Different Approaches to control GPIO Pins of the Raspberry Pi using Haskell

The functional programming language Haskell allows the writing of elegant code and reduces the likelihood of runtime errors. This advantage can also be used when programming the General Purpose Input/Output (GPIO) pins on the Raspberry Pi. This paper presents three approaches in Haskell for controlling GPIO pins. The first method uses the GPIO sysfs interface, the second sends commands via sockets to the Python library gpiozero, and the third uses the Foreign Function Interface (FFI) to call functions from the C library bcm2835. The approaches described have different strengths and weaknesses, and it depends on the use case which approach is most suitable.