1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
|
/* postgres can not */
/* syntax version 1 */
/* yt can not */
$s = <|a:1, b:2u/1u, c:Just(Just(1))|>;
$js = Just($s);
$es = Nothing(Struct<a:Int32, b:Uint32?, c:Int32??>?);
-- result of TryMember() when member is not present is third argument
-- (optional third arg if struct is optional, but third arg is not)
select
TryMember($s, "z", 'qqq'),
TryMember($js, "z", null),
TryMember($es, "z", Just(Just('qqq'))),
TryMember($js, "z", 'zzz'),
;
-- fully equivalent to <struct>.<name>
select
TryMember($s, "a", null),
TryMember($s, "b", null),
TryMember($s, "c", null),
TryMember($js, "a", null),
TryMember($js, "b", null),
TryMember($js, "c", null),
TryMember($es, "a", null),
TryMember($es, "b", null),
TryMember($es, "c", null),
;
-- TypeOf TryMember is type of third argument
-- field type should either match third type exactly, or (if the third type is optional)
-- Optional(field) should be equal to third type
select
TryMember($s, "a", 999),
TryMember($s, "a", Just(999)),
TryMember($s, "b", Just(999u)),
TryMember($s, "c", Just(Just(999))),
TryMember($js, "a", 999),
TryMember($js, "a", Just(999)),
TryMember($js, "b", Just(999u)),
TryMember($js, "c", Just(Just(999))),
TryMember($es, "a", 999),
TryMember($es, "a", Just(999)),
TryMember($es, "b", Just(999u)),
TryMember($es, "c", Just(Just(999))),
;
|
