https://github.com/akkartik/mu/blob/main/linux/apps/advent2020/2a.mu

     1 # https://adventofcode.com/2020/day/2
     2 #
     3 # To run (on Linux):
     4 #   $ git clone https://github.com/akkartik/mu
     5 #   $ cd mu
     6 #   $ ./translate apps/advent2020/2a.mu
     7 #   $ ./a.elf < input
     8 #
     9 # You'll need to register to download the 'input' file for yourself.
    10
    11 fn main -> _/ebx: int {
    12   var valid-password-count/edi: int <- copy 0
    13   var line-storage: (stream byte 0x100)  # 256 bytes
    14   var line/edx: (addr stream byte) <- address line-storage
    15   var slice-storage: slice
    16   var slice/ecx: (addr slice) <- address slice-storage
    17   {
    18     # read line from stdin
    19     clear-stream line
    20     read-line-from-real-keyboard line
    21     # if line is empty (not even a newline), quit
    22     var done?/eax: boolean <- stream-empty? line
    23     compare done?, 0/false
    24     break-if-!=
    25     print-stream-to-real-screen line
    26     # slice = next-token(line, '-')
    27     next-token line, 0x2d, slice
    28     # start = parse-int(slice)
    29     var _start/eax: int <- parse-decimal-int-from-slice slice
    30     var start/ebx: int <- copy _start
    31     var dash/eax: byte <- read-byte line  # skip '-'
    32     # slice = next-token(line, ' ')
    33     next-token line, 0x20, slice
    34     var _end/eax: int <- parse-decimal-int-from-slice slice
    35     var end/esi: int <- copy _end
    36     print-int32-decimal 0, start
    37     print-string 0, " "
    38     print-int32-decimal 0, end
    39     print-string 0, "\n"
    40     # letter = next non-space
    41     skip-chars-matching-whitespace line
    42     var letter/eax: byte <- read-byte line
    43     # skip some stuff
    44     {
    45       var colon/eax: byte <- read-byte line  # skip ':'
    46     }
    47     skip-chars-matching-whitespace line
    48     # now check the rest of the line
    49     var valid?/eax: boolean <- valid? start, end, letter, line
    50     compare valid?, 0/false
    51     {
    52       break-if-=
    53       print-string 0, "valid!\n"
    54       valid-password-count <- increment
    55     }
    56     loop
    57   }
    58   print-int32-decimal 0, valid-password-count
    59   print-string 0, "\n"
    60   return 0
    61 }
    62
    63 fn valid? start: int, end: int, letter: byte, password: (addr stream byte) -> _/eax: boolean {
    64   var letter-count/edi: int <- copy 0
    65   # for every c in password
    66   #   if (c == letter)
    67   #     ++letter-count
    68   {
    69     var done?/eax: boolean <- stream-empty? password
    70     compare done?, 0/false
    71     break-if-!=
    72     var c/eax: byte <- read-byte password
    73     compare c, letter
    74     {
    75       break-if-!=
    76       letter-count <- increment
    77     }
    78     loop
    79   }
    80   # return (start <= letter-count <= end)
    81   compare letter-count, start
    82   {
    83     break-if->=
    84     return 0/false
    85   }
    86   compare letter-count, end
    87   {
    88     break-if-<=
    89     return 0/false
    90   }
    91   return 1/true
    92 }