1 use std::collections::BTreeMap;
2
3 use clap::{command, value_parser, Arg, ArgAction, ArgGroup, ArgMatches, Command};
4
main()5 fn main() {
6 let matches = cli().get_matches();
7 let values = Value::from_matches(&matches);
8 println!("{values:#?}");
9 }
10
cli() -> Command11 fn cli() -> Command {
12 command!()
13 .group(ArgGroup::new("tests").multiple(true))
14 .next_help_heading("TESTS")
15 .args([
16 position_sensitive_flag(Arg::new("empty"))
17 .long("empty")
18 .action(ArgAction::Append)
19 .help("File is empty and is either a regular file or a directory")
20 .group("tests"),
21 Arg::new("name")
22 .long("name")
23 .action(ArgAction::Append)
24 .help("Base of file name (the path with the leading directories removed) matches shell pattern pattern")
25 .group("tests")
26 ])
27 .group(ArgGroup::new("operators").multiple(true))
28 .next_help_heading("OPERATORS")
29 .args([
30 position_sensitive_flag(Arg::new("or"))
31 .short('o')
32 .long("or")
33 .action(ArgAction::Append)
34 .help("expr2 is not evaluate if exp1 is true")
35 .group("operators"),
36 position_sensitive_flag(Arg::new("and"))
37 .short('a')
38 .long("and")
39 .action(ArgAction::Append)
40 .help("Same as `expr1 expr1`")
41 .group("operators"),
42 ])
43 }
44
position_sensitive_flag(arg: Arg) -> Arg45 fn position_sensitive_flag(arg: Arg) -> Arg {
46 // Flags don't track the position of each occurrence, so we need to emulate flags with
47 // value-less options to get the same result
48 arg.num_args(0)
49 .value_parser(value_parser!(bool))
50 .default_missing_value("true")
51 .default_value("false")
52 }
53
54 #[derive(Clone, PartialEq, Eq, Hash, Debug)]
55 pub enum Value {
56 Bool(bool),
57 String(String),
58 }
59
60 impl Value {
from_matches(matches: &ArgMatches) -> Vec<(clap::Id, Self)>61 pub fn from_matches(matches: &ArgMatches) -> Vec<(clap::Id, Self)> {
62 let mut values = BTreeMap::new();
63 for id in matches.ids() {
64 if matches.try_get_many::<clap::Id>(id.as_str()).is_ok() {
65 // ignore groups
66 continue;
67 }
68 let value_source = matches
69 .value_source(id.as_str())
70 .expect("id came from matches");
71 if value_source != clap::parser::ValueSource::CommandLine {
72 // Any other source just gets tacked on at the end (like default values)
73 continue;
74 }
75 if Self::extract::<String>(matches, id, &mut values) {
76 continue;
77 }
78 if Self::extract::<bool>(matches, id, &mut values) {
79 continue;
80 }
81 unimplemented!("unknown type for {id}: {matches:?}");
82 }
83 values.into_values().collect::<Vec<_>>()
84 }
85
extract<T: Clone + Into<Value> + Send + Sync + 'static>( matches: &ArgMatches, id: &clap::Id, output: &mut BTreeMap<usize, (clap::Id, Self)>, ) -> bool86 fn extract<T: Clone + Into<Value> + Send + Sync + 'static>(
87 matches: &ArgMatches,
88 id: &clap::Id,
89 output: &mut BTreeMap<usize, (clap::Id, Self)>,
90 ) -> bool {
91 match matches.try_get_many::<T>(id.as_str()) {
92 Ok(Some(values)) => {
93 for (value, index) in values.zip(
94 matches
95 .indices_of(id.as_str())
96 .expect("id came from matches"),
97 ) {
98 output.insert(index, (id.clone(), value.clone().into()));
99 }
100 true
101 }
102 Ok(None) => {
103 unreachable!("`ids` only reports what is present")
104 }
105 Err(clap::parser::MatchesError::UnknownArgument { .. }) => {
106 unreachable!("id came from matches")
107 }
108 Err(clap::parser::MatchesError::Downcast { .. }) => false,
109 Err(_) => {
110 unreachable!("id came from matches")
111 }
112 }
113 }
114 }
115
116 impl From<String> for Value {
from(other: String) -> Self117 fn from(other: String) -> Self {
118 Self::String(other)
119 }
120 }
121
122 impl From<bool> for Value {
from(other: bool) -> Self123 fn from(other: bool) -> Self {
124 Self::Bool(other)
125 }
126 }
127