Syntax diagrams are provided in dotted decimal format for users
accessing the Information Center using a screen reader. In dotted
decimal format, each syntax element is written on a separate line.
If two or more syntax elements are always present together (or always
absent together), they can appear on the same line, because they
can be considered as a single compound syntax element.
Each line starts with a dotted decimal number; for example, 3 or
3.1 or 3.1.1. To hear these numbers correctly, make sure that your
screen reader is set to read out punctuation. All the syntax elements
that have the same dotted decimal number (for example, all the syntax
elements that have the number 3.1) are mutually exclusive alternatives.
If you hear the lines 3.1 USERID and 3.1 SYSTEMID, you know that
your syntax can include either USERID or SYSTEMID, but not both.
The dotted decimal numbering level denotes the level of nesting.
For example, if a syntax element with dotted decimal number 3 is
followed by a series of syntax elements with dotted decimal number
3.1, all the syntax elements numbered 3.1 are subordinate to the syntax
element numbered 3.
Certain words and symbols are used next to the dotted decimal numbers
to add information about the syntax elements. Occasionally, these
words and symbols might occur at the beginning of the element itself.
For ease of identification, if the word or symbol is a part of the
syntax element, it is preceded by the backslash (\) character. The
* symbol can be used next to a dotted decimal number to indicate
that the syntax element repeats. For example, syntax element *FILE
with dotted decimal number 3 is given the format 3 \* FILE. Format
3* FILE indicates that syntax element FILE repeats. Format 3* \*
FILE indicates that syntax element * FILE repeats.
Characters such as commas, which are used to separate a string
of syntax elements, are shown in the syntax just before the items
they separate. These characters can appear on the same line as each
item, or on a separate line with the same dotted decimal number as
the relevant items. The line can also show another symbol giving
information about the syntax elements. For example, the lines 5.1*,
5.1 LASTRUN, and 5.1 DELETE mean that if you use more than one of
the LASTRUN and DELETE syntax elements, the elements must be separated
by a comma. If no separator is given, assume that you use a blank
to separate each syntax element.
If a syntax element is preceded by the % symbol, this indicates
a reference that is defined elsewhere. The string following the %
symbol is the name of a syntax fragment rather than a literal. For
example, the line 2.1 %OP1 means that you should refer to separate
syntax fragment OP1.
The following words and symbols are used next to the dotted decimal
numbers:
- ? means an optional syntax element. A dotted decimal number
followed by the ? symbol indicates that all the syntax elements with
a corresponding dotted decimal number, and any subordinate syntax
elements, are optional. If there is only one syntax element with a
dotted decimal number, the ? symbol is displayed on the same line
as the syntax element, (for example 5? NOTIFY). If there is more
than one syntax element with a dotted decimal number, the ? symbol
is displayed on a line by itself, followed by the syntax elements
that are optional. For example, if you hear the lines 5 ?, 5 NOTIFY,
and 5 UPDATE, you know that syntax elements NOTIFY and UPDATE are
optional; that is, you can choose one or none of them. The ? symbol
is equivalent to a bypass line in a railroad diagram.
- ! means a default syntax element. A dotted decimal number followed
by the ! symbol and a syntax element indicates that the syntax element
is the default option for all syntax elements that share the same
dotted decimal number. Only one of the syntax elements that share
the same dotted decimal number can specify a ! symbol. For example,
if you hear the lines 2? FILE, 2.1! (KEEP), and 2.1 (DELETE), you
know that (KEEP) is the default option for the FILE keyword. In this
example, if you include the FILE keyword but do not specify an option,
default option KEEP will be applied. A default option also applies
to the next higher dotted decimal number. In this example, if the
FILE keyword is omitted, default FILE(KEEP) is used. However, if
you hear the lines 2? FILE, 2.1, 2.1.1! (KEEP), and 2.1.1 (DELETE),
the default option KEEP only applies to the next higher dotted decimal
number, 2.1 (which does not have an associated keyword), and does
not apply to 2? FILE. Nothing is used if the keyword FILE is omitted.
- * means a syntax element that can be repeated 0 or more
times. A dotted decimal number followed by the * symbol indicates
that this syntax element can be used zero or more times; that is,
it is optional and can be repeated. For example, if you hear the
line 5.1* data area, you know that you can include one data area,
more than one data area, or no data area. If you hear the lines 3*,
3 HOST, and 3 STATE, you know that you can include HOST, STATE, both
together, or nothing.
Note: - If a dotted decimal number has an asterisk (*) next to it and
there is only one item with that dotted decimal number, you can repeat
that same item more than once.
- If a dotted decimal number has an asterisk next to it and several
items have that dotted decimal number, you can use more than one
item from the list, but you cannot use the items more than once each.
In the previous example, you could write HOST STATE, but you could
not write HOST HOST.
- The * symbol is equivalent to a loop-back line in a railroad syntax
diagram.
- + means a syntax element that must be included one or
more times. A dotted decimal number followed by the + symbol indicates
that this syntax element must be included one or more times; that
is, it must be included at least once and can be repeated. For example,
if you hear the line 6.1+ data area, you must include at least one
data area. If you hear the lines 2+, 2 HOST, and 2 STATE, you know
that you must include HOST, STATE, or both. Similar to the * symbol,
the + symbol can only repeat a particular item if it is the
only item with that dotted decimal number. The + symbol, like the
* symbol, is equivalent to a loop-back line in a railroad syntax diagram.