Looping over datasets and targetlists

Imagine we wish to harcode a list of 4 directories that we will apply our target to

all
  req: tgz('MyDir1') tgz('MyDir2') tgz('MyDir3') tgz('MyDir4')
          

This isn't ideal; instead we can set up a data section, and automatically create a set of targets using the prolog target/3 predicate.

[
MyDir1
MyDir2
MyDir3
MyDir4

all
  req-l: L             {setof(tgz(X),pkg(X),L)}
          

See the prolog section