分类：
2008-12-01 14:19:17
Names: Letters (case-sensitive), digits, and hyphen.
Module names: Start upper case.
Type reference names: Start upper case.
Identifiers (for sequence components, choice alternatives, named bits, named numbers, and enumerations): Start lower case.
Value reference names: Start lower case.
It is common to use either or both of hyphens or upper case within names to separate parts of the name. (e.g. My-type or MyType)
Single-line comments start with -- and end with -- or new line.
Block comments start with /* and end with */.
Block comments can contain other block comments and/or double
hyphen comments.
For historical reasons, multiple single-line comments are often used instead of block comments.
MY-MODULE
{
DEFINITIONS
AUTOMATIC TAGS ::=
BEGIN
EXPORTS
IMPORTS
END
e.g.:
Age ::=
INTEGER
Country-name
::= UTF8String
Greeting ::=
UTF8String
Hex-string
::= OCTET
STRING
e.g.:
twenty-one-today
Age ::= 21
when
GeneralizedTime ::=
"200208192349.57894Z"
large-prime
INTEGER ::=
1999999973
e.g.:
sixty-five-today
::=
my-octets
::=
plain-greeting
::=
bells-and-whistles-greeting
::=
(This also illustrates use of simple value notation in DEFAULTs)
My-sequence
::= SEQUENCE {
first BOOLEAN,
second INTEGER OPTIONAL,
third INTEGER DEFAULT 129,
fourth BOOLEAN DEFAULT TRUE,
fifth REAL DEFAULT 0.629,
-- Or DEFAULT 62.9E-2
sixth UTF8String DEFAULT
"????????",
-- Unicode characters
seventh IA5String DEFAULT
"James Morrison",
-- ASCII characters
eighth BIT STRING DEFAULT
'101100011'B,
ninth OCTET STRING DEFAULT
'89AEF764'H,
tenth Alternatives }
Alternatives
::= CHOICE {
first-alternative TypeA,
second-alternative TypeB,
third-alternative NULL }
DailyMaxTemperaturesForMonth
::=
SEQUENCE (SIZE(28..31)) OF temperature INTEGER
VersionsSupported
::= BIT STRING {
version1 (0),
version2 (1),
version3 (2) }
Message
::= SEQUENCE { ....... ,
version-bit-map VersionsSupported
DEFAULT {version1} }
Color ::=
INTEGER {
red(10), orange(20), yellow(30),
green(40),
blue(50), indigo(60), violet(70) }
(0..80)
Codes ::= ENUMERATED
{code1(0),code2(1),code3(2)}
EXPORTS TypeA,
TypeB, valueC ;
-- Note the semi-colon
IMPORTS TypeA,
TypeB, valueC FROM
MODULE-A { ....... }
TypeD, TypeE FROM
MODULE-B { ....... } ;
oid1 OBJECT IDENTIFIER ::=
{iso standard 2345 modules (0) basic-types (1)}
oid2 OBJECT IDENTIFIER ::= {joint-iso-itu-t ds(5)}
oid3
OBJECT IDENTIFIER ::= { oid2 modules(0) }
oid4
OBJECT IDENTIFIER ::= { oid3 basic-types(1) }
oid5
OBJECT IDENTIFIER ::= { 2 5 0 1 } - -
equals oid4
INTEGER
(0..MAX) --
only non-negative values
INTEGER
(-6..3 | 10..30) --
only -6 to 3 or 10-30
INTEGER
(ALL EXCEPT 0) --
0 not allowed
SEQUENCE
(SIZE (0..10)) OF INTEGER
IA5String
(SIZE (1..25))(FROM ("A" .. "Z"))
-- Only sizes 1-25 and characters
"A"-"Z" allowed
OCTET
STRING (CONTAINING My-Type
ENCODED BY perBasicAligned)
-- perBasicAligned is imported
-- from the ASN.1 standards
UTF8String
(PATTERN "\d#4-\d#2-\d#2")
BIT
STRING (CONSTRAINED
BY ....... )
SEQUENCE
{.......} (WITH COMPONENTS .......)
