READLIST Statement

Reads a list from POINTER-FILE and assigns it to a variable for program manipulation. See also the GETLIST statement.

Syntax

READLIST dyn-array FROM ["list-id" || "list-id account-name"] {SETTING setting-var} [THEN statement(s) | ELSE statement(s)]

Syntax Elements

dyn-array is the name of the variable to which the list is assigned as a dynamic array.

list-id is the name of the list saved in POINTER-FILE.

account-name specifies an account, other than the current account, from which the list was saved.

setting-var is the name of the variable to which the number of items in the list is assigned if the SETTING clause is used.

statement(s) is either a THEN or an ELSE clause (or both). A statement must be included. The THEN clause is executed if the read is successful. The ELSE clause is executed otherwise.

Operation

The item-ids from the saved list are separated by attribute marks.

READLIST allows a DataBasic program to read in a saved list, place the contents in a variable, and then modify or search its contents.

If you READ a list, modify it, and want to save it in the POINTER-FILE again, use the WRITELIST statement.

Examples

READLIST A FROM ITEMX ELSE STOP

Reads the list identified by the contents of variable into variable A.

X = "MYLIST"
READLIST LIST1 FROM X ELSE PRINT "CANNOT READ ":X; STOP

Reads the list from POINTER-FILE MYLIST into variable LIST1.  If the list cannot be read, an error message is displayed and the program is terminated.

READLIST LIST1 FROM '60-90' ELSE GOTO 100

READLIST LIST2 FROM 'OVER-90' ELSE GOTO 100

LIST3 = LIST1:AM:LIST2 ; * Combine the lists

WRITELIST LIST3 ON 'OVER-60'

.

.

GETLIST 'OVER-60' TO ALIST SETTING ACCOUNT THEN

  FOR I = 1 TO ACCOUNT

   READNEXT ID FROM ALIST ELSE PRINT 'ERROR'

   READ AITEM FROM AFILE,ID ELSE AITEM = ''

   .

   .

  NEXT I

END

Reads the lists saved in 60-90 and OVER-90 and combines them into a new list.  The new list is then written back to the POINTER-FILE using the WRITELIST statement. This new list can then be manipulated by the program.

See Also

READLIST Statement (MultiValue Compatibility).