function asp_part_1 ( string , x_function ) ...
... calculates all "subset-strings" ( see test example below ) as an array_of_char
... for every result x_function is called

function asp_part_2 ( array_of_char ) ...
... joins array_of_char to a string
... all permutations of this string are pushed to asp_result

function asp ( string ) ...
... calculates all "subset-strings" of parameter string
... for every "subset-strings" all permutations are pushed to asp_result