-- PATTERN, CONSTRAINED BY and
WITH COMPONENTS
-- are
out of the scope of this reference card
Message
::= SEQUENCE {
sender-id OBJECT
IDENTIFIER,
urgency ENUMERATED
{ high, normal, low },
actions SEQUENCE
OF CHOICE {
insert InsertionDetails,
remove RemovalDetails,
update UpdateDetails},
names SEQUENCE OF name UTF8String,
confirm BOOLEAN }
This can
be used to validate the following XML document:
xml-document ::=
Message ::= SEQUENCE {
first TypeA,
second TypeB,
... ,
[[2: version2 TypeC ]],
[[4: version4-first TypeD,
version4-second TypeE ]],
[[6: version6 TypeF ]] }
Alternatives
::= CHOICE {
first TypeA,
second TypeB,
... ,
version2 TypeC }
Codes ::= ENUMERATED {code1, code2, ...,
v2-code, another-code}
NameSizes
::= INTEGER (1..64, ..., 65..MAX)
Obsolete, not commonly used or deprecated syntax is greyed out below. Other syntax is for advanced use. These constructions are out of the scope of this reference card.
MODULE-NAME.TypeName
ABSTRACT-SYNTAX
IMPLICIT TAGS
EXPLICIT TAGS
EXPORTS ALL
EXTENSIBILITY IMPLIED
selection < ChoiceTYpe
COMPONENTS OF SequenceType
SEQUENCE {
first [0] INTEGER OPTIONAL,
second [1] EXPLICIT INTEGER,
last [99] IMPLICIT UserData }
SEQUENCE { ......., ... !29 }
[APPLICATION 29], [PRIVATE 6]
SET { ....... }
SET OF
RELATIVE-OID
EMBEDDED PDV
EXTERNAL
INSTANCE OF
My-values INTEGER ::=
{Set1 INTERSECTION (Set2 UNION
Set3)EXCEPT Set4}
PrintableString (SIZE (NameSizes) )
--where-- NameSizes ::= INTEGER
(0..64)
CHARACTER STRING
ObjectDescriptor
UTCTime
BMPString
GeneralString
GraphicString
ISO646String
NumericString
PrintableString
T61String
TeletexString
UniversalString
VideotexString
VisibleString
Information object class names and words in WITH SYNTAX clauses are all upper case.
Information object
names start with lower-case, information object
set names start with upper case.
MY-SIMPLE-CLASS
::= TYPE-IDENTIFIER
MY-CLASS
::= CLASS {
-- Note use of upper/lower case after &.
-- This is semantically significant.
&id OBJECT
IDENTIFIER UNIQUE,
&simple-value ENUMERATED
{high, medium, low} DEFAULT
medium,
&Set-of-values INTEGER OPTIONAL,
&Any-type,
&an-inform-object SOME-CLASS,
&A-set-of-objects SOME-OTHER-CLASS }
WITH SYNTAX
{ KEY &id
[ URGENCY &simple-value ] --
Optional
[ VALUE-RANGE &Set-of-values ]
PARAMETERS &Any-type
SYNTAX &an-inform-object
MATCHING-RULES
&A-set-of-objects
-- WORDS are optional and commas
can be used
-- as separators --}
my-object
MY-CLASS ::= {
KEY { ....... }
URGENCY high
VALUE-RANGE { 1..10 | 20..30 }
PARAMETERS My-type
SYNTAX defined-syntax
MATCHING-RULES { at-start | at-end | exact }
}
My-object-set MY-CLASS ::= {
object1|object2|object3,
...,
version2-object }
Message ::= SEQUENCE {
key MY-CLASS.&id ({My-object-set}),
-- Has to be an OBJECT-ID from the
set
parms MY-CLASS.&Any-type ({My-object-set} {@key})
-- Has to be the PARAMETERS for
the
-- object with KEY. -- }
--
Variable type value fields and value set fields
-- are
out of the scope of this reference card
Invoke-message
{INTEGER:normal-priority, Parameter} ::=
SEQUENCE {
component1 INTEGER DEFAULT normal-priority,
component2 Parameter }
Messages
::= CHOICE {
first Invoke-message {
low-priority, Type1 },
second Invoke-message {
high-priority, Type2 },
... }
PER: A compact binary encoding transferring the minimum
information needed to identify a value.
XER: Encoding ASN.1 values as XML syntax.
BER: A tag-length-value style of binary encoding very popular
in the 1980s.
DER: An encoding with only one way to encode a given value,
used in security work.
CER: Another security-related encoding, not much used.
An encoding control notation (ECN) is available to completely determine the encoding of ASN.1 values. There are also Encoding Instructions that can vary XER and other encodings, for example, to determine which components of a sequence are to be encoded as XML attributes. These are not in the scope of this Reference Card.
