import ballerina/io;
// A `const` is immutable.
const s = "Anne";
type Row record {
// Both the field and its value are immutable.
readonly string k;
int value;
};
table<Row> key(k) t = table [
{k: "John", value: 17}
];
public function main() {
// Can safely use `s` as a key.
t.add({k: s, value: 18});
io:println(t);
}
Readonly typeThe |
import ballerina/io;
const s = "Anne";
A const
is immutable.
type Row record {
readonly string k;
int value;
Both the field and its value are immutable.
};
table<Row> key(k) t = table [
{k: "John", value: 17}
];
public function main() {
t.add({k: s, value: 18});
Can safely use s
as a key.
io:println(t);
}
bal run readonly_type.bal
[{"k":"John","value":17},{"k":"Anne","value":18}]