PAIRLIS$.html -- ACL2 Version 6.3

### PAIRLIS$

zipper together two lists

    Major Section:  ACL2-BUILT-INS

The Common Lisp language allows its `pairlis` function to construct an alist in any order! So we have to define our own version, `pairlis$`. It returns the list of pairs obtained by `cons`ing together successive respective members of the given lists until the first list runs out. (Hence in particular, if the second argument is `nil` then each element of the first argument is paired with `nil`.)

The guard for `pairlis$` requires that its arguments are true lists.

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