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
|
package participle_test
import (
"strings"
"testing"
require "github.com/alecthomas/assert/v2"
"github.com/alecthomas/participle/v2"
)
func TestEBNF(t *testing.T) {
parser := mustTestParser[EBNF](t)
expected := `
EBNF = Production* .
Production = <ident> "=" Expression+ "." .
Expression = Sequence ("|" Sequence)* .
Sequence = Term+ .
Term = <ident> | Literal | Range | Group | LookaheadGroup | EBNFOption | Repetition | Negation .
Literal = <string> .
Range = <string> "…" <string> .
Group = "(" Expression ")" .
LookaheadGroup = "(" "?" ("=" | "!") Expression ")" .
EBNFOption = "[" Expression "]" .
Repetition = "{" Expression "}" .
Negation = "!" Expression .
`
require.Equal(t, strings.TrimSpace(expected), parser.String())
}
func TestEBNF_Other(t *testing.T) {
type Grammar struct {
PositiveLookahead string ` (?= 'good') @Ident`
NegativeLookahead string `| (?! 'bad' | "worse") @Ident`
Negation string `| !("anything" | 'but')`
}
parser := mustTestParser[Grammar](t)
expected := `Grammar = ((?= "good") <ident>) | ((?! "bad" | "worse") <ident>) | ~("anything" | "but") .`
require.Equal(t, expected, parser.String())
}
type (
EBNFUnion interface{ ebnfUnion() }
EBNFUnionA struct {
A string `@Ident`
}
EBNFUnionB struct {
B string `@String`
}
EBNFUnionC struct {
C string `@Float`
}
)
func (EBNFUnionA) ebnfUnion() {}
func (EBNFUnionB) ebnfUnion() {}
func (EBNFUnionC) ebnfUnion() {}
func TestEBNF_Union(t *testing.T) {
type Grammar struct {
TheUnion EBNFUnion `@@`
}
parser := mustTestParser[Grammar](t, participle.Union[EBNFUnion](EBNFUnionA{}, EBNFUnionB{}, EBNFUnionC{}))
require.Equal(t,
strings.TrimSpace(`
Grammar = EBNFUnion .
EBNFUnion = EBNFUnionA | EBNFUnionB | EBNFUnionC .
EBNFUnionA = <ident> .
EBNFUnionB = <string> .
EBNFUnionC = <float> .
`),
parser.String())
}
|
