pub fn main(world: World) -> Void raises {
    var reversed_buf: [6]u8 = [0_u8; 6]
    let reversed: Maybe<Span<u8>> = std.str.reverse(reversed_buf, "drawer")
    let trimmed: Span<u8> = std.str.trimAscii("  zero text  ")
    var small: [3]u8 = [0_u8; 3]
    let overflow: Maybe<Span<u8>> = std.str.reverse(small, "drawer")
    var ok: Bool = true
    if !reversed.has {
        ok = false
    }
    if reversed.has {
        if !std.mem.eql(reversed.value, "reward") {
            ok = false
        }
    }
    if overflow.has {
        ok = false
    }
    if std.str.countByte("banana", 97_u8) != 3 {
        ok = false
    }
    if !std.str.startsWith("zero text syntax", "zero") {
        ok = false
    }
    if !std.str.endsWith("zero text syntax", "syntax") {
        ok = false
    }
    if !std.str.contains("zero text syntax", "text") {
        ok = false
    }
    if std.str.contains("zero text syntax", "column") {
        ok = false
    }
    if !std.str.contains("zero", "") {
        ok = false
    }
    if !std.mem.eql(trimmed, "zero text") {
        ok = false
    }
    if std.str.wordCountAscii("zero text syntax") != 3 {
        ok = false
    }
    if ok {
        check world.out.write("std str ok\n")
    }
}