aboutsummaryrefslogtreecommitdiffhomepage
path: root/docs/jq_grammar.md
blob: 430e01d980e85260131aee7f77673a7e4a9549f7 (plain)
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
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
# Jq Grammar


## Notation

* `'A'`: Terminal symbol
* `A`: Non-terminal symbol
* `A / B`: A or B
* `A?`: Optional A
* `{ A }+`: 1 or more repetitions of A
* `{ A }*`: 0 or more repetitions of A
* `{ A | S }+`: 1 or more repetitions of A separated by S
    * Equivalent to `A { S A }*`
* `{ A | S }*`: 0 or more repetitions of A separated by S
    * Equivalent to `{ A | S }+?`
* `{ A |? S }+`: 1 or more repetitions of A separated by S, allowing optional trailing S
    * Equivalent to `A { S A }* S?`
* `{ A |? S }*`: 1 or more repetitions of A separated by S, allowing optional trailing S
    * Equivalent to `{ A |? S }+?`
* `( A )`: Grouping
* `# ...`: Additional constraints


## Implemented Grammar

```
program:
    body

body:
    query

query:
    query2

query2:
    query3 '|' query3
    query3

query3:
    expr ',' expr
    expr

expr:
    expr2 '//' expr2
    expr2

expr2:
    expr3 '=' expr3
    expr3 '|=' expr3
    expr3 '//=' expr3
    expr3 '+=' expr3
    expr3 '-=' expr3
    expr3 '*=' expr3
    expr3 '/=' expr3
    expr3 '%=' expr3
    expr3

expr3:
    expr4 'or' expr4
    expr4

expr4:
    expr5 'and' expr5
    expr5

expr5:
    expr6 '==' expr6
    expr6 '!=' expr6
    expr6 '<' expr6
    expr6 '>' expr6
    expr6 '<=' expr6
    expr6 '>=' expr6
    expr6

expr6:
    expr7 '+' expr7
    expr7 '-' expr7
    expr7

expr7:
    term '*' term
    term '/' term
    term '%' term
    term

term:
    primary { suffix }*

suffix:
    '[' ']'
    '[' query ']' '?'?
    '[' query ':' query ']' '?'?
    '[' query ':' ']' '?'?
    '[' ':' query ']' '?'?

primary:
    'null'
    'true'
    'false'
    NUMBER
    STRING
    '.'
    FIELD '?'?
    '[' ']'
    '{' '}'
    '[' query ']'
    '(' query ')'
```


## Complete Grammar

```
program:
    module? imports body

module:
    'module' query ';'

imports:
    { import }+

import:
    'import' STRING 'as' BINDING query? ';'
    'import' STRING 'as' IDENT query? ';'
    'include' STRING query? ';'

body:
    funcdefs
    query

funcdefs:
    { funcdef }+

funcdef:
    'def' IDENT ':' query ';'
    'def' IDENT '(' params ')' ':' query ';'

params:
    { param | ';' }+

param:
    BINDING
    IDENT

query:
    funcdef query
    expr 'as' patterns '|' query
    'label' BINDING '|' query
    query2

query2:
    query3 '|' query3
    query3

query3:
    expr ',' expr
    expr

expr:
    expr2 '//' expr2
    expr2

expr2:
    expr3 '=' expr3
    expr3 '|=' expr3
    expr3 '//=' expr3
    expr3 '+=' expr3
    expr3 '-=' expr3
    expr3 '*=' expr3
    expr3 '/=' expr3
    expr3 '%=' expr3
    expr3

expr3:
    expr4 'or' expr4
    expr4

expr4:
    expr5 'and' expr5
    expr5

expr5:
    expr6 '==' expr6
    expr6 '!=' expr6
    expr6 '<' expr6
    expr6 '>' expr6
    expr6 '<=' expr6
    expr6 '>=' expr6
    expr6

expr6:
    expr7 '+' expr7
    expr7 '-' expr7
    expr7

expr7:
    term '*' term
    term '/' term
    term '%' term
    term

term:
    '.'
    '..'
    'break' BINDING
    term FIELD
    FIELD
    term '.' STRING
    '.' STRING
    term '[' query ']'
    term '.' '[' query ']'
    term '[' ']'
    term '.' '[' ']'
    term '[' query ':' query ']'
    term '[' query ':' ']'
    term '[' ':' query ']'
    term '?'
    'null'
    'true'
    'false'
    NUMBER
    STRING
    FORMAT
    '-' term
    '(' query ')'
    '[' query ']'
    '[' ']'
    '{' dict-pairs '}'
    'reduce' expr 'as' patterns '(' query ';' query ')'
    'foreach' expr 'as' patterns '(' query ';' query ';' query ')'
    'foreach' expr 'as' patterns '(' query ';' query ')'
    'if' query 'then' query else-body
    'try' expr 'catch' expr
    'try' expr
    BINDING
    '$__loc__'
    IDENT
    IDENT '(' args ')'

else-body:
    'elif' query 'then' query else-body
    'else' query 'end'
    'end'

args:
    { query | ';' }+

rep-patterns:
    { pattern | '?//' }

patterns:
    { pattern | '?//' }

pattern:
    BINDING
    '[' array-patterns ']'
    '{' obj-patterns '}'

array-patterns:
    { pattern | ',' }

obj-patterns:
    { obj-pattern | ',' }

obj-pattern:
    BINDING
    BINDING ':' pattern
    IDENT ':' pattern
    KEYWORD ':' pattern
    STRING ':' pattern
    '(' query ')' ':' pattern

dict-pairs:
    { dict-pair | ',' }*

dict-pair:
    IDENT ':' dict-expr
    KEYWORD ':' dict-expr
    STRING ':' dict-expr
    STRING
    BINDING ':' dict-expr
    BINDING
    IDENT
    "$__loc__"
    KEYWORD
    '(' query ')' ':' dict-expr

dict-expr:
    { expr | '|' }
```