I’ve been recently drawn to Ada (once again). Now, I’m a Lisper through and through and in a way Ada is the exact opposite of Lisp, especially in terms of typing, but perhaps because of that I find it quite interesting. Showing the end result right now, here is the canonical blinking LED done in Ada:

Searching around I found the Make With Ada competition, and I went looking for ways to use Ada with what I had immediately available. I found the AVR-Ada project which looked great. The build process depends on specific versions of the different components (which is quite common), and I spent some time following the manual build process… but then I remembered that I use Docker as a way to encapsulate certain environments.

Since I didn’t founf an existing AVR-Ada image I created one, built on the shoulders of Tero Koskinen‘s Fedora 25 RPMs and available here: https://hub.docker.com/r/fsmunoz/avr-ada/. The goal is to reduce the “cost of entry” for using AVR-Ada.

As an example, building a typical “make the internal LED of the Arduino blink” solution will be as simple as:

Downloading the docker image

docker pull fsmunoz/avr-ada

Create the container with something like the following (I use alias for most docker containers and then just use them as commands in the terminal):

alias avr-ada="docker run -it --rm \ -v $HOME/src:/src:Z \ --device /dev/ttyACM0 \ --name avr-ada \ --group-add dialout \ fsmunoz/avr-ada"

Create an initial project; I would suggest Tero’s blinking led repository . To get an idea of what the code looks like… here it is:

In the docker image navigate to the source dir (which is why in the example above you can see I mapped ~/src to /src in the container).

Do a “make” and a “make upload”; something like this

$ make blink.prog avr-gnatmake -XMCU=atmega328p -p -Pbuild.gpr -XAVRADA_MAIN=blink avr-gnatmake: "/src/ada/arduino/blink/blink.elf" up to date. avrdude -p atmega328p -P /dev/ttyACM0 -c arduino -U flash:w:blink.hex avrdude: AVR device initialized and ready to accept instructions Reading | ################################################## | 100% 0.00s avrdude: Device signature = 0x1e950f (probably m328p) avrdude: NOTE: "flash" memory has been specified, an erase cycle will be performed To disable this feature, specify the -D option. avrdude: erasing chip avrdude: reading input file "blink.hex" avrdude: input file blink.hex auto detected as Intel Hex avrdude: writing flash (1096 bytes): Writing | ################################################## | 100% 0.19s avrdude: 1096 bytes of flash written avrdude: verifying flash memory against blink.hex: avrdude: load data flash data from input file blink.hex: avrdude: input file blink.hex auto detected as Intel Hex avrdude: input file blink.hex contains 1096 bytes avrdude: reading on-chip flash data: Reading | ################################################## | 100% 0.15s avrdude: verifying ... avrdude: 1096 bytes of flash verified avrdude: safemode: Fuses OK (E:00, H:00, L:00) avrdude done. Thank you.

Relaxen und watchen das blinkenlichten.

On a more general note I confess that I find the typical objections to Ada tiresome, especially the “bondage and discipline language designed by committee”. I also read the Jargon File and I was raised in that very same culture, but it comes a time when one needs to go a bit deeper, and the “designed by committee” objection is more of an ideological statement than a practical one. Additionally, I have read some comments on how AdaCore (the main company behind Ada technoloy, but no the only one) is somehow “wrong” in supplying all the tools (which include an advanced IDE, GNAT) but not providing an exception clause to the GPL. I must say that I find this usage perfectly natural and to the spirit of the GPL: the exception clause on GCC was always a tactical measure, not a strategic one, and AdaCore is as far as I know working steadily on the GPL edition, and this is actually the whole idea behind the GPL.

This is a completely different topic but the “business friendly” mantra that BSDers in general like to use is mostly the liberty for companies to use code and then close it up and profit, and this is seen as good – but when a company opens up the code by using the GPL and thus benefits users it is seen as “unfriendly”. As with most things an analysis of good and bad is dependent on who has to gain – cui bono? This is perhaps worthy of a different post.

PS: The use of Ada in Astrophysics is also interesting, as this video shows.