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Did anyone else face a NullPointerException on trying out the example test code given in the ReadMe?

When I try running the abnfofabnf.abnf file in the demo directory throught the parser generator, it tells me that the grammar is not LR(1). Is this the case?

Thanks,

Stephan

Hi can you look at the included abnf, the parser is reporting a problem with the input file. The file is cut and paste from a published rfc, so should be compliant.

The input ABNF file is not a well-formed ABNF file. Please read [RFC5234], modify your ABNF file and try again.

module-stmt = optsep module-keyword sep identifier-arg-str
optsep
"{" stmtsep
module-header-stmts
linkage-stmts
meta-stmts
revision-stmts
body-stmts
"}" optsep

submodule-stmt = optsep submodule-keyword sep identifier-arg-str
optsep
"{" stmtsep
submodule-header-stmts
linkage-stmts
meta-stmts
revision-stmts
body-stmts
"}" optsep

module-header-stmts = ;; these stmts can appear in any order
[yang-version-stmt stmtsep]
namespace-stmt stmtsep
prefix-stmt stmtsep

submodule-header-stmts =
;; these stmts can appear in any order
[yang-version-stmt stmtsep]
belongs-to-stmt stmtsep

meta-stmts = ;; these stmts can appear in any order
[organization-stmt stmtsep]
[contact-stmt stmtsep]
[description-stmt stmtsep]
[reference-stmt stmtsep]

linkage-stmts = ;; these stmts can appear in any order
*(import-stmt stmtsep)
*(include-stmt stmtsep)

revision-stmts = *(revision-stmt stmtsep)

body-stmts = *((extension-stmt /
feature-stmt /
identity-stmt /
typedef-stmt /
grouping-stmt /
data-def-stmt /
augment-stmt /
rpc-stmt /
notification-stmt /
deviation-stmt) stmtsep)

data-def-stmt = container-stmt /
leaf-stmt /
leaf-list-stmt /
list-stmt /
choice-stmt /
anyxml-stmt /
uses-stmt

yang-version-stmt = yang-version-keyword sep yang-version-arg-str
optsep stmtend

yang-version-arg-str = < a string that matches the rule
yang-version-arg >

yang-version-arg = "1"

import-stmt = import-keyword sep identifier-arg-str optsep
"{" stmtsep
prefix-stmt stmtsep
[revision-date-stmt stmtsep]
"}"

include-stmt = include-keyword sep identifier-arg-str optsep
(";" /
"{" stmtsep
[revision-date-stmt stmtsep]
"}")

namespace-stmt = namespace-keyword sep uri-str optsep stmtend

uri-str = < a string that matches the rule
URI in RFC 3986 >

prefix-stmt = prefix-keyword sep prefix-arg-str
optsep stmtend

belongs-to-stmt = belongs-to-keyword sep identifier-arg-str
optsep
"{" stmtsep
prefix-stmt stmtsep
"}"

organization-stmt = organization-keyword sep string
optsep stmtend

contact-stmt = contact-keyword sep string optsep stmtend

description-stmt = description-keyword sep string optsep
stmtend

reference-stmt = reference-keyword sep string optsep stmtend

units-stmt = units-keyword sep string optsep stmtend

revision-stmt = revision-keyword sep revision-date optsep
(";" /
"{" stmtsep
[description-stmt stmtsep]
[reference-stmt stmtsep]
"}")

revision-date = date-arg-str

revision-date-stmt = revision-date-keyword sep revision-date stmtend

extension-stmt = extension-keyword sep identifier-arg-str optsep
(";" /
"{" stmtsep
;; these stmts can appear in any order
[argument-stmt stmtsep]
[status-stmt stmtsep]
[description-stmt stmtsep]
[reference-stmt stmtsep]
"}")

argument-stmt = argument-keyword sep identifier-arg-str optsep
(";" /
"{" stmtsep
[yin-element-stmt stmtsep]
"}")

