People keep adding material and helping in the proofreading of the Nim tutorial. Here is the address:
https://github.com/FemtoEmacs/nimacros
As I told before, the Della-Vos group decided to expand the scope of the text to create a Nim book, not only a tutorial about macros. Besides proofreading, the most important correction was to fix the fable of the rabbits, that Leonardo Bigollo Pisano tells in chapter 12 of his Liber Abaci. Sergio Teixeira and Stephanie Bourdieu think that the algorithm must mirror Fibonacci's fable. According to Fibonacci, the farmer started with a pair of adult rabbits. At the end of the first month, the pair of rabbits reproduced. Therefore, Fibonacci(0)= 1 and Fibonacci(1)= 2. In the words of Fibonacci himself:
Quidam posuit unum par cuniculorum in quodam loco, qui erat undique pariete circundatus, ut sciret, quot ex eo paria germinarentur in uno anno: cum natura eorum sit per singulum mensem aliud par germinare; et in secundo mense ab eorum nativitate germinant. Quia suprascriptum par in primo mense germinat, duplicabis ipsum, erunt paria duo in uno mense. Ex quibus unum, silicet primum, in secundo mense geminat; et sic sunt in secundo mense paria 3, etc.
Fibonacci says that the initial couple had a pair of baby rabbits right away in the first month, which means that they were adults. Therefore, for n=0, Fibonacci(n)=1 -- the original pair, and for n=1, Fibonacci(n)= 2, since a baby pair was added to the population. The edition I am using is from 1228, on recommendation of Stephanie.