Development of a Bitrout compiler, a programming language for a primitive architecture

fn to_hex(in:4b| out:8b) {
    var check;
    leeq in 9 check;
    is in out[-4..];
    if check {
        add "0" out;
    } else {
        add "a" out;
    }
}

fn example(a, b:1, c:2b, d:3r | e, f:1, g:4b, h:1r)
                ^    ^     ^  ^
                |    |     |  \_ explicit length
                |    |     \____ bitwise length
                |    \__________ bitwise length reversed
                \_______________ mutability seperator

fn print(string:8b){...}

{
    print "abc";
}

fn print(string:8b){...}

{
    print "c";
    print "b";
    print "a";
}

⋮
var E;
syscall1 arg1 E;
set arg2 E;
syscall2 arg3 E;
if E {
    var E2;
    set "Catching exception!" E2;
}

fn ComptimeIncrement(|A){
    var length;
    lenOf A length;

    var T;
    neq length 0 T;
    if T {
        if A[0]{
          is 0 A[0];
          ComptimeIncrement A[1..];
        } else {
            is 1 A[0];
        }
    }
}

fn _inc(|A:1b, Carry:1){
    if Carry {
        is A Carry;
        not A;
    }
}

fn inc(|A) {
    var Carry:1 = 1;
    _inc A Carry;
}