yin-element-stmt = yin-element-keyword sep yin-element-arg-str
stmtend

yin-element-arg-str = < a string that matches the rule
yin-element-arg >

yin-element-arg = true-keyword / false-keyword

identity-stmt = identity-keyword sep identifier-arg-str optsep
(";" /
"{" stmtsep
;; these stmts can appear in any order
[base-stmt stmtsep]
[status-stmt stmtsep]
[description-stmt stmtsep]
[reference-stmt stmtsep]
"}")

base-stmt = base-keyword sep identifier-ref-arg-str
optsep stmtend

feature-stmt = feature-keyword sep identifier-arg-str optsep
(";" /
"{" stmtsep
;; these stmts can appear in any order
*(if-feature-stmt stmtsep)
[status-stmt stmtsep]
[description-stmt stmtsep]
[reference-stmt stmtsep]
"}")

if-feature-stmt = if-feature-keyword sep identifier-ref-arg-str
optsep stmtend

typedef-stmt = typedef-keyword sep identifier-arg-str optsep
"{" stmtsep
;; these stmts can appear in any order
type-stmt stmtsep
[units-stmt stmtsep]
[default-stmt stmtsep]
[status-stmt stmtsep]
[description-stmt stmtsep]
[reference-stmt stmtsep]
"}"

type-stmt = type-keyword sep identifier-ref-arg-str optsep
(";" /
"{" stmtsep
type-body-stmts
"}")

type-body-stmts = numerical-restrictions /
decimal64-specification /
string-restrictions /
enum-specification /
leafref-specification /
identityref-specification /
instance-identifier-specification /
bits-specification /
union-specification

numerical-restrictions = range-stmt stmtsep

range-stmt = range-keyword sep range-arg-str optsep
(";" /
"{" stmtsep
;; these stmts can appear in any order
[error-message-stmt stmtsep]
[error-app-tag-stmt stmtsep]
[description-stmt stmtsep]
[reference-stmt stmtsep]
"}")

decimal64-specification = fraction-digits-stmt

fraction-digits-stmt = fraction-digits-keyword sep
fraction-digits-arg-str stmtend

fraction-digits-arg-str = < a string that matches the rule
fraction-digits-arg >

fraction-digits-arg = ("1" ["0" / "1" / "2" / "3" / "4" /
"5" / "6" / "7" / "8"])
/ "2" / "3" / "4" / "5" / "6" / "7" / "8" / "9"

string-restrictions = ;; these stmts can appear in any order
[length-stmt stmtsep]
*(pattern-stmt stmtsep)

length-stmt = length-keyword sep length-arg-str optsep
(";" /
"{" stmtsep
;; these stmts can appear in any order
[error-message-stmt stmtsep]
[error-app-tag-stmt stmtsep]
[description-stmt stmtsep]
[reference-stmt stmtsep]
"}")

pattern-stmt = pattern-keyword sep string optsep
(";" /
"{" stmtsep
;; these stmts can appear in any order
[error-message-stmt stmtsep]
[error-app-tag-stmt stmtsep]
[description-stmt stmtsep]
[reference-stmt stmtsep]
"}")

default-stmt = default-keyword sep string stmtend

enum-specification = 1*(enum-stmt stmtsep)

enum-stmt = enum-keyword sep string optsep
(";" /
"{" stmtsep
;; these stmts can appear in any order
[value-stmt stmtsep]
[status-stmt stmtsep]
[description-stmt stmtsep]
[reference-stmt stmtsep]
"}")

leafref-specification =
;; these stmts can appear in any order
path-stmt stmtsep
[require-instance-stmt stmtsep]

path-stmt = path-keyword sep path-arg-str stmtend

require-instance-stmt = require-instance-keyword sep
require-instance-arg-str stmtend

require-instance-arg-str = < a string that matches the rule
require-instance-arg >

require-instance-arg = true-keyword / false-keyword

instance-identifier-specification =
[require-instance-stmt stmtsep]

identityref-specification =
base-stmt stmtsep

union-specification = 1*(type-stmt stmtsep)

bits-specification = 1*(bit-stmt stmtsep)

