compiler/tests/fixtures/runtime/hosted-system-alone/main.ldn

1--  D476: a program that never waits on anything uses hosted/system alone.
2--  It reads no stream and writes none, since the system's handle is no
3--  world, so it answers with its exit status: zero when its arguments,
4--  its environment, a file opened, examined and closed, a directory read,
5--  random bytes and the wall clock all came from the one handle, and the
6--  number of the first that did not otherwise.
7import core/cmp
8import core/io
9import core/text
10import core/time
11import hosted/system
12
13--  The arguments are `one` and the path of an eleven-byte input file.
14checked: (host: system.host) -> (failed: i32) ! ... =
15    failed = 2
16    return when io.argument_count(host) <> 2
17    first: []u8 = text.host_bytes(try io.argument_at(host, 0))
18    return when cmp.compare(first, "one") <> cmp.equal
19    failed = 3
20    _ = io.variable_count(host)
21    _ = io.variable_named(host, text.host_over("LANDIN_NO_SUCH_VARIABLE"))
22        else (problem)
23        failed = if problem == io.no_variable then 4 else 3 end if
24    end
25    return when failed <> 4
26    path: text.host_string = try io.argument_at(host, 1)
27    opened: io.file = try io.open_read(host, path)
28    found: io.status = try io.status_of_file(host, opened)
29    try io.close(host, opened)
30    return when found.size <> 11
31    failed = 5
32    mut buffer: [io.directory_buffer]u8 = zeroed
33    mut listing := try io.open_directory(host, text.host_over("."), buffer)
34    item: io.entry = try io.read_entry(host, listing)
35    named: bool = lenof text.host_bytes(item.name) > 0
36    try io.close_directory(host, listing)
37    return when not named
38    failed = 6
39    mut bytes: [16]u8 = zeroed
40    try io.fill_random(host, bytes[0..<16])
41    failed = 7
42    now: time.wall_time = time.wall_now(host)
43    return when now.seconds < 1600000000
44    failed = 0
45end checked
46
47public main: () -> (code: i32) =
48    code = checked(system.new()) else (problem)
49        _ = problem
50        code = 1
51        return
52    end
53end main