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
use crate::{Environment, eval::apply::eval_apply, value::Value};
pub(crate) fn builtin(
args: &[Value],
is_upper: bool,
env: &Environment,
) -> Option<(Value, Environment)> {
if let [val] = &args[..] {
match eval_apply(val, env) {
Some((Value::String(s), _)) => Some((
Value::String(if is_upper {
s.to_uppercase()
} else {
s.to_lowercase()
}),
Environment::new(),
)),
Some((e, _)) => {
eprintln!(
concat!(
"Error[ksl::builtin::string_case]: ",
"Expected a string, but got `{:?}`."
),
e
);
None
}
None => {
eprintln!(
concat!(
"Error[ksl::builtin::string_case]: ",
"Cannot evaluate expression {:?}."
),
val
);
None
}
}
} else {
eprintln!(
concat!(
"Error[ksl::builtin::string_case]: ",
"Only accepts 1 argument, but {} were passed."
),
args.len()
);
None
}
}