bit-stmt = bit-keyword sep identifier-arg-str optsep
(";" /
"{" stmtsep
;; these stmts can appear in any order
[position-stmt stmtsep]
[status-stmt stmtsep]
[description-stmt stmtsep]
[reference-stmt stmtsep]
"}"
"}")

position-stmt = position-keyword sep
position-value-arg-str stmtend

position-value-arg-str = < a string that matches the rule
position-value-arg >

position-value-arg = non-negative-integer-value

status-stmt = status-keyword sep status-arg-str stmtend

status-arg-str = < a string that matches the rule
status-arg >

status-arg = current-keyword /
obsolete-keyword /
deprecated-keyword

config-stmt = config-keyword sep
config-arg-str stmtend

config-arg-str = < a string that matches the rule
config-arg >

config-arg = true-keyword / false-keyword

mandatory-stmt = mandatory-keyword sep
mandatory-arg-str stmtend

mandatory-arg-str = < a string that matches the rule
mandatory-arg >

mandatory-arg = true-keyword / false-keyword

presence-stmt = presence-keyword sep string stmtend

ordered-by-stmt = ordered-by-keyword sep
ordered-by-arg-str stmtend

ordered-by-arg-str = < a string that matches the rule
ordered-by-arg >

ordered-by-arg = user-keyword / system-keyword

must-stmt = must-keyword sep string optsep
(";" /
"{" stmtsep
;; these stmts can appear in any order
[error-message-stmt stmtsep]
[error-app-tag-stmt stmtsep]
[description-stmt stmtsep]
[reference-stmt stmtsep]
"}")

error-message-stmt = error-message-keyword sep string stmtend

error-app-tag-stmt = error-app-tag-keyword sep string stmtend

min-elements-stmt = min-elements-keyword sep
min-value-arg-str stmtend

min-value-arg-str = < a string that matches the rule
min-value-arg >

min-value-arg = non-negative-integer-value

max-elements-stmt = max-elements-keyword sep
max-value-arg-str stmtend

max-value-arg-str = < a string that matches the rule
max-value-arg >

max-value-arg = unbounded-keyword /
positive-integer-value

value-stmt = value-keyword sep integer-value stmtend

grouping-stmt = grouping-keyword sep identifier-arg-str optsep
(";" /
"{" stmtsep
;; these stmts can appear in any order
[status-stmt stmtsep]
[description-stmt stmtsep]
[reference-stmt stmtsep]
*((typedef-stmt /
grouping-stmt) stmtsep)
*(data-def-stmt stmtsep)
"}")

container-stmt = container-keyword sep identifier-arg-str optsep
(";" /
"{" stmtsep
;; these stmts can appear in any order
[when-stmt stmtsep]
*(if-feature-stmt stmtsep)
*(must-stmt stmtsep)
[presence-stmt stmtsep]
[config-stmt stmtsep]
[status-stmt stmtsep]
[description-stmt stmtsep]
[reference-stmt stmtsep]
*((typedef-stmt /
grouping-stmt) stmtsep)
*(data-def-stmt stmtsep)
"}")

leaf-stmt = leaf-keyword sep identifier-arg-str optsep
"{" stmtsep
;; these stmts can appear in any order
[when-stmt stmtsep]
*(if-feature-stmt stmtsep)
type-stmt stmtsep
[units-stmt stmtsep]
*(must-stmt stmtsep)
[default-stmt stmtsep]
[config-stmt stmtsep]
[mandatory-stmt stmtsep]
[status-stmt stmtsep]
[description-stmt stmtsep]
[reference-stmt stmtsep]
"}"

leaf-list-stmt = leaf-list-keyword sep identifier-arg-str optsep
"{" stmtsep
;; these stmts can appear in any order
[when-stmt stmtsep]
*(if-feature-stmt stmtsep)
type-stmt stmtsep
[units-stmt stmtsep]
*(must-stmt stmtsep)
[config-stmt stmtsep]
[min-elements-stmt stmtsep]
[max-elements-stmt stmtsep]
[ordered-by-stmt stmtsep]
[status-stmt stmtsep]
[description-stmt stmtsep]
[reference-stmt stmtsep]
"}"

