cfg-examples 0.1.0

Library for manipulating context-free grammars.
Documentation 
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
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64

use cfg::{
    NamedCfgRule,
    classify::{CfgClassifyExt, recursive::RecursionKind},
    named_cfg_rule,
};
use cfg_examples::c::grammar;

#[test]
fn test_useful() {
    let mut grammar = grammar();
    assert!(grammar.usefulness().all_useful());
}

#[test]
fn test_recursive() {
    let grammar = grammar();
    let recursion = grammar.recursion();
    let actual_recursive_rules: Vec<_> = recursion
        .recursive_rules()
        .map(|rec| (rec.rule.named(grammar.sym_source()), rec.recursion))
        .take(2) // TODO full
        .collect();
    let expected_recursive_rules: Vec<(NamedCfgRule, RecursionKind)> = vec![
        (
            named_cfg_rule!(primary_expression ::= lparen expression rparen),
            RecursionKind::Middle,
        ),
        (
            named_cfg_rule!(postfix_expression ::= primary_expression),
            RecursionKind::All,
        ),
    ];
    assert_eq!(actual_recursive_rules, expected_recursive_rules);
}

#[test]
fn test_recursive_distances() {
    let grammar = grammar();
    let recursion = grammar.recursion();
    let actual_recursive_rules: Vec<_> = recursion
        .minimal_distances()
        .map(|rec| {
            (
                rec.rule.named(grammar.sym_source()),
                rec.recursion,
                rec.distances,
            )
        })
        .take(2) // TODO full
        .collect();
    let expected_recursive_rules: Vec<(NamedCfgRule, RecursionKind, Option<(usize, usize)>)> = vec![
        (
            named_cfg_rule!(primary_expression ::= lparen expression rparen),
            RecursionKind::Middle,
            Some((0, 1)),
        ),
        (
            named_cfg_rule!(postfix_expression ::= primary_expression),
            RecursionKind::All,
            Some((0, 1)),
        ),
    ];
    assert_eq!(actual_recursive_rules, expected_recursive_rules);
}