Print Width: OPW
The value of this variable determines the length of the output line for both the
display and printer. The value can be from 30 to 390. In a clear workspace,
the value is 64. If this variable is set to a value greater than the length of one
line across the display or printer, the output will overflow onto the next line.
Random Link: ORL
The value of this variable is used in generating random numbers. The value can
be from 1 to Z3 ‘-2. In a clear workspace, the value is 7*5 (16807). This value
is changed by the system each time a random number is generated.
Line Counter: OLC
This variable is a vector. The first element is the function statement number
currently being executed. The next element is the number of the statement
(in another function) that invoked the function being executed. The remaining
elements follow the same pattern. The user cannot set this variable but can dis-
play it. Attempts to modify ULC are ignored by the system. For more informa-
tion on OLC, see Chapter 7.
Workspace Available: 0 WA
The value in this variable indicates the amount of unused space (the number of
unused bytes) in the active workspace. The user cannot set the value for this
variable but can display it. Attempts to modify OWA are ignored by the system.
Latent Expression: 0 LX
A character vector assigned to the latent expression variable is automatically
executed as an expression by the execute (2) function when a stored workspace
containing the latent expression is loaded into the active workspace.
Uses of the latent expression variable include the form ULXC’G’, where a func-
tion named G is executed when the stored workspace is made active. The form
OLX+’”MESSAGE WHEN WORKSPACE IS MADE ACTIVE”’ displays the mes-
sage MESSAGE WHEN WORKSPACE IS MADE ACTIVE when the stored work-
space is loaded into the active workspace.
Atomic Vector: OAV
The atomic vector is a 256-element vector that includes all possible APL charac-
ters. The following example shows it can be used to determine the indices of any
known characters in the vector (assuming 010 is 1):
I
UAV! ‘ABC’
87 88 89
126
Appendix D
contains a list of the characters in the atomic vector. The most com-
mon use of the atomic vector is for generating line feed and cursor return charac-
ters to arrange output. The following example shows how the atomic vector can
be used to generate these characters.
The function called NAMES will display your first and last name. Each name will
start at the left margin and each character in the name will be one line lower than
the previous character:
1
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