rust
let x = 1;
let s = stringify!(
"a" => x,
"b" => 2,
"c" => 3,
"d" => "name age"
);
assert_eq!(s, "a=1&b=2&c=3&d=name+age");
let mut m = BTreeMap::new();
m.insert("a", 1);
m.insert("b", 2);
m.insert("c", 3);
let s = stringify!(m);
assert_eq!(s, "a=1&b=2&c=3");
let s = stringify![
("a", 1),
("b", 2),
("c", 3)
];
assert_eq!(s, "a=1&b=2&c=3");