When a program updates a composite string, the variables which make up the composite will be updated automatically.

Example 1:

Given the following Composite definition and values

0100 DIM X$:IOL=1000
1000 IOLIST A$,B$,X,Y

X$="SYBEX LTD"+SEP+"MIKE"+SEP+"123"

Will result in:

X.A$="SYBEX LTD" X.B$="MIKE"
X.X = 123
X.Y = 0

Since the data assigned to the composite string X$ only contains 3 fields, the fourth field (X.Y) will be set to zero.

Example 2:

Given the following:

0100 DIM CST$:IOL=1000
1000 IOLIST NAME$:[CHR(20)],ADR1$:[CHR(20)]

CST.NAME$="Sybex Ltd" CST.ADR1$="8920 Woodbine"

LET CST$(1,20)=""

The above LET will result in the field CST.NAME$ being set to a NULL string.