Question

Is there a way to loop over multiple lists in parallel in a makefile or CMake file?

I would like to do something like the following in CMake, except AFAICT this syntax isn’t supported:

set(a_values a0 a1 a2)
set(b_values b0 b1 b2)
foreach(a in a_values b in b_values)
  do_something_with(a b)
endforeach(a b)

This would execute:

do_something_with(a0 b0)
do_something_with(a1 b1)
do_something_with(a2 b2)

I would accept an answer in either CMake or Make, though CMake would be preferred. Thanks!

Answer 1

Here you go:

set(list1 1 2 3 4 5)
set(list2 6 7 8 9 0)

list(LENGTH list1 len1)
math(EXPR len2 "${len1} - 1")

foreach(val RANGE ${len2})
  list(GET list1 ${val} val1)
  list(GET list2 ${val} val2)
  message(STATUS "${val1}  ${val2}")
endforeach()