list-stmt = list-keyword sep identifier-arg-str optsep
"{" stmtsep
;; these stmts can appear in any order
[when-stmt stmtsep]
(if-feature-stmt stmtsep)
*(must-stmt stmtsep)
[key-stmt stmtsep]
*(unique-stmt stmtsep)
[config-stmt stmtsep]
[min-elements-stmt stmtsep]
[max-elements-stmt stmtsep]
[ordered-by-stmt stmtsep]
[status-stmt stmtsep]
[description-stmt stmtsep]
[reference-stmt stmtsep]
*((typedef-stmt /
grouping-stmt) stmtsep)
1(data-def-stmt stmtsep)
"}"

key-stmt = key-keyword sep key-arg-str stmtend

key-arg-str = < a string that matches the rule
key-arg >

key-arg = node-identifier *(sep node-identifier)

unique-stmt = unique-keyword sep unique-arg-str stmtend

unique-arg-str = < a string that matches the rule
unique-arg >

unique-arg = descendant-schema-nodeid
*(sep descendant-schema-nodeid)

choice-stmt = choice-keyword sep identifier-arg-str optsep
(";" /
"{" stmtsep
;; these stmts can appear in any order
[when-stmt stmtsep]
*(if-feature-stmt stmtsep)
[default-stmt stmtsep]
[config-stmt stmtsep]
[mandatory-stmt stmtsep]
[status-stmt stmtsep]
[description-stmt stmtsep]
[reference-stmt stmtsep]
*((short-case-stmt / case-stmt) stmtsep)
"}")

short-case-stmt = container-stmt /
leaf-stmt /
leaf-list-stmt /
list-stmt /
anyxml-stmt

case-stmt = case-keyword sep identifier-arg-str optsep
(";" /
"{" stmtsep
;; these stmts can appear in any order
[when-stmt stmtsep]
*(if-feature-stmt stmtsep)
[status-stmt stmtsep]
[description-stmt stmtsep]
[reference-stmt stmtsep]
*(data-def-stmt stmtsep)
"}")

anyxml-stmt = anyxml-keyword sep identifier-arg-str optsep
(";" /
"{" stmtsep
;; these stmts can appear in any order
[when-stmt stmtsep]
*(if-feature-stmt stmtsep)
*(must-stmt stmtsep)
[config-stmt stmtsep]
[mandatory-stmt stmtsep]
[status-stmt stmtsep]
[description-stmt stmtsep]
[reference-stmt stmtsep]
"}")

uses-stmt = uses-keyword sep identifier-ref-arg-str optsep
(";" /
"{" stmtsep
;; these stmts can appear in any order
[when-stmt stmtsep]
*(if-feature-stmt stmtsep)
[status-stmt stmtsep]
[description-stmt stmtsep]
[reference-stmt stmtsep]
*(refine-stmt stmtsep)
*(uses-augment-stmt stmtsep)
"}")

refine-stmt = refine-keyword sep refine-arg-str optsep
(";" /
"{" stmtsep
(refine-container-stmts /
refine-leaf-stmts /
refine-leaf-list-stmts /
refine-list-stmts /
refine-choice-stmts /
refine-case-stmts /
refine-anyxml-stmts)
"}")

refine-arg-str = < a string that matches the rule
refine-arg >

refine-arg = descendant-schema-nodeid
refine-container-stmts =
;; these stmts can appear in any order
*(must-stmt stmtsep)
[presence-stmt stmtsep]
[config-stmt stmtsep]
[description-stmt stmtsep]
[reference-stmt stmtsep]

refine-leaf-stmts = ;; these stmts can appear in any order
*(must-stmt stmtsep)
[default-stmt stmtsep]
[config-stmt stmtsep]
[mandatory-stmt stmtsep]
[description-stmt stmtsep]
[reference-stmt stmtsep]

refine-leaf-list-stmts =
;; these stmts can appear in any order
*(must-stmt stmtsep)
[config-stmt stmtsep]
[min-elements-stmt stmtsep]
[max-elements-stmt stmtsep]
[description-stmt stmtsep]
[reference-stmt stmtsep]

