pub fn main(world: World) -> Void raises {
    let text: String = "slices"
    let middle: Span<u8> = text[1..4]
    let suffix: Span<u8> = text[2..]
    let prefix: Span<u8> = text[..3]
    let all: Span<u8> = text[..]
    if "zero"[0] == 122 && text[1] == 108 && std.mem.eqlBytes(middle, std.mem.span("lic")) && std.mem.eqlBytes(suffix, std.mem.span("ices")) && std.mem.eqlBytes(prefix, std.mem.span("sli")) && std.mem.len(all) == 6 {
        check world.out.write("string slices ok\n")
    }
}