MoveFromId (Stringlist subroutine): Difference between revisions

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{{Template:Stringlist:MoveFromId syntax}}
{{Template:Stringlist:MoveFromId syntax}}
===Syntax terms===
===Syntax terms===
<dl>
<table class="syntaxTable">
<dt>%sl
<tr><th>sl </th>
<dd>A Stringlist object.<dt>listid<dd>The $list identifier of the $list from which data is to be moved.  
<td>A Stringlist object.</td></tr>
</dl>
<tr><th>listid</th>
<td>The $list identifier of the $list from which data is to be moved.</td></tr>
</table>


==Usage notes==
==Usage notes==

Revision as of 21:03, 16 January 2011

Move data from $list to Stringlist (Stringlist class)


This method moves data ($list items) from a $list to a Stringlist. MoveFromId is a subroutine that accepts one argument: the $list identifier of the $list from which data is to be moved. For more information about $list identifiers, see the Sirius Functions Reference Manual.

MoveFromId is a member of the Stringlist class.

Syntax

sl:MoveFromId( listId)

Syntax terms

sl A Stringlist object.
listid The $list identifier of the $list from which data is to be moved.

Usage notes

  • All errors in MoveFromId result in request cancellation.
  • After the MovefromId method is invoked, the source $list is empty, though the $list identifier is still valid.
  • MoveFromId discards the original contents of the method Stringlist.
  • The MoveFromId method copies to the method Stringlist any image association that is set via $listimg.
  • MoveFromid simply moves the pointers to the $list data to the object Stringlist. It does not actually perform any data movement; therefore, it is extremely efficient.
  • MoveFromid is intended to facilitate migration to Stringlists of existing applications that use $lists. For example, suppose complex subroutine Summarize takes a $list identifier as its input parameter. Further suppose that the subroutine is rewritten to use Stringlists rather than $lists. The following code illustrates how this can be accomplished:
    subroutine summarize(%listId is float)
    %list is object stringList
    %list = new
    %list:moveFromid(%listId)
    ...
    %list:moveToid(%listId)
    return
    

    Of course, if the subroutine "forgets" to restore the input $list contents with MoveToId, the input $list remains empty at the end of the subroutine. Stringlists should always be used in preference to $lists, so MoveFromId is provided only for the migration of existing $list applications to the use of Stringlists.