refine-list-stmts = ;; these stmts can appear in any order
*(must-stmt stmtsep)
[config-stmt stmtsep]
[min-elements-stmt stmtsep]
[max-elements-stmt stmtsep]
[description-stmt stmtsep]
[reference-stmt stmtsep]

refine-choice-stmts = ;; these stmts can appear in any order
[default-stmt stmtsep]
[config-stmt stmtsep]
[mandatory-stmt stmtsep]
[description-stmt stmtsep]
[reference-stmt stmtsep]

refine-case-stmts = ;; these stmts can appear in any order
[description-stmt stmtsep]
[reference-stmt stmtsep]

refine-anyxml-stmts = ;; these stmts can appear in any order
*(must-stmt stmtsep)
[config-stmt stmtsep]
[mandatory-stmt stmtsep]
[description-stmt stmtsep]
[reference-stmt stmtsep]

uses-augment-stmt = augment-keyword sep uses-augment-arg-str optsep
"{" stmtsep
;; these stmts can appear in any order
[when-stmt stmtsep]
(if-feature-stmt stmtsep)
[status-stmt stmtsep]
[description-stmt stmtsep]
[reference-stmt stmtsep]
1((data-def-stmt stmtsep) /
(case-stmt stmtsep))
"}"

uses-augment-arg-str = < a string that matches the rule
uses-augment-arg >

uses-augment-arg = descendant-schema-nodeid

augment-stmt = augment-keyword sep augment-arg-str optsep
"{" stmtsep
;; these stmts can appear in any order
[when-stmt stmtsep]
(if-feature-stmt stmtsep)
[status-stmt stmtsep]
[description-stmt stmtsep]
[reference-stmt stmtsep]
1((data-def-stmt stmtsep) /
(case-stmt stmtsep))
"}"

augment-arg-str = < a string that matches the rule
augment-arg >

augment-arg = absolute-schema-nodeid

unknown-statement = prefix ":" identifier [sep string] optsep
(";" / "{" *unknown-statement2 "}")

unknown-statement2 = [prefix ":"] identifier [sep string] optsep
(";" / "{" *unknown-statement2 "}")

when-stmt = when-keyword sep string optsep
(";" /
"{" stmtsep
;; these stmts can appear in any order
[description-stmt stmtsep]
[reference-stmt stmtsep]
"}")

rpc-stmt = rpc-keyword sep identifier-arg-str optsep
(";" /
"{" stmtsep
;; these stmts can appear in any order
*(if-feature-stmt stmtsep)
[status-stmt stmtsep]
[description-stmt stmtsep]
[reference-stmt stmtsep]
*((typedef-stmt /
grouping-stmt) stmtsep)
[input-stmt stmtsep]
[output-stmt stmtsep]
"}")

input-stmt = input-keyword optsep
"{" stmtsep
;; these stmts can appear in any order
((typedef-stmt /
grouping-stmt) stmtsep)
1(data-def-stmt stmtsep)
"}"

output-stmt = output-keyword optsep
"{" stmtsep
;; these stmts can appear in any order
((typedef-stmt /
grouping-stmt) stmtsep)
1(data-def-stmt stmtsep)
"}"

notification-stmt = notification-keyword sep
identifier-arg-str optsep
(";" /
"{" stmtsep
;; these stmts can appear in any order
(if-feature-stmt stmtsep)
[status-stmt stmtsep]
[description-stmt stmtsep]
[reference-stmt stmtsep]
*((typedef-stmt /
grouping-stmt) stmtsep)
*(data-def-stmt stmtsep)
"}")
deviation-stmt = deviation-keyword sep
deviation-arg-str optsep
"{" stmtsep
;; these stmts can appear in any order
[description-stmt stmtsep]
[reference-stmt stmtsep]
(deviate-not-supported-stmt /
1(deviate-add-stmt /
deviate-replace-stmt /
deviate-delete-stmt))
"}"

