collect up all first components of pairs in a list
Major Section:  ACL2-BUILT-INS

(strip-cars x) is the list obtained by walking through the list x and collecting up all first components (cars). This function is implemented in a tail-recursive way, despite its logical definition.

(strip-cars x) has a guard of (alistp x).

To see the ACL2 definition of this function, see pf.