Comment by excessive

This one seems backwards to me:

    (2 '(a b c))

In addition to being data structures, I like to think of lists/arrays as functions which map integers to the contents. This nicely generalizes to hash tables / associative arrays, and then further to actual functions. If that's all reasonable, then

    ('(a b c) 2)

is the right order for application.

However, maybe pg is just thinking of 2 as a shorthand for cadr or similar.