impressive that he was able to fit in 100 seconds also a non trivial example of macro (playground):
import macros
macro timesTwo(statements: untyped): untyped =
result = statements
for s in statements:
for node in s:
if node.kind == nnkIntLit:
node.intVal = node.intVal*2
timesTwo:
echo 1 # 2
echo 2 # 4
echo 3 # 6