palindrome_2_3.wsf

# Rosetta Code
# Find palindromic numbers in both binary and ternary bases
# https://rosettacode.org/wiki/Find_palindromic_numbers_in_both_binary_and_ternary_bases

    "@int" import

    0 ^ readi retrieve # n

    # Handle 0 separately
    0 call print_pal

    # Iterate chunked by magnitude so that palindromes are visited in
    # order.
    1 ^ # i found
.loop_magnitude: # IVs: i found
    ^1 2* swap # hi = i*2

    ^2 # j = i
.loop_odd: # IVs: found j
    ^ 2 call int.make_palindrome_odd
    ^ ^ 3 call int.reverse_digits j= .is_pal_odd
    drop
.loop_odd_continue:
    1+ # j++
    ^ ^3 j< .loop_odd # j < hi
    drop

    ^2 # j = i
.loop_even: # IVs: found j
    ^ 2 call int.make_palindrome_even
    ^ ^ 3 call int.reverse_digits j= .is_pal_even
    drop
.loop_even_continue:
    1+ # j++
    ^ ^3 j< .loop_even # j < hi
    drop

    swap drop swap 2* swap # i *= 2
    jmp .loop_magnitude

.is_pal_odd:
    call print_pal
    swap 1+ swap # j++
    ^1 ^5 j< .loop_odd_continue # found < n
    jmp .end
.is_pal_even:
    call print_pal
    swap 1+ swap # j++
    ^1 ^5 j< .loop_even_continue # found < n
.end:
    5drop end

# print_pal prints a palindrome in decimal, binary, and ternary.
# (n -- )
print_pal:
    ^ printi ' ' printc
    ^ 3 call int.print_base ' ' printc
    2 call int.print_base '\n' printc
    ret