MoveFromId (Stringlist subroutine): Difference between revisions
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==Usage notes== | ==Usage notes== | ||
<ul><li>All errors in <var>MoveFromId</var> result in request cancellation.<li>After | <ul><li>All errors in <var>MoveFromId</var> result in request cancellation.<li>After <var>MovefromId</var> is invoked, the source <var>$list</var> will be emptied, although the <var>$list</var> identifier is still valid.<li><var>MoveFromId</var> discards any current contents of the method <var>stringlist</var>.<li><var>MoveFromId</var> copies to the method <var>stringlist</var> any image association that is set via <var>$listimg</var>.<li><var>MoveFromid</var> simply moves the internal <var>$list</var> data pointers to the object <var>stringlist</var>. It does <b><i>not</i></b> actually perform any data movement; therefore, it is extremely efficient.<li><var>MoveFromid</var> is intended to facilitate migration to <var>stringlists</var> of existing applications that use <var>$lists</var>.<li> <var>stringlists</var> should always be used in preference to <var>$lists</var>, so <var>MoveFromId</var> is provided only for the migration of existing <var>$list</var> applications to the use of <var>Stringlists</var>.</ul> | ||
==Examples== | ==Examples== | ||
Suppose complex subroutine Summarize takes a <var>$list</var> identifier as its input parameter. Further suppose that the subroutine is rewritten to use <var>Stringlist</var>s rather than <var>$list</var>. The following code illustrates how this can be accomplished: | <ol><li>Suppose complex subroutine Summarize takes a <var>$list</var> identifier as its input parameter. Further suppose that the subroutine is rewritten to use <var>Stringlist</var>s rather than <var>$list</var>. The following code illustrates how this can be accomplished: | ||
<p class="code">subroutine summarize(%listId is float) | <p class="code">subroutine summarize(%listId is float) | ||
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</p> | </p> | ||
Of course, if the subroutine "forgets" to restore the input <var>$list</var> contents with <var>MoveToId</var>, the input <var>$list</var> remains empty at the end of the subroutine. | Of course, if the subroutine "forgets" to restore the input <var>$list</var> contents with <var>MoveToId</var>, the input <var>$list</var> remains empty at the end of the subroutine.</ol> | ||
==See also== | ==See also== | ||
{{Template:Stringlist:MoveFromId footer}} | {{Template:Stringlist:MoveFromId footer}} | ||
Revision as of 02:55, 27 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 MovefromId is invoked, the source $list will be emptied, although the $list identifier is still valid.
- MoveFromId discards any current contents of the method stringlist.
- MoveFromId copies to the method stringlist any image association that is set via $listimg.
- MoveFromid simply moves the internal $list data pointers 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.
- 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.
Examples
- Suppose complex subroutine Summarize takes a $list identifier as its input parameter. Further suppose that the subroutine is rewritten to use Stringlists rather than $list. 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.