2.9 Reserved Words
Syntax
This paragraph
was deleted.
Discussion: Reserved words have special
meaning in the syntax. In addition, certain reserved words are used as
attribute names.
The syntactic category
identifier
no longer allows reserved words. We have added the few reserved words
that are legal explicitly to the syntax for
attribute_reference.
Allowing identifier to include reserved words has been a source of confusion
for some users, and differs from the way they are treated in the C and
Pascal language definitions.
| abort | else | new | return |
|
| abs | elsif | not | reverse |
|
| abstract | end | null | |
|
| accept | entry | | select |
|
| access | exception | of | separate |
|
| aliased | exit | or | some |
|
| all | | others | subtype |
|
| and | for | out | synchronized |
|
| array | function | overriding | |
|
| at | | | tagged |
|
| | generic | package | task |
|
| begin | goto | pragma | terminate |
|
| body | | private | then |
|
| | if | procedure | type |
|
| case | in | protected | |
|
| constant | interface | | until |
|
| | is | raise | use |
|
| declare | | range | |
|
| delay | limited | record | when |
|
| delta | loop | rem | while |
|
| digits | | renames | with |
|
| do | mod | requeue | |
|
| | | | xor |
|
7 The reserved words appear in
lower
case boldface in this International Standard, except when used in
the
designator
of an attribute (see
4.1.4). Lower case boldface
is also used for a reserved word in a
string_literal
used as an
operator_symbol.
This is merely a convention — programs may be written in whatever
typeface is desired and available.
Incompatibilities With Ada 83
The following words are
not reserved in Ada 83, but are reserved in Ada 95:
abstract,
aliased,
protected,
requeue,
tagged,
until.
Wording Changes from Ada 83
Incompatibilities With Ada 95
{
AI95-00284-02}
The following words are not reserved in Ada 95, but
are reserved in Ada 2005:
interface,
overriding,
synchronized.
A special allowance is made for
pragma Interface (see
J.12).
Uses of these words as identifiers will need to be changed, but we do
not expect them to be common.
Wording Changes from Ada 95
{
AI95-00395-01}
The definition of upper case equivalence has been modified to allow identifiers
using all of the characters of ISO 10646. This change has no effect on
the character sequences that are reserved words, but does make some unusual
sequences of characters illegal.
Incompatibilities With Ada 2005
{
AI05-0091-1}
Correction: Removed
other_format
characters from reserved words in order to be compatible with the latest
Unicode recommendations. This change can only affect programs written
for original Ada 2005, and there is little reason to put
other_format
characters into reserved words in the first place, so there should be
very few such programs.
{
AI05-0176-1}
The following word is not reserved in Ada 2005, but is reserved in Ada
2012:
some. Uses of this word as an identifier will need to be
changed, but we do not expect them to be common.
Ada 2005 and 2012 Editions sponsored in part by Ada-Europe
