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
|
$vartype = Variant<Int32, Bool, String>;
$handle_num = ($x) -> { return 2 * $x; };
$handle_flag = ($x) -> { return If($x, 200, 10); };
$handle_str = ($x) -> { return Unwrap(CAST(LENGTH($x) AS Int32)); };
$visitor = ($var) -> { return Visit($var, $handle_num, $handle_flag, $handle_str); };
SELECT
$visitor(Variant(5, "0", $vartype)),
$visitor(Just(Variant(True, "1", $vartype))),
$visitor(Just(Variant("somestr", "2", $vartype))),
$visitor(Nothing(OptionalType($vartype))),
$visitor(NULL)
;
$visitor_def = ($var) -> { return VisitOrDefault($var, $handle_num, $handle_flag, 999); };
SELECT
$visitor_def(Variant(5, "0", $vartype)),
$visitor_def(Just(Variant(True, "1", $vartype))),
$visitor_def(Just(Variant("somestr", "2", $vartype))),
$visitor_def(Nothing(OptionalType($vartype))),
$visitor_def(NULL)
;
$vartype1 = Variant<Int32, Int32, Int32>;
SELECT
VariantItem(Variant(7, "1", $vartype1)),
VariantItem(Just(Variant(5, "0", $vartype1))),
VariantItem(Nothing(OptionalType($vartype1))),
VariantItem(NULL)
;
|
