$List Add Ordered: Difference between revisions
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Revision as of 21:21, 22 November 2011
Add an item to an ordered $list
Most Sirius $functions have been deprecated in favor of Object Oriented methods. The OO equivalent for the $List_Add_Ordered function is the AddOrdered (Stringlist function).
This function adds an item to a (presumably) ordered $list, inserting the item at the proper position to maintain the $list's order.
$List_Add_Ordered accepts two arguments and returns the item number of the inserted string. It is a callable $function (see Calling Sirius Mods $functions).
The first argument is the $list identifier of the $list to which the string is to be added. This is a required argument.
The second argument is the string to add to the $list. This is a required argument.
Syntax
<section begin="syntax" /> [%RC =] $List_Add_Ordered(list, string) <section end="syntax" />
All errors in $List_Add_Ordered result in request cancellation.
$List_Add_Ordered always adds the indicated string even if that string already exists on the $list but the new item is inserted so that the $list is in EBCDIC order. $List_Add_Ordered assumes that the $list is in EBCDIC order so it does a pseudo binary search to locate the correct insertion point. $List_Add_Ordered does not validate that the $list is in order and, it it isn't, the insertion point is unpredictable.
The following code builds a sorted output $list from an input $list.
FOR %I FROM 1 TO $ListCnt(%INLIST) %STRING = $ListInf(%INLIST, %I) %RC = $List_Add_Ordered(%OUTLIST, %STRING) END FOR
While in general it would be more efficient to simply copy and sort (via $ListSort) the input $list such a technique might be useful if the target $list already as a large number of items.
Because $List_Add_Ordered will insert items into the middle of a $list it will be susceptible to the same page-splitting, sparse $list leaf page issues as $ListIns.
This $function is new in Version 6.3.