0 Data can be exchanged between APL and BASIC or other systems via commun-
ications; therefore, the following characters have been added to the APL char-
acter set:
$, #, @, &, r, %, ”
The display screen is 64 characters wide; therefore, the initial values for OPW
and UPP system variables are 64 and 5 instead of 120 and 10.
If the print width is altered to something greater than 64, any output that ex-
ceeds 64 characters is wrapped to another line on the display screen.
0 Bare (1) output followed by bare (PJ) input yields a different reply. For
APLSV, the [II input is prefixed by the same number of blanks as the previous
[I1 output. For 5100 APL, the (II input is prefixed by the previous (II output.
(See Chapter 6 for more information on bare output followed by bare input.)
9
0 The display screen provides the ability to edit lines of data directly; therefore,
the following changes were made to function definition:
“01 - Now displays line N
in the display screen lines 1 and 0 for
editing.
[NOMI - Has the same result as [NO]; the M is erased when execute is
pressed.
[AN]
- Allows line N
to be deleted. N
must be a single line number.
The use of the ATTN key to delete a line works, but only in function de-
finition mode, not while entering function definition mode.
To prevent problems when displaying or editing statements in a user-defined
function, the print width (OPW) is automatically set to 390 when the 5100
is in fuhction definition mode. The print width automatically returns to its
previous setting when the function definition is closed.
There is only limited editing space; therefore, function statements that are
greater than 115 characters cannot be
edited, and the message
LINE TOO LONG is displayed.
0 The 5100 will insert a quote if an uneven number of quotes is entered.
3

Glossary
IBM is grateful to the American National Standards
Institute (ANSI) for permission to reprint its definitions
from the American National Standard Vocabulary for
Information Processing (Copyright 0 1970 by American
National Standards Institute, Incorporated), which was
prepared by Subcommittee X3K5 on Terminology and
Glossary of the American National Standards Committee
x3.
ANSI definitions are identified by an asterisk. An asterisk
to the right of the term indicates that the entire entry is
reprinted from the American National Standard Vocabuby
for Information Processing; where definitions from other
sources are included in the entry, ANSI definitions are iden-
tified by an asterisk to the right of the item number.
active referent: The usage of a name that was most recently
localized, or the global usage if the name is not localized.
active workspace: A part of internal storage where data and
user-defined functions are stored and calculations are
performed .
ADD operation: Using a shared variable to add informa-
tion to an existing data file.
alphameric keys: The keys on the left side of the keyboard
that are arranged similar to a typewriter keyboard.
APL internal data format: See internal data format.
arguments: Data supplied to APL functions.
array: A collection of data that can range from a single
item to a multidimensional data configuration. Each ele-
ment of an array must be
the same type as the other ele-
ments (all characters, all numeric, or all logical).
assign: To use the + (assignment arrow) to associate a
name with a value.
available storage: The number of unused 1024-byte blocks
of storage in a file on tape.
bare output: To display output without the cursor return-
ing to the next line.
branch instruction: An instruction that modifies the nor-
mal order of execution indicated by the statement mem-
bers. Branch instructions always begin with a -t (branch
arrow).
branching: Modifying the normal order of execution indi-
cated by the statement numbers.
built-in function: See primitive function.
byte: A unit of storage. For example, a character takes
one byte of storage.
character constant: Characters that do not represent num-
bers, variables, or functions. Character constants are en-
closed in single quotes when they are entered (except for
Oinput); however, the single quotes do not appear when
the character constants are displayed.
command keyword: The name of a system command in-
cluding the right parenthesis. For example, the command
keyword for the )MARK command is )MARK.
comment: An instruction or statement that is not to be
executed. A comment is indicated by a A as the first
character.
conditional branch: A branch that is taken only when a
certain condition is true.
coordinate: A subset of data elements in an array. For
example, a matrix has a row coordinate and a column
coordinate.
wsar: The flashing character on the display that indicates
where the next input from the keyboard will be displayed.
209