MoveFromId (Stringlist subroutine): Difference between revisions
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===Syntax terms=== | ===Syntax terms=== | ||
<table class="syntaxTable"> | <table class="syntaxTable"> | ||
<tr><th>sl </th> | <tr><th>sl</th> | ||
<td>A <var>Stringlist</var> object.</td></tr> | <td>A <var>Stringlist</var> object.</td></tr> | ||
<tr><th>listid</th> | <tr><th>listid</th> | ||
| Line 14: | Line 14: | ||
==Usage notes== | ==Usage notes== | ||
<ul><li>All errors in MoveFromId result in request cancellation.<li>After the MovefromId method is invoked, the source $list is empty, though the $list identifier is still valid.<li>MoveFromId discards the original contents of the method <var>Stringlist</var>.<li>The MoveFromId method copies to the method <var>Stringlist</var> any image association that is set via $listimg.<li>MoveFromid simply moves the pointers to the $list data to the object <var>Stringlist</var>. It does '''not''' actually perform any data movement; therefore, it is extremely efficient.<li>MoveFromid is intended to facilitate migration to <var>Stringlist</var>s 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 <var>Stringlist</var>s rather than $lists. | <ul><li>All errors in MoveFromId result in request cancellation.<li>After the MovefromId method is invoked, the source $list is empty, though the $list identifier is still valid.<li>MoveFromId discards the original contents of the method <var>Stringlist</var>.<li>The MoveFromId method copies to the method <var>Stringlist</var> any image association that is set via $listimg.<li>MoveFromid simply moves the pointers to the $list data to the object <var>Stringlist</var>. It does '''not''' actually perform any data movement; therefore, it is extremely efficient.<li>MoveFromid is intended to facilitate migration to <var>Stringlist</var>s 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 <var>Stringlist</var>s rather than $lists. | ||
The following code illustrates how this can be accomplished: | The following code illustrates how this can be accomplished: | ||
Revision as of 15:49, 19 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.
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.