deviation-arg-str = < a string that matches the rule
deviation-arg >

deviation-arg = absolute-schema-nodeid

deviate-not-supported-stmt =
deviate-keyword sep
not-supported-keyword optsep
(";" /
"{" stmtsep
"}")

deviate-add-stmt = deviate-keyword sep add-keyword optsep
(";" /
"{" stmtsep
[units-stmt stmtsep]
*(must-stmt stmtsep)
*(unique-stmt stmtsep)
[default-stmt stmtsep]
[config-stmt stmtsep]
[mandatory-stmt stmtsep]
[min-elements-stmt stmtsep]
[max-elements-stmt stmtsep]
"}")

deviate-delete-stmt = deviate-keyword sep delete-keyword optsep
(";" /
"{" stmtsep
[units-stmt stmtsep]
*(must-stmt stmtsep)
*(unique-stmt stmtsep)
[default-stmt stmtsep]
"}")
deviate-replace-stmt = deviate-keyword sep replace-keyword optsep
(";" /
"{" stmtsep
[type-stmt stmtsep]
[units-stmt stmtsep]
[default-stmt stmtsep]
[config-stmt stmtsep]
[mandatory-stmt stmtsep]
[min-elements-stmt stmtsep]
[max-elements-stmt stmtsep]
"}")

;; Ranges

range-arg-str = < a string that matches the rule
range-arg >

range-arg = range-part *(optsep "|" optsep range-part)

range-part = range-boundary
[optsep ".." optsep range-boundary]

range-boundary = min-keyword / max-keyword /
integer-value / decimal-value

;; Lengths

length-arg-str = < a string that matches the rule
length-arg >

length-arg = length-part *(optsep "|" optsep length-part)

length-part = length-boundary
[optsep ".." optsep length-boundary]

length-boundary = min-keyword / max-keyword /
non-negative-integer-value

;; Date

date-arg-str = < a string that matches the rule
date-arg >

date-arg = 4DIGIT "-" 2DIGIT "-" 2DIGIT

;; Schema Node Identifiers

schema-nodeid = absolute-schema-nodeid /
descendant-schema-nodeid

absolute-schema-nodeid = 1*("/" node-identifier)

descendant-schema-nodeid =
node-identifier
absolute-schema-nodeid

node-identifier = [prefix ":"] identifier

;; Instance Identifiers

instance-identifier = 1*("/" (node-identifier *predicate))

predicate = "[" *WSP (predicate-expr / pos) *WSP "]"

predicate-expr = (node-identifier / ".") *WSP "=" *WSP
((DQUOTE string DQUOTE) /
(SQUOTE string SQUOTE))

pos = non-negative-integer-value

;; leafref path

path-arg-str = < a string that matches the rule
path-arg >

path-arg = absolute-path / relative-path

absolute-path = 1*("/" (node-identifier *path-predicate))

relative-path = 1*(".." "/") descendant-path

descendant-path = node-identifier
[*path-predicate absolute-path]

path-predicate = "[" *WSP path-equality-expr *WSP "]"

path-equality-expr = node-identifier *WSP "=" *WSP path-key-expr

path-key-expr = current-function-invocation WSP "/" *WSP
rel-path-keyexpr
rel-path-keyexpr = 1(".." *WSP "/" *WSP)
*(node-identifier *WSP "/" *WSP)
node-identifier

