Nim Macros - Beginner & Intermediate Exercises
With detailed notes and thought processes.
I've been practising metaprogramming with Nim recently.
I've not found macros to be simple, or at least not as simple as the phrase 'code substitution' itself suggests.
Thus I took extensive notes while doing these exercises, which I leave here in their entirety. I hope they will help your understanding should you be newly dipping your toes in the topic of macros. (Leave a note if you find them helpful!)
Each exercise builds on earlier knowledge, so you may want to study/try them in order. I've verified the example code to work, but let me know otherwise.
Beginner Level: quote do & backticks
info(expr) macro - Print the type/value of any expression.
double(x) macro - Take an identifier and generate code that doubles its value in-place.
logvars(a, b, c) macro - Log several variables at once.
Intermediate Level: basic AST use
assertPositive(expr) macro - Check if the expression is > 0.
swap(a, b) macro - Swap the values of two variables.
timed(expr) macro - Measure and print how long an expression takes to run.