux distributions including the Raspberry Pi, where it runs natively.

Simple installation
In the Raspbian distribution Lazarus and Free Pascal are easily installed with the following shell commands:

This installs a ready-to-use precompiled version of Lazarus, however not necessarily the newest one.

Compiling from sources
The newest versions of Lazarus are distributed as source code. In order to compile Lazarus from subversion sources see Michell Computing: Lazarus on the Raspberry Pi for details. An updated version covering Free Pascal 2.7.x is the article FreePascal 2.7.1 on Raspberry Pi by the same author.

The article How to install Lazarus Pascal on Raspberry Pi 2 (Raspbian) is a comprehensive description of the steps that are necessary to install a trunk version of Lazarus 1.5.x on the Raspberry Pi 2.

Accessing low-level hardware
Hardware hacking is easily possible with the Lazarus wrapper unit for Gordon Henderson's wiringPi C library (see below). Alternatively, the GPIO port is also accessible directly from Free Pascal as described in the article on RPi Low-level peripherals or, in more detail, in the Lazarus Wiki.