how to make pointer arithmetic safe?
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Alternative 1: use arrays with length constraints instead

    byte#[strlen(value)]^ p;
    
    if (p^#[0] == 0) return;
    p = @p^#[1];
    

Alternative 2: use special pointer types, and none values

    typedef cchar = enum(1..255)?;

    cchar>^ p;
    if (not p:next()) return;