lalrpop 0.12.2

convenient LR(1) parser generator
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
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100

use parser;
use test_util::compare;

use super::expand_macros;

#[test]
fn test_comma() {
    let grammar = parser::parse_grammar(r#"
grammar;
    Comma<E>: Vec<E> =
       <v:(<E> ",")*> <e:E?> =>
           v.into_iter().chain(e.into_iter()).collect();

    Ids = Comma<"Id">;
"#).unwrap();

    let actual = expand_macros(grammar).unwrap();

    let expected = parser::parse_grammar(r##"
grammar;
    Ids = `Comma<"Id">`;

    `Comma<"Id">`: Vec<#"Id"#> =
        <v:`(<"Id"> ",")*`> <e:`"Id"?`> => v.into_iter().chain(e.into_iter()).collect();

    #[inline]
    `"Id"?`: ::std::option::Option<#"Id"#> = {
        "Id" => Some(<>),
        => None
    };

    #[inline]
    `(<"Id"> ",")*`: ::std::vec::Vec<#`(<"Id"> ",")`#> = {
        => vec![],
        <v:`(<"Id"> ",")+`> => v,
    };

    #[inline]
    `(<"Id"> ",")`: #"Id"# = {
        <"Id"> "," => (<>),
    };

    `(<"Id"> ",")+`: ::std::vec::Vec<#`(<"Id"> ",")`#> = {
        `(<"Id"> ",")` => vec![<>],
        <v:`(<"Id"> ",")+`> <e:`(<"Id"> ",")`> => { let mut v = v; v.push(e); v },
    };
"##).unwrap();

    compare(actual, expected);
}

#[test]
fn test_if_match() {
    let grammar = parser::parse_grammar(r#"
grammar;
    Expr<E> = {
       "A" if E == "A*C",
       "B" if E ~~ "^A*C$",
       "C" if E != "A*C",
       "D" if E !~ "^A*C$"
    };

    Expr1 = Expr<"A*C">;
    Expr2 = Expr<"AAC">;
    Expr3 = Expr<"ABC">;
"#).unwrap();

    let actual = expand_macros(grammar).unwrap();

    let expected = parser::parse_grammar(r#"
grammar;
    Expr1 = `Expr<"A*C">`;
    Expr2 = `Expr<"AAC">`;
    Expr3 = `Expr<"ABC">`;

    `Expr<"ABC">` = { "C", "D" };
    `Expr<"AAC">` = { "B", "C" };
    `Expr<"A*C">` = { "A", "D" };
"#).unwrap();

    compare(actual, expected);
}

#[test]
fn test_lookahead() {
    let grammar = parser::parse_grammar(r#"
        grammar;
        Expr = @L;
"#).unwrap();

    let actual = expand_macros(grammar).unwrap();

    let expected = parser::parse_grammar(r#"
        grammar;
        Expr = `@L`;
        #[inline] `@L` = =>@L;
"#).unwrap();

    compare(actual, expected);
}