Boolean

// A boolean holds one of exactly two values, `true` or `false`. It is the answer to a yes-or-no
// question — is the file open, has the player won — and later parts lean on it constantly: a
// comparison produces one, and `if` and `while` choose what to run by one.
//
// `bool` is the everyday spelling. It is another name for `bool8`, a boolean stored in one byte.
// `bool16`, `bool32` and `bool64` hold the same two values in two, four and eight bytes, and
// `bool128`, `bool256` and `bool512` in 16, 32 and 64. They exist to match the layout of data
// shared with code written in other languages: the Windows API, for one, uses a four-byte
// boolean, which is a `bool32` here.
import Io::PrintLine;

func Main() -> int {
    // `true` and `false` are the only boolean literals, and either one makes a `bool`.
    let ready = true;
    let finished = false;
    PrintLine("ready     {}", ready);
    PrintLine("finished  {}", finished);

    // The type can be written out, as with any variable.
    let visible: bool = true;
    PrintLine("visible   {}", visible);

    // The wider types print the same way. Only their size differs.
    let flag8: bool8 = true;
    let flag16: bool16 = false;
    let flag32: bool32 = true;
    let flag64: bool64 = false;
    PrintLine("bool8     {}", flag8);
    PrintLine("bool16    {}", flag16);
    PrintLine("bool32    {}", flag32);
    PrintLine("bool64    {}", flag64);

    let flag128: bool128 = true;
    let flag256: bool256 = false;
    let flag512: bool512 = true;
    PrintLine("bool128   {}", flag128);
    PrintLine("bool256   {}", flag256);
    PrintLine("bool512   {}", flag512);

    // A boolean is not a number. Some languages treat 0 as false and 1 as true; Rux does not mix
    // them up on its own:
    //
    //     let on: bool = 1;
    //         error: cannot assign 'int' to 'bool8'
    //
    // The message names `bool8` because that is what `bool` is. Turning a number into a boolean,
    // or back, is a conversion you ask for, and the Convert lesson shows how.
    return 0;
}