"std" import

[ 1 2 + ] eval
[ 3 ] = assert

[ 1 2 3 ] [ clone * ] map
[ 1 4 9 ] = assert

1 [ 2 3 7 ] [ * ] fold
42 = assert

42 wrap
[ 42 ] = assert

[ 1 2 ] unwrap +
3 = assert

[ 2 ] 1 prepend
[ 1 2 ] = assert