;;; Keywords, using abnfgen's syntax for case-sensitive strings

;; statement keywords
anyxml-keyword = 'anyxml'
argument-keyword = 'argument'
augment-keyword = 'augment'
base-keyword = 'base'
belongs-to-keyword = 'belongs-to'
bit-keyword = 'bit'
case-keyword = 'case'
choice-keyword = 'choice'
config-keyword = 'config'
contact-keyword = 'contact'
container-keyword = 'container'
default-keyword = 'default'
description-keyword = 'description'
enum-keyword = 'enum'
error-app-tag-keyword = 'error-app-tag'
error-message-keyword = 'error-message'
extension-keyword = 'extension'
deviation-keyword = 'deviation'
deviate-keyword = 'deviate'
feature-keyword = 'feature'
fraction-digits-keyword = 'fraction-digits'
grouping-keyword = 'grouping'
identity-keyword = 'identity'
if-feature-keyword = 'if-feature'
import-keyword = 'import'
include-keyword = 'include'
input-keyword = 'input'
key-keyword = 'key'
leaf-keyword = 'leaf'
leaf-list-keyword = 'leaf-list'
length-keyword = 'length'
list-keyword = 'list'
mandatory-keyword = 'mandatory'
max-elements-keyword = 'max-elements'
min-elements-keyword = 'min-elements'
module-keyword = 'module'
must-keyword = 'must'
namespace-keyword = 'namespace'
notification-keyword= 'notification'
ordered-by-keyword = 'ordered-by'
organization-keyword= 'organization'
output-keyword = 'output'
path-keyword = 'path'
pattern-keyword = 'pattern'
position-keyword = 'position'
prefix-keyword = 'prefix'
presence-keyword = 'presence'
range-keyword = 'range'
reference-keyword = 'reference'
refine-keyword = 'refine'
require-instance-keyword = 'require-instance'
revision-keyword = 'revision'
revision-date-keyword = 'revision-date'
rpc-keyword = 'rpc'
status-keyword = 'status'
submodule-keyword = 'submodule'
type-keyword = 'type'
typedef-keyword = 'typedef'
unique-keyword = 'unique'
units-keyword = 'units'
uses-keyword = 'uses'
value-keyword = 'value'
when-keyword = 'when'
yang-version-keyword= 'yang-version'
yin-element-keyword = 'yin-element'

;; other keywords

add-keyword = 'add'
current-keyword = 'current'
delete-keyword = 'delete'
deprecated-keyword = 'deprecated'
false-keyword = 'false'
max-keyword = 'max'
min-keyword = 'min'
not-supported-keyword = 'not-supported'
obsolete-keyword = 'obsolete'
replace-keyword = 'replace'
system-keyword = 'system'
true-keyword = 'true'
unbounded-keyword = 'unbounded'
user-keyword = 'user'
current-function-invocation = current-keyword *WSP "(" *WSP ")"

;; Basic Rules

prefix-arg-str = < a string that matches the rule
prefix-arg >

prefix-arg = prefix

prefix = identifier

identifier-arg-str = < a string that matches the rule
identifier-arg >

identifier-arg = identifier

;; An identifier MUST NOT start with (('X'|'x') ('M'|'m') ('L'|'l'))
identifier = (ALPHA / "")
*(ALPHA / DIGIT / "" / "-" / ".")

identifier-ref-arg-str = < a string that matches the rule
identifier-ref-arg >

identifier-ref-arg = [prefix ":"] identifier

string = < an unquoted string as returned by
the scanner >

integer-value = ("-" non-negative-integer-value) /
non-negative-integer-value

non-negative-integer-value = "0" / positive-integer-value

positive-integer-value = (non-zero-digit *DIGIT)

zero-integer-value = 1*DIGIT

stmtend = ";" / "{" *unknown-statement "}"

sep = 1*(WSP / line-break)
; unconditional separator

optsep = *(WSP / line-break)

stmtsep = *(WSP / line-break / unknown-statement)

line-break = CRLF / LF

non-zero-digit = %x31-39

decimal-value = integer-value ("." zero-integer-value)

SQUOTE = %x27
; ' (Single Quote)

;;
;; RFC 5234 core rules.
;;

ALPHA = %x41-5A / %x61-7A
; A-Z / a-z

CR = %x0D
; carriage return

CRLF = CR LF
; Internet standard new line

DIGIT = %x30-39
; 0-9

DQUOTE = %x22
; " (Double Quote)

HEXDIG = DIGIT /
%x61 / %x62 / %x63 / %x64 / %x65 / %x66
; only lower-case a..f

HTAB = %x09
; horizontal tab

LF = %x0A
; linefeed

SP = %x20
; space

VCHAR = %x21-7E
; visible (printing) characters

WSP = SP / HTAB
; whitespace

Refer to issue #1