Some of the programming syntax in this book is presented
using notational symbols. This is to maintain consistency with descriptions
of the same syntax in other IBM publications, or to allow the syntax
to be shown on single lines within a table or heading.
- Braces, { }, indicate
a choice of entry. Unless an item is underlined, indicating a default,
or the items are enclosed in brackets, you must choose at least
one of the entries.
- Items separated by a single vertical bar,
|, are alternative items. You can select only one of the group of
items separated by single vertical bars. (Double vertical bars,
||, specify a concatenation operation, not alternative items. See
the PL/I Language Reference for
more information on double vertical bars.)
- Anything enclosed in brackets, [ ],
is optional. If the items are vertically stacked within the brackets,
you can specify only one item.
- An ellipsis, ..., indicates that multiple
entries of the type immediately preceding the ellipsis are allowed.
Example of notation
The following example of PL/I syntax illustrates the notational
symbols described In How to read the notational symbols:
DCL file-reference FILE STREAM
{INPUT | OUTPUT [PRINT]}
ENVIRONMENT(option ...);
Interpret this example as follows:
- You must spell and enter the first line as shown, except for file-reference,
for which you must substitute the name of the file you are referencing.
- In the second line, you can specify INPUT or OUTPUT, but not
both. If you specify OUTPUT, you can optionally specify PRINT as
well. If you do not specify either alternative, INPUT takes effect
by default.
- You must enter and spell the last line as shown (including the
parentheses and semicolon), except for option ..., for
which you must substitute one or more options separated from each
other by one or more blanks.
|
This information center is powered by Eclipse technology. (http://www.eclipse.org)