Appendix A. Collected ABNF Grammars
Appendix A. Collected ABNF Grammars
This appendix collects the ABNF grammar from the ABNF passages used throughout the document.
Figure 2 contains the collected ABNF grammar that defines the syntax of a JSONPath query.
jsonpath-query = root-identifier segments
segments = *(S segment)
B = %x20 / ; Space
%x09 / ; Horizontal tab
%x0A / ; Line feed or New line
%x0D ; Carriage return
S = *B ; optional blank space
root-identifier = "$"
selector = name-selector /
wildcard-selector /
slice-selector /
index-selector /
filter-selector
name-selector = string-literal
string-literal = %x22 *double-quoted %x22 / ; "string"
%x27 *single-quoted %x27 ; 'string'
double-quoted = unescaped /
%x27 / ; '
ESC %x22 / ; \"
ESC escapable
single-quoted = unescaped /
%x22 / ; "
ESC %x27 / ; \'
ESC escapable
ESC = %x5C ; \ backslash
unescaped = %x20-21 / ; see RFC 8259
; omit 0x22 "
%x23-26 /
; omit 0x27 '
%x28-5B /
; omit 0x5C \
%x5D-D7FF /
; skip surrogate code points
%xE000-10FFFF
escapable = %x62 / ; b BS backspace U+0008
%x66 / ; f FF form feed U+000C
%x6E / ; n LF line feed U+000A
%x72 / ; r CR carriage return U+000D
%x74 / ; t HT horizontal tab U+0009
"/" / ; / slash (solidus) U+002F
"\" / ; \ backslash (reverse solidus) U+005C
(%x75 hexchar) ; uXXXX U+XXXX
hexchar = non-surrogate /
(high-surrogate "\" %x75 low-surrogate)
non-surrogate = ((DIGIT / "A"/"B"/"C" / "E"/"F") 3HEXDIG) /
("D" %x30-37 2HEXDIG )
high-surrogate = "D" ("8"/"9"/"A"/"B") 2HEXDIG
low-surrogate = "D" ("C"/"D"/"E"/"F") 2HEXDIG
HEXDIG = DIGIT / "A" / "B" / "C" / "D" / "E" / "F"
wildcard-selector = "*"
index-selector = int ; decimal integer
int = "0" /
(["-"] DIGIT1 *DIGIT) ; - optional
DIGIT1 = %x31-39 ; 1-9 non-zero digit
slice-selector = [start S] ":" S [end S] [":" [S step ]]
start = int ; included in selection end = int ; not included in selection step = int ; default: 1 filter-selector = "?" S logical-expr logical-expr = logical-or-expr logical-or-expr = logical-and-expr *(S "||" S logical-and-expr) ; disjunction ; binds less tightly than conjunction logical-and-expr = basic-expr *(S "&&" S basic-expr) ; conjunction ; binds more tightly than disjunction
basic-expr = paren-expr /
comparison-expr /
test-expr
paren-expr = [logical-not-op S] "(" S logical-expr S ")"
; parenthesized expression
logical-not-op = "!" ; logical NOT operator
test-expr = [logical-not-op S]
(filter-query / ; existence/non-existence
function-expr) ; LogicalType or NodesType
filter-query = rel-query / jsonpath-query
rel-query = current-node-identifier segments
current-node-identifier = "@"
comparison-expr = comparable S comparison-op S comparable
literal = number / string-literal /
true / false / null
comparable = literal /
singular-query / ; singular query value
function-expr ; ValueType
comparison-op = "==" / "!=" /
"<=" / ">=" /
"<" / ">"
singular-query = rel-singular-query / abs-singular-query
rel-singular-query = current-node-identifier singular-query-segments
abs-singular-query = root-identifier singular-query-segments
singular-query-segments = *(S (name-segment / index-segment))
name-segment = ("[" name-selector "]") /
("." member-name-shorthand)
index-segment = "[" index-selector "]"
number = (int / "-0") [ frac ] [ exp ] ; decimal number
frac = "." 1*DIGIT ; decimal fraction
exp = "e" [ "-" / "+" ] 1*DIGIT ; decimal exponent
true = %x74.72.75.65 ; true
false = %x66.61.6c.73.65 ; false
null = %x6e.75.6c.6c ; null
function-name = function-name-first *function-name-char
function-name-first = LCALPHA
function-name-char = function-name-first / "_" / DIGIT
LCALPHA = %x61-7A ; "a".."z"
function-expr = function-name "(" S [function-argument
*(S "," S function-argument)] S ")"
function-argument = literal /
filter-query / ; (includes singular-query)
logical-expr /
function-expr
segment = child-segment / descendant-segment
child-segment = bracketed-selection /
("."
(wildcard-selector /
member-name-shorthand))
bracketed-selection = "[" S selector *(S "," S selector) S "]"
member-name-shorthand = name-first *name-char
name-first = ALPHA /
"_" /
%x80-D7FF /
; skip surrogate code points
%xE000-10FFFF
name-char = name-first / DIGIT
DIGIT = %x30-39 ; 0-9
ALPHA = %x41-5A / %x61-7A ; A-Z / a-z
descendant-segment = ".." (bracketed-selection /
wildcard-selector /
member-name-shorthand)
Figure 2: Collected ABNF of JSONPath Queries
Figure 3 contains the collected ABNF grammar that defines the syntax of a JSONPath Normalized Path while also using the rules root- identifier, ESC, DIGIT, and DIGIT1 from Figure 2.
normalized-path = root-identifier *(normal-index-segment)
normal-index-segment = "[" normal-selector "]"
normal-selector = normal-name-selector / normal-index-selector
normal-name-selector = %x27 *normal-single-quoted %x27 ; 'string'
normal-single-quoted = normal-unescaped /
ESC normal-escapable
normal-unescaped = ; omit %x0-1F control codes
%x20-26 /
; omit 0x27 '
%x28-5B /
; omit 0x5C \
%x5D-D7FF /
; skip surrogate code points
%xE000-10FFFF
normal-escapable = %x62 / ; b BS backspace U+0008
%x66 / ; f FF form feed U+000C
%x6E / ; n LF line feed U+000A
%x72 / ; r CR carriage return U+000D
%x74 / ; t HT horizontal tab U+0009
"'" / ; ' apostrophe U+0027
"\" / ; \ backslash (reverse solidus) U+005C
(%x75 normal-hexchar)
; certain values u00xx U+00XX
normal-hexchar = "0" "0"
(
("0" %x30-37) / ; "00"-"07"
; omit U+0008-U+000A BS HT LF
("0" %x62) / ; "0b"
; omit U+000C-U+000D FF CR
("0" %x65-66) / ; "0e"-"0f"
("1" normal-HEXDIG)
)
normal-HEXDIG = DIGIT / %x61-66 ; "0"-"9", "a"-"f"
normal-index-selector = "0" / (DIGIT1 *DIGIT)
; non-negative decimal integer
Figure 3: Collected ABNF of JSONPath Normalized Paths