RosettaCodeData/Task/CUSIP/Langur/cusip-2.langur

val .isCusip = fn(.s) {
    if .s is not string or len(.s) != 9 {
        return false
    }

    val .sum = for[=0] .i of 8 {
        val .c = .s[.i]
        var .v = 0

        switch[and] .c {
            case >= '0', <= '9':
                .v = .c-'0'

            case >= 'A', <= 'Z':
                .v = .c-55 # .c-'A'+10

            case '*': .v = 36
            case '@': .v = 37
            case '#': .v = 38

            default: return false
        }

        if .i div 2: .v *= 2
        _for += .v \ 10 + .v rem 10
    }

    .s[9]-'0' == (10-(.sum rem 10)) rem 10
}

val .candidates = w/037833100 17275R102 38259P508 594918104 68389X106 68389X105/

for .c in .candidates {
    writeln .c, ": ", if(.isCusip(.c): "good" ; "bad")
}