SIMSCRIPT II.5 Programming Language

SIMSCRIPT II.5 Programming Language
let POPULATION(CITY,STATE) = 400000
let POPULATION(NEW.YORK) = 8000000
interpreted as:
let POPULATION(NEW.YORK,STATE) = 8000000
Note that because attributes are stored as arrays, and the use of the unsubscripted name in a freeform
read implies input of the entire attribute array, when implied subscripts are used in free-form
read statements to reference attributes of permanent entities, the entire attribute array is input.
Although implicit subscripting may be convenient, the absence of subscripting renders it difficult
to distinguish attributes from simple variables. Recalling that periods following a name are ignored
by the SIMSCRIPT II.5 compiler, a commonly-used notation is to append two periods to a name to
indicate an implied subscript. This is purely a programming convention, used to distinguish attributes.
It has no effect on the interpretation of the statements. It will be used in subsequent examples
to make clear when implicit subscripting is being used.
4-13 Displaying Attribute Values
Specific attribute values can be output by conventional print and write statements. An attribute
reference appearing in an output list calls for the retrieval and display of a single value, just as does
a subscripted variable or function reference. Some examples of attributes used in print and
write statements are:
print 1 line with POPULATION(STATE) as follows
POPULATION IS ********
write I, INDEX(I), NAME(INDEX(I)) as /, 2 I 5, T *
for each CARROT in BUNCH,
write LENGTH(CARROT) as I 4
Implied subscripts can be used in print and formatted write statements, as well as in computational
statements. Attributes declared by the statement:
permanent entities
every BOOK has a PAGE.COUNT, a SUBJECT and an
AUTHOR
can be displayed by the statement:
for every BOOK,
write PAGE.COUNT.., SUBJECT.. and AUTHOR..
as I 4, 2 T 12
The list statement can be used to display all the attributes of an entity without writing all their
names. Three forms are available:
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