Mirror: The magical sticky regex-based parser generator 🧙
Add shorthand support to parsers
+76
-22
+14
-7
src/parser.js
+14
-7
src/parser.js
···
12
12
let currentGroup = null;
13
13
let lastMatch;
14
14
let currentSequence = rootSequence;
15
+
let capture;
15
16
16
17
for (
17
18
let quasiIndex = 0, stackIndex = 0;
···
19
20
stackIndex++
20
21
) {
21
22
if (stackIndex % 2 !== 0) {
22
-
currentSequence.push({
23
-
expression: expressions[stackIndex++ >> 1],
24
-
});
23
+
const expression = expressions[stackIndex++ >> 1];
24
+
currentSequence.push({ expression, capture });
25
+
capture = undefined;
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}
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27
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const quasi = quasis[stackIndex >> 1];
···
36
37
if (!currentSequence) syntaxError(char);
37
38
} else if (char === '(') {
38
39
sequenceStack.push(currentSequence);
39
-
currentSequence.push((currentGroup = { sequence: [] }));
40
+
currentSequence.push((currentGroup = { sequence: [], capture }));
40
41
currentSequence = currentGroup.sequence;
42
+
capture = undefined;
43
+
} else if (char === ':' || char === '=' || char === '!') {
44
+
capture = char;
45
+
const nextChar = quasi[quasiIndex];
46
+
if (quasi[quasiIndex] && quasi[quasiIndex] !== '(') syntaxError(char);
41
47
} else if (char === '?' && !currentSequence.length && currentGroup) {
42
-
const nextChar = quasi[quasiIndex++];
43
-
if (nextChar === ':' || nextChar === '=' || nextChar === '!') {
44
-
currentGroup.capture = nextChar;
48
+
capture = quasi[quasiIndex++];
49
+
if (capture === ':' || capture === '=' || capture === '!') {
50
+
currentGroup.capture = capture;
51
+
capture = undefined;
45
52
} else {
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53
syntaxError(char);
47
54
}
+62
-15
src/parser.test.js
+62
-15
src/parser.test.js
···
42
42
expect(ast).toHaveProperty('0.sequence.0.quantifier', undefined);
43
43
});
44
44
45
-
it('supports non-capturing groups', () => {
46
-
const ast = parseTag`(?: ${1})`;
47
-
expect(ast).toHaveProperty('length', 1);
48
-
expect(ast).toHaveProperty('0.capture', ':');
49
-
expect(ast).toHaveProperty('0.sequence.length', 1);
45
+
describe('non-capturing syntax', () => {
46
+
it('supports regex-like syntax', () => {
47
+
const ast = parseTag`(?: ${1})`;
48
+
expect(ast).toHaveProperty('length', 1);
49
+
expect(ast).toHaveProperty('0.capture', ':');
50
+
expect(ast).toHaveProperty('0.sequence.length', 1);
51
+
});
52
+
53
+
it('supports shorthand', () => {
54
+
let ast = parseTag`:${1}`;
55
+
expect(ast).toHaveProperty('length', 1);
56
+
expect(ast).toHaveProperty('0.capture', ':');
57
+
expect(ast).toHaveProperty('0.expression', 1);
58
+
ast = parseTag`:(${1})`;
59
+
expect(ast).toHaveProperty('length', 1);
60
+
expect(ast).toHaveProperty('0.capture', ':');
61
+
expect(ast).toHaveProperty('0.sequence.length', 1);
62
+
});
63
+
64
+
it('fails on invalid usage', () => {
65
+
expect(() => parseTag`${1} : ${2}`).toThrow();
66
+
expect(() => parseTag`${1} :|${2}`).toThrow();
67
+
});
50
68
});
51
69
52
-
it('supports positive lookahead groups', () => {
53
-
const ast = parseTag`(?= ${1})`;
54
-
expect(ast).toHaveProperty('length', 1);
55
-
expect(ast).toHaveProperty('0.capture', '=');
56
-
expect(ast).toHaveProperty('0.sequence.length', 1);
70
+
describe('positive lookaheads syntax', () => {
71
+
it('supports regex-like syntax', () => {
72
+
const ast = parseTag`(?= ${1})`;
73
+
expect(ast).toHaveProperty('length', 1);
74
+
expect(ast).toHaveProperty('0.capture', '=');
75
+
expect(ast).toHaveProperty('0.sequence.length', 1);
76
+
});
77
+
78
+
it('supports shorthand', () => {
79
+
let ast = parseTag`=${1}`;
80
+
expect(ast).toHaveProperty('length', 1);
81
+
expect(ast).toHaveProperty('0.capture', '=');
82
+
expect(ast).toHaveProperty('0.expression', 1);
83
+
ast = parseTag`=(${1})`;
84
+
expect(ast).toHaveProperty('length', 1);
85
+
expect(ast).toHaveProperty('0.capture', '=');
86
+
expect(ast).toHaveProperty('0.sequence.length', 1);
87
+
});
57
88
});
58
89
59
-
it('supports negative lookahead groups', () => {
60
-
const ast = parseTag`(?! ${1})`;
61
-
expect(ast).toHaveProperty('length', 1);
62
-
expect(ast).toHaveProperty('0.capture', '!');
63
-
expect(ast).toHaveProperty('0.sequence.length', 1);
90
+
describe('negative lookaheads syntax', () => {
91
+
it('supports regex-like syntax', () => {
92
+
const ast = parseTag`(?! ${1})`;
93
+
expect(ast).toHaveProperty('length', 1);
94
+
expect(ast).toHaveProperty('0.capture', '!');
95
+
expect(ast).toHaveProperty('0.sequence.length', 1);
96
+
});
97
+
98
+
it('supports shorthand', () => {
99
+
let ast = parseTag`!${1}`;
100
+
expect(ast).toHaveProperty('length', 1);
101
+
expect(ast).toHaveProperty('0.capture', '!');
102
+
expect(ast).toHaveProperty('0.expression', 1);
103
+
ast = parseTag`!(${1})`;
104
+
expect(ast).toHaveProperty('length', 1);
105
+
expect(ast).toHaveProperty('0.capture', '!');
106
+
expect(ast).toHaveProperty('0.sequence.length', 1);
107
+
});
64
108
});
65
109
66
110
it('supports groups with alternates', () => {
67
111
expect(parseTag`(${1} | ${2}) ${3}`).toMatchInlineSnapshot(`
68
112
Array [
69
113
Object {
114
+
"capture": undefined,
70
115
"sequence": Array [
71
116
Object {
117
+
"capture": undefined,
72
118
"expression": 1,
73
119
},
74
120
],
75
121
},
76
122
Object {
123
+
"capture": undefined,
77
124
"expression": 3,
78
125
},
79
126
]