Those of us who had nested functions/procedures and “procedural types” in Pascal (or Algol, but that’s beyond my experience) back in the day have :-) Then K&R

Those of us who had nested functions/procedures and “procedural types” in Pascal (or Algol, but that’s beyond my experience) back in the day have :-) Then K&R came, and took our nice toys away. Fortunately, the GNU Pascal compiler needed nested subroutines, so they exposed the feature in their C compiler, as well.