pounce gets a better map word that allows use of the stack below, as if the accumulator was there (not clogging up the stack like the first version did)

map-v2.pounce

list_module import
{
 named-args:[c q]
 local-words:{
    init-accum:[[[ ]] [accum] local-def]
    update-accum: [accum cons [] cons [accum] local-def]
    destructive-first:[c pop swap [] cons [c] local-def]
    maponto:[c list-length 0 > 
        [destructive-first q apply update-accum maponto ]
   [] if-else]
 }
 definition: [init-accum maponto accum]
} [maptest] define
[0 1 2 3] [9 +] maptest
10 10 10 10 [0 1 2 3] [*] maptest 
[1 2 3] [dup 3 + swap -1 * 7 + [] cons cons] maptest
[dup 3 + swap -1 * 7 + [] cons cons] [myword] def
[1 2 3] [myword] maptest