IBM 5100

DAN
THE FUNCTION DAN GIVES XX THE VALUE
100
AND CALLS THE FUNCTION DAVE
THE FUNCTION DAVE GIVES XX THE VALUE
200
AND CALLS THE FUNCTION JERRY
THE FUNCTION JERRY GIVES XX THE VALUE
300
AND RETURNS TO DAVE
WHEN JERRY IS THROUGH EXECUTING AND EXECUTION RETURNS
TO DAVE, XX ONCE AGAIN HAS THE VALUE
200
WHEN DAVE IS THROUGH EXECUTING AND EXECUTION RETURNS
TO DAN, XX ONCE AGAIN HAS THE VALUE
100
XX
VALUE ERROI~
XX
The )SIV command causes the SIV list (state indicator with local variables and
local user-defined functions listing) to be displayed. The SIV list contains a com-
plete
set of referents of a name.
Note; See System Functions in Chapter 5 for an example of a local user-defined
function using the
OFX system function.
If the SIV list is scanned downward, the first occurrence of a variable name is its
active referent.
If the name appears again, it is a latent referent. Global names
are not found in this list; they can be displayed with the )VARS command and
)FNS command.
In the following
SI V display, variable P has referents as follows:
G1:7]
FI:'+J
G[:~J
R[2J
G[~~]
)SIV
~fZ X I
P ..J ...... --- Active referent of P is local to function F.
*C X T
P ..... ____ First latent referent of P
Z X I is local to function R.
As the state indicator is cleared (see Chapter 7), latent